Stirling-PDF/frontend/src/hooks/useFileHandler.ts

import { useCallback } from 'react';
import { useFileState, useFileActions } from '../contexts/FileContext';
import { FileMetadata } from '../types/file';
import { FileId } from '../types/fileContext';

export const useFileHandler = () => {
  const { state } = useFileState(); // Still needed for addStoredFiles
  const { actions } = useFileActions();

  const addToActiveFiles = useCallback(async (file: File) => {
    // Let FileContext handle deduplication with quickKey logic
    await actions.addFiles([file]);
  }, [actions.addFiles]);

  const addMultipleFiles = useCallback(async (files: File[]) => {
    // Let FileContext handle deduplication with quickKey logic
    await actions.addFiles(files);
  }, [actions.addFiles]);

  // Add stored files preserving their original IDs to prevent session duplicates
  const addStoredFiles = useCallback(async (filesWithMetadata: Array<{ file: File; originalId: string; metadata: FileMetadata }>) => {
    // Filter out files that already exist with the same ID (exact match)
    const newFiles = filesWithMetadata.filter(({ originalId }) => {
      return state.files.byId[originalId as FileId] === undefined;
    });
    
    if (newFiles.length > 0) {
      await actions.addStoredFiles(newFiles.map(({file, originalId, metadata}) => ({
        file, 
        originalId: originalId as FileId, 
        metadata
      })));
    }
    
    console.log(`📁 Added ${newFiles.length} stored files (${filesWithMetadata.length - newFiles.length} skipped as duplicates)`);
  }, [state.files.byId, actions.addStoredFiles]);

  return {
    addToActiveFiles,
    addMultipleFiles,
    addStoredFiles,
  };
};