Merge branch 'V2' into feature/v2/embed-pdf

# Description of Changes
Changes it so that callers of `useBaseTool` know what actual type the
parameters hook that they passed in returned, so they can actually make
use of any extra methods that that params hook has.

frontend/package.json

@@ -52,16 +52,18 @@
   },
   "scripts": {
     "predev": "npm run generate-icons",
-    "dev": "npx tsc --noEmit && vite",
+    "dev": "npm run typecheck && vite",
     "prebuild": "npm run generate-icons",
-    "lint": "npx eslint",
-    "build": "npx tsc --noEmit && vite build",
+    "lint": "eslint",
+    "build": "npm run typecheck && vite build",
     "preview": "vite preview",
     "typecheck": "tsc --noEmit",
+    "check": "npm run typecheck && npm run lint && npm run test:run",
     "generate-licenses": "node scripts/generate-licenses.js",
     "generate-icons": "node scripts/generate-icons.js",
     "generate-icons:verbose": "node scripts/generate-icons.js --verbose",
     "test": "vitest",
+    "test:run": "vitest run",
     "test:watch": "vitest --watch",
     "test:coverage": "vitest --coverage",
     "test:e2e": "playwright test",

frontend/public/locales/en-GB/translation.json

@@ -51,11 +51,11 @@
   "filesSelected": "{{count}} files selected",
   "files": {
     "title": "Files",
-    "placeholder": "Select a PDF file in the main view to get started",
     "upload": "Upload",
     "uploadFiles": "Upload Files",
     "addFiles": "Add files",
-    "selectFromWorkbench": "Select files from the workbench or "
+    "selectFromWorkbench": "Select files from the workbench or ",
+    "selectMultipleFromWorkbench": "Select at least {{count}} files from the workbench or "
   },
   "noFavourites": "No favourites added",
   "downloadComplete": "Download Complete",
@@ -498,13 +498,9 @@
       "title": "Show Javascript",
       "desc": "Searches and displays any JS injected into a PDF"
     },
-    "autoRedact": {
-      "title": "Auto Redact",
-      "desc": "Auto Redacts(Blacks out) text in a PDF based on input text"
-    },
     "redact": {
-      "title": "Manual Redaction",
-      "desc": "Redacts a PDF based on selected text, drawn shapes and/or selected page(s)"
+      "title": "Redact",
+      "desc": "Redacts (blacks out) a PDF based on selected text, drawn shapes and/or selected page(s)"
     },
     "overlay-pdfs": {
       "title": "Overlay PDFs",
@@ -648,11 +644,29 @@
   "merge": {
     "tags": "merge,Page operations,Back end,server side",
     "title": "Merge",
-    "header": "Merge multiple PDFs (2+)",
-    "sortByName": "Sort by name",
-    "sortByDate": "Sort by date",
-    "removeCertSign": "Remove digital signature in the merged file?",
-    "submit": "Merge"
+    "removeDigitalSignature": "Remove digital signature in the merged file?",
+    "generateTableOfContents": "Generate table of contents in the merged file?",
+    "removeDigitalSignature.tooltip": {
+      "title": "Remove Digital Signature",
+      "description": "Digital signatures will be invalidated when merging files. Check this to remove them from the final merged PDF."
+    },
+    "generateTableOfContents.tooltip": {
+      "title": "Generate Table of Contents",
+      "description": "Automatically creates a clickable table of contents in the merged PDF based on the original file names and page numbers."
+    },
+    "submit": "Merge",
+    "sortBy": {
+      "description": "Files will be merged in the order they're selected. Drag to reorder or sort below.",
+      "label": "Sort By",
+      "filename": "File Name",
+      "dateModified": "Date Modified",
+      "ascending": "Ascending",
+      "descending": "Descending",
+      "sort": "Sort"
+    },
+    "error": {
+      "failed": "An error occurred while merging the PDFs."
+    }
   },
   "split": {
     "tags": "Page operations,divide,Multi Page,cut,server side",
@@ -1454,7 +1468,6 @@
     "submit": "Submit"
   },
   "scalePages": {
-    "tags": "resize,modify,dimension,adapt",
     "title": "Adjust page-scale",
     "header": "Adjust page-scale",
     "pageSize": "Size of a page of the document.",
@@ -1462,6 +1475,44 @@
     "scaleFactor": "Zoom level (crop) of a page.",
     "submit": "Submit"
   },
+  "adjustPageScale": {
+    "tags": "resize,modify,dimension,adapt",
+    "title": "Adjust Page Scale",
+    "header": "Adjust Page Scale",
+    "scaleFactor": {
+      "label": "Scale Factor"
+    },
+    "pageSize": {
+      "label": "Target Page Size",
+      "keep": "Keep Original Size",
+      "letter": "Letter",
+      "legal": "Legal"
+    },
+    "submit": "Adjust Page Scale",
+    "error": {
+      "failed": "An error occurred while adjusting the page scale."
+    },
+    "tooltip": {
+      "header": {
+        "title": "Page Scale Settings Overview"
+      },
+      "description": {
+        "title": "Description",
+        "text": "Adjust the size of PDF content and change the page dimensions."
+      },
+      "scaleFactor": {
+        "title": "Scale Factor",
+        "text": "Controls how large or small the content appears on the page. Content is scaled and centred - if scaled content is larger than the page size, it may be cropped.",
+        "bullet1": "1.0 = Original size",
+        "bullet2": "0.5 = Half size (50% smaller)",
+        "bullet3": "2.0 = Double size (200% larger, may crop)"
+      },
+      "pageSize": {
+        "title": "Target Page Size",
+        "text": "Sets the dimensions of the output PDF pages. 'Keep Original Size' maintains current dimensions, whilst other options resize to standard paper sizes."
+      }
+    }
+  },
   "add-page-numbers": {
     "tags": "paginate,label,organize,index"
   },
@@ -1583,25 +1634,97 @@
     "downloadJS": "Download Javascript",
     "submit": "Show"
   },
-  "autoRedact": {
-    "tags": "Redact,Hide,black out,black,marker,hidden",
-    "title": "Auto Redact",
+  "redact": {
+    "tags": "Redact,Hide,black out,black,marker,hidden,auto redact,manual redact",
+    "title": "Redact",
+    "submit": "Redact",
+    "error": {
+      "failed": "An error occurred while redacting the PDF."
+    },
+    "modeSelector": {
+      "title": "Redaction Method",
+      "mode": "Mode",
+      "automatic": "Automatic",
+      "automaticDesc": "Redact text based on search terms",
+      "manual": "Manual",
+      "manualDesc": "Click and drag to redact specific areas",
+      "manualComingSoon": "Manual redaction coming soon"
+    },
+    "auto": {
       "header": "Auto Redact",
-    "colorLabel": "Colour",
-    "textsToRedactLabel": "Text to Redact (line-separated)",
-    "textsToRedactPlaceholder": "e.g. \\nConfidential \\nTop-Secret",
+      "settings": {
+        "title": "Redaction Settings",
+        "advancedTitle": "Advanced"
+      },
+      "colorLabel": "Box Colour",
+      "wordsToRedact": {
+        "title": "Words to Redact",
+        "placeholder": "Enter a word",
+        "add": "Add",
+        "examples": "Examples: Confidential, Top-Secret"
+      },
       "useRegexLabel": "Use Regex",
       "wholeWordSearchLabel": "Whole Word Search",
       "customPaddingLabel": "Custom Extra Padding",
-    "convertPDFToImageLabel": "Convert PDF to PDF-Image (Used to remove text behind the box)",
-    "submitButton": "Submit"
+      "convertPDFToImageLabel": "Convert PDF to PDF-Image"
     },
-  "redact": {
-    "tags": "Redact,Hide,black out,black,marker,hidden,manual",
+    "tooltip": {
+      "mode": {
+        "header": {
+          "title": "Redaction Method"
+        },
+        "automatic": {
+          "title": "Automatic Redaction",
+          "text": "Automatically finds and redacts specified text throughout the document. Perfect for removing consistent sensitive information like names, addresses, or confidential markers."
+        },
+        "manual": {
           "title": "Manual Redaction",
+          "text": "Click and drag to manually select specific areas to redact. Gives you precise control over what gets redacted. (Coming soon)"
+        }
+      },
+      "words": {
+        "header": {
+          "title": "Words to Redact"
+        },
+        "description": {
+          "title": "Text Matching",
+          "text": "Enter words or phrases to find and redact in your document. Each word will be searched for separately."
+        },
+        "bullet1": "Add one word at a time",
+        "bullet2": "Press Enter or click 'Add Another' to add",
+        "bullet3": "Click × to remove words",
+        "examples": {
+          "title": "Common Examples",
+          "text": "Typical words to redact include: bank details, email addresses, or specific names."
+        }
+      },
+      "advanced": {
+        "header": {
+          "title": "Advanced Redaction Settings"
+        },
+        "color": {
+          "title": "Box Colour & Padding",
+          "text": "Customise the appearance of redaction boxes. Black is standard, but you can choose any colour. Padding adds extra space around the found text."
+        },
+        "regex": {
+          "title": "Use Regex",
+          "text": "Enable regular expressions for advanced pattern matching. Useful for finding phone numbers, emails, or complex patterns.",
+          "bullet1": "Example: \\d{4}-\\d{2}-\\d{2} to match any dates in YYYY-MM-DD format",
+          "bullet2": "Use with caution - test thoroughly"
+        },
+        "wholeWord": {
+          "title": "Whole Word Search",
+          "text": "Only match complete words, not partial matches. 'John' won't match 'Johnson' when enabled."
+        },
+        "convert": {
+          "title": "Convert to PDF-Image",
+          "text": "Converts the PDF to an image-based PDF after redaction. This ensures text behind redaction boxes is completely removed and unrecoverable."
+        }
+      }
+    },
+    "manual": {
       "header": "Manual Redaction",
-    "submit": "Redact",
-    "textBasedRedaction": "Text based Redaction",
+      "textBasedRedaction": "Text-based Redaction",
       "pageBasedRedaction": "Page-based Redaction",
       "convertPDFToImageLabel": "Convert PDF to PDF-Image (Used to remove text behind the box)",
       "pageRedactionNumbers": {
@@ -1609,7 +1732,7 @@
         "placeholder": "(e.g. 1,2,8 or 4,7,12-16 or 2n-1)"
       },
       "redactionColor": {
-      "title": "Redaction Color"
+        "title": "Redaction Colour"
       },
       "export": "Export",
       "upload": "Upload",
@@ -1622,11 +1745,12 @@
       "toggleSidebar": "Toggle Sidebar",
       "showThumbnails": "Show Thumbnails",
       "showDocumentOutline": "Show Document Outline (double-click to expand/collapse all items)",
-    "showAttatchments": "Show Attachments",
+      "showAttachments": "Show Attachments",
       "showLayers": "Show Layers (double-click to reset all layers to the default state)",
       "colourPicker": "Colour Picker",
       "findCurrentOutlineItem": "Find current outline item",
       "applyChanges": "Apply Changes"
+    }
   },
   "tableExtraxt": {
     "tags": "CSV,Table Extraction,extract,convert"
@@ -1837,6 +1961,11 @@
     "title": "Compress",
     "desc": "Compress PDFs to reduce their file size.",
     "header": "Compress PDF",
+    "method": {
+      "title": "Compression Method",
+      "quality": "Quality",
+      "filesize": "File Size"
+    },
     "credit": "This service uses qpdf for PDF Compress/Optimisation.",
     "grayscale": {
       "label": "Apply Grayscale for Compression"

frontend/src/assets/3rdPartyLicenses.json

@@ -385,6 +385,13 @@
             "moduleLicense": "MIT",
             "moduleLicenseUrl": "https://opensource.org/licenses/MIT"
         },
+        {
+            "moduleName": "@posthog/core",
+            "moduleUrl": "https://github.com/PostHog/posthog-js",
+            "moduleVersion": "1.0.2",
+            "moduleLicense": "MIT",
+            "moduleLicenseUrl": "https://opensource.org/licenses/MIT"
+        },
         {
             "moduleName": "@tailwindcss/node",
             "moduleUrl": "https://github.com/tailwindlabs/tailwindcss",
@@ -742,6 +749,13 @@
             "moduleLicense": "MIT",
             "moduleLicenseUrl": "https://opensource.org/licenses/MIT"
         },
+        {
+            "moduleName": "core-js",
+            "moduleUrl": "https://github.com/zloirock/core-js",
+            "moduleVersion": "3.45.1",
+            "moduleLicense": "MIT",
+            "moduleLicenseUrl": "https://opensource.org/licenses/MIT"
+        },
         {
             "moduleName": "core-util-is",
             "moduleUrl": "https://github.com/isaacs/core-util-is",
@@ -924,6 +938,13 @@
             "moduleLicense": "MIT",
             "moduleLicenseUrl": "https://opensource.org/licenses/MIT"
         },
+        {
+            "moduleName": "fflate",
+            "moduleUrl": "https://github.com/101arrowz/fflate",
+            "moduleVersion": "0.4.8",
+            "moduleLicense": "MIT",
+            "moduleLicenseUrl": "https://opensource.org/licenses/MIT"
+        },
         {
             "moduleName": "file-selector",
             "moduleUrl": "https://github.com/react-dropzone/file-selector",
@@ -1533,6 +1554,20 @@
             "moduleLicense": "MIT",
             "moduleLicenseUrl": "https://opensource.org/licenses/MIT"
         },
+        {
+            "moduleName": "posthog-js",
+            "moduleUrl": "https://github.com/PostHog/posthog-js",
+            "moduleVersion": "1.261.0",
+            "moduleLicense": "MIT*",
+            "moduleLicenseUrl": "https://opensource.org/licenses/MIT"
+        },
+        {
+            "moduleName": "preact",
+            "moduleUrl": "https://github.com/preactjs/preact",
+            "moduleVersion": "10.27.1",
+            "moduleLicense": "MIT",
+            "moduleLicenseUrl": "https://opensource.org/licenses/MIT"
+        },
         {
             "moduleName": "pretty-format",
             "moduleUrl": "https://github.com/facebook/jest",
@@ -1928,7 +1963,7 @@
         {
             "moduleName": "typescript",
             "moduleUrl": "https://github.com/microsoft/TypeScript",
-            "moduleVersion": "5.8.3",
+            "moduleVersion": "5.9.2",
             "moduleLicense": "Apache-2.0",
             "moduleLicenseUrl": "https://www.apache.org/licenses/LICENSE-2.0"
         },
@@ -1995,6 +2030,13 @@
             "moduleLicense": "Apache-2.0",
             "moduleLicenseUrl": "https://www.apache.org/licenses/LICENSE-2.0"
         },
+        {
+            "moduleName": "web-vitals",
+            "moduleUrl": "https://github.com/GoogleChrome/web-vitals",
+            "moduleVersion": "4.2.4",
+            "moduleLicense": "Apache-2.0",
+            "moduleLicenseUrl": "https://www.apache.org/licenses/LICENSE-2.0"
+        },
         {
             "moduleName": "webidl-conversions",
             "moduleUrl": "https://github.com/jsdom/webidl-conversions",

frontend/src/components/shared/ButtonSelector.test.tsx

@@ -0,0 +1,216 @@
+import { describe, expect, test, vi, beforeEach } from 'vitest';
+import { render, screen, fireEvent } from '@testing-library/react';
+import { MantineProvider } from '@mantine/core';
+import ButtonSelector from './ButtonSelector';
+
+// Wrapper component to provide Mantine context
+const TestWrapper = ({ children }: { children: React.ReactNode }) => (
+  <MantineProvider>{children}</MantineProvider>
+);
+
+describe('ButtonSelector', () => {
+  const mockOnChange = vi.fn();
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  test('should render all options as buttons', () => {
+    const options = [
+      { value: 'option1', label: 'Option 1' },
+      { value: 'option2', label: 'Option 2' },
+    ];
+
+    render(
+      <TestWrapper>
+        <ButtonSelector
+          value="option1"
+          onChange={mockOnChange}
+          options={options}
+          label="Test Label"
+        />
+      </TestWrapper>
+    );
+
+    expect(screen.getByText('Test Label')).toBeInTheDocument();
+    expect(screen.getByText('Option 1')).toBeInTheDocument();
+    expect(screen.getByText('Option 2')).toBeInTheDocument();
+  });
+
+  test('should highlight selected button with filled variant', () => {
+    const options = [
+      { value: 'option1', label: 'Option 1' },
+      { value: 'option2', label: 'Option 2' },
+    ];
+
+    render(
+      <TestWrapper>
+        <ButtonSelector
+          value="option1"
+          onChange={mockOnChange}
+          options={options}
+          label="Selection Label"
+        />
+      </TestWrapper>
+    );
+
+    const selectedButton = screen.getByRole('button', { name: 'Option 1' });
+    const unselectedButton = screen.getByRole('button', { name: 'Option 2' });
+
+    // Check data-variant attribute for filled/outline
+    expect(selectedButton).toHaveAttribute('data-variant', 'filled');
+    expect(unselectedButton).toHaveAttribute('data-variant', 'outline');
+    expect(screen.getByText('Selection Label')).toBeInTheDocument();
+  });
+
+  test('should call onChange when button is clicked', () => {
+    const options = [
+      { value: 'option1', label: 'Option 1' },
+      { value: 'option2', label: 'Option 2' },
+    ];
+
+    render(
+      <TestWrapper>
+        <ButtonSelector
+          value="option1"
+          onChange={mockOnChange}
+          options={options}
+        />
+      </TestWrapper>
+    );
+
+    fireEvent.click(screen.getByRole('button', { name: 'Option 2' }));
+
+    expect(mockOnChange).toHaveBeenCalledWith('option2');
+  });
+
+  test('should handle undefined value (no selection)', () => {
+    const options = [
+      { value: 'option1', label: 'Option 1' },
+      { value: 'option2', label: 'Option 2' },
+    ];
+
+    render(
+      <TestWrapper>
+        <ButtonSelector
+          value={undefined}
+          onChange={mockOnChange}
+          options={options}
+        />
+      </TestWrapper>
+    );
+
+    // Both buttons should be outlined when no value is selected
+    const button1 = screen.getByRole('button', { name: 'Option 1' });
+    const button2 = screen.getByRole('button', { name: 'Option 2' });
+
+    expect(button1).toHaveAttribute('data-variant', 'outline');
+    expect(button2).toHaveAttribute('data-variant', 'outline');
+  });
+
+  test.each([
+    {
+      description: 'disable buttons when disabled prop is true',
+      options: [
+        { value: 'option1', label: 'Option 1' },
+        { value: 'option2', label: 'Option 2' },
+      ],
+      globalDisabled: true,
+      expectedStates: [true, true],
+    },
+    {
+      description: 'disable individual options when option.disabled is true',
+      options: [
+        { value: 'option1', label: 'Option 1' },
+        { value: 'option2', label: 'Option 2', disabled: true },
+      ],
+      globalDisabled: false,
+      expectedStates: [false, true],
+    },
+  ])('should $description', ({ options, globalDisabled, expectedStates }) => {
+    render(
+      <TestWrapper>
+        <ButtonSelector
+          value="option1"
+          onChange={mockOnChange}
+          options={options}
+          disabled={globalDisabled}
+        />
+      </TestWrapper>
+    );
+
+    options.forEach((option, index) => {
+      const button = screen.getByRole('button', { name: option.label });
+      expect(button).toHaveProperty('disabled', expectedStates[index]);
+    });
+  });
+
+  test('should not call onChange when disabled button is clicked', () => {
+    const options = [
+      { value: 'option1', label: 'Option 1' },
+      { value: 'option2', label: 'Option 2', disabled: true },
+    ];
+
+    render(
+      <TestWrapper>
+        <ButtonSelector
+          value="option1"
+          onChange={mockOnChange}
+          options={options}
+        />
+      </TestWrapper>
+    );
+
+    fireEvent.click(screen.getByRole('button', { name: 'Option 2' }));
+
+    expect(mockOnChange).not.toHaveBeenCalled();
+  });
+
+  test('should not apply fullWidth styling when fullWidth is false', () => {
+    const options = [
+      { value: 'option1', label: 'Option 1' },
+      { value: 'option2', label: 'Option 2' },
+    ];
+
+    render(
+      <TestWrapper>
+        <ButtonSelector
+          value="option1"
+          onChange={mockOnChange}
+          options={options}
+          fullWidth={false}
+          label="Layout Label"
+        />
+      </TestWrapper>
+    );
+
+    const button = screen.getByRole('button', { name: 'Option 1' });
+    expect(button).not.toHaveStyle({ flex: '1' });
+    expect(screen.getByText('Layout Label')).toBeInTheDocument();
+  });
+
+  test('should not render label element when not provided', () => {
+    const options = [
+      { value: 'option1', label: 'Option 1' },
+      { value: 'option2', label: 'Option 2' },
+    ];
+
+    const { container } = render(
+      <TestWrapper>
+        <ButtonSelector
+          value="option1"
+          onChange={mockOnChange}
+          options={options}
+        />
+      </TestWrapper>
+    );
+
+    // Should render buttons
+    expect(screen.getByText('Option 1')).toBeInTheDocument();
+    expect(screen.getByText('Option 2')).toBeInTheDocument();
+    
+    // Stack should only contain the Group (buttons), no Text element for label
+    const stackElement = container.querySelector('[class*="mantine-Stack-root"]');
+    expect(stackElement?.children).toHaveLength(1); // Only the Group, no label Text
+  });
+});

frontend/src/components/shared/ButtonSelector.tsx

@@ -0,0 +1,59 @@
+import { Button, Group, Stack, Text } from "@mantine/core";
+
+export interface ButtonOption<T> {
+  value: T;
+  label: string;
+  disabled?: boolean;
+}
+
+interface ButtonSelectorProps<T> {
+  value: T | undefined;
+  onChange: (value: T) => void;
+  options: ButtonOption<T>[];
+  label?: string;
+  disabled?: boolean;
+  fullWidth?: boolean;
+}
+
+const ButtonSelector = <T extends string>({
+  value,
+  onChange,
+  options,
+  label = undefined,
+  disabled = false,
+  fullWidth = true,
+}: ButtonSelectorProps<T>) => {
+  return (
+    <Stack gap='var(--mantine-spacing-sm)'>
+      {/* Label (if it exists) */}
+      {label && <Text style={{
+        fontSize: "var(--mantine-font-size-sm)",
+        lineHeight: "var(--mantine-line-height-sm)",
+        fontWeight: "var(--font-weight-medium)",
+      }}>{label}</Text>}
+
+      {/* Buttons */}
+      <Group gap='4px'>
+        {options.map((option) => (
+          <Button
+            key={option.value}
+            variant={value === option.value ? 'filled' : 'outline'}
+            color={value === option.value ? 'var(--color-primary-500)' : 'var(--text-muted)'}
+            onClick={() => onChange(option.value)}
+            disabled={disabled || option.disabled}
+            style={{
+              flex: fullWidth ? 1 : undefined,
+              height: 'auto',
+              minHeight: '2.5rem',
+              fontSize: 'var(--mantine-font-size-sm)'
+            }}
+          >
+            {option.label}
+          </Button>
+        ))}
+      </Group>
+    </Stack>
+  );
+};
+
+export default ButtonSelector;

frontend/src/components/tools/addPassword/AddPasswordSettings.tsx

@@ -4,7 +4,7 @@ import { AddPasswordParameters } from "../../../hooks/tools/addPassword/useAddPa
 
 interface AddPasswordSettingsProps {
   parameters: AddPasswordParameters;
-  onParameterChange: (key: keyof AddPasswordParameters, value: any) => void;
+  onParameterChange: <K extends keyof AddPasswordParameters>(key: K, value: AddPasswordParameters[K]) => void;
   disabled?: boolean;
 }
 

frontend/src/components/tools/addWatermark/WatermarkTypeSettings.tsx

@@ -1,5 +1,5 @@
-import { Button, Stack } from "@mantine/core";
 import { useTranslation } from "react-i18next";
+import ButtonSelector from "../../shared/ButtonSelector";
 
 interface WatermarkTypeSettingsProps {
   watermarkType?: 'text' | 'image';
@@ -11,32 +11,21 @@ const WatermarkTypeSettings = ({ watermarkType, onWatermarkTypeChange, disabled
   const { t } = useTranslation();
 
   return (
-    <Stack gap="sm">
-      <div style={{ display: 'flex', gap: '4px' }}>
-        <Button
-          variant={watermarkType === 'text' ? 'filled' : 'outline'}
-          color={watermarkType === 'text' ? 'blue' : 'var(--text-muted)'}
-          onClick={() => onWatermarkTypeChange('text')}
+    <ButtonSelector
+      value={watermarkType}
+      onChange={onWatermarkTypeChange}
+      options={[
+        {
+          value: 'text',
+          label: t('watermark.watermarkType.text', 'Text'),
+        },
+        {
+          value: 'image',
+          label: t('watermark.watermarkType.image', 'Image'),
+        },
+      ]}
       disabled={disabled}
-          style={{ flex: 1, height: 'auto', minHeight: '40px', fontSize: '11px' }}
-        >
-          <div style={{ textAlign: 'center', lineHeight: '1.1', fontSize: '11px' }}>
-            {t('watermark.watermarkType.text', 'Text')}
-          </div>
-        </Button>
-        <Button
-          variant={watermarkType === 'image' ? 'filled' : 'outline'}
-          color={watermarkType === 'image' ? 'blue' : 'var(--text-muted)'}
-          onClick={() => onWatermarkTypeChange('image')}
-          disabled={disabled}
-          style={{ flex: 1, height: 'auto', minHeight: '40px', fontSize: '11px' }}
-        >
-          <div style={{ textAlign: 'center', lineHeight: '1.1', fontSize: '11px' }}>
-            {t('watermark.watermarkType.image', 'Image')}
-          </div>
-        </Button>
-      </div>
-    </Stack>
+    />
   );
 };
 

frontend/src/components/tools/adjustPageScale/AdjustPageScaleSettings.test.tsx

@@ -0,0 +1,64 @@
+import { describe, expect, test, vi, beforeEach } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import { MantineProvider } from '@mantine/core';
+import AdjustPageScaleSettings from './AdjustPageScaleSettings';
+import { AdjustPageScaleParameters, PageSize } from '../../../hooks/tools/adjustPageScale/useAdjustPageScaleParameters';
+
+// Mock useTranslation with predictable return values
+const mockT = vi.fn((key: string, fallback?: string) => fallback || `mock-${key}`);
+vi.mock('react-i18next', () => ({
+  useTranslation: () => ({ t: mockT })
+}));
+
+// Wrapper component to provide Mantine context
+const TestWrapper = ({ children }: { children: React.ReactNode }) => (
+  <MantineProvider>{children}</MantineProvider>
+);
+
+describe('AdjustPageScaleSettings', () => {
+  const defaultParameters: AdjustPageScaleParameters = {
+    scaleFactor: 1.0,
+    pageSize: PageSize.KEEP,
+  };
+
+  const mockOnParameterChange = vi.fn();
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  test('should render without crashing', () => {
+    render(
+      <TestWrapper>
+        <AdjustPageScaleSettings
+          parameters={defaultParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    // Basic render test - component renders without throwing
+    expect(screen.getByText('Scale Factor')).toBeInTheDocument();
+    expect(screen.getByText('Target Page Size')).toBeInTheDocument();
+  });
+
+  test('should render with custom parameters', () => {
+    const customParameters: AdjustPageScaleParameters = {
+      scaleFactor: 2.5,
+      pageSize: PageSize.A4,
+    };
+
+    render(
+      <TestWrapper>
+        <AdjustPageScaleSettings
+          parameters={customParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    // Component renders successfully with custom parameters
+    expect(screen.getByText('Scale Factor')).toBeInTheDocument();
+    expect(screen.getByText('Target Page Size')).toBeInTheDocument();
+  });
+});

frontend/src/components/tools/adjustPageScale/AdjustPageScaleSettings.tsx

@@ -0,0 +1,55 @@
+import { Stack, NumberInput, Select } from "@mantine/core";
+import { useTranslation } from "react-i18next";
+import { AdjustPageScaleParameters, PageSize } from "../../../hooks/tools/adjustPageScale/useAdjustPageScaleParameters";
+
+interface AdjustPageScaleSettingsProps {
+  parameters: AdjustPageScaleParameters;
+  onParameterChange: <K extends keyof AdjustPageScaleParameters>(key: K, value: AdjustPageScaleParameters[K]) => void;
+  disabled?: boolean;
+}
+
+const AdjustPageScaleSettings = ({ parameters, onParameterChange, disabled = false }: AdjustPageScaleSettingsProps) => {
+  const { t } = useTranslation();
+
+  const pageSizeOptions = [
+    { value: PageSize.KEEP, label: t('adjustPageScale.pageSize.keep', 'Keep Original Size') },
+    { value: PageSize.A0, label: 'A0' },
+    { value: PageSize.A1, label: 'A1' },
+    { value: PageSize.A2, label: 'A2' },
+    { value: PageSize.A3, label: 'A3' },
+    { value: PageSize.A4, label: 'A4' },
+    { value: PageSize.A5, label: 'A5' },
+    { value: PageSize.A6, label: 'A6' },
+    { value: PageSize.LETTER, label: t('adjustPageScale.pageSize.letter', 'Letter') },
+    { value: PageSize.LEGAL, label: t('adjustPageScale.pageSize.legal', 'Legal') },
+  ];
+
+  return (
+    <Stack gap="md">
+      <NumberInput
+        label={t('adjustPageScale.scaleFactor.label', 'Scale Factor')}
+        value={parameters.scaleFactor}
+        onChange={(value) => onParameterChange('scaleFactor', typeof value === 'number' ? value : 1.0)}
+        min={0.1}
+        max={10.0}
+        step={0.1}
+        decimalScale={2}
+        disabled={disabled}
+      />
+
+      <Select
+        label={t('adjustPageScale.pageSize.label', 'Target Page Size')}
+        value={parameters.pageSize}
+        onChange={(value) => {
+          if (value && Object.values(PageSize).includes(value as PageSize)) {
+            onParameterChange('pageSize', value as PageSize);
+          }
+        }}
+        data={pageSizeOptions}
+        disabled={disabled}
+      />
+    </Stack>
+  );
+};
+
+export default AdjustPageScaleSettings;

frontend/src/components/tools/changePermissions/ChangePermissionsSettings.tsx

@@ -4,7 +4,7 @@ import { ChangePermissionsParameters } from "../../../hooks/tools/changePermissi
 
 interface ChangePermissionsSettingsProps {
   parameters: ChangePermissionsParameters;
-  onParameterChange: (key: keyof ChangePermissionsParameters, value: boolean) => void;
+  onParameterChange: <K extends keyof ChangePermissionsParameters>(key: K, value: ChangePermissionsParameters[K]) => void;
   disabled?: boolean;
 }
 

frontend/src/components/tools/compress/CompressSettings.tsx

@@ -1,11 +1,12 @@
 import React, { useState } from "react";
-import { Button, Stack, Text, NumberInput, Select, Divider } from "@mantine/core";
+import { Stack, Text, NumberInput, Select, Divider } from "@mantine/core";
 import { useTranslation } from "react-i18next";
 import { CompressParameters } from "../../../hooks/tools/compress/useCompressParameters";
+import ButtonSelector from "../../shared/ButtonSelector";
 
 interface CompressSettingsProps {
   parameters: CompressParameters;
-  onParameterChange: (key: keyof CompressParameters, value: any) => void;
+  onParameterChange: <K extends keyof CompressParameters>(key: K, value: CompressParameters[K]) => void;
   disabled?: boolean;
 }
 
@@ -18,33 +19,16 @@ const CompressSettings = ({ parameters, onParameterChange, disabled = false }: C
 
       <Divider ml='-md'></Divider>
       {/* Compression Method */}
-      <Stack gap="sm">
-        <Text size="sm" fw={500}>Compression Method</Text>
-        <div style={{ display: 'flex', gap: '4px' }}>
-          <Button
-            variant={parameters.compressionMethod === 'quality' ? 'filled' : 'outline'}
-            color={parameters.compressionMethod === 'quality' ? 'blue' : 'var(--text-muted)'}
-            onClick={() => onParameterChange('compressionMethod', 'quality')}
+      <ButtonSelector
+        label={t('compress.method.title', 'Compression Method')}
+        value={parameters.compressionMethod}
+        onChange={(value) => onParameterChange('compressionMethod', value)}
+        options={[
+          { value: 'quality', label: t('compress.method.quality', 'Quality') },
+          { value: 'filesize', label: t('compress.method.filesize', 'File Size') },
+        ]}
         disabled={disabled}
-            style={{ flex: 1, height: 'auto', minHeight: '40px', fontSize: '11px' }}
-          >
-            <div style={{ textAlign: 'center', lineHeight: '1.1', fontSize: '11px' }}>
-              Quality
-            </div>
-          </Button>
-          <Button
-            variant={parameters.compressionMethod === 'filesize' ? 'filled' : 'outline'}
-            color={parameters.compressionMethod === 'filesize' ? 'blue' : 'var(--text-muted)'}
-            onClick={() => onParameterChange('compressionMethod', 'filesize')}
-            disabled={disabled}
-            style={{ flex: 1, height: 'auto', minHeight: '40px', fontSize: '11px' }}
-          >
-            <div style={{ textAlign: 'center', lineHeight: '1.1', fontSize: '11px' }}>
-              File Size
-            </div>
-          </Button>
-        </div>
-      </Stack>
+      />
 
       {/* Quality Adjustment */}
       {parameters.compressionMethod === 'quality' && (

frontend/src/components/tools/convert/ConvertFromEmailSettings.tsx

@@ -5,7 +5,7 @@ import { ConvertParameters } from '../../../hooks/tools/convert/useConvertParame
 
 interface ConvertFromEmailSettingsProps {
   parameters: ConvertParameters;
-  onParameterChange: (key: keyof ConvertParameters, value: any) => void;
+  onParameterChange: <K extends keyof ConvertParameters>(key: K, value: ConvertParameters[K]) => void;
   disabled?: boolean;
 }
 

frontend/src/components/tools/convert/ConvertFromImageSettings.tsx

@@ -6,7 +6,7 @@ import { ConvertParameters } from "../../../hooks/tools/convert/useConvertParame
 
 interface ConvertFromImageSettingsProps {
   parameters: ConvertParameters;
-  onParameterChange: (key: keyof ConvertParameters, value: any) => void;
+  onParameterChange: <K extends keyof ConvertParameters>(key: K, value: ConvertParameters[K]) => void;
   disabled?: boolean;
 }
 

frontend/src/components/tools/convert/ConvertFromWebSettings.tsx

@@ -5,7 +5,7 @@ import { ConvertParameters } from '../../../hooks/tools/convert/useConvertParame
 
 interface ConvertFromWebSettingsProps {
   parameters: ConvertParameters;
-  onParameterChange: (key: keyof ConvertParameters, value: any) => void;
+  onParameterChange: <K extends keyof ConvertParameters>(key: K, value: ConvertParameters[K]) => void;
   disabled?: boolean;
 }
 

frontend/src/components/tools/convert/ConvertSettings.tsx

@@ -26,7 +26,7 @@ import { StirlingFile } from "../../../types/fileContext";
 
 interface ConvertSettingsProps {
   parameters: ConvertParameters;
-  onParameterChange: (key: keyof ConvertParameters, value: any) => void;
+  onParameterChange: <K extends keyof ConvertParameters>(key: K, value: ConvertParameters[K]) => void;
   getAvailableToExtensions: (fromExtension: string) => Array<{value: string, label: string, group: string}>;
   selectedFiles: StirlingFile[];
   disabled?: boolean;

frontend/src/components/tools/convert/ConvertToImageSettings.tsx

@@ -6,7 +6,7 @@ import { ConvertParameters } from "../../../hooks/tools/convert/useConvertParame
 
 interface ConvertToImageSettingsProps {
   parameters: ConvertParameters;
-  onParameterChange: (key: keyof ConvertParameters, value: any) => void;
+  onParameterChange: <K extends keyof ConvertParameters>(key: K, value: ConvertParameters[K]) => void;
   disabled?: boolean;
 }
 

frontend/src/components/tools/convert/ConvertToPdfaSettings.tsx

@@ -7,7 +7,7 @@ import { StirlingFile } from '../../../types/fileContext';
 
 interface ConvertToPdfaSettingsProps {
   parameters: ConvertParameters;
-  onParameterChange: (key: keyof ConvertParameters, value: any) => void;
+  onParameterChange: <K extends keyof ConvertParameters>(key: K, value: ConvertParameters[K]) => void;
   selectedFiles: StirlingFile[];
   disabled?: boolean;
 }

frontend/src/components/tools/merge/MergeFileSorter.test.tsx

@@ -0,0 +1,182 @@
+import { describe, expect, test, vi, beforeEach } from 'vitest';
+import { render, screen, fireEvent } from '@testing-library/react';
+import { MantineProvider } from '@mantine/core';
+import MergeFileSorter from './MergeFileSorter';
+
+// Mock useTranslation with predictable return values
+const mockT = vi.fn((key: string) => `mock-${key}`);
+vi.mock('react-i18next', () => ({
+  useTranslation: () => ({ t: mockT })
+}));
+
+// Wrapper component to provide Mantine context
+const TestWrapper = ({ children }: { children: React.ReactNode }) => (
+  <MantineProvider>{children}</MantineProvider>
+);
+
+describe('MergeFileSorter', () => {
+  const mockOnSortFiles = vi.fn();
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  test('should render sort options dropdown, direction toggle, and sort button', () => {
+    render(
+      <TestWrapper>
+        <MergeFileSorter onSortFiles={mockOnSortFiles} />
+      </TestWrapper>
+    );
+
+    // Should have a select dropdown (Mantine Select uses textbox role)
+    expect(screen.getByRole('textbox')).toBeInTheDocument();
+
+    // Should have direction toggle button
+    const buttons = screen.getAllByRole('button');
+    expect(buttons).toHaveLength(2); // ActionIcon + Sort Button
+
+    // Should have sort button with text
+    expect(screen.getByText('mock-merge.sortBy.sort')).toBeInTheDocument();
+  });
+
+  test('should render description text', () => {
+    render(
+      <TestWrapper>
+        <MergeFileSorter onSortFiles={mockOnSortFiles} />
+      </TestWrapper>
+    );
+
+    expect(screen.getByText('mock-merge.sortBy.description')).toBeInTheDocument();
+  });
+
+  test('should have filename selected by default', () => {
+    render(
+      <TestWrapper>
+        <MergeFileSorter onSortFiles={mockOnSortFiles} />
+      </TestWrapper>
+    );
+
+    const select = screen.getByRole('textbox');
+    expect(select).toHaveValue('mock-merge.sortBy.filename');
+  });
+
+  test('should show ascending direction by default', () => {
+    render(
+      <TestWrapper>
+        <MergeFileSorter onSortFiles={mockOnSortFiles} />
+      </TestWrapper>
+    );
+
+    // Should show ascending arrow icon
+    const directionButton = screen.getAllByRole('button')[0];
+    expect(directionButton).toHaveAttribute('title', 'mock-merge.sortBy.ascending');
+  });
+
+  test('should toggle direction when direction button is clicked', () => {
+    render(
+      <TestWrapper>
+        <MergeFileSorter onSortFiles={mockOnSortFiles} />
+      </TestWrapper>
+    );
+
+    const directionButton = screen.getAllByRole('button')[0];
+
+    // Initially ascending
+    expect(directionButton).toHaveAttribute('title', 'mock-merge.sortBy.ascending');
+
+    // Click to toggle to descending
+    fireEvent.click(directionButton);
+    expect(directionButton).toHaveAttribute('title', 'mock-merge.sortBy.descending');
+
+    // Click again to toggle back to ascending
+    fireEvent.click(directionButton);
+    expect(directionButton).toHaveAttribute('title', 'mock-merge.sortBy.ascending');
+  });
+
+  test('should call onSortFiles with correct parameters when sort button is clicked', () => {
+    render(
+      <TestWrapper>
+        <MergeFileSorter onSortFiles={mockOnSortFiles} />
+      </TestWrapper>
+    );
+
+    const sortButton = screen.getByText('mock-merge.sortBy.sort');
+    fireEvent.click(sortButton);
+
+    // Should be called with default values (filename, ascending)
+    expect(mockOnSortFiles).toHaveBeenCalledWith('filename', true);
+  });
+
+  test('should call onSortFiles with dateModified when dropdown is changed', () => {
+    render(
+      <TestWrapper>
+        <MergeFileSorter onSortFiles={mockOnSortFiles} />
+      </TestWrapper>
+    );
+
+    // Open the dropdown by clicking on the current selected value
+    const currentSelection = screen.getByText('mock-merge.sortBy.filename');
+    fireEvent.mouseDown(currentSelection);
+    
+    // Click on the dateModified option
+    const dateModifiedOption = screen.getByText('mock-merge.sortBy.dateModified');
+    fireEvent.click(dateModifiedOption);
+
+    const sortButton = screen.getByText('mock-merge.sortBy.sort');
+    fireEvent.click(sortButton);
+
+    expect(mockOnSortFiles).toHaveBeenCalledWith('dateModified', true);
+  });
+
+  test('should call onSortFiles with descending direction when toggled', () => {
+    render(
+      <TestWrapper>
+        <MergeFileSorter onSortFiles={mockOnSortFiles} />
+      </TestWrapper>
+    );
+
+    const directionButton = screen.getAllByRole('button')[0];
+    const sortButton = screen.getByText('mock-merge.sortBy.sort');
+
+    // Toggle to descending
+    fireEvent.click(directionButton);
+
+    // Click sort
+    fireEvent.click(sortButton);
+
+    expect(mockOnSortFiles).toHaveBeenCalledWith('filename', false);
+  });
+
+  test('should handle complex user interaction sequence', () => {
+    render(
+      <TestWrapper>
+        <MergeFileSorter onSortFiles={mockOnSortFiles} />
+      </TestWrapper>
+    );
+
+    const directionButton = screen.getAllByRole('button')[0];
+    const sortButton = screen.getByText('mock-merge.sortBy.sort');
+
+    // 1. Change to dateModified
+    const currentSelection = screen.getByText('mock-merge.sortBy.filename');
+    fireEvent.mouseDown(currentSelection);
+    const dateModifiedOption = screen.getByText('mock-merge.sortBy.dateModified');
+    fireEvent.click(dateModifiedOption);
+
+    // 2. Toggle to descending
+    fireEvent.click(directionButton);
+
+    // 3. Click sort
+    fireEvent.click(sortButton);
+
+    expect(mockOnSortFiles).toHaveBeenCalledWith('dateModified', false);
+
+    // 4. Toggle back to ascending
+    fireEvent.click(directionButton);
+
+    // 5. Sort again
+    fireEvent.click(sortButton);
+
+    expect(mockOnSortFiles).toHaveBeenCalledWith('dateModified', true);
+  });
+});

frontend/src/components/tools/merge/MergeFileSorter.tsx

@@ -0,0 +1,77 @@
+import React, { useState } from 'react';
+import { Group, Button, Text, ActionIcon, Stack, Select } from '@mantine/core';
+import { useTranslation } from 'react-i18next';
+import SortIcon from '@mui/icons-material/Sort';
+import ArrowUpwardIcon from '@mui/icons-material/ArrowUpward';
+import ArrowDownwardIcon from '@mui/icons-material/ArrowDownward';
+
+interface MergeFileSorterProps {
+  onSortFiles: (sortType: 'filename' | 'dateModified', ascending: boolean) => void;
+  disabled?: boolean;
+}
+
+const MergeFileSorter: React.FC<MergeFileSorterProps> = ({
+  onSortFiles,
+  disabled = false,
+}) => {
+  const { t } = useTranslation();
+  const [sortType, setSortType] = useState<'filename' | 'dateModified'>('filename');
+  const [ascending, setAscending] = useState(true);
+
+  const sortOptions = [
+    { value: 'filename', label: t('merge.sortBy.filename', 'File Name') },
+    { value: 'dateModified', label: t('merge.sortBy.dateModified', 'Date Modified') },
+  ];
+
+  const handleSort = () => {
+    onSortFiles(sortType, ascending);
+  };
+
+  const handleDirectionToggle = () => {
+    setAscending(!ascending);
+  };
+
+  return (
+    <Stack gap="xs">
+      <Text size="sm" fw={500}>
+        {t('merge.sortBy.description', "Files will be merged in the order they're selected. Drag to reorder or sort below.")}
+      </Text>
+      <Stack gap="xs">
+        <Group gap="xs" align="end" justify="space-between">
+          <Select
+            data={sortOptions}
+            value={sortType}
+            onChange={(value) => setSortType(value as 'filename' | 'dateModified')}
+            disabled={disabled}
+            label={t('merge.sortBy.label', 'Sort By')}
+            size='xs'
+            style={{ flex: 1 }}
+          />
+
+          <ActionIcon
+            variant="light"
+            size="md"
+            onClick={handleDirectionToggle}
+            disabled={disabled}
+            title={ascending ? t('merge.sortBy.ascending', 'Ascending') : t('merge.sortBy.descending', 'Descending')}
+          >
+            {ascending ? <ArrowUpwardIcon /> : <ArrowDownwardIcon />}
+          </ActionIcon>
+        </Group>
+
+        <Button
+          variant="light"
+          size="xs"
+          leftSection={<SortIcon />}
+          onClick={handleSort}
+          disabled={disabled}
+          fullWidth
+        >
+          {t('merge.sortBy.sort', 'Sort')}
+        </Button>
+      </Stack>
+    </Stack>
+  );
+};
+
+export default MergeFileSorter;

frontend/src/components/tools/merge/MergeSettings.test.tsx

@@ -0,0 +1,100 @@
+import { describe, expect, test, vi, beforeEach } from 'vitest';
+import { render, screen, fireEvent } from '@testing-library/react';
+import { MantineProvider } from '@mantine/core';
+import MergeSettings from './MergeSettings';
+import { MergeParameters } from '../../../hooks/tools/merge/useMergeParameters';
+
+// Mock useTranslation with predictable return values
+const mockT = vi.fn((key: string) => `mock-${key}`);
+vi.mock('react-i18next', () => ({
+  useTranslation: () => ({ t: mockT })
+}));
+
+// Wrapper component to provide Mantine context
+const TestWrapper = ({ children }: { children: React.ReactNode }) => (
+  <MantineProvider>{children}</MantineProvider>
+);
+
+describe('MergeSettings', () => {
+  const defaultParameters: MergeParameters = {
+    removeDigitalSignature: false,
+    generateTableOfContents: false,
+  };
+
+  const mockOnParameterChange = vi.fn();
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  test('should render both merge option checkboxes', () => {
+    render(
+      <TestWrapper>
+        <MergeSettings
+          parameters={defaultParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    // Should render one checkbox for each parameter
+    const expectedCheckboxCount = Object.keys(defaultParameters).length;
+    const checkboxes = screen.getAllByRole('checkbox');
+    expect(checkboxes).toHaveLength(expectedCheckboxCount);
+  });
+
+  test('should show correct initial checkbox states based on parameters', () => {
+    render(
+      <TestWrapper>
+        <MergeSettings
+          parameters={defaultParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    const checkboxes = screen.getAllByRole('checkbox');
+
+    // Both checkboxes should be unchecked initially
+    checkboxes.forEach(checkbox => {
+      expect(checkbox).not.toBeChecked();
+    });
+  });
+
+  test('should call onParameterChange with correct parameters when checkboxes are clicked', () => {
+    render(
+      <TestWrapper>
+        <MergeSettings
+          parameters={defaultParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    const checkboxes = screen.getAllByRole('checkbox');
+
+    // Click the first checkbox (removeDigitalSignature - should toggle from false to true)
+    fireEvent.click(checkboxes[0]);
+    expect(mockOnParameterChange).toHaveBeenCalledWith('removeDigitalSignature', true);
+
+    // Click the second checkbox (generateTableOfContents - should toggle from false to true)
+    fireEvent.click(checkboxes[1]);
+    expect(mockOnParameterChange).toHaveBeenCalledWith('generateTableOfContents', true);
+  });
+
+  test('should call translation function with correct keys', () => {
+    render(
+      <TestWrapper>
+        <MergeSettings
+          parameters={defaultParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    // Verify that translation keys are being called
+    expect(mockT).toHaveBeenCalledWith('merge.removeDigitalSignature', 'Remove digital signature in the merged file?');
+    expect(mockT).toHaveBeenCalledWith('merge.generateTableOfContents', 'Generate table of contents in the merged file?');
+  });
+  
+});

frontend/src/components/tools/merge/MergeSettings.tsx

@@ -0,0 +1,38 @@
+import React from 'react';
+import { Stack, Checkbox } from '@mantine/core';
+import { useTranslation } from 'react-i18next';
+import { MergeParameters } from '../../../hooks/tools/merge/useMergeParameters';
+
+interface MergeSettingsProps {
+  parameters: MergeParameters;
+  onParameterChange: <K extends keyof MergeParameters>(key: K, value: MergeParameters[K]) => void;
+  disabled?: boolean;
+}
+
+const MergeSettings: React.FC<MergeSettingsProps> = ({
+  parameters,
+  onParameterChange,
+  disabled = false,
+}) => {
+  const { t } = useTranslation();
+
+  return (
+    <Stack gap="md">
+      <Checkbox
+        label={t('merge.removeDigitalSignature', 'Remove digital signature in the merged file?')}
+        checked={parameters.removeDigitalSignature}
+        onChange={(event) => onParameterChange('removeDigitalSignature', event.currentTarget.checked)}
+        disabled={disabled}
+      />
+
+      <Checkbox
+        label={t('merge.generateTableOfContents', 'Generate table of contents in the merged file?')}
+        checked={parameters.generateTableOfContents}
+        onChange={(event) => onParameterChange('generateTableOfContents', event.currentTarget.checked)}
+        disabled={disabled}
+      />
+    </Stack>
+  );
+};
+
+export default MergeSettings;

frontend/src/components/tools/ocr/AdvancedOCRSettings.tsx

@@ -16,7 +16,7 @@ interface AdvancedOption {
 interface AdvancedOCRSettingsProps {
   advancedOptions: string[];
   ocrRenderType?: string;
-  onParameterChange: (key: keyof OCRParameters, value: any) => void;
+  onParameterChange: <K extends keyof OCRParameters>(key: K, value: OCRParameters[K]) => void;
   disabled?: boolean;
 }
 

frontend/src/components/tools/ocr/OCRSettings.tsx

@@ -6,7 +6,7 @@ import { OCRParameters } from '../../../hooks/tools/ocr/useOCRParameters';
 
 interface OCRSettingsProps {
   parameters: OCRParameters;
-  onParameterChange: (key: keyof OCRParameters, value: any) => void;
+  onParameterChange: <K extends keyof OCRParameters>(key: K, value: OCRParameters[K]) => void;
   disabled?: boolean;
 }
 

frontend/src/components/tools/redact/RedactAdvancedSettings.test.tsx

@@ -0,0 +1,211 @@
+import { describe, expect, test, vi, beforeEach } from 'vitest';
+import { render, screen, fireEvent } from '@testing-library/react';
+import { MantineProvider } from '@mantine/core';
+import RedactAdvancedSettings from './RedactAdvancedSettings';
+import { defaultParameters } from '../../../hooks/tools/redact/useRedactParameters';
+
+// Mock useTranslation
+const mockT = vi.fn((_key: string, fallback: string) => fallback);
+vi.mock('react-i18next', () => ({
+  useTranslation: () => ({ t: mockT })
+}));
+
+// Wrapper component to provide Mantine context
+const TestWrapper = ({ children }: { children: React.ReactNode }) => (
+  <MantineProvider>{children}</MantineProvider>
+);
+
+describe('RedactAdvancedSettings', () => {
+  const mockOnParameterChange = vi.fn();
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  test('should render all advanced settings controls', () => {
+    render(
+      <TestWrapper>
+        <RedactAdvancedSettings
+          parameters={defaultParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    expect(screen.getByText('Box Colour')).toBeInTheDocument();
+    expect(screen.getByText('Custom Extra Padding')).toBeInTheDocument();
+    expect(screen.getByText('Use Regex')).toBeInTheDocument();
+    expect(screen.getByText('Whole Word Search')).toBeInTheDocument();
+    expect(screen.getByText('Convert PDF to PDF-Image (Used to remove text behind the box)')).toBeInTheDocument();
+  });
+
+  test('should display current parameter values', () => {
+    const customParameters = {
+      ...defaultParameters,
+      redactColor: '#FF0000',
+      customPadding: 0.5,
+      useRegex: true,
+      wholeWordSearch: true,
+      convertPDFToImage: false,
+    };
+
+    render(
+      <TestWrapper>
+        <RedactAdvancedSettings
+          parameters={customParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    // Check color input value
+    const colorInput = screen.getByDisplayValue('#FF0000');
+    expect(colorInput).toBeInTheDocument();
+
+    // Check number input value
+    const paddingInput = screen.getByDisplayValue('0.5');
+    expect(paddingInput).toBeInTheDocument();
+
+    // Check checkbox states
+    const useRegexCheckbox = screen.getByLabelText('Use Regex');
+    const wholeWordCheckbox = screen.getByLabelText('Whole Word Search');
+    const convertCheckbox = screen.getByLabelText('Convert PDF to PDF-Image (Used to remove text behind the box)');
+
+    expect(useRegexCheckbox).toBeChecked();
+    expect(wholeWordCheckbox).toBeChecked();
+    expect(convertCheckbox).not.toBeChecked();
+  });
+
+  test('should call onParameterChange when color is changed', () => {
+    render(
+      <TestWrapper>
+        <RedactAdvancedSettings
+          parameters={defaultParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    const colorInput = screen.getByDisplayValue('#000000');
+    fireEvent.change(colorInput, { target: { value: '#FF0000' } });
+
+    expect(mockOnParameterChange).toHaveBeenCalledWith('redactColor', '#FF0000');
+  });
+
+  test('should call onParameterChange when padding is changed', () => {
+    render(
+      <TestWrapper>
+        <RedactAdvancedSettings
+          parameters={defaultParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    const paddingInput = screen.getByDisplayValue('0.1');
+    fireEvent.change(paddingInput, { target: { value: '0.5' } });
+
+    expect(mockOnParameterChange).toHaveBeenCalledWith('customPadding', 0.5);
+  });
+
+  test('should handle invalid padding values', () => {
+    render(
+      <TestWrapper>
+        <RedactAdvancedSettings
+          parameters={defaultParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    const paddingInput = screen.getByDisplayValue('0.1');
+
+    // Simulate NumberInput onChange with invalid value (empty string)
+    const numberInput = paddingInput.closest('.mantine-NumberInput-root');
+    if (numberInput) {
+      // Find the input and trigger change with empty value
+      fireEvent.change(paddingInput, { target: { value: '' } });
+
+      // The component should default to 0.1 for invalid values
+      expect(mockOnParameterChange).toHaveBeenCalledWith('customPadding', 0.1);
+    }
+  });
+
+  test.each([
+    {
+      paramName: 'useRegex' as const,
+      label: 'Use Regex',
+      initialValue: false,
+      expectedValue: true,
+    },
+    {
+      paramName: 'wholeWordSearch' as const,
+      label: 'Whole Word Search',
+      initialValue: false,
+      expectedValue: true,
+    },
+    {
+      paramName: 'convertPDFToImage' as const,
+      label: 'Convert PDF to PDF-Image (Used to remove text behind the box)',
+      initialValue: true,
+      expectedValue: false,
+    },
+  ])('should call onParameterChange when $paramName checkbox is toggled', ({ paramName, label, initialValue, expectedValue }) => {
+    const customParameters = {
+      ...defaultParameters,
+      [paramName]: initialValue,
+    };
+
+    render(
+      <TestWrapper>
+        <RedactAdvancedSettings
+          parameters={customParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    const checkbox = screen.getByLabelText(label);
+    fireEvent.click(checkbox);
+
+    expect(mockOnParameterChange).toHaveBeenCalledWith(paramName, expectedValue);
+  });
+
+  test.each([
+    { controlType: 'color input', getValue: () => screen.getByDisplayValue('#000000') },
+    { controlType: 'padding input', getValue: () => screen.getByDisplayValue('0.1') },
+    { controlType: 'useRegex checkbox', getValue: () => screen.getByLabelText('Use Regex') },
+    { controlType: 'wholeWordSearch checkbox', getValue: () => screen.getByLabelText('Whole Word Search') },
+    { controlType: 'convertPDFToImage checkbox', getValue: () => screen.getByLabelText('Convert PDF to PDF-Image (Used to remove text behind the box)') },
+  ])('should disable $controlType when disabled prop is true', ({ getValue }) => {
+    render(
+      <TestWrapper>
+        <RedactAdvancedSettings
+          parameters={defaultParameters}
+          onParameterChange={mockOnParameterChange}
+          disabled={true}
+        />
+      </TestWrapper>
+    );
+
+    const control = getValue();
+    expect(control).toBeDisabled();
+  });
+
+  test('should have correct padding input constraints', () => {
+    render(
+      <TestWrapper>
+        <RedactAdvancedSettings
+          parameters={defaultParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    // NumberInput in Mantine might not expose these attributes directly on the input element
+    // Instead, check that the NumberInput component is rendered with correct placeholder
+    const paddingInput = screen.getByPlaceholderText('0.1');
+    expect(paddingInput).toBeInTheDocument();
+    expect(paddingInput).toHaveDisplayValue('0.1');
+  });
+});

frontend/src/components/tools/redact/RedactAdvancedSettings.tsx

@@ -0,0 +1,69 @@
+import { Stack, NumberInput, ColorInput, Checkbox } from "@mantine/core";
+import { useTranslation } from "react-i18next";
+import { RedactParameters } from "../../../hooks/tools/redact/useRedactParameters";
+
+interface RedactAdvancedSettingsProps {
+  parameters: RedactParameters;
+  onParameterChange: <K extends keyof RedactParameters>(key: K, value: RedactParameters[K]) => void;
+  disabled?: boolean;
+}
+
+const RedactAdvancedSettings = ({ parameters, onParameterChange, disabled = false }: RedactAdvancedSettingsProps) => {
+  const { t } = useTranslation();
+
+  return (
+    <Stack gap="md">
+      {/* Box Color */}
+      <ColorInput
+        label={t('redact.auto.colorLabel', 'Box Colour')}
+        value={parameters.redactColor}
+        onChange={(value) => onParameterChange('redactColor', value)}
+        disabled={disabled}
+        size="sm"
+        format="hex"
+      />
+
+      {/* Box Padding */}
+      <NumberInput
+        label={t('redact.auto.customPaddingLabel', 'Custom Extra Padding')}
+        value={parameters.customPadding}
+        onChange={(value) => onParameterChange('customPadding', typeof value === 'number' ? value : 0.1)}
+        min={0}
+        max={10}
+        step={0.1}
+        disabled={disabled}
+        size="sm"
+        placeholder="0.1"
+      />
+
+      {/* Use Regex */}
+      <Checkbox
+        label={t('redact.auto.useRegexLabel', 'Use Regex')}
+        checked={parameters.useRegex}
+        onChange={(e) => onParameterChange('useRegex', e.currentTarget.checked)}
+        disabled={disabled}
+        size="sm"
+      />
+
+      {/* Whole Word Search */}
+      <Checkbox
+        label={t('redact.auto.wholeWordSearchLabel', 'Whole Word Search')}
+        checked={parameters.wholeWordSearch}
+        onChange={(e) => onParameterChange('wholeWordSearch', e.currentTarget.checked)}
+        disabled={disabled}
+        size="sm"
+      />
+
+      {/* Convert PDF to PDF-Image */}
+      <Checkbox
+        label={t('redact.auto.convertPDFToImageLabel', 'Convert PDF to PDF-Image (Used to remove text behind the box)')}
+        checked={parameters.convertPDFToImage}
+        onChange={(e) => onParameterChange('convertPDFToImage', e.currentTarget.checked)}
+        disabled={disabled}
+        size="sm"
+      />
+    </Stack>
+  );
+};
+
+export default RedactAdvancedSettings;

frontend/src/components/tools/redact/RedactModeSelector.tsx

@@ -0,0 +1,33 @@
+import { useTranslation } from 'react-i18next';
+import { RedactMode } from '../../../hooks/tools/redact/useRedactParameters';
+import ButtonSelector from '../../shared/ButtonSelector';
+
+interface RedactModeSelectorProps {
+  mode: RedactMode;
+  onModeChange: (mode: RedactMode) => void;
+  disabled?: boolean;
+}
+
+export default function RedactModeSelector({ mode, onModeChange, disabled }: RedactModeSelectorProps) {
+  const { t } = useTranslation();
+
+  return (
+    <ButtonSelector
+      label={t('redact.modeSelector.mode', 'Mode')}
+      value={mode}
+      onChange={onModeChange}
+      options={[
+        {
+          value: 'automatic' as const,
+          label: t('redact.modeSelector.automatic', 'Automatic'),
+        },
+        {
+          value: 'manual' as const,
+          label: t('redact.modeSelector.manual', 'Manual'),
+          disabled: true, // Keep manual mode disabled until implemented
+        },
+      ]}
+      disabled={disabled}
+    />
+  );
+}

frontend/src/components/tools/redact/RedactSingleStepSettings.test.tsx

@@ -0,0 +1,183 @@
+import { describe, expect, test, vi, beforeEach } from 'vitest';
+import { render, screen, fireEvent } from '@testing-library/react';
+import { MantineProvider } from '@mantine/core';
+import RedactSingleStepSettings from './RedactSingleStepSettings';
+import { defaultParameters } from '../../../hooks/tools/redact/useRedactParameters';
+
+// Mock useTranslation
+vi.mock('react-i18next', () => ({
+  useTranslation: () => ({ t: vi.fn((_key: string, fallback: string) => fallback) })
+}));
+
+// Wrapper component to provide Mantine context
+const TestWrapper = ({ children }: { children: React.ReactNode }) => (
+  <MantineProvider>{children}</MantineProvider>
+);
+
+describe('RedactSingleStepSettings', () => {
+  const mockOnParameterChange = vi.fn();
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  test('should render mode selector', () => {
+    render(
+      <TestWrapper>
+        <RedactSingleStepSettings
+          parameters={defaultParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    expect(screen.getByText('Mode')).toBeInTheDocument();
+    expect(screen.getByRole('button', { name: 'Automatic' })).toBeInTheDocument();
+    expect(screen.getByRole('button', { name: 'Manual' })).toBeInTheDocument();
+  });
+
+  test('should render automatic mode settings when mode is automatic', () => {
+    render(
+      <TestWrapper>
+        <RedactSingleStepSettings
+          parameters={defaultParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    // Default mode is automatic, so these should be visible
+    expect(screen.getByText('Words to Redact')).toBeInTheDocument();
+    expect(screen.getByPlaceholderText('Enter a word')).toBeInTheDocument();
+    expect(screen.getByText('Box Colour')).toBeInTheDocument();
+    expect(screen.getByText('Use Regex')).toBeInTheDocument();
+  });
+
+  test('should render manual mode settings when mode is manual', () => {
+    const manualParameters = {
+      ...defaultParameters,
+      mode: 'manual' as const,
+    };
+
+    render(
+      <TestWrapper>
+        <RedactSingleStepSettings
+          parameters={manualParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    // Manual mode should show placeholder text
+    expect(screen.getByText('Manual redaction interface will be available here when implemented.')).toBeInTheDocument();
+
+    // Automatic mode settings should not be visible
+    expect(screen.queryByText('Words to Redact')).not.toBeInTheDocument();
+  });
+
+  test('should pass through parameter changes from automatic settings', () => {
+    render(
+      <TestWrapper>
+        <RedactSingleStepSettings
+          parameters={defaultParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    // Test adding a word
+    const input = screen.getByPlaceholderText('Enter a word');
+    const addButton = screen.getByRole('button', { name: '+ Add' });
+
+    fireEvent.change(input, { target: { value: 'TestWord' } });
+    fireEvent.click(addButton);
+
+    expect(mockOnParameterChange).toHaveBeenCalledWith('wordsToRedact', ['TestWord']);
+  });
+
+  test('should pass through parameter changes from advanced settings', () => {
+    render(
+      <TestWrapper>
+        <RedactSingleStepSettings
+          parameters={defaultParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    // Test changing color
+    const colorInput = screen.getByDisplayValue('#000000');
+    fireEvent.change(colorInput, { target: { value: '#FF0000' } });
+
+    expect(mockOnParameterChange).toHaveBeenCalledWith('redactColor', '#FF0000');
+  });
+
+  test('should disable all controls when disabled prop is true', () => {
+    render(
+      <TestWrapper>
+        <RedactSingleStepSettings
+          parameters={defaultParameters}
+          onParameterChange={mockOnParameterChange}
+          disabled={true}
+        />
+      </TestWrapper>
+    );
+
+    // Mode selector buttons should be disabled
+    expect(screen.getByRole('button', { name: 'Automatic' })).toBeDisabled();
+    expect(screen.getByRole('button', { name: 'Manual' })).toBeDisabled();
+
+    // Automatic settings controls should be disabled
+    expect(screen.getByPlaceholderText('Enter a word')).toBeDisabled();
+    expect(screen.getByRole('button', { name: '+ Add' })).toBeDisabled();
+    expect(screen.getByDisplayValue('#000000')).toBeDisabled();
+  });
+
+  test('should show current parameter values in automatic mode', () => {
+    const customParameters = {
+      ...defaultParameters,
+      wordsToRedact: ['Word1', 'Word2'],
+      redactColor: '#FF0000',
+      useRegex: true,
+      customPadding: 0.5,
+    };
+
+    render(
+      <TestWrapper>
+        <RedactSingleStepSettings
+          parameters={customParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    // Check that word tags are displayed
+    expect(screen.getByText('Word1')).toBeInTheDocument();
+    expect(screen.getByText('Word2')).toBeInTheDocument();
+
+    // Check that color is displayed
+    expect(screen.getByDisplayValue('#FF0000')).toBeInTheDocument();
+
+    // Check that regex checkbox is checked
+    const useRegexCheckbox = screen.getByLabelText('Use Regex');
+    expect(useRegexCheckbox).toBeChecked();
+
+    // Check that padding value is displayed
+    expect(screen.getByDisplayValue('0.5')).toBeInTheDocument();
+  });
+
+  test('should maintain consistent spacing and layout', () => {
+    render(
+      <TestWrapper>
+        <RedactSingleStepSettings
+          parameters={defaultParameters}
+          onParameterChange={mockOnParameterChange}
+        />
+      </TestWrapper>
+    );
+
+    // Check that the Stack container exists
+    const container = screen.getByText('Mode').closest('.mantine-Stack-root');
+    expect(container).toBeInTheDocument();
+  });
+});

frontend/src/components/tools/redact/RedactSingleStepSettings.tsx

@@ -0,0 +1,61 @@
+import { Stack, Divider } from "@mantine/core";
+import { RedactParameters } from "../../../hooks/tools/redact/useRedactParameters";
+import RedactModeSelector from "./RedactModeSelector";
+import WordsToRedactInput from "./WordsToRedactInput";
+import RedactAdvancedSettings from "./RedactAdvancedSettings";
+
+interface RedactSingleStepSettingsProps {
+  parameters: RedactParameters;
+  onParameterChange: <K extends keyof RedactParameters>(key: K, value: RedactParameters[K]) => void;
+  disabled?: boolean;
+}
+
+const RedactSingleStepSettings = ({ parameters, onParameterChange, disabled = false }: RedactSingleStepSettingsProps) => {
+  return (
+    <Stack gap="md">
+      {/* Mode Selection */}
+      <RedactModeSelector
+        mode={parameters.mode}
+        onModeChange={(mode) => onParameterChange('mode', mode)}
+        disabled={disabled}
+      />
+
+      {/* Automatic Mode Settings */}
+      {parameters.mode === 'automatic' && (
+        <>
+          <Divider />
+
+          {/* Words to Redact */}
+          <WordsToRedactInput
+            wordsToRedact={parameters.wordsToRedact}
+            onWordsChange={(words) => onParameterChange('wordsToRedact', words)}
+            disabled={disabled}
+          />
+
+          <Divider />
+
+          {/* Advanced Settings */}
+          <RedactAdvancedSettings
+            parameters={parameters}
+            onParameterChange={onParameterChange}
+            disabled={disabled}
+          />
+        </>
+      )}
+
+      {/* Manual Mode Placeholder */}
+      {parameters.mode === 'manual' && (
+        <>
+          <Divider />
+          <Stack gap="md">
+            <div style={{ padding: '20px', textAlign: 'center', color: '#666' }}>
+              Manual redaction interface will be available here when implemented.
+            </div>
+          </Stack>
+        </>
+      )}
+    </Stack>
+  );
+};
+
+export default RedactSingleStepSettings;

frontend/src/components/tools/redact/WordsToRedactInput.test.tsx

@@ -0,0 +1,191 @@
+import { describe, expect, test, vi, beforeEach } from 'vitest';
+import { render, screen, fireEvent } from '@testing-library/react';
+import { MantineProvider } from '@mantine/core';
+import WordsToRedactInput from './WordsToRedactInput';
+
+// Mock useTranslation
+const mockT = vi.fn((_key: string, fallback: string) => fallback);
+vi.mock('react-i18next', () => ({
+  useTranslation: () => ({ t: mockT })
+}));
+
+// Wrapper component to provide Mantine context
+const TestWrapper = ({ children }: { children: React.ReactNode }) => (
+  <MantineProvider>{children}</MantineProvider>
+);
+
+describe('WordsToRedactInput', () => {
+  const mockOnWordsChange = vi.fn();
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  test('should render with title and input field', () => {
+    render(
+      <TestWrapper>
+        <WordsToRedactInput
+          wordsToRedact={[]}
+          onWordsChange={mockOnWordsChange}
+        />
+      </TestWrapper>
+    );
+
+    expect(screen.getByText('Words to Redact')).toBeInTheDocument();
+    expect(screen.getByPlaceholderText('Enter a word')).toBeInTheDocument();
+    expect(screen.getByRole('button', { name: '+ Add' })).toBeInTheDocument();
+  });
+
+  test.each([
+    { trigger: 'Add button click', action: (_input: HTMLElement, addButton: HTMLElement) => fireEvent.click(addButton) },
+    { trigger: 'Enter key press', action: (input: HTMLElement) => fireEvent.keyDown(input, { key: 'Enter', code: 'Enter' }) },
+  ])('should add word when $trigger', ({ action }) => {
+    render(
+      <TestWrapper>
+        <WordsToRedactInput
+          wordsToRedact={[]}
+          onWordsChange={mockOnWordsChange}
+        />
+      </TestWrapper>
+    );
+
+    const input = screen.getByPlaceholderText('Enter a word');
+    const addButton = screen.getByRole('button', { name: '+ Add' });
+
+    fireEvent.change(input, { target: { value: 'TestWord' } });
+    action(input, addButton);
+
+    expect(mockOnWordsChange).toHaveBeenCalledWith(['TestWord']);
+  });
+
+  test('should not add empty word', () => {
+    render(
+      <TestWrapper>
+        <WordsToRedactInput
+          wordsToRedact={[]}
+          onWordsChange={mockOnWordsChange}
+        />
+      </TestWrapper>
+    );
+
+    const addButton = screen.getByRole('button', { name: '+ Add' });
+
+    fireEvent.click(addButton);
+
+    expect(mockOnWordsChange).not.toHaveBeenCalled();
+  });
+
+  test('should not add duplicate word', () => {
+    render(
+      <TestWrapper>
+        <WordsToRedactInput
+          wordsToRedact={['Existing']}
+          onWordsChange={mockOnWordsChange}
+        />
+      </TestWrapper>
+    );
+
+    const input = screen.getByPlaceholderText('Enter a word');
+    const addButton = screen.getByRole('button', { name: '+ Add' });
+
+    fireEvent.change(input, { target: { value: 'Existing' } });
+    fireEvent.click(addButton);
+
+    expect(mockOnWordsChange).not.toHaveBeenCalled();
+  });
+
+  test('should trim whitespace when adding word', () => {
+    render(
+      <TestWrapper>
+        <WordsToRedactInput
+          wordsToRedact={[]}
+          onWordsChange={mockOnWordsChange}
+        />
+      </TestWrapper>
+    );
+
+    const input = screen.getByPlaceholderText('Enter a word');
+    const addButton = screen.getByRole('button', { name: '+ Add' });
+
+    fireEvent.change(input, { target: { value: '  TestWord  ' } });
+    fireEvent.click(addButton);
+
+    expect(mockOnWordsChange).toHaveBeenCalledWith(['TestWord']);
+  });
+
+  test('should remove word when x button is clicked', () => {
+    render(
+      <TestWrapper>
+        <WordsToRedactInput
+          wordsToRedact={['Word1', 'Word2']}
+          onWordsChange={mockOnWordsChange}
+        />
+      </TestWrapper>
+    );
+
+    const removeButtons = screen.getAllByText('×');
+    fireEvent.click(removeButtons[0]);
+
+    expect(mockOnWordsChange).toHaveBeenCalledWith(['Word2']);
+  });
+
+  test('should clear input after adding word', () => {
+    render(
+      <TestWrapper>
+        <WordsToRedactInput
+          wordsToRedact={[]}
+          onWordsChange={mockOnWordsChange}
+        />
+      </TestWrapper>
+    );
+
+    const input = screen.getByPlaceholderText('Enter a word') as HTMLInputElement;
+    const addButton = screen.getByRole('button', { name: '+ Add' });
+
+    fireEvent.change(input, { target: { value: 'TestWord' } });
+    fireEvent.click(addButton);
+
+    expect(input.value).toBe('');
+  });
+
+  test.each([
+    { description: 'disable Add button when input is empty', inputValue: '', expectedDisabled: true },
+    { description: 'enable Add button when input has text', inputValue: 'TestWord', expectedDisabled: false },
+  ])('should $description', ({ inputValue, expectedDisabled }) => {
+    render(
+      <TestWrapper>
+        <WordsToRedactInput
+          wordsToRedact={[]}
+          onWordsChange={mockOnWordsChange}
+        />
+      </TestWrapper>
+    );
+
+    const input = screen.getByPlaceholderText('Enter a word');
+    const addButton = screen.getByRole('button', { name: '+ Add' });
+
+    fireEvent.change(input, { target: { value: inputValue } });
+
+    expect(addButton).toHaveProperty('disabled', expectedDisabled);
+  });
+
+  test('should disable all controls when disabled prop is true', () => {
+    render(
+      <TestWrapper>
+        <WordsToRedactInput
+          wordsToRedact={['Word1']}
+          onWordsChange={mockOnWordsChange}
+          disabled={true}
+        />
+      </TestWrapper>
+    );
+
+    const input = screen.getByPlaceholderText('Enter a word');
+    const addButton = screen.getByRole('button', { name: '+ Add' });
+    const removeButton = screen.getByText('×');
+
+    expect(input).toBeDisabled();
+    expect(addButton).toBeDisabled();
+    expect(removeButton.closest('button')).toBeDisabled();
+  });
+});

frontend/src/components/tools/redact/WordsToRedactInput.tsx

@@ -0,0 +1,99 @@
+import React, { useState } from 'react';
+import { useTranslation } from 'react-i18next';
+import { Stack, Text, TextInput, Button, Group, ActionIcon } from '@mantine/core';
+
+interface WordsToRedactInputProps {
+  wordsToRedact: string[];
+  onWordsChange: (words: string[]) => void;
+  disabled?: boolean;
+}
+
+export default function WordsToRedactInput({ wordsToRedact, onWordsChange, disabled }: WordsToRedactInputProps) {
+  const { t } = useTranslation();
+  const [currentWord, setCurrentWord] = useState('');
+
+  const addWord = () => {
+    if (currentWord.trim() && !wordsToRedact.includes(currentWord.trim())) {
+      onWordsChange([...wordsToRedact, currentWord.trim()]);
+      setCurrentWord('');
+    }
+  };
+
+  const removeWord = (index: number) => {
+    onWordsChange(wordsToRedact.filter((_, i) => i !== index));
+  };
+
+  const handleKeyPress = (e: React.KeyboardEvent) => {
+    if (e.key === 'Enter') {
+      e.preventDefault();
+      addWord();
+    }
+  };
+
+  return (
+    <Stack gap="sm">
+      <Text size="sm" fw={500}>
+        {t('redact.auto.wordsToRedact.title', 'Words to Redact')}
+      </Text>
+
+      {/* Current words */}
+      {wordsToRedact.map((word, index) => (
+        <Group key={index} justify="space-between" p="sm" style={{
+          borderRadius: 'var(--mantine-radius-sm)',
+          border: `1px solid var(--mantine-color-gray-3)`,
+          backgroundColor: 'var(--mantine-color-gray-0)'
+        }}>
+          <Text
+            size="sm"
+            style={{
+              maxWidth: '80%',
+              overflow: 'hidden',
+              textOverflow: 'ellipsis',
+              whiteSpace: 'nowrap'
+            }}
+            title={word}
+          >
+            {word}
+          </Text>
+          <ActionIcon
+            size="sm"
+            variant="subtle"
+            color="red"
+            onClick={() => removeWord(index)}
+            disabled={disabled}
+          >
+            ×
+          </ActionIcon>
+        </Group>
+      ))}
+
+      {/* Add new word input */}
+      <Group gap="sm" align="end">
+        <TextInput
+          placeholder={t('redact.auto.wordsToRedact.placeholder', 'Enter a word')}
+          value={currentWord}
+          onChange={(e) => setCurrentWord(e.target.value)}
+          onKeyDown={handleKeyPress}
+          disabled={disabled}
+          size="sm"
+          style={{ flex: 1 }}
+        />
+        <Button
+          size="sm"
+          variant="light"
+          onClick={addWord}
+          disabled={disabled || !currentWord.trim()}
+        >
+          + {t('redact.auto.wordsToRedact.add', 'Add')}
+        </Button>
+      </Group>
+
+      {/* Examples */}
+      {wordsToRedact.length === 0 && (
+        <Text size="xs" c="dimmed">
+          {t('redact.auto.wordsToRedact.examples', 'Examples: Confidential, Top-Secret')}
+        </Text>
+      )}
+    </Stack>
+  );
+}

frontend/src/components/tools/removePassword/RemovePasswordSettings.tsx

@@ -4,7 +4,7 @@ import { RemovePasswordParameters } from "../../../hooks/tools/removePassword/us
 
 interface RemovePasswordSettingsProps {
   parameters: RemovePasswordParameters;
-  onParameterChange: (key: keyof RemovePasswordParameters, value: string) => void;
+  onParameterChange: <K extends keyof RemovePasswordParameters>(key: K, value: RemovePasswordParameters[K]) => void;
   disabled?: boolean;
 }
 

frontend/src/components/tools/sanitize/SanitizeSettings.tsx

@@ -4,7 +4,7 @@ import { SanitizeParameters, defaultParameters } from "../../../hooks/tools/sani
 
 interface SanitizeSettingsProps {
   parameters: SanitizeParameters;
-  onParameterChange: (key: keyof SanitizeParameters, value: boolean) => void;
+  onParameterChange: <K extends keyof SanitizeParameters>(key: K, value: SanitizeParameters[K]) => void;
   disabled?: boolean;
 }
 

frontend/src/components/tools/shared/FileStatusIndicator.tsx

@@ -10,11 +10,12 @@ import { StirlingFile } from "../../../types/fileContext";
 
 export interface FileStatusIndicatorProps {
   selectedFiles?: StirlingFile[];
-  placeholder?: string;
+  minFiles?: number;
 }
 
 const FileStatusIndicator = ({
   selectedFiles = [],
+  minFiles = 1,
 }: FileStatusIndicatorProps) => {
   const { t } = useTranslation();
   const { openFilesModal, onFilesSelect } = useFilesModalContext();
@@ -55,6 +56,14 @@ const FileStatusIndicator = ({
     return null;
   }
 
+  const getPlaceholder = () => {
+    if (minFiles === undefined || minFiles === 1) {
+      return t("files.selectFromWorkbench", "Select files from the workbench or ");
+    } else {
+      return t("files.selectMultipleFromWorkbench", "Select at least {{count}} files from the workbench or ", { count: minFiles });
+    }
+  };
+
   // Check if there are no files in the workbench
   if (stirlingFileStubs.length === 0) {
     // If no recent files, show upload button
@@ -89,12 +98,12 @@ const FileStatusIndicator = ({
   }
 
   // Show selection status when there are files in workbench
-  if (selectedFiles.length === 0) {
+  if (selectedFiles.length < minFiles) {
     // If no recent files, show upload option
     if (!hasRecentFiles) {
       return (
         <Text size="sm" c="dimmed">
-          {t("files.selectFromWorkbench", "Select files from the workbench or ") + " "}
+          {getPlaceholder() + " "}
           <Anchor
             size="sm"
             onClick={handleNativeUpload}
@@ -109,7 +118,7 @@ const FileStatusIndicator = ({
       // If there are recent files, show add files option
       return (
         <Text size="sm" c="dimmed">
-          {t("files.selectFromWorkbench", "Select files from the workbench or ") + " "}
+          {getPlaceholder() + " "}
           <Anchor
             size="sm"
             onClick={() => openFilesModal()}

frontend/src/components/tools/shared/FilesToolStep.tsx

@@ -7,7 +7,7 @@ export interface FilesToolStepProps {
   selectedFiles: StirlingFile[];
   isCollapsed?: boolean;
   onCollapsedClick?: () => void;
-  placeholder?: string;
+  minFiles?: number;
 }
 
 export function createFilesToolStep(
@@ -23,7 +23,7 @@ export function createFilesToolStep(
   }, (
     <FileStatusIndicator
       selectedFiles={props.selectedFiles}
-      placeholder={props.placeholder || t("files.placeholder", "Select a PDF file in the main view to get started")}
+      minFiles={props.minFiles}
     />
   ));
 }

frontend/src/components/tools/shared/ToolStep.tsx

@@ -53,7 +53,7 @@ const renderTooltipTitle = (
           <Text fw={400} size="sm">
             {title}
           </Text>
-          <LocalIcon icon="gpp-maybe-outline-rounded" width="1.25rem" height="1.25rem" style={{ color: 'var(--icon-files-color)' }} />
+          <LocalIcon icon="info-outline-rounded" width="1.25rem" height="1.25rem" style={{ color: 'var(--icon-files-color)' }} />
         </Flex>
       </Tooltip>
     );

frontend/src/components/tools/shared/ToolWorkflowTitle.tsx

@@ -22,7 +22,7 @@ export function ToolWorkflowTitle({ title, tooltip, description }: ToolWorkflowT
       <Text fw={500} size="lg" p="xs">
         {title}
       </Text>
-      {tooltip && <LocalIcon icon="gpp-maybe-outline-rounded" width="1.25rem" height="1.25rem" style={{ color: 'var(--icon-files-color)' }} />}
+      {tooltip && <LocalIcon icon="info-outline-rounded" width="1.25rem" height="1.25rem" style={{ color: 'var(--icon-files-color)' }} />}
     </Flex>
   );
 

frontend/src/components/tools/shared/createToolFlow.tsx

@@ -9,7 +9,7 @@ import { StirlingFile } from '../../../types/fileContext';
 export interface FilesStepConfig {
   selectedFiles: StirlingFile[];
   isCollapsed?: boolean;
-  placeholder?: string;
+  minFiles?: number;
   onCollapsedClick?: () => void;
   isVisible?: boolean;
 }
@@ -76,7 +76,7 @@ export function createToolFlow(config: ToolFlowConfig) {
         {config.files.isVisible !== false && steps.createFilesStep({
           selectedFiles: config.files.selectedFiles,
           isCollapsed: config.files.isCollapsed,
-          placeholder: config.files.placeholder,
+          minFiles: config.files.minFiles,
           onCollapsedClick: config.files.onCollapsedClick
         })}
 

frontend/src/components/tools/split/SplitSettings.tsx

@@ -1,11 +1,11 @@
 import { Stack, TextInput, Select, Checkbox } from '@mantine/core';
 import { useTranslation } from 'react-i18next';
-import { isSplitMode, SPLIT_MODES, SPLIT_TYPES } from '../../../constants/splitConstants';
+import { isSplitMode, isSplitType, SPLIT_MODES, SPLIT_TYPES } from '../../../constants/splitConstants';
 import { SplitParameters } from '../../../hooks/tools/split/useSplitParameters';
 
 export interface SplitSettingsProps {
   parameters: SplitParameters;
-  onParameterChange: (parameter: keyof SplitParameters, value: string | boolean) => void;
+  onParameterChange: <K extends keyof SplitParameters>(key: K, value: SplitParameters[K]) => void;
   disabled?: boolean;
 }
 
@@ -62,7 +62,7 @@ const SplitSettings = ({
       <Select
         label={t("split-by-size-or-count.type.label", "Split Type")}
         value={parameters.splitType}
-        onChange={(v) => v && onParameterChange('splitType', v)}
+        onChange={(v) => isSplitType(v) && onParameterChange('splitType', v)}
         disabled={disabled}
         data={[
           { value: SPLIT_TYPES.SIZE, label: t("split-by-size-or-count.type.size", "By Size") },

frontend/src/components/tooltips/useAdjustPageScaleTips.ts

@@ -0,0 +1,31 @@
+import { useTranslation } from 'react-i18next';
+import { TooltipContent } from '../../types/tips';
+
+export const useAdjustPageScaleTips = (): TooltipContent => {
+  const { t } = useTranslation();
+
+  return {
+    header: {
+      title: t("adjustPageScale.tooltip.header.title", "Page Scale Settings Overview")
+    },
+    tips: [
+      {
+        title: t("adjustPageScale.tooltip.description.title", "Description"),
+        description: t("adjustPageScale.tooltip.description.text", "Adjust the size of PDF content and change the page dimensions.")
+      },
+      {
+        title: t("adjustPageScale.tooltip.scaleFactor.title", "Scale Factor"),
+        description: t("adjustPageScale.tooltip.scaleFactor.text", "Controls how large or small the content appears on the page. Content is scaled and centered - if scaled content is larger than the page size, it may be cropped."),
+        bullets: [
+          t("adjustPageScale.tooltip.scaleFactor.bullet1", "1.0 = Original size"),
+          t("adjustPageScale.tooltip.scaleFactor.bullet2", "0.5 = Half size (50% smaller)"),
+          t("adjustPageScale.tooltip.scaleFactor.bullet3", "2.0 = Double size (200% larger, may crop)")
+        ]
+      },
+      {
+        title: t("adjustPageScale.tooltip.pageSize.title", "Target Page Size"),
+        description: t("adjustPageScale.tooltip.pageSize.text", "Sets the dimensions of the output PDF pages. 'Keep Original Size' maintains current dimensions, while other options resize to standard paper sizes.")
+      }
+    ]
+  };
+};

frontend/src/components/tooltips/useMergeTips.tsx

@@ -0,0 +1,19 @@
+import { useTranslation } from 'react-i18next';
+import { TooltipContent } from '../../types/tips';
+
+export const useMergeTips = (): TooltipContent => {
+  const { t } = useTranslation();
+
+  return {
+    tips: [
+      {
+        title: t('merge.removeDigitalSignature.tooltip.title', 'Remove Digital Signature'),
+        description: t('merge.removeDigitalSignature.tooltip.description', 'Digital signatures will be invalidated when merging files. Check this to remove them from the final merged PDF.')
+      },
+      {
+        title: t('merge.generateTableOfContents.tooltip.title', 'Generate Table of Contents'),
+        description: t('merge.generateTableOfContents.tooltip.description', 'Automatically creates a clickable table of contents in the merged PDF based on the original file names and page numbers.')
+      }
+    ]
+  };
+};

frontend/src/components/tooltips/useRedactTips.ts

@@ -0,0 +1,79 @@
+import { useTranslation } from 'react-i18next';
+import { TooltipContent } from '../../types/tips';
+
+export const useRedactModeTips = (): TooltipContent => {
+  const { t } = useTranslation();
+
+  return {
+    header: {
+      title: t("redact.tooltip.mode.header.title", "Redaction Method")
+    },
+    tips: [
+      {
+        title: t("redact.tooltip.mode.automatic.title", "Automatic Redaction"),
+        description: t("redact.tooltip.mode.automatic.text", "Automatically finds and redacts specified text throughout the document. Perfect for removing consistent sensitive information like names, SSNs, or confidential markers.")
+      },
+      {
+        title: t("redact.tooltip.mode.manual.title", "Manual Redaction"),
+        description: t("redact.tooltip.mode.manual.text", "Click and drag to manually select specific areas to redact. Gives you precise control over what gets redacted. (Coming soon)")
+      }
+    ]
+  };
+};
+
+export const useRedactWordsTips = (): TooltipContent => {
+  const { t } = useTranslation();
+
+  return {
+    header: {
+      title: t("redact.tooltip.words.header.title", "Words to Redact")
+    },
+    tips: [
+      {
+        title: t("redact.tooltip.words.description.title", "Text Matching"),
+        description: t("redact.tooltip.words.description.text", "Enter words or phrases to find and redact in your document. Each word will be searched for separately."),
+        bullets: [
+          t("redact.tooltip.words.bullet1", "Add one word at a time"),
+          t("redact.tooltip.words.bullet2", "Press Enter or click 'Add Another' to add"),
+          t("redact.tooltip.words.bullet3", "Click × to remove words")
+        ]
+      },
+      {
+        title: t("redact.tooltip.words.examples.title", "Common Examples"),
+        description: t("redact.tooltip.words.examples.text", "Typical words to redact include: bank details, email addresses, or specific names.")
+      }
+    ]
+  };
+};
+
+export const useRedactAdvancedTips = (): TooltipContent => {
+  const { t } = useTranslation();
+
+  return {
+    header: {
+      title: t("redact.tooltip.advanced.header.title", "Advanced Redaction Settings")
+    },
+    tips: [
+      {
+        title: t("redact.tooltip.advanced.color.title", "Box Colour & Padding"),
+        description: t("redact.tooltip.advanced.color.text", "Customise the appearance of redaction boxes. Black is standard, but you can choose any colour. Padding adds extra space around the found text."),
+      },
+      {
+        title: t("redact.tooltip.advanced.regex.title", "Use Regex"),
+        description: t("redact.tooltip.advanced.regex.text", "Enable regular expressions for advanced pattern matching. Useful for finding phone numbers, emails, or complex patterns."),
+        bullets: [
+          t("redact.tooltip.advanced.regex.bullet1", "Example: \\d{4}-\\d{2}-\\d{2} to match any dates in YYYY-MM-DD format"),
+          t("redact.tooltip.advanced.regex.bullet2", "Use with caution - test thoroughly")
+        ]
+      },
+      {
+        title: t("redact.tooltip.advanced.wholeWord.title", "Whole Word Search"),
+        description: t("redact.tooltip.advanced.wholeWord.text", "Only match complete words, not partial matches. 'John' won't match 'Johnson' when enabled.")
+      },
+      {
+        title: t("redact.tooltip.advanced.convert.title", "Convert to PDF-Image"),
+        description: t("redact.tooltip.advanced.convert.text", "Converts the PDF to an image-based PDF after redaction. This ensures text behind redaction boxes is completely removed and unrecoverable.")
+      }
+    ]
+  };
+};

frontend/src/components/viewer/EmbedPdfViewer.tsx

@@ -6,9 +6,11 @@ import CloseIcon from '@mui/icons-material/Close';
 
 import { useFileState } from "../../contexts/FileContext";
 import { useFileWithUrl } from "../../hooks/useFileWithUrl";
+import { ViewerProvider, useViewer } from "../../contexts/ViewerContext";
 import { LocalEmbedPDF } from './LocalEmbedPDF';
 import { PdfViewerToolbar } from './PdfViewerToolbar';
 import { ThumbnailSidebar } from './ThumbnailSidebar';
+import '../../types/embedPdf';
 
 export interface EmbedPdfViewerProps {
   sidebarsVisible: boolean;
@@ -17,7 +19,7 @@ export interface EmbedPdfViewerProps {
   previewFile?: File | null;
 }
 
-const EmbedPdfViewer = ({
+const EmbedPdfViewerContent = ({
   sidebarsVisible,
   setSidebarsVisible,
   onClose,
@@ -28,7 +30,7 @@ const EmbedPdfViewer = ({
   const { colorScheme } = useMantineColorScheme();
   const viewerRef = React.useRef<HTMLDivElement>(null);
   const [isViewerHovered, setIsViewerHovered] = React.useState(false);
-  const [isThumbnailSidebarVisible, setIsThumbnailSidebarVisible] = React.useState(false);
+  const { isThumbnailSidebarVisible, toggleThumbnailSidebar } = useViewer();
 
   // Get current file from FileContext
   const { selectors } = useFileState();
@@ -68,7 +70,7 @@ const EmbedPdfViewer = ({
         event.preventDefault();
         event.stopPropagation();
 
-        const zoomAPI = (window as any).embedPdfZoom;
+        const zoomAPI = window.embedPdfZoom;
         if (zoomAPI) {
           if (event.deltaY < 0) {
             // Scroll up - zoom in
@@ -97,7 +99,7 @@ const EmbedPdfViewer = ({
 
       // Check if Ctrl (Windows/Linux) or Cmd (Mac) is pressed
       if (event.ctrlKey || event.metaKey) {
-        const zoomAPI = (window as any).embedPdfZoom;
+        const zoomAPI = window.embedPdfZoom;
         if (zoomAPI) {
           if (event.key === '=' || event.key === '+') {
             // Ctrl+= or Ctrl++ for zoom in
@@ -120,14 +122,12 @@ const EmbedPdfViewer = ({
 
   // Expose toggle functions globally for right rail buttons
   React.useEffect(() => {
-    (window as any).toggleThumbnailSidebar = () => {
-      setIsThumbnailSidebarVisible(prev => !prev);
-    };
+    window.toggleThumbnailSidebar = toggleThumbnailSidebar;
     
     return () => {
-      delete (window as any).toggleThumbnailSidebar;
+      delete window.toggleThumbnailSidebar;
     };
-  }, []);
+  }, [toggleThumbnailSidebar]);
 
   return (
     <Box 
@@ -212,7 +212,7 @@ const EmbedPdfViewer = ({
               }}
               dualPage={false}
               onDualPageToggle={() => {
-                (window as any).embedPdfSpread?.toggleSpreadMode();
+                window.embedPdfSpread?.toggleSpreadMode();
               }}
               currentZoom={100}
             />
@@ -224,11 +224,19 @@ const EmbedPdfViewer = ({
       {/* Thumbnail Sidebar */}
       <ThumbnailSidebar
         visible={isThumbnailSidebarVisible}
-        onToggle={() => setIsThumbnailSidebarVisible(prev => !prev)}
+        onToggle={toggleThumbnailSidebar}
         colorScheme={colorScheme}
       />
     </Box>
   );
 };
 
+const EmbedPdfViewer = (props: EmbedPdfViewerProps) => {
+  return (
+    <ViewerProvider>
+      <EmbedPdfViewerContent {...props} />
+    </ViewerProvider>
+  );
+};
+
 export default EmbedPdfViewer;

frontend/src/components/viewer/OldViewer.tsx

@@ -1,687 +0,0 @@
-import React, { useEffect, useState, useRef, useCallback } from "react";
-import { Paper, Stack, Text, ScrollArea, Center, Button, Group, NumberInput, useMantineTheme, ActionIcon, Box, Tabs } from "@mantine/core";
-import { useTranslation } from "react-i18next";
-import { pdfWorkerManager } from "../../services/pdfWorkerManager";
-import ArrowBackIosNewIcon from "@mui/icons-material/ArrowBackIosNew";
-import ArrowForwardIosIcon from "@mui/icons-material/ArrowForwardIos";
-import FirstPageIcon from "@mui/icons-material/FirstPage";
-import LastPageIcon from "@mui/icons-material/LastPage";
-import ViewWeekIcon from "@mui/icons-material/ViewWeek"; // for dual page (book)
-import DescriptionIcon from "@mui/icons-material/Description"; // for single page
-import CloseIcon from "@mui/icons-material/Close";
-import { fileStorage } from "../../services/fileStorage";
-import SkeletonLoader from '../shared/SkeletonLoader';
-import { useFileState } from "../../contexts/FileContext";
-import { useFileWithUrl } from "../../hooks/useFileWithUrl";
-import { isFileObject } from "../../types/fileContext";
-import { FileId } from "../../types/file";
-
-
-// Lazy loading page image component
-interface LazyPageImageProps {
-  pageIndex: number;
-  zoom: number;
-  theme: any;
-  isFirst: boolean;
-  renderPage: (pageIndex: number) => Promise<string | null>;
-  pageImages: (string | null)[];
-  setPageRef: (index: number, ref: HTMLImageElement | null) => void;
-}
-
-const LazyPageImage = ({
-  pageIndex, zoom, theme, isFirst, renderPage, pageImages, setPageRef
-}: LazyPageImageProps) => {
-  const [isVisible, setIsVisible] = useState(false);
-  const [imageUrl, setImageUrl] = useState<string | null>(null);
-  const imgRef = useRef<HTMLImageElement>(null);
-
-  useEffect(() => {
-    const observer = new IntersectionObserver(
-      (entries) => {
-        entries.forEach((entry) => {
-          if (entry.isIntersecting && !imageUrl) {
-            setIsVisible(true);
-          }
-        });
-      },
-      {
-        rootMargin: '200px', // Start loading 200px before visible
-        threshold: 0.1
-      }
-    );
-
-    if (imgRef.current) {
-      observer.observe(imgRef.current);
-    }
-
-    return () => observer.disconnect();
-  }, [imageUrl]);
-
-  // Update local state when pageImages changes (from preloading)
-  useEffect(() => {
-    if (pageImages[pageIndex]) {
-      setImageUrl(pageImages[pageIndex]);
-    }
-  }, [pageImages, pageIndex]);
-
-  useEffect(() => {
-    if (isVisible && !imageUrl) {
-      renderPage(pageIndex).then((url) => {
-        if (url) setImageUrl(url);
-      });
-    }
-  }, [isVisible, imageUrl, pageIndex, renderPage]);
-
-  useEffect(() => {
-    if (imgRef.current) {
-      setPageRef(pageIndex, imgRef.current);
-    }
-  }, [pageIndex, setPageRef]);
-
-  if (imageUrl) {
-    return (
-      <img
-        ref={imgRef}
-        src={imageUrl}
-        alt={`Page ${pageIndex + 1}`}
-        style={{
-          width: `${100 * zoom}%`,
-          maxWidth: 700 * zoom,
-          boxShadow: "0 2px 8px rgba(0,0,0,0.08)",
-          borderRadius: 8,
-          marginTop: isFirst ? theme.spacing.xl : 0,
-        }}
-      />
-    );
-  }
-
-  // Placeholder while loading
-  return (
-    <div
-      ref={imgRef}
-      style={{
-        width: `${100 * zoom}%`,
-        maxWidth: 700 * zoom,
-        height: 800 * zoom, // Estimated height
-        backgroundColor: '#f5f5f5',
-        display: 'flex',
-        alignItems: 'center',
-        justifyContent: 'center',
-        borderRadius: 8,
-        marginTop: isFirst ? theme.spacing.xl : 0,
-        border: '1px dashed #ccc'
-      }}
-    >
-      {isVisible ? (
-        <div style={{ textAlign: 'center' }}>
-          <div style={{
-            width: 20,
-            height: 20,
-            border: '2px solid #ddd',
-            borderTop: '2px solid #666',
-            borderRadius: '50%',
-            animation: 'spin 1s linear infinite',
-            margin: '0 auto 8px'
-          }} />
-          <Text size="sm" c="dimmed">Loading page {pageIndex + 1}...</Text>
-        </div>
-      ) : (
-        <Text size="sm" c="dimmed">Page {pageIndex + 1}</Text>
-      )}
-    </div>
-  );
-};
-
-export interface ViewerProps {
-  sidebarsVisible: boolean;
-  setSidebarsVisible: (v: boolean) => void;
-  onClose?: () => void;
-  previewFile: File | null; // For preview mode - bypasses context
-}
-
-const Viewer = ({
-  onClose,
-  previewFile,
-}: ViewerProps) => {
-  const { t } = useTranslation();
-  const theme = useMantineTheme();
-
-  // Get current file from FileContext
-  const { selectors } = useFileState();
-
-  const activeFiles = selectors.getFiles();
-
-  // Tab management for multiple files
-  const [activeTab, setActiveTab] = useState<string>("0");
-
-  // Reset PDF state when switching tabs
-  const handleTabChange = (newTab: string) => {
-    setActiveTab(newTab);
-    setNumPages(0);
-    setPageImages([]);
-    setCurrentPage(null);
-    setLoading(true);
-  };
-  const [numPages, setNumPages] = useState<number>(0);
-  const [pageImages, setPageImages] = useState<string[]>([]);
-  const [loading, setLoading] = useState<boolean>(false);
-  const [currentPage, setCurrentPage] = useState<number | null>(null);
-  const [dualPage, setDualPage] = useState(false);
-  const [zoom, setZoom] = useState(1); // 1 = 100%
-  const pageRefs = useRef<(HTMLImageElement | null)[]>([]);
-
-  // Memoize setPageRef to prevent infinite re-renders
-  const setPageRef = useCallback((index: number, ref: HTMLImageElement | null) => {
-    pageRefs.current[index] = ref;
-  }, []);
-
-  // Get files with URLs for tabs - we'll need to create these individually
-  const file0WithUrl = useFileWithUrl(activeFiles[0]);
-  const file1WithUrl = useFileWithUrl(activeFiles[1]);
-  const file2WithUrl = useFileWithUrl(activeFiles[2]);
-  const file3WithUrl = useFileWithUrl(activeFiles[3]);
-  const file4WithUrl = useFileWithUrl(activeFiles[4]);
-
-  const filesWithUrls = React.useMemo(() => {
-    return [file0WithUrl, file1WithUrl, file2WithUrl, file3WithUrl, file4WithUrl]
-      .slice(0, activeFiles.length)
-      .filter(Boolean);
-  }, [file0WithUrl, file1WithUrl, file2WithUrl, file3WithUrl, file4WithUrl, activeFiles.length]);
-
-  // Use preview file if available, otherwise use active tab file
-  const effectiveFile = React.useMemo(() => {
-    if (previewFile) {
-      // Validate the preview file
-      if (!isFileObject(previewFile)) {
-        return null;
-      }
-
-      if (previewFile.size === 0) {
-        return null;
-      }
-
-      return { file: previewFile, url: null };
-    } else {
-      // Use the file from the active tab
-      const tabIndex = parseInt(activeTab);
-      return filesWithUrls[tabIndex] || null;
-    }
-  }, [previewFile, filesWithUrls, activeTab]);
-
-  const scrollAreaRef = useRef<HTMLDivElement>(null);
-  const pdfDocRef = useRef<any>(null);
-  const renderingPagesRef = useRef<Set<number>>(new Set());
-  const currentArrayBufferRef = useRef<ArrayBuffer | null>(null);
-  const preloadingRef = useRef<boolean>(false);
-
-  // Function to render a specific page on-demand
-  const renderPage = async (pageIndex: number): Promise<string | null> => {
-    if (!pdfDocRef.current || renderingPagesRef.current.has(pageIndex)) {
-      return null;
-    }
-
-    const pageNum = pageIndex + 1;
-    if (pageImages[pageIndex]) {
-      return pageImages[pageIndex]; // Already rendered
-    }
-
-    renderingPagesRef.current.add(pageIndex);
-
-    try {
-      const page = await pdfDocRef.current.getPage(pageNum);
-      const viewport = page.getViewport({ scale: 1.2 });
-      const canvas = document.createElement("canvas");
-      canvas.width = viewport.width;
-      canvas.height = viewport.height;
-      const ctx = canvas.getContext("2d");
-
-      if (ctx) {
-        await page.render({ canvasContext: ctx, viewport }).promise;
-        const dataUrl = canvas.toDataURL();
-
-        // Update the pageImages array
-        setPageImages(prev => {
-          const newImages = [...prev];
-          newImages[pageIndex] = dataUrl;
-          return newImages;
-        });
-
-        renderingPagesRef.current.delete(pageIndex);
-        return dataUrl;
-      }
-    } catch (error) {
-      console.error(`Failed to render page ${pageNum}:`, error);
-    }
-
-    renderingPagesRef.current.delete(pageIndex);
-    return null;
-  };
-
-  // Progressive preloading function
-  const startProgressivePreload = async () => {
-    if (!pdfDocRef.current || preloadingRef.current || numPages === 0) return;
-
-    preloadingRef.current = true;
-
-    // Start with first few pages for immediate viewing
-    const priorityPages = [0, 1, 2, 3, 4]; // First 5 pages
-
-    // Render priority pages first
-    for (const pageIndex of priorityPages) {
-      if (pageIndex < numPages && !pageImages[pageIndex]) {
-        await renderPage(pageIndex);
-        // Small delay to allow UI to update
-        await new Promise(resolve => setTimeout(resolve, 50));
-      }
-    }
-
-    // Then render remaining pages in background
-    for (let pageIndex = 5; pageIndex < numPages; pageIndex++) {
-      if (!pageImages[pageIndex]) {
-        await renderPage(pageIndex);
-        // Longer delay for background loading to not block UI
-        await new Promise(resolve => setTimeout(resolve, 100));
-      }
-    }
-
-    preloadingRef.current = false;
-  };
-
-  // Initialize current page when PDF loads
-  useEffect(() => {
-    if (numPages > 0 && !currentPage) {
-      setCurrentPage(1);
-    }
-  }, [numPages, currentPage]);
-
-  // Function to scroll to a specific page
-  const scrollToPage = (pageNumber: number) => {
-    const el = pageRefs.current[pageNumber - 1];
-    const scrollArea = scrollAreaRef.current;
-
-    if (el && scrollArea) {
-      const scrollAreaRect = scrollArea.getBoundingClientRect();
-      const elRect = el.getBoundingClientRect();
-      const currentScrollTop = scrollArea.scrollTop;
-
-      // Position page near top of viewport with some padding
-      const targetScrollTop = currentScrollTop + (elRect.top - scrollAreaRect.top) - 20;
-
-      scrollArea.scrollTo({
-        top: targetScrollTop,
-        behavior: "smooth"
-      });
-    }
-  };
-
-  // Throttled scroll handler to prevent jerky updates
-  const handleScrollThrottled = useCallback(() => {
-    const scrollArea = scrollAreaRef.current;
-    if (!scrollArea || !pageRefs.current.length) return;
-
-    const areaRect = scrollArea.getBoundingClientRect();
-    const viewportCenter = areaRect.top + areaRect.height / 2;
-    let closestIdx = 0;
-    let minDist = Infinity;
-
-    pageRefs.current.forEach((img, idx) => {
-      if (img) {
-        const imgRect = img.getBoundingClientRect();
-        const imgCenter = imgRect.top + imgRect.height / 2;
-        const dist = Math.abs(imgCenter - viewportCenter);
-        if (dist < minDist) {
-          minDist = dist;
-          closestIdx = idx;
-        }
-      }
-    });
-
-    // Update page number display only if changed
-    if (currentPage !== closestIdx + 1) {
-      setCurrentPage(closestIdx + 1);
-    }
-  }, [currentPage]);
-
-  // Throttle scroll events to reduce jerkiness
-  const handleScroll = useCallback(() => {
-    if (window.requestAnimationFrame) {
-      window.requestAnimationFrame(handleScrollThrottled);
-    } else {
-      handleScrollThrottled();
-    }
-  }, [handleScrollThrottled]);
-
-  useEffect(() => {
-    let cancelled = false;
-    async function loadPdfInfo() {
-      if (!effectiveFile) {
-        setNumPages(0);
-        setPageImages([]);
-        return;
-      }
-      setLoading(true);
-      try {
-        let pdfData;
-
-        // For preview files, use ArrayBuffer directly to avoid blob URL issues
-        if (previewFile && effectiveFile.file === previewFile) {
-          const arrayBuffer = await previewFile.arrayBuffer();
-          pdfData = { data: arrayBuffer };
-        }
-        // Handle special IndexedDB URLs for large files
-        else if (effectiveFile.url?.startsWith('indexeddb:')) {
-          const fileId = effectiveFile.url.replace('indexeddb:', '') as FileId /* FIX ME: Not sure this is right - at least probably not the right place for this logic */;
-
-          // Get data directly from IndexedDB
-          const arrayBuffer = await fileStorage.getFileData(fileId);
-          if (!arrayBuffer) {
-            throw new Error('File not found in IndexedDB - may have been purged by browser');
-          }
-
-          // Store reference for cleanup
-          currentArrayBufferRef.current = arrayBuffer;
-          pdfData = { data: arrayBuffer };
-        } else if (effectiveFile.url) {
-          // Standard blob URL or regular URL
-          pdfData = effectiveFile.url;
-        } else {
-          throw new Error('No valid PDF source available');
-        }
-
-        const pdf = await pdfWorkerManager.createDocument(pdfData);
-        pdfDocRef.current = pdf;
-        setNumPages(pdf.numPages);
-        if (!cancelled) {
-          setPageImages(new Array(pdf.numPages).fill(null));
-          // Start progressive preloading after a short delay
-          setTimeout(() => startProgressivePreload(), 100);
-        }
-      } catch {
-        if (!cancelled) {
-          setPageImages([]);
-          setNumPages(0);
-        }
-      }
-      if (!cancelled) setLoading(false);
-    }
-    loadPdfInfo();
-    return () => {
-      cancelled = true;
-      // Stop any ongoing preloading
-      preloadingRef.current = false;
-      // Cleanup PDF document using worker manager
-      if (pdfDocRef.current) {
-        pdfWorkerManager.destroyDocument(pdfDocRef.current);
-        pdfDocRef.current = null;
-      }
-      // Cleanup ArrayBuffer reference to help garbage collection
-      currentArrayBufferRef.current = null;
-    };
-  }, [effectiveFile, previewFile]);
-
-  useEffect(() => {
-    const viewport = scrollAreaRef.current;
-    if (!viewport) return;
-    const handler = () => {
-      handleScroll();
-    };
-    viewport.addEventListener("scroll", handler);
-    return () => viewport.removeEventListener("scroll", handler);
-  }, [pageImages]);
-
-  return (
-    <Box style={{ position: 'relative', height: '100%', display: 'flex', flexDirection: 'column' }}>
-      {/* Close Button - Only show in preview mode */}
-      {onClose && previewFile && (
-        <ActionIcon
-          variant="filled"
-          color="gray"
-          size="lg"
-          style={{
-            position: 'absolute',
-            top: '1rem',
-            right: '1rem',
-            zIndex: 1000,
-            borderRadius: '50%',
-          }}
-          onClick={onClose}
-        >
-          <CloseIcon />
-        </ActionIcon>
-      )}
-
-      {!effectiveFile ? (
-        <Center style={{ flex: 1 }}>
-          <Text c="red">Error: No file provided to viewer</Text>
-        </Center>
-      ) : (
-        <>
-          {/* Tabs for multiple files */}
-          {activeFiles.length > 1 && !previewFile && (
-            <Box
-              style={{
-                borderBottom: '1px solid var(--mantine-color-gray-3)',
-                backgroundColor: 'var(--mantine-color-body)',
-                position: 'relative',
-                zIndex: 100,
-                marginTop: '60px' // Push tabs below TopControls
-              }}
-            >
-              <Tabs value={activeTab} onChange={(value) => handleTabChange(value || "0")}>
-                <Tabs.List>
-                  {activeFiles.map((file: any, index: number) => (
-                    <Tabs.Tab key={index} value={index.toString()}>
-                      {file.name.length > 20 ? `${file.name.substring(0, 20)}...` : file.name}
-                    </Tabs.Tab>
-                  ))}
-                </Tabs.List>
-              </Tabs>
-            </Box>
-          )}
-
-          {loading ? (
-            <div style={{ flex: 1, padding: '1rem' }}>
-              <SkeletonLoader type="viewer" />
-            </div>
-          ) : (
-        <ScrollArea
-          style={{ flex: 1, position: "relative"}}
-          viewportRef={scrollAreaRef}
-        >
-          <Stack gap="xl" align="center" >
-            {numPages === 0 && (
-              <Text color="dimmed">{t("viewer.noPagesToDisplay", "No pages to display.")}</Text>
-            )}
-            {dualPage
-              ? Array.from({ length: Math.ceil(numPages / 2) }).map((_, i) => (
-                  <Group key={i} gap="md" align="flex-start" style={{ width: "100%", justifyContent: "center" }}>
-                    <LazyPageImage
-                      pageIndex={i * 2}
-                      zoom={zoom}
-                      theme={theme}
-                      isFirst={i === 0}
-                      renderPage={renderPage}
-                      pageImages={pageImages}
-                      setPageRef={setPageRef}
-                    />
-                    {i * 2 + 1 < numPages && (
-                      <LazyPageImage
-                        pageIndex={i * 2 + 1}
-                        zoom={zoom}
-                        theme={theme}
-                        isFirst={i === 0}
-                        renderPage={renderPage}
-                        pageImages={pageImages}
-                        setPageRef={setPageRef}
-                      />
-                    )}
-                  </Group>
-                ))
-              : Array.from({ length: numPages }).map((_, idx) => (
-                  <LazyPageImage
-                    key={idx}
-                    pageIndex={idx}
-                    zoom={zoom}
-                    theme={theme}
-                    isFirst={idx === 0}
-                    renderPage={renderPage}
-                    pageImages={pageImages}
-                    setPageRef={setPageRef}
-                  />
-                ))}
-          </Stack>
-          {/* Navigation bar overlays the scroll area */}
-          <div
-            style={{
-              position: "absolute",
-              left: 0,
-              right: 0,
-              bottom: 0,
-              zIndex: 50,
-              display: "flex",
-              justifyContent: "center",
-              pointerEvents: "none",
-              background: "transparent",
-
-            }}
-          >
-            <Paper
-              radius="xl xl 0 0"
-              shadow="sm"
-              p={12}
-              pb={12}
-              style={{
-                display: "flex",
-                alignItems: "center",
-                gap: 10,
-                borderTopLeftRadius: 16,
-                borderTopRightRadius: 16,
-                borderBottomLeftRadius: 0,
-                borderBottomRightRadius: 0,
-                boxShadow: "0 -2px 8px rgba(0,0,0,0.04)",
-                pointerEvents: "auto",
-                minWidth: 420,
-                maxWidth: 700,
-                flexWrap: "wrap",
-              }}
-            >
-              <Button
-                variant="subtle"
-                color="blue"
-                size="md"
-                px={8}
-                radius="xl"
-                onClick={() => {
-                  scrollToPage(1);
-                }}
-                disabled={currentPage === 1}
-                style={{ minWidth: 36 }}
-              >
-                <FirstPageIcon fontSize="small" />
-              </Button>
-              <Button
-                variant="subtle"
-                color="blue"
-                size="md"
-                px={8}
-                radius="xl"
-                onClick={() => {
-                  const prevPage = Math.max(1, (currentPage || 1) - 1);
-                  scrollToPage(prevPage);
-                }}
-                disabled={currentPage === 1}
-                style={{ minWidth: 36 }}
-              >
-                <ArrowBackIosNewIcon fontSize="small" />
-              </Button>
-              <NumberInput
-                value={currentPage || 1}
-                onChange={value => {
-                  const page = Number(value);
-                  if (!isNaN(page) && page >= 1 && page <= numPages) {
-                    scrollToPage(page);
-                  }
-                }}
-                min={1}
-                max={numPages}
-                hideControls
-                styles={{
-                  input: { width: 48, textAlign: "center", fontWeight: 500, fontSize: 16},
-                }}
-              />
-              <span style={{ fontWeight: 500, fontSize: 16 }}>
-                / {numPages}
-              </span>
-              <Button
-                variant="subtle"
-                color="blue"
-                size="md"
-                px={8}
-                radius="xl"
-                onClick={() => {
-                  const nextPage = Math.min(numPages, (currentPage || 1) + 1);
-                  scrollToPage(nextPage);
-                }}
-                disabled={currentPage === numPages}
-                style={{ minWidth: 36 }}
-              >
-                <ArrowForwardIosIcon fontSize="small" />
-              </Button>
-              <Button
-                variant="subtle"
-                color="blue"
-                size="md"
-                px={8}
-                radius="xl"
-                onClick={() => {
-                  scrollToPage(numPages);
-                }}
-                disabled={currentPage === numPages}
-                style={{ minWidth: 36 }}
-              >
-                <LastPageIcon fontSize="small" />
-              </Button>
-              <Button
-                variant={dualPage ? "filled" : "light"}
-                color="blue"
-                size="md"
-                radius="xl"
-                onClick={() => setDualPage(v => !v)}
-                style={{ minWidth: 36 }}
-                title={dualPage ? t("viewer.singlePageView", "Single Page View") : t("viewer.dualPageView", "Dual Page View")}
-              >
-                {dualPage ? <DescriptionIcon fontSize="small" /> : <ViewWeekIcon fontSize="small" />}
-              </Button>
-              <Group gap={4} align="center" style={{ marginLeft: 16 }}>
-                <Button
-                  variant="subtle"
-                  color="blue"
-                  size="md"
-                  radius="xl"
-                  onClick={() => setZoom(z => Math.max(0.1, z - 0.1))}
-                  style={{ minWidth: 32, padding: 0 }}
-                  title={t("viewer.zoomOut", "Zoom out")}
-                >−</Button>
-                <span style={{ minWidth: 40, textAlign: "center" }}>{Math.round(zoom * 100)}%</span>
-                <Button
-                  variant="subtle"
-                  color="blue"
-                  size="md"
-                  radius="xl"
-                  onClick={() => setZoom(z => Math.min(5, z + 0.1))}
-                  style={{ minWidth: 32, padding: 0 }}
-                  title={t("viewer.zoomIn", "Zoom in")}
-                >+</Button>
-              </Group>
-            </Paper>
-          </div>
-        </ScrollArea>
-          )}
-        </>
-      )}
-
-    </Box>
-  );
-};
-
-export default Viewer;

frontend/src/components/viewer/PdfViewerToolbar.tsx

@@ -7,6 +7,7 @@ import ArrowForwardIosIcon from '@mui/icons-material/ArrowForwardIos';
 import LastPageIcon from '@mui/icons-material/LastPage';
 import DescriptionIcon from '@mui/icons-material/Description';
 import ViewWeekIcon from '@mui/icons-material/ViewWeek';
+import '../../types/embedPdf';
 
 interface PdfViewerToolbarProps {
   // Page navigation props (placeholders for now)
@@ -41,23 +42,23 @@ export function PdfViewerToolbar({
   useEffect(() => {
     const updateState = () => {
       // Update zoom
-      if ((window as any).embedPdfZoom) {
-        const zoomPercent = (window as any).embedPdfZoom.zoomPercent || currentZoom;
+      if (window.embedPdfZoom) {
+        const zoomPercent = window.embedPdfZoom.zoomPercent || currentZoom;
         setDynamicZoom(zoomPercent);
       }
       
       // Update scroll/page state
-      if ((window as any).embedPdfScroll) {
-        const currentPageNum = (window as any).embedPdfScroll.currentPage || currentPage;
-        const totalPagesNum = (window as any).embedPdfScroll.totalPages || totalPages;
+      if (window.embedPdfScroll) {
+        const currentPageNum = window.embedPdfScroll.currentPage || currentPage;
+        const totalPagesNum = window.embedPdfScroll.totalPages || totalPages;
         setDynamicPage(currentPageNum);
         setDynamicTotalPages(totalPagesNum);
         setPageInput(currentPageNum);
       }
       
       // Update pan mode state
-      if ((window as any).embedPdfPan) {
-        const panState = (window as any).embedPdfPan.isPanning || false;
+      if (window.embedPdfPan) {
+        const panState = window.embedPdfPan.isPanning || false;
         setIsPanning(panState);
       }
     };
@@ -72,20 +73,20 @@ export function PdfViewerToolbar({
   }, [currentZoom, currentPage, totalPages]);
 
   const handleZoomOut = () => {
-    if ((window as any).embedPdfZoom) {
-      (window as any).embedPdfZoom.zoomOut();
+    if (window.embedPdfZoom) {
+      window.embedPdfZoom.zoomOut();
     }
   };
 
   const handleZoomIn = () => {
-    if ((window as any).embedPdfZoom) {
-      (window as any).embedPdfZoom.zoomIn();
+    if (window.embedPdfZoom) {
+      window.embedPdfZoom.zoomIn();
     }
   };
 
   const handlePageNavigation = (page: number) => {
-    if ((window as any).embedPdfScroll) {
-      (window as any).embedPdfScroll.scrollToPage(page);
+    if (window.embedPdfScroll) {
+      window.embedPdfScroll.scrollToPage(page);
     } else if (onPageChange) {
       onPageChange(page);
     }
@@ -93,32 +94,32 @@ export function PdfViewerToolbar({
   };
 
   const handleFirstPage = () => {
-    if ((window as any).embedPdfScroll) {
-      (window as any).embedPdfScroll.scrollToFirstPage();
+    if (window.embedPdfScroll) {
+      window.embedPdfScroll.scrollToFirstPage();
     } else {
       handlePageNavigation(1);
     }
   };
 
   const handlePreviousPage = () => {
-    if ((window as any).embedPdfScroll) {
-      (window as any).embedPdfScroll.scrollToPreviousPage();
+    if (window.embedPdfScroll) {
+      window.embedPdfScroll.scrollToPreviousPage();
     } else {
       handlePageNavigation(Math.max(1, dynamicPage - 1));
     }
   };
 
   const handleNextPage = () => {
-    if ((window as any).embedPdfScroll) {
-      (window as any).embedPdfScroll.scrollToNextPage();
+    if (window.embedPdfScroll) {
+      window.embedPdfScroll.scrollToNextPage();
     } else {
       handlePageNavigation(Math.min(dynamicTotalPages, dynamicPage + 1));
     }
   };
 
   const handleLastPage = () => {
-    if ((window as any).embedPdfScroll) {
-      (window as any).embedPdfScroll.scrollToLastPage();
+    if (window.embedPdfScroll) {
+      window.embedPdfScroll.scrollToLastPage();
     } else {
       handlePageNavigation(dynamicTotalPages);
     }

frontend/src/components/viewer/ThumbnailSidebar.tsx

@@ -1,6 +1,7 @@
 import React, { useState, useEffect } from 'react';
 import { Box, ScrollArea, ActionIcon, Tooltip } from '@mantine/core';
 import { LocalIcon } from '../shared/LocalIcon';
+import '../../types/embedPdf';
 
 interface ThumbnailSidebarProps {
   visible: boolean;
@@ -18,7 +19,7 @@ export function ThumbnailSidebar({ visible, onToggle, colorScheme }: ThumbnailSi
 
   // Get total pages from scroll API
   useEffect(() => {
-    const scrollAPI = (window as any).embedPdfScroll;
+    const scrollAPI = window.embedPdfScroll;
     if (scrollAPI && scrollAPI.totalPages) {
       setTotalPages(scrollAPI.totalPages);
     }
@@ -28,7 +29,7 @@ export function ThumbnailSidebar({ visible, onToggle, colorScheme }: ThumbnailSi
   useEffect(() => {
     if (!visible || totalPages === 0) return;
 
-    const thumbnailAPI = (window as any).embedPdfThumbnail?.thumbnailAPI;
+    const thumbnailAPI = window.embedPdfThumbnail?.thumbnailAPI;
     console.log('📄 ThumbnailSidebar useEffect triggered:', {
       visible,
       thumbnailAPI: !!thumbnailAPI,
@@ -88,14 +89,14 @@ export function ThumbnailSidebar({ visible, onToggle, colorScheme }: ThumbnailSi
         }
       });
     };
-  }, [visible, totalPages, thumbnails]);
+  }, [visible, totalPages]);
 
   const handlePageClick = (pageIndex: number) => {
     const pageNumber = pageIndex + 1; // Convert to 1-based
     setSelectedPage(pageNumber);
     
     // Use scroll API to navigate to page
-    const scrollAPI = (window as any).embedPdfScroll;
+    const scrollAPI = window.embedPdfScroll;
     if (scrollAPI && scrollAPI.scrollToPage) {
       scrollAPI.scrollToPage(pageNumber);
     }

frontend/src/contexts/ViewerContext.tsx

@@ -0,0 +1,46 @@
+import React, { createContext, useContext, useState, ReactNode } from 'react';
+
+interface ViewerContextType {
+  // Thumbnail sidebar state
+  isThumbnailSidebarVisible: boolean;
+  toggleThumbnailSidebar: () => void;
+  setThumbnailSidebarVisible: (visible: boolean) => void;
+}
+
+const ViewerContext = createContext<ViewerContextType | null>(null);
+
+interface ViewerProviderProps {
+  children: ReactNode;
+}
+
+export const ViewerProvider: React.FC<ViewerProviderProps> = ({ children }) => {
+  const [isThumbnailSidebarVisible, setIsThumbnailSidebarVisible] = useState(false);
+
+  const toggleThumbnailSidebar = () => {
+    setIsThumbnailSidebarVisible(prev => !prev);
+  };
+
+  const setThumbnailSidebarVisible = (visible: boolean) => {
+    setIsThumbnailSidebarVisible(visible);
+  };
+
+  const value: ViewerContextType = {
+    isThumbnailSidebarVisible,
+    toggleThumbnailSidebar,
+    setThumbnailSidebarVisible,
+  };
+
+  return (
+    <ViewerContext.Provider value={value}>
+      {children}
+    </ViewerContext.Provider>
+  );
+};
+
+export const useViewer = (): ViewerContextType => {
+  const context = useContext(ViewerContext);
+  if (!context) {
+    throw new Error('useViewer must be used within a ViewerProvider');
+  }
+  return context;
+};

frontend/src/contexts/file/FileReducer.ts

@@ -145,12 +145,17 @@ export function fileContextReducer(state: FileContextState, action: FileContextA
 
       // Validate that all IDs exist in current state
       const validIds = orderedFileIds.filter(id => state.files.byId[id]);
-
+      // Reorder selected files by passed order
+      const selectedFileIds = orderedFileIds.filter(id => state.ui.selectedFileIds.includes(id));
       return {
         ...state,
         files: {
           ...state.files,
           ids: validIds
+        },
+        ui: {
+          ...state.ui,
+          selectedFileIds,
         }
       };
     }
@@ -234,11 +239,14 @@ export function fileContextReducer(state: FileContextState, action: FileContextA
 
     case 'CONSUME_FILES': {
       const { inputFileIds, outputStirlingFileStubs } = action.payload;
+
       return processFileSwap(state, inputFileIds, outputStirlingFileStubs);
     }
 
+
     case 'UNDO_CONSUME_FILES': {
       const { inputStirlingFileStubs, outputFileIds } = action.payload;
+
       return processFileSwap(state, outputFileIds, inputStirlingFileStubs);
     }
 

frontend/src/contexts/file/fileHooks.ts

@@ -136,13 +136,13 @@ export function useAllFiles(): { files: StirlingFile[]; records: StirlingFileStu
 /**
  * Hook for selected files (optimized for selection-based UI)
  */
-export function useSelectedFiles(): { files: StirlingFile[]; records: StirlingFileStub[]; fileIds: FileId[] } {
+export function useSelectedFiles(): { selectedFiles: StirlingFile[]; selectedRecords: StirlingFileStub[]; selectedFileIds: FileId[] } {
   const { state, selectors } = useFileState();
 
   return useMemo(() => ({
-    files: selectors.getSelectedFiles(),
-    records: selectors.getSelectedStirlingFileStubs(),
-    fileIds: state.ui.selectedFileIds
+    selectedFiles: selectors.getSelectedFiles(),
+    selectedRecords: selectors.getSelectedStirlingFileStubs(),
+    selectedFileIds: state.ui.selectedFileIds
   }), [state.ui.selectedFileIds, selectors]);
 }
 
@@ -169,7 +169,6 @@ export function useFileContext() {
     recordOperation: (_fileId: FileId, _operation: any) => {}, // Operation tracking not implemented
     markOperationApplied: (_fileId: FileId, _operationId: string) => {}, // Operation tracking not implemented
     markOperationFailed: (_fileId: FileId, _operationId: string, _error: string) => {}, // Operation tracking not implemented
-
     // File ID lookup
     findFileId: (file: File) => {
       return state.files.ids.find(id => {

frontend/src/data/useTranslatedToolRegistry.tsx

@@ -11,6 +11,7 @@ import ChangePermissions from "../tools/ChangePermissions";
 import RemovePassword from "../tools/RemovePassword";
 import { SubcategoryId, ToolCategoryId, ToolRegistry } from "./toolsTaxonomy";
 import AddWatermark from "../tools/AddWatermark";
+import Merge from '../tools/Merge';
 import Repair from "../tools/Repair";
 import AutoRename from "../tools/AutoRename";
 import SingleLargePage from "../tools/SingleLargePage";
@@ -30,8 +31,10 @@ import { ocrOperationConfig } from "../hooks/tools/ocr/useOCROperation";
 import { convertOperationConfig } from "../hooks/tools/convert/useConvertOperation";
 import { removeCertificateSignOperationConfig } from "../hooks/tools/removeCertificateSign/useRemoveCertificateSignOperation";
 import { changePermissionsOperationConfig } from "../hooks/tools/changePermissions/useChangePermissionsOperation";
+import { mergeOperationConfig } from '../hooks/tools/merge/useMergeOperation';
 import { autoRenameOperationConfig } from "../hooks/tools/autoRename/useAutoRenameOperation";
 import { flattenOperationConfig } from "../hooks/tools/flatten/useFlattenOperation";
+import { redactOperationConfig } from "../hooks/tools/redact/useRedactOperation";
 import CompressSettings from "../components/tools/compress/CompressSettings";
 import SplitSettings from "../components/tools/split/SplitSettings";
 import AddPasswordSettings from "../components/tools/addPassword/AddPasswordSettings";
@@ -44,7 +47,13 @@ import OCRSettings from "../components/tools/ocr/OCRSettings";
 import ConvertSettings from "../components/tools/convert/ConvertSettings";
 import ChangePermissionsSettings from "../components/tools/changePermissions/ChangePermissionsSettings";
 import FlattenSettings from "../components/tools/flatten/FlattenSettings";
+import RedactSingleStepSettings from "../components/tools/redact/RedactSingleStepSettings";
+import Redact from "../tools/Redact";
+import AdjustPageScale from "../tools/AdjustPageScale";
 import { ToolId } from "../types/toolId";
+import MergeSettings from '../components/tools/merge/MergeSettings';
+import { adjustPageScaleOperationConfig } from "../hooks/tools/adjustPageScale/useAdjustPageScaleOperation";
+import AdjustPageScaleSettings from "../components/tools/adjustPageScale/AdjustPageScaleSettings";
 
 const showPlaceholderTools = true; // Show all tools; grey out unavailable ones in UI
 
@@ -331,11 +340,14 @@ export function useFlatToolRegistry(): ToolRegistry {
       "adjust-page-size-scale": {
         icon: <LocalIcon icon="crop-free-rounded" width="1.5rem" height="1.5rem" />,
         name: t("home.scalePages.title", "Adjust page size/scale"),
-        component: null,
-
+        component: AdjustPageScale,
         description: t("home.scalePages.desc", "Change the size/scale of a page and/or its contents."),
         categoryId: ToolCategoryId.STANDARD_TOOLS,
         subcategoryId: SubcategoryId.PAGE_FORMATTING,
+        maxFiles: -1,
+        endpoints: ["scale-pages"],
+        operationConfig: adjustPageScaleOperationConfig,
+        settingsComponent: AdjustPageScaleSettings,
       },
       addPageNumbers: {
         icon: <LocalIcon icon="123-rounded" width="1.5rem" height="1.5rem" />,
@@ -669,12 +681,14 @@ export function useFlatToolRegistry(): ToolRegistry {
       mergePdfs: {
         icon: <LocalIcon icon="library-add-rounded" width="1.5rem" height="1.5rem" />,
         name: t("home.merge.title", "Merge"),
-        component: null,
-
+        component: Merge,
         description: t("home.merge.desc", "Merge multiple PDFs into a single document"),
         categoryId: ToolCategoryId.RECOMMENDED_TOOLS,
         subcategoryId: SubcategoryId.GENERAL,
         maxFiles: -1,
+        endpoints: ["merge-pdfs"],
+        operationConfig: mergeOperationConfig,
+        settingsComponent: MergeSettings
       },
       "multi-tool": {
         icon: <LocalIcon icon="dashboard-customize-rounded" width="1.5rem" height="1.5rem" />,
@@ -701,10 +715,14 @@ export function useFlatToolRegistry(): ToolRegistry {
       redact: {
         icon: <LocalIcon icon="visibility-off-rounded" width="1.5rem" height="1.5rem" />,
         name: t("home.redact.title", "Redact"),
-        component: null,
+        component: Redact,
         description: t("home.redact.desc", "Permanently remove sensitive information from PDF documents"),
         categoryId: ToolCategoryId.RECOMMENDED_TOOLS,
         subcategoryId: SubcategoryId.GENERAL,
+        maxFiles: -1,
+        endpoints: ["auto-redact"],
+        operationConfig: redactOperationConfig,
+        settingsComponent: RedactSingleStepSettings,
       },
     };
 

frontend/src/hooks/tools/adjustPageScale/useAdjustPageScaleOperation.ts

@@ -0,0 +1,30 @@
+import { useTranslation } from 'react-i18next';
+import { useToolOperation, ToolType } from '../shared/useToolOperation';
+import { createStandardErrorHandler } from '../../../utils/toolErrorHandler';
+import { AdjustPageScaleParameters, defaultParameters } from './useAdjustPageScaleParameters';
+
+export const buildAdjustPageScaleFormData = (parameters: AdjustPageScaleParameters, file: File): FormData => {
+  const formData = new FormData();
+  formData.append("fileInput", file);
+  formData.append("scaleFactor", parameters.scaleFactor.toString());
+  formData.append("pageSize", parameters.pageSize);
+  return formData;
+};
+
+export const adjustPageScaleOperationConfig = {
+  toolType: ToolType.singleFile,
+  buildFormData: buildAdjustPageScaleFormData,
+  operationType: 'adjustPageScale',
+  endpoint: '/api/v1/general/scale-pages',
+  filePrefix: 'scaled_',
+  defaultParameters,
+} as const;
+
+export const useAdjustPageScaleOperation = () => {
+  const { t } = useTranslation();
+
+  return useToolOperation<AdjustPageScaleParameters>({
+    ...adjustPageScaleOperationConfig,
+    getErrorMessage: createStandardErrorHandler(t('adjustPageScale.error.failed', 'An error occurred while adjusting the page scale.'))
+  });
+};

frontend/src/hooks/tools/adjustPageScale/useAdjustPageScaleParameters.test.ts

@@ -0,0 +1,142 @@
+import { describe, expect, test } from 'vitest';
+import { renderHook, act } from '@testing-library/react';
+import { useAdjustPageScaleParameters, defaultParameters, PageSize, AdjustPageScaleParametersHook } from './useAdjustPageScaleParameters';
+
+describe('useAdjustPageScaleParameters', () => {
+  test('should initialize with default parameters', () => {
+    const { result } = renderHook(() => useAdjustPageScaleParameters());
+
+    expect(result.current.parameters).toStrictEqual(defaultParameters);
+    expect(result.current.parameters.scaleFactor).toBe(1.0);
+    expect(result.current.parameters.pageSize).toBe(PageSize.KEEP);
+  });
+
+  test.each([
+    { paramName: 'scaleFactor' as const, value: 0.5 },
+    { paramName: 'scaleFactor' as const, value: 2.0 },
+    { paramName: 'scaleFactor' as const, value: 10.0 },
+    { paramName: 'pageSize' as const, value: PageSize.A4 },
+    { paramName: 'pageSize' as const, value: PageSize.LETTER },
+    { paramName: 'pageSize' as const, value: PageSize.LEGAL },
+  ])('should update parameter $paramName to $value', ({ paramName, value }) => {
+    const { result } = renderHook(() => useAdjustPageScaleParameters());
+
+    act(() => {
+      result.current.updateParameter(paramName, value);
+    });
+
+    expect(result.current.parameters[paramName]).toBe(value);
+  });
+
+  test('should reset parameters to defaults', () => {
+    const { result } = renderHook(() => useAdjustPageScaleParameters());
+
+    // First, change some parameters
+    act(() => {
+      result.current.updateParameter('scaleFactor', 2.5);
+      result.current.updateParameter('pageSize', PageSize.A3);
+    });
+
+    expect(result.current.parameters.scaleFactor).toBe(2.5);
+    expect(result.current.parameters.pageSize).toBe(PageSize.A3);
+
+    // Then reset
+    act(() => {
+      result.current.resetParameters();
+    });
+
+    expect(result.current.parameters).toStrictEqual(defaultParameters);
+  });
+
+  test('should return correct endpoint name', () => {
+    const { result } = renderHook(() => useAdjustPageScaleParameters());
+
+    expect(result.current.getEndpointName()).toBe('scale-pages');
+  });
+
+  test.each([
+    {
+      description: 'with default parameters',
+      setup: () => {},
+      expected: true
+    },
+    {
+      description: 'with valid scale factor 0.1',
+      setup: (hook: AdjustPageScaleParametersHook) => {
+        hook.updateParameter('scaleFactor', 0.1);
+      },
+      expected: true
+    },
+    {
+      description: 'with valid scale factor 10.0',
+      setup: (hook: AdjustPageScaleParametersHook) => {
+        hook.updateParameter('scaleFactor', 10.0);
+      },
+      expected: true
+    },
+    {
+      description: 'with A4 page size',
+      setup: (hook: AdjustPageScaleParametersHook) => {
+        hook.updateParameter('pageSize', PageSize.A4);
+      },
+      expected: true
+    },
+    {
+      description: 'with invalid scale factor 0',
+      setup: (hook: AdjustPageScaleParametersHook) => {
+        hook.updateParameter('scaleFactor', 0);
+      },
+      expected: false
+    },
+    {
+      description: 'with negative scale factor',
+      setup: (hook: AdjustPageScaleParametersHook) => {
+        hook.updateParameter('scaleFactor', -0.5);
+      },
+      expected: false
+    }
+  ])('should validate parameters correctly $description', ({ setup, expected }) => {
+    const { result } = renderHook(() => useAdjustPageScaleParameters());
+
+    act(() => {
+      setup(result.current);
+    });
+
+    expect(result.current.validateParameters()).toBe(expected);
+  });
+
+  test('should handle all PageSize enum values', () => {
+    const { result } = renderHook(() => useAdjustPageScaleParameters());
+
+    Object.values(PageSize).forEach(pageSize => {
+      act(() => {
+        result.current.updateParameter('pageSize', pageSize);
+      });
+
+      expect(result.current.parameters.pageSize).toBe(pageSize);
+      expect(result.current.validateParameters()).toBe(true);
+    });
+  });
+
+  test('should handle scale factor edge cases', () => {
+    const { result } = renderHook(() => useAdjustPageScaleParameters());
+
+    // Test very small valid scale factor
+    act(() => {
+      result.current.updateParameter('scaleFactor', 0.01);
+    });
+    expect(result.current.validateParameters()).toBe(true);
+
+    // Test scale factor just above zero
+    act(() => {
+      result.current.updateParameter('scaleFactor', 0.001);
+    });
+    expect(result.current.validateParameters()).toBe(true);
+
+    // Test exactly zero (invalid)
+    act(() => {
+      result.current.updateParameter('scaleFactor', 0);
+    });
+    expect(result.current.validateParameters()).toBe(false);
+  });
+});

frontend/src/hooks/tools/adjustPageScale/useAdjustPageScaleParameters.ts

@@ -0,0 +1,37 @@
+import { BaseParameters } from '../../../types/parameters';
+import { useBaseParameters, BaseParametersHook } from '../shared/useBaseParameters';
+
+export enum PageSize {
+  KEEP = 'KEEP',
+  A0 = 'A0',
+  A1 = 'A1',
+  A2 = 'A2',
+  A3 = 'A3',
+  A4 = 'A4',
+  A5 = 'A5',
+  A6 = 'A6',
+  LETTER = 'LETTER',
+  LEGAL = 'LEGAL'
+}
+
+export interface AdjustPageScaleParameters extends BaseParameters {
+  scaleFactor: number;
+  pageSize: PageSize;
+}
+
+export const defaultParameters: AdjustPageScaleParameters = {
+  scaleFactor: 1.0,
+  pageSize: PageSize.KEEP,
+};
+
+export type AdjustPageScaleParametersHook = BaseParametersHook<AdjustPageScaleParameters>;
+
+export const useAdjustPageScaleParameters = (): AdjustPageScaleParametersHook => {
+  return useBaseParameters({
+    defaultParameters,
+    endpointName: 'scale-pages',
+    validateFn: (params) => {
+      return params.scaleFactor > 0;
+    },
+  });
+};

frontend/src/hooks/tools/merge/useMergeOperation.test.ts

@@ -0,0 +1,138 @@
+import { describe, expect, test, vi, beforeEach } from 'vitest';
+import { renderHook } from '@testing-library/react';
+import { useMergeOperation } from './useMergeOperation';
+import type { MergeParameters } from './useMergeParameters';
+
+// Mock the useToolOperation hook
+vi.mock('../shared/useToolOperation', async () => {
+  const actual = await vi.importActual('../shared/useToolOperation');
+  return {
+    ...actual,
+    useToolOperation: vi.fn()
+  };
+});
+
+// Mock the translation hook
+const mockT = vi.fn((key: string) => `translated-${key}`);
+vi.mock('react-i18next', () => ({
+  useTranslation: () => ({ t: mockT })
+}));
+
+// Mock the error handler
+vi.mock('../../../utils/toolErrorHandler', () => ({
+  createStandardErrorHandler: vi.fn(() => 'error-handler-function')
+}));
+
+// Import the mocked function
+import { MultiFileToolOperationConfig, ToolOperationHook, useToolOperation } from '../shared/useToolOperation';
+
+describe('useMergeOperation', () => {
+  const mockUseToolOperation = vi.mocked(useToolOperation<MergeParameters>);
+
+  const getToolConfig = () => mockUseToolOperation.mock.calls[0][0] as MultiFileToolOperationConfig<MergeParameters>;
+
+  const mockToolOperationReturn: ToolOperationHook<unknown> = {
+    files: [],
+    thumbnails: [],
+    downloadUrl: null,
+    downloadFilename: '',
+    isLoading: false,
+    errorMessage: null,
+    status: '',
+    isGeneratingThumbnails: false,
+    progress: null,
+    executeOperation: vi.fn(),
+    resetResults: vi.fn(),
+    clearError: vi.fn(),
+    cancelOperation: vi.fn(),
+    undoOperation: function (): Promise<void> {
+      throw new Error('Function not implemented.');
+    }
+  };
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+    mockUseToolOperation.mockReturnValue(mockToolOperationReturn);
+  });
+
+  test('should build FormData correctly', () => {
+    renderHook(() => useMergeOperation());
+
+    const config = getToolConfig();
+    const mockFiles = [
+      new File(['content1'], 'file1.pdf', { type: 'application/pdf' }),
+      new File(['content2'], 'file2.pdf', { type: 'application/pdf' })
+    ];
+    const parameters: MergeParameters = {
+      removeDigitalSignature: true,
+      generateTableOfContents: false
+    };
+
+    const formData = config.buildFormData(parameters, mockFiles);
+
+    // Verify files are appended
+    expect(formData.getAll('fileInput')).toHaveLength(2);
+    expect(formData.getAll('fileInput')[0]).toBe(mockFiles[0]);
+    expect(formData.getAll('fileInput')[1]).toBe(mockFiles[1]);
+
+    // Verify parameters are appended correctly
+    expect(formData.get('sortType')).toBe('orderProvided');
+    expect(formData.get('removeCertSign')).toBe('true');
+    expect(formData.get('generateToc')).toBe('false');
+  });
+
+  test('should handle response correctly', () => {
+    renderHook(() => useMergeOperation());
+
+    const config = getToolConfig();
+    const mockBlob = new Blob(['merged content'], { type: 'application/pdf' });
+    const mockFiles = [
+      new File(['content1'], 'file1.pdf', { type: 'application/pdf' }),
+      new File(['content2'], 'file2.pdf', { type: 'application/pdf' })
+    ];
+
+    const result = config.responseHandler!(mockBlob, mockFiles) as File[];
+
+    expect(result).toHaveLength(1);
+    expect(result[0].name).toBe('merged_file1.pdf');
+    expect(result[0].type).toBe('application/pdf');
+    expect(result[0].size).toBe(mockBlob.size);
+  });
+
+  test('should return the hook result from useToolOperation', () => {
+    const { result } = renderHook(() => useMergeOperation());
+
+    expect(result.current).toBe(mockToolOperationReturn);
+  });
+
+  test('should use correct translation keys for error handling', () => {
+    renderHook(() => useMergeOperation());
+
+    expect(mockT).toHaveBeenCalledWith('merge.error.failed', 'An error occurred while merging the PDFs.');
+  });
+
+  test('should build FormData with different parameter combinations', () => {
+    renderHook(() => useMergeOperation());
+
+    const config = getToolConfig();
+    const mockFiles = [new File(['test'], 'test.pdf', { type: 'application/pdf' })];
+
+    // Test case 1: All options disabled
+    const params1: MergeParameters = {
+      removeDigitalSignature: false,
+      generateTableOfContents: false
+    };
+    const formData1 = config.buildFormData(params1, mockFiles);
+    expect(formData1.get('removeCertSign')).toBe('false');
+    expect(formData1.get('generateToc')).toBe('false');
+
+    // Test case 2: All options enabled
+    const params2: MergeParameters = {
+      removeDigitalSignature: true,
+      generateTableOfContents: true
+    };
+    const formData2 = config.buildFormData(params2, mockFiles);
+    expect(formData2.get('removeCertSign')).toBe('true');
+    expect(formData2.get('generateToc')).toBe('true');
+  });
+});

frontend/src/hooks/tools/merge/useMergeOperation.ts

@@ -0,0 +1,41 @@
+import { useTranslation } from 'react-i18next';
+import { useToolOperation, ResponseHandler, ToolOperationConfig, ToolType } from '../shared/useToolOperation';
+import { createStandardErrorHandler } from '../../../utils/toolErrorHandler';
+import { MergeParameters } from './useMergeParameters';
+
+const buildFormData = (parameters: MergeParameters, files: File[]): FormData => {
+  const formData = new FormData();
+
+  files.forEach((file) => {
+    formData.append("fileInput", file);
+  });
+  formData.append("sortType", "orderProvided"); // Always use orderProvided since UI handles sorting
+  formData.append("removeCertSign", parameters.removeDigitalSignature.toString());
+  formData.append("generateToc", parameters.generateTableOfContents.toString());
+
+  return formData;
+};
+
+const mergeResponseHandler: ResponseHandler = (blob: Blob, originalFiles: File[]): File[] => {
+  const filename = `merged_${originalFiles[0].name}`
+  return [new File([blob], filename, { type: 'application/pdf' })];
+};
+
+// Operation configuration for automation
+export const mergeOperationConfig: ToolOperationConfig<MergeParameters> = {
+  toolType: ToolType.multiFile,
+  buildFormData,
+  operationType: 'merge',
+  endpoint: '/api/v1/general/merge-pdfs',
+  filePrefix: 'merged_',
+  responseHandler: mergeResponseHandler,
+};
+
+export const useMergeOperation = () => {
+  const { t } = useTranslation();
+
+  return useToolOperation<MergeParameters>({
+    ...mergeOperationConfig,
+    getErrorMessage: createStandardErrorHandler(t('merge.error.failed', 'An error occurred while merging the PDFs.'))
+  });
+};

frontend/src/hooks/tools/merge/useMergeParameters.test.ts

@@ -0,0 +1,68 @@
+import { describe, expect, test } from 'vitest';
+import { renderHook, act } from '@testing-library/react';
+import { useMergeParameters, defaultParameters } from './useMergeParameters';
+
+describe('useMergeParameters', () => {
+  test('should initialize with default parameters', () => {
+    const { result } = renderHook(() => useMergeParameters());
+
+    expect(result.current.parameters).toStrictEqual(defaultParameters);
+  });
+
+  test.each([
+    { paramName: 'removeDigitalSignature' as const, value: true },
+    { paramName: 'removeDigitalSignature' as const, value: false },
+    { paramName: 'generateTableOfContents' as const, value: true },
+    { paramName: 'generateTableOfContents' as const, value: false }
+  ])('should update parameter $paramName to $value', ({ paramName, value }) => {
+    const { result } = renderHook(() => useMergeParameters());
+
+    act(() => {
+      result.current.updateParameter(paramName, value);
+    });
+
+    expect(result.current.parameters[paramName]).toBe(value);
+  });
+
+  test('should reset parameters to defaults', () => {
+    const { result } = renderHook(() => useMergeParameters());
+
+    // First, change some parameters
+    act(() => {
+      result.current.updateParameter('removeDigitalSignature', true);
+      result.current.updateParameter('generateTableOfContents', true);
+    });
+
+    expect(result.current.parameters.removeDigitalSignature).toBe(true);
+    expect(result.current.parameters.generateTableOfContents).toBe(true);
+
+    // Then reset
+    act(() => {
+      result.current.resetParameters();
+    });
+
+    expect(result.current.parameters).toStrictEqual(defaultParameters);
+  });
+
+  test('should validate parameters correctly - always returns true', () => {
+    const { result } = renderHook(() => useMergeParameters());
+
+    // Default state should be valid
+    expect(result.current.validateParameters()).toBe(true);
+
+    // Change parameters and validate again
+    act(() => {
+      result.current.updateParameter('removeDigitalSignature', true);
+      result.current.updateParameter('generateTableOfContents', true);
+    });
+
+    expect(result.current.validateParameters()).toBe(true);
+
+    // Reset and validate again
+    act(() => {
+      result.current.resetParameters();
+    });
+
+    expect(result.current.validateParameters()).toBe(true);
+  });
+});

frontend/src/hooks/tools/merge/useMergeParameters.ts

@@ -0,0 +1,21 @@
+import { BaseParameters } from '../../../types/parameters';
+import { BaseParametersHook, useBaseParameters } from '../shared/useBaseParameters';
+
+export interface MergeParameters extends BaseParameters {
+  removeDigitalSignature: boolean;
+  generateTableOfContents: boolean;
+};
+
+export const defaultParameters: MergeParameters = {
+  removeDigitalSignature: false,
+  generateTableOfContents: false,
+};
+
+export type MergeParametersHook = BaseParametersHook<MergeParameters>;
+
+export const useMergeParameters = (): MergeParametersHook => {
+  return useBaseParameters({
+    defaultParameters,
+    endpointName: "merge-pdfs",
+  });
+};

frontend/src/hooks/tools/redact/useRedactOperation.test.ts

@@ -0,0 +1,142 @@
+import { describe, expect, test, vi, beforeEach } from 'vitest';
+import { renderHook } from '@testing-library/react';
+import { buildRedactFormData, redactOperationConfig, useRedactOperation } from './useRedactOperation';
+import { defaultParameters, RedactParameters } from './useRedactParameters';
+
+// Mock the useToolOperation hook
+vi.mock('../shared/useToolOperation', async () => {
+  const actual = await vi.importActual('../shared/useToolOperation');  // Need to keep ToolType etc.
+  return {
+    ...actual,
+    useToolOperation: vi.fn()
+  };
+});
+
+// Mock the translation hook
+vi.mock('react-i18next', () => ({
+  useTranslation: () => ({ t: vi.fn((_key: string, fallback: string) => fallback) })
+}));
+
+// Mock the error handler utility
+vi.mock('../../../utils/toolErrorHandler', () => ({
+  createStandardErrorHandler: vi.fn(() => vi.fn())
+}));
+
+describe('buildRedactFormData', () => {
+  const mockFile = new File(['test content'], 'test.pdf', { type: 'application/pdf' });
+
+  test('should build form data for automatic mode', () => {
+    const parameters: RedactParameters = {
+      ...defaultParameters,
+      mode: 'automatic',
+      wordsToRedact: ['Confidential', 'Secret'],
+      useRegex: true,
+      wholeWordSearch: true,
+      redactColor: '#FF0000',
+      customPadding: 0.5,
+      convertPDFToImage: false,
+    };
+
+    const formData = buildRedactFormData(parameters, mockFile);
+
+    expect(formData.get('fileInput')).toBe(mockFile);
+    expect(formData.get('listOfText')).toBe('Confidential\nSecret');
+    expect(formData.get('useRegex')).toBe('true');
+    expect(formData.get('wholeWordSearch')).toBe('true');
+    expect(formData.get('redactColor')).toBe('FF0000'); // Hash should be removed
+    expect(formData.get('customPadding')).toBe('0.5');
+    expect(formData.get('convertPDFToImage')).toBe('false');
+  });
+
+  test('should handle empty words array', () => {
+    const parameters: RedactParameters = {
+      ...defaultParameters,
+      mode: 'automatic',
+      wordsToRedact: [],
+    };
+
+    const formData = buildRedactFormData(parameters, mockFile);
+
+    expect(formData.get('listOfText')).toBe('');
+  });
+
+  test('should join multiple words with newlines', () => {
+    const parameters: RedactParameters = {
+      ...defaultParameters,
+      mode: 'automatic',
+      wordsToRedact: ['Word1', 'Word2', 'Word3'],
+    };
+
+    const formData = buildRedactFormData(parameters, mockFile);
+
+    expect(formData.get('listOfText')).toBe('Word1\nWord2\nWord3');
+  });
+
+  test.each([
+    { description: 'remove hash from redact color', redactColor: '#123456', expected: '123456' },
+    { description: 'handle redact color without hash', redactColor: 'ABCDEF', expected: 'ABCDEF' },
+  ])('should $description', ({ redactColor, expected }) => {
+    const parameters: RedactParameters = {
+      ...defaultParameters,
+      mode: 'automatic',
+      redactColor,
+    };
+
+    const formData = buildRedactFormData(parameters, mockFile);
+
+    expect(formData.get('redactColor')).toBe(expected);
+  });
+
+  test('should convert boolean parameters to strings', () => {
+    const parameters: RedactParameters = {
+      ...defaultParameters,
+      mode: 'automatic',
+      useRegex: false,
+      wholeWordSearch: true,
+      convertPDFToImage: false,
+    };
+
+    const formData = buildRedactFormData(parameters, mockFile);
+
+    expect(formData.get('useRegex')).toBe('false');
+    expect(formData.get('wholeWordSearch')).toBe('true');
+    expect(formData.get('convertPDFToImage')).toBe('false');
+  });
+
+  test('should throw error for manual mode (not implemented)', () => {
+    const parameters: RedactParameters = {
+      ...defaultParameters,
+      mode: 'manual',
+    };
+
+    expect(() => buildRedactFormData(parameters, mockFile)).toThrow('Manual redaction not yet implemented');
+  });
+});
+
+describe('useRedactOperation', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  test('should call useToolOperation with correct configuration', async () => {
+    const { useToolOperation } = await import('../shared/useToolOperation');
+    const mockUseToolOperation = vi.mocked(useToolOperation);
+
+    renderHook(() => useRedactOperation());
+
+    expect(mockUseToolOperation).toHaveBeenCalledWith({
+      ...redactOperationConfig,
+      getErrorMessage: expect.any(Function),
+    });
+  });
+
+  test('should provide error handler to useToolOperation', async () => {
+    const { useToolOperation } = await import('../shared/useToolOperation');
+    const mockUseToolOperation = vi.mocked(useToolOperation);
+
+    renderHook(() => useRedactOperation());
+
+    const callArgs = mockUseToolOperation.mock.calls[0][0];
+    expect(typeof callArgs.getErrorMessage).toBe('function');
+  });
+});

frontend/src/hooks/tools/redact/useRedactOperation.ts

@@ -0,0 +1,51 @@
+import { useTranslation } from 'react-i18next';
+import { useToolOperation, ToolType } from '../shared/useToolOperation';
+import { createStandardErrorHandler } from '../../../utils/toolErrorHandler';
+import { RedactParameters, defaultParameters } from './useRedactParameters';
+
+// Static configuration that can be used by both the hook and automation executor
+export const buildRedactFormData = (parameters: RedactParameters, file: File): FormData => {
+  const formData = new FormData();
+  formData.append("fileInput", file);
+
+  if (parameters.mode === 'automatic') {
+    // Convert array to newline-separated string as expected by backend
+    formData.append("listOfText", parameters.wordsToRedact.join('\n'));
+    formData.append("useRegex", parameters.useRegex.toString());
+    formData.append("wholeWordSearch", parameters.wholeWordSearch.toString());
+    formData.append("redactColor", parameters.redactColor.replace('#', ''));
+    formData.append("customPadding", parameters.customPadding.toString());
+    formData.append("convertPDFToImage", parameters.convertPDFToImage.toString());
+  } else {
+    // Manual mode parameters would go here when implemented
+    throw new Error('Manual redaction not yet implemented');
+  }
+
+  return formData;
+};
+
+// Static configuration object
+export const redactOperationConfig = {
+  toolType: ToolType.singleFile,
+  buildFormData: buildRedactFormData,
+  operationType: 'redact',
+  endpoint: (parameters: RedactParameters) => {
+    if (parameters.mode === 'automatic') {
+      return '/api/v1/security/auto-redact';
+    } else {
+      // Manual redaction endpoint would go here when implemented
+      throw new Error('Manual redaction not yet implemented');
+    }
+  },
+  filePrefix: 'redacted_',
+  defaultParameters,
+} as const;
+
+export const useRedactOperation = () => {
+  const { t } = useTranslation();
+
+  return useToolOperation<RedactParameters>({
+    ...redactOperationConfig,
+    getErrorMessage: createStandardErrorHandler(t('redact.error.failed', 'An error occurred while redacting the PDF.'))
+  });
+};

frontend/src/hooks/tools/redact/useRedactParameters.test.ts

@@ -0,0 +1,134 @@
+import { describe, expect, test } from 'vitest';
+import { renderHook, act } from '@testing-library/react';
+import { useRedactParameters, defaultParameters } from './useRedactParameters';
+
+describe('useRedactParameters', () => {
+  test('should initialize with default parameters', () => {
+    const { result } = renderHook(() => useRedactParameters());
+
+    expect(result.current.parameters).toStrictEqual(defaultParameters);
+  });
+
+  test.each([
+    { paramName: 'mode' as const, value: 'manual' as const },
+    { paramName: 'wordsToRedact' as const, value: ['word1', 'word2'] },
+    { paramName: 'useRegex' as const, value: true },
+    { paramName: 'wholeWordSearch' as const, value: true },
+    { paramName: 'redactColor' as const, value: '#FF0000' },
+    { paramName: 'customPadding' as const, value: 0.5 },
+    { paramName: 'convertPDFToImage' as const, value: false }
+  ])('should update parameter $paramName', ({ paramName, value }) => {
+    const { result } = renderHook(() => useRedactParameters());
+
+    act(() => {
+      result.current.updateParameter(paramName, value);
+    });
+
+    expect(result.current.parameters[paramName]).toStrictEqual(value);
+  });
+
+  test('should reset parameters to defaults', () => {
+    const { result } = renderHook(() => useRedactParameters());
+
+    // Modify some parameters
+    act(() => {
+      result.current.updateParameter('mode', 'manual');
+      result.current.updateParameter('wordsToRedact', ['test']);
+      result.current.updateParameter('useRegex', true);
+    });
+
+    // Reset parameters
+    act(() => {
+      result.current.resetParameters();
+    });
+
+    expect(result.current.parameters).toStrictEqual(defaultParameters);
+  });
+
+  describe('validation', () => {
+    test.each([
+      { description: 'validate when wordsToRedact has non-empty words in automatic mode', wordsToRedact: ['word1', 'word2'], expected: true },
+      { description: 'not validate when wordsToRedact is empty in automatic mode', wordsToRedact: [], expected: false },
+      { description: 'not validate when wordsToRedact contains only empty strings in automatic mode', wordsToRedact: ['', '  ', ''], expected: false },
+      { description: 'validate when wordsToRedact contains at least one non-empty word in automatic mode', wordsToRedact: ['', 'valid', '  '], expected: true },
+    ])('should $description', ({ wordsToRedact, expected }) => {
+      const { result } = renderHook(() => useRedactParameters());
+
+      act(() => {
+        result.current.updateParameter('mode', 'automatic');
+        result.current.updateParameter('wordsToRedact', wordsToRedact);
+      });
+
+      expect(result.current.validateParameters()).toBe(expected);
+    });
+
+    test('should not validate in manual mode (not implemented)', () => {
+      const { result } = renderHook(() => useRedactParameters());
+
+      act(() => {
+        result.current.updateParameter('mode', 'manual');
+      });
+
+      expect(result.current.validateParameters()).toBe(false);
+    });
+  });
+
+  describe('endpoint handling', () => {
+    test('should return correct endpoint for automatic mode', () => {
+      const { result } = renderHook(() => useRedactParameters());
+
+      act(() => {
+        result.current.updateParameter('mode', 'automatic');
+      });
+
+      expect(result.current.getEndpointName()).toBe('/api/v1/security/auto-redact');
+    });
+
+    test('should throw error for manual mode (not implemented)', () => {
+      const { result } = renderHook(() => useRedactParameters());
+
+      act(() => {
+        result.current.updateParameter('mode', 'manual');
+      });
+
+      expect(() => result.current.getEndpointName()).toThrow('Manual redaction not yet implemented');
+    });
+  });
+
+  test('should maintain parameter state across updates', () => {
+    const { result } = renderHook(() => useRedactParameters());
+
+    act(() => {
+      result.current.updateParameter('redactColor', '#FF0000');
+      result.current.updateParameter('customPadding', 0.5);
+      result.current.updateParameter('wordsToRedact', ['word1']);
+    });
+
+    // All parameters should be updated
+    expect(result.current.parameters.redactColor).toBe('#FF0000');
+    expect(result.current.parameters.customPadding).toBe(0.5);
+    expect(result.current.parameters.wordsToRedact).toEqual(['word1']);
+
+    // Other parameters should remain at defaults
+    expect(result.current.parameters.mode).toBe('automatic');
+    expect(result.current.parameters.useRegex).toBe(false);
+    expect(result.current.parameters.wholeWordSearch).toBe(false);
+    expect(result.current.parameters.convertPDFToImage).toBe(true);
+  });
+
+  test('should handle array parameter updates correctly', () => {
+    const { result } = renderHook(() => useRedactParameters());
+
+    act(() => {
+      result.current.updateParameter('wordsToRedact', ['initial']);
+    });
+
+    expect(result.current.parameters.wordsToRedact).toEqual(['initial']);
+
+    act(() => {
+      result.current.updateParameter('wordsToRedact', ['updated', 'multiple']);
+    });
+
+    expect(result.current.parameters.wordsToRedact).toEqual(['updated', 'multiple']);
+  });
+});

frontend/src/hooks/tools/redact/useRedactParameters.ts

@@ -0,0 +1,48 @@
+import { BaseParameters } from '../../../types/parameters';
+import { useBaseParameters, BaseParametersHook } from '../shared/useBaseParameters';
+
+export type RedactMode = 'automatic' | 'manual';
+
+export interface RedactParameters extends BaseParameters {
+  mode: RedactMode;
+
+  // Automatic redaction parameters
+  wordsToRedact: string[];
+  useRegex: boolean;
+  wholeWordSearch: boolean;
+  redactColor: string;
+  customPadding: number;
+  convertPDFToImage: boolean;
+}
+
+export const defaultParameters: RedactParameters = {
+  mode: 'automatic',
+  wordsToRedact: [],
+  useRegex: false,
+  wholeWordSearch: false,
+  redactColor: '#000000',
+  customPadding: 0.1,
+  convertPDFToImage: true,
+};
+
+export type RedactParametersHook = BaseParametersHook<RedactParameters>;
+
+export const useRedactParameters = (): RedactParametersHook => {
+  return useBaseParameters({
+    defaultParameters,
+    endpointName: (params) => {
+      if (params.mode === 'automatic') {
+        return '/api/v1/security/auto-redact';
+      }
+      // Manual redaction endpoint would go here when implemented
+      throw new Error('Manual redaction not yet implemented');
+    },
+    validateFn: (params) => {
+      if (params.mode === 'automatic') {
+        return params.wordsToRedact.length > 0 && params.wordsToRedact.some(word => word.trim().length > 0);
+      }
+      // Manual mode validation would go here when implemented
+      return false;
+    }
+  });
+};

frontend/src/hooks/tools/shared/useBaseTool.ts

@@ -6,12 +6,12 @@ import { ToolOperationHook } from './useToolOperation';
 import { BaseParametersHook } from './useBaseParameters';
 import { StirlingFile } from '../../../types/fileContext';
 
-interface BaseToolReturn<TParams> {
+interface BaseToolReturn<TParams, TParamsHook extends BaseParametersHook<TParams>> {
   // File management
   selectedFiles: StirlingFile[];
 
   // Tool-specific hooks
-  params: BaseParametersHook<TParams>;
+  params: TParamsHook;
   operation: ToolOperationHook<TParams>;
 
   // Endpoint validation
@@ -33,12 +33,14 @@ interface BaseToolReturn<TParams> {
 /**
  * Base tool hook for tool components. Manages standard behaviour for tools.
  */
-export function useBaseTool<TParams>(
+export function useBaseTool<TParams, TParamsHook extends BaseParametersHook<TParams>>(
   toolName: string,
-  useParams: () => BaseParametersHook<TParams>,
+  useParams: () => TParamsHook,
   useOperation: () => ToolOperationHook<TParams>,
   props: BaseToolProps,
-): BaseToolReturn<TParams> {
+  options?: { minFiles?: number }
+): BaseToolReturn<TParams, TParamsHook> {
+  const minFiles = options?.minFiles ?? 1;
   const { onPreviewFile, onComplete, onError } = props;
 
   // File selection
@@ -96,7 +98,7 @@ export function useBaseTool<TParams>(
   }, [operation, onPreviewFile]);
 
   // Standard computed state
-  const hasFiles = selectedFiles.length > 0;
+  const hasFiles = selectedFiles.length >= minFiles;
   const hasResults = operation.files.length > 0 || operation.downloadUrl !== null;
   const settingsCollapsed = !hasFiles || hasResults;
 

frontend/src/i18n.ts

@@ -59,6 +59,7 @@ i18n
   .init({
     fallbackLng: 'en-GB',
     supportedLngs: Object.keys(supportedLanguages),
+    load: 'currentOnly',
     nonExplicitSupportedLngs: false,
     debug: process.env.NODE_ENV === 'development',
 

frontend/src/tools/AdjustPageScale.tsx

@@ -0,0 +1,58 @@
+import { useTranslation } from "react-i18next";
+import { createToolFlow } from "../components/tools/shared/createToolFlow";
+import AdjustPageScaleSettings from "../components/tools/adjustPageScale/AdjustPageScaleSettings";
+import { useAdjustPageScaleParameters } from "../hooks/tools/adjustPageScale/useAdjustPageScaleParameters";
+import { useAdjustPageScaleOperation } from "../hooks/tools/adjustPageScale/useAdjustPageScaleOperation";
+import { useBaseTool } from "../hooks/tools/shared/useBaseTool";
+import { BaseToolProps, ToolComponent } from "../types/tool";
+import { useAdjustPageScaleTips } from "../components/tooltips/useAdjustPageScaleTips";
+
+const AdjustPageScale = (props: BaseToolProps) => {
+  const { t } = useTranslation();
+  const adjustPageScaleTips = useAdjustPageScaleTips();
+
+  const base = useBaseTool(
+    'adjustPageScale',
+    useAdjustPageScaleParameters,
+    useAdjustPageScaleOperation,
+    props
+  );
+
+  return createToolFlow({
+    files: {
+      selectedFiles: base.selectedFiles,
+      isCollapsed: base.hasResults,
+    },
+    steps: [
+      {
+        title: "Settings",
+        isCollapsed: base.settingsCollapsed,
+        onCollapsedClick: base.settingsCollapsed ? base.handleSettingsReset : undefined,
+        tooltip: adjustPageScaleTips,
+        content: (
+          <AdjustPageScaleSettings
+            parameters={base.params.parameters}
+            onParameterChange={base.params.updateParameter}
+            disabled={base.endpointLoading}
+          />
+        ),
+      },
+    ],
+    executeButton: {
+      text: t("adjustPageScale.submit", "Adjust Page Scale"),
+      isVisible: !base.hasResults,
+      loadingText: t("loading"),
+      onClick: base.handleExecute,
+      disabled: !base.params.validateParameters() || !base.hasFiles || !base.endpointEnabled,
+    },
+    review: {
+      isVisible: base.hasResults,
+      operation: base.operation,
+      title: t("adjustPageScale.title", "Page Scale Results"),
+      onFileClick: base.handleThumbnailClick,
+      onUndo: base.handleUndo,
+    },
+  });
+};
+
+export default AdjustPageScale as ToolComponent;

frontend/src/tools/Automate.tsx

@@ -1,4 +1,4 @@
-import React, { useState, useMemo } from "react";
+import React, { useState } from "react";
 import { useTranslation } from "react-i18next";
 import { useFileSelection } from "../contexts/FileContext";
 import { useNavigationActions } from "../contexts/NavigationContext";
@@ -161,25 +161,10 @@ const Automate = ({ onPreviewFile, onComplete, onError }: BaseToolProps) => {
     content
   });
 
-  // Dynamic file placeholder based on supported types
-  const filesPlaceholder = useMemo(() => {
-    if (currentStep === AUTOMATION_STEPS.RUN && stepData.automation?.operations?.length) {
-      const firstOperation = stepData.automation.operations[0];
-      const toolConfig = toolRegistry[firstOperation.operation as keyof typeof toolRegistry];
-
-      // Check if the tool has supportedFormats that include non-PDF formats
-      if (toolConfig?.supportedFormats && toolConfig.supportedFormats.length > 1) {
-        return t('automate.files.placeholder.multiFormat', 'Select files to process (supports various formats)');
-      }
-    }
-    return t('automate.files.placeholder', 'Select PDF files to process with this automation');
-  }, [currentStep, stepData.automation, toolRegistry, t]);
-
   // Always create files step to avoid conditional hook calls
   const filesStep = createFilesToolStep(createStep, {
     selectedFiles,
     isCollapsed: hasResults,
-    placeholder: filesPlaceholder
   });
 
   const automationSteps = [

frontend/src/tools/Convert.tsx

@@ -100,7 +100,6 @@ const Convert = ({ onPreviewFile, onComplete, onError }: BaseToolProps) => {
     files: {
       selectedFiles,
       isCollapsed: hasResults,
-      placeholder: t("convert.selectFilesPlaceholder", "Select files in the main view to get started"),
     },
     steps: [
       {

frontend/src/tools/Flatten.tsx

@@ -22,7 +22,6 @@ const Flatten = (props: BaseToolProps) => {
     files: {
       selectedFiles: base.selectedFiles,
       isCollapsed: base.hasResults,
-      placeholder: t("flatten.files.placeholder", "Select a PDF file in the main view to get started"),
     },
     steps: [
       {

frontend/src/tools/Merge.tsx

@@ -0,0 +1,98 @@
+import { useCallback } from "react";
+import { useTranslation } from "react-i18next";
+import { createToolFlow } from "../components/tools/shared/createToolFlow";
+import MergeSettings from "../components/tools/merge/MergeSettings";
+import MergeFileSorter from "../components/tools/merge/MergeFileSorter";
+import { useMergeParameters } from "../hooks/tools/merge/useMergeParameters";
+import { useMergeOperation } from "../hooks/tools/merge/useMergeOperation";
+import { useBaseTool } from "../hooks/tools/shared/useBaseTool";
+import { BaseToolProps, ToolComponent } from "../types/tool";
+import { useMergeTips } from "../components/tooltips/useMergeTips";
+import { useFileManagement, useSelectedFiles, useAllFiles } from "../contexts/FileContext";
+
+const Merge = (props: BaseToolProps) => {
+  const { t } = useTranslation();
+  const mergeTips = useMergeTips();
+
+  // File selection hooks for custom sorting
+  const { fileIds } = useAllFiles();
+  const { selectedRecords } = useSelectedFiles();
+  const { reorderFiles } = useFileManagement();
+
+  const base = useBaseTool(
+    'merge',
+    useMergeParameters,
+    useMergeOperation,
+    props,
+    { minFiles: 2 }
+  );
+
+  // Custom file sorting logic for merge tool
+  const sortFiles = useCallback((sortType: 'filename' | 'dateModified', ascending: boolean = true) => {
+    const sortedRecords = [...selectedRecords].sort((recordA, recordB) => {
+      let comparison = 0;
+      switch (sortType) {
+        case 'filename':
+          comparison = recordA.name.localeCompare(recordB.name);
+          break;
+        case 'dateModified':
+          comparison = recordA.lastModified - recordB.lastModified;
+          break;
+      }
+      return ascending ? comparison : -comparison;
+    });
+
+    const selectedIds = sortedRecords.map(record => record.id);
+    const deselectedIds = fileIds.filter(id => !selectedIds.includes(id));
+    reorderFiles([...selectedIds, ...deselectedIds]);
+  }, [selectedRecords, fileIds, reorderFiles]);
+
+  return createToolFlow({
+    files: {
+      selectedFiles: base.selectedFiles,
+      isCollapsed: base.hasResults,
+      minFiles: 2,
+    },
+    steps: [
+      {
+        title: "Sort Files",
+        isCollapsed: base.settingsCollapsed,
+        content: (
+          <MergeFileSorter
+            onSortFiles={sortFiles}
+            disabled={!base.hasFiles || base.endpointLoading}
+          />
+        ),
+      },
+      {
+        title: "Settings",
+        isCollapsed: base.settingsCollapsed,
+        onCollapsedClick: base.settingsCollapsed ? base.handleSettingsReset : undefined,
+        tooltip: mergeTips,
+        content: (
+          <MergeSettings
+            parameters={base.params.parameters}
+            onParameterChange={base.params.updateParameter}
+            disabled={base.endpointLoading}
+          />
+        ),
+      },
+    ],
+    executeButton: {
+      text: t("merge.submit", "Merge PDFs"),
+      isVisible: !base.hasResults,
+      loadingText: t("loading"),
+      onClick: base.handleExecute,
+      disabled: !base.params.validateParameters() || !base.hasFiles || !base.endpointEnabled,
+    },
+    review: {
+      isVisible: base.hasResults,
+      operation: base.operation,
+      title: t("merge.title", "Merge Results"),
+      onFileClick: base.handleThumbnailClick,
+      onUndo: base.handleUndo,
+    },
+  });
+};
+
+export default Merge as ToolComponent;

frontend/src/tools/Redact.tsx

@@ -0,0 +1,120 @@
+import { useTranslation } from "react-i18next";
+import { useState } from "react";
+import { createToolFlow } from "../components/tools/shared/createToolFlow";
+import RedactModeSelector from "../components/tools/redact/RedactModeSelector";
+import { useRedactParameters } from "../hooks/tools/redact/useRedactParameters";
+import { useRedactOperation } from "../hooks/tools/redact/useRedactOperation";
+import { useBaseTool } from "../hooks/tools/shared/useBaseTool";
+import { BaseToolProps, ToolComponent } from "../types/tool";
+import { useRedactModeTips, useRedactWordsTips, useRedactAdvancedTips } from "../components/tooltips/useRedactTips";
+import RedactAdvancedSettings from "../components/tools/redact/RedactAdvancedSettings";
+import WordsToRedactInput from "../components/tools/redact/WordsToRedactInput";
+
+const Redact = (props: BaseToolProps) => {
+  const { t } = useTranslation();
+
+  // State for managing step collapse status
+  const [methodCollapsed, setMethodCollapsed] = useState(false);
+  const [wordsCollapsed, setWordsCollapsed] = useState(false);
+  const [advancedCollapsed, setAdvancedCollapsed] = useState(true);
+
+  const base = useBaseTool(
+    'redact',
+    useRedactParameters,
+    useRedactOperation,
+    props
+  );
+
+  // Tooltips for each step
+  const modeTips = useRedactModeTips();
+  const wordsTips = useRedactWordsTips();
+  const advancedTips = useRedactAdvancedTips();
+
+  const isExecuteDisabled = () => {
+    if (base.params.parameters.mode === 'manual') {
+      return true; // Manual mode not implemented yet
+    }
+    return !base.params.validateParameters() || !base.hasFiles || !base.endpointEnabled;
+  };
+
+  // Compute actual collapsed state based on results and user state
+  const getActualCollapsedState = (userCollapsed: boolean) => {
+    return (!base.hasFiles || base.hasResults) ? true : userCollapsed; // Force collapse when results are shown
+  };
+
+  // Build conditional steps based on redaction mode
+  const buildSteps = () => {
+    const steps = [
+      // Method selection step (always present)
+      {
+        title: t("redact.modeSelector.title", "Redaction Method"),
+        isCollapsed: getActualCollapsedState(methodCollapsed),
+        onCollapsedClick: () => base.settingsCollapsed ? base.handleSettingsReset() : setMethodCollapsed(!methodCollapsed),
+        tooltip: modeTips,
+        content: (
+          <RedactModeSelector
+            mode={base.params.parameters.mode}
+            onModeChange={(mode) => base.params.updateParameter('mode', mode)}
+            disabled={base.endpointLoading}
+          />
+        ),
+      }
+    ];
+
+    // Add mode-specific steps
+    if (base.params.parameters.mode === 'automatic') {
+      steps.push(
+        {
+          title: t("redact.auto.settings.title", "Redaction Settings"),
+          isCollapsed: getActualCollapsedState(wordsCollapsed),
+          onCollapsedClick: () => base.settingsCollapsed ? base.handleSettingsReset() : setWordsCollapsed(!wordsCollapsed),
+          tooltip: wordsTips,
+          content: <WordsToRedactInput
+            wordsToRedact={base.params.parameters.wordsToRedact}
+            onWordsChange={(words) => base.params.updateParameter('wordsToRedact', words)}
+            disabled={base.endpointLoading}
+          />,
+        },
+        {
+          title: t("redact.auto.settings.advancedTitle", "Advanced Settings"),
+          isCollapsed: getActualCollapsedState(advancedCollapsed),
+          onCollapsedClick: () => base.settingsCollapsed ? base.handleSettingsReset() : setAdvancedCollapsed(!advancedCollapsed),
+          tooltip: advancedTips,
+          content: <RedactAdvancedSettings
+            parameters={base.params.parameters}
+            onParameterChange={base.params.updateParameter}
+            disabled={base.endpointLoading}
+          />,
+        },
+      );
+    } else if (base.params.parameters.mode === 'manual') {
+      // Manual mode steps would go here when implemented
+    }
+
+    return steps;
+  };
+
+  return createToolFlow({
+    files: {
+      selectedFiles: base.selectedFiles,
+      isCollapsed: base.hasResults,
+    },
+    steps: buildSteps(),
+    executeButton: {
+      text: t("redact.submit", "Redact"),
+      isVisible: !base.hasResults,
+      loadingText: t("loading"),
+      onClick: base.handleExecute,
+      disabled: isExecuteDisabled(),
+    },
+    review: {
+      isVisible: base.hasResults,
+      operation: base.operation,
+      title: t("redact.title", "Redaction Results"),
+      onFileClick: base.handleThumbnailClick,
+      onUndo: base.handleUndo,
+    },
+  });
+};
+
+export default Redact as ToolComponent;

frontend/src/tools/RemoveCertificateSign.tsx

@@ -19,7 +19,6 @@ const RemoveCertificateSign = (props: BaseToolProps) => {
     files: {
       selectedFiles: base.selectedFiles,
       isCollapsed: base.hasResults,
-      placeholder: t("removeCertSign.files.placeholder", "Select a PDF file in the main view to get started"),
     },
     steps: [],
     executeButton: {

frontend/src/tools/Repair.tsx

@@ -19,7 +19,6 @@ const Repair = (props: BaseToolProps) => {
     files: {
       selectedFiles: base.selectedFiles,
       isCollapsed: base.hasResults,
-      placeholder: t("repair.files.placeholder", "Select a PDF file in the main view to get started"),
     },
     steps: [],
     executeButton: {

frontend/src/tools/Sanitize.tsx

@@ -20,7 +20,6 @@ const Sanitize = (props: BaseToolProps) => {
     files: {
       selectedFiles: base.selectedFiles,
       isCollapsed: base.hasResults,
-      placeholder: t("sanitize.files.placeholder", "Select a PDF file in the main view to get started"),
     },
     steps: [
       {

frontend/src/tools/SingleLargePage.tsx

@@ -19,7 +19,6 @@ const SingleLargePage = (props: BaseToolProps) => {
     files: {
       selectedFiles: base.selectedFiles,
       isCollapsed: base.hasResults,
-      placeholder: t("pdfToSinglePage.files.placeholder", "Select a PDF file in the main view to get started"),
     },
     steps: [],
     executeButton: {

frontend/src/tools/UnlockPdfForms.tsx

@@ -19,7 +19,6 @@ const UnlockPdfForms = (props: BaseToolProps) => {
     files: {
       selectedFiles: base.selectedFiles,
       isCollapsed: base.hasFiles || base.hasResults,
-      placeholder: t("unlockPDFForms.files.placeholder", "Select a PDF file in the main view to get started"),
     },
     steps: [],
     executeButton: {

frontend/src/types/embedPdf.ts

@@ -0,0 +1,43 @@
+// Types for EmbedPDF global APIs
+export interface EmbedPdfZoomAPI {
+  zoomPercent: number;
+  zoomIn: () => void;
+  zoomOut: () => void;
+}
+
+export interface EmbedPdfScrollAPI {
+  currentPage: number;
+  totalPages: number;
+  scrollToPage: (page: number) => void;
+  scrollToFirstPage: () => void;
+  scrollToPreviousPage: () => void;
+  scrollToNextPage: () => void;
+  scrollToLastPage: () => void;
+}
+
+export interface EmbedPdfPanAPI {
+  isPanning: boolean;
+}
+
+export interface EmbedPdfSpreadAPI {
+  toggleSpreadMode: () => void;
+}
+
+export interface EmbedPdfThumbnailAPI {
+  thumbnailAPI: {
+    renderThumb: (pageIndex: number, scale: number) => {
+      toPromise: () => Promise<Blob>;
+    };
+  };
+}
+
+declare global {
+  interface Window {
+    embedPdfZoom?: EmbedPdfZoomAPI;
+    embedPdfScroll?: EmbedPdfScrollAPI;
+    embedPdfPan?: EmbedPdfPanAPI;
+    embedPdfSpread?: EmbedPdfSpreadAPI;
+    embedPdfThumbnail?: EmbedPdfThumbnailAPI;
+    toggleThumbnailSidebar?: () => void;
+  }
+}

frontend/tsconfig.json

@@ -31,7 +31,6 @@
     "moduleResolution": "bundler",                     /* Specify how TypeScript looks up a file from a given module specifier. */
     "baseUrl": "./",                                  /* Specify the base directory to resolve non-relative module names. */
     "paths": {                                       /* Specify a set of entries that re-map imports to additional lookup locations. */
-      // "@framework": ["vendor/embed-pdf-viewer/packages/core/src/react/adapter.ts"]
     },
     // "rootDirs": [],                                   /* Allow multiple folders to be treated as one when resolving modules. */
     // "typeRoots": [],                                  /* Specify multiple folders that act like './node_modules/@types'. */

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testing/test_pdf_2.pdf

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