Stirling-PDF/src/main/java/stirling/software/SPDF/utils/GeneralUtils.java

package stirling.software.SPDF.utils;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.*;
import java.nio.charset.StandardCharsets;
import java.nio.file.*;
import java.nio.file.attribute.BasicFileAttributes;
import java.security.MessageDigest;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Deque;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.UUID;

import org.springframework.web.multipart.MultipartFile;

import com.fathzer.soft.javaluator.DoubleEvaluator;

import io.github.pixee.security.HostValidator;
import io.github.pixee.security.Urls;

import lombok.extern.slf4j.Slf4j;

import stirling.software.SPDF.config.InstallationPathConfig;

@Slf4j
public class GeneralUtils {

    public static File convertMultipartFileToFile(MultipartFile multipartFile) throws IOException {
        File tempFile = Files.createTempFile("temp", null).toFile();
        try (FileOutputStream os = new FileOutputStream(tempFile)) {
            os.write(multipartFile.getBytes());
        }
        return tempFile;
    }

    public static void deleteDirectory(Path path) throws IOException {
        Files.walkFileTree(
                path,
                new SimpleFileVisitor<Path>() {
                    @Override
                    public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
                            throws IOException {
                        Files.deleteIfExists(file);
                        return FileVisitResult.CONTINUE;
                    }

                    @Override
                    public FileVisitResult postVisitDirectory(Path dir, IOException exc)
                            throws IOException {
                        Files.deleteIfExists(dir);
                        return FileVisitResult.CONTINUE;
                    }
                });
    }

    public static String convertToFileName(String name) {
        String safeName = name.replaceAll("[^a-zA-Z0-9]", "_");
        if (safeName.length() > 50) {
            safeName = safeName.substring(0, 50);
        }
        return safeName;
    }

    public static boolean isValidURL(String urlStr) {
        try {
            Urls.create(
                    urlStr, Urls.HTTP_PROTOCOLS, HostValidator.DENY_COMMON_INFRASTRUCTURE_TARGETS);
            return true;
        } catch (MalformedURLException e) {
            return false;
        }
    }

    public static boolean isURLReachable(String urlStr) {
        try {
            // Parse the URL
            URL url = URI.create(urlStr).toURL();

            // Allow only http and https protocols
            String protocol = url.getProtocol();
            if (!"http".equals(protocol) && !"https".equals(protocol)) {
                return false; // Disallow other protocols
            }

            // Check if the host is a local address
            String host = url.getHost();
            if (isLocalAddress(host)) {
                return false; // Exclude local addresses
            }

            // Check if the URL is reachable
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("HEAD");
            // connection.setConnectTimeout(5000); // Set connection timeout
            // connection.setReadTimeout(5000);    // Set read timeout
            int responseCode = connection.getResponseCode();
            return (200 <= responseCode && responseCode <= 399);
        } catch (Exception e) {
            return false; // Return false in case of any exception
        }
    }

    private static boolean isLocalAddress(String host) {
        try {
            // Resolve DNS to IP address
            InetAddress address = InetAddress.getByName(host);

            // Check for local addresses
            return address.isAnyLocalAddress()
                    || // Matches 0.0.0.0 or similar
                    address.isLoopbackAddress()
                    || // Matches 127.0.0.1 or ::1
                    address.isSiteLocalAddress()
                    || // Matches private IPv4 ranges: 192.168.x.x, 10.x.x.x, 172.16.x.x to
                    // 172.31.x.x
                    address.getHostAddress()
                            .startsWith("fe80:"); // Matches link-local IPv6 addresses
        } catch (Exception e) {
            return false; // Return false for invalid or unresolved addresses
        }
    }

    public static File multipartToFile(MultipartFile multipart) throws IOException {
        Path tempFile = Files.createTempFile("overlay-", ".pdf");
        try (InputStream in = multipart.getInputStream();
                FileOutputStream out = new FileOutputStream(tempFile.toFile())) {
            byte[] buffer = new byte[1024];
            int bytesRead;
            while ((bytesRead = in.read(buffer)) != -1) {
                out.write(buffer, 0, bytesRead);
            }
        }
        return tempFile.toFile();
    }

    public static Long convertSizeToBytes(String sizeStr) {
        if (sizeStr == null) {
            return null;
        }

        sizeStr = sizeStr.trim().toUpperCase();
        sizeStr = sizeStr.replace(",", ".").replace(" ", "");
        try {
            if (sizeStr.endsWith("KB")) {
                return (long)
                        (Double.parseDouble(sizeStr.substring(0, sizeStr.length() - 2)) * 1024);
            } else if (sizeStr.endsWith("MB")) {
                return (long)
                        (Double.parseDouble(sizeStr.substring(0, sizeStr.length() - 2))
                                * 1024
                                * 1024);
            } else if (sizeStr.endsWith("GB")) {
                return (long)
                        (Double.parseDouble(sizeStr.substring(0, sizeStr.length() - 2))
                                * 1024
                                * 1024
                                * 1024);
            } else if (sizeStr.endsWith("B")) {
                return Long.parseLong(sizeStr.substring(0, sizeStr.length() - 1));
            } else {
                // Assume MB if no unit is specified
                return (long) (Double.parseDouble(sizeStr) * 1024 * 1024);
            }
        } catch (NumberFormatException e) {
            // The numeric part of the input string cannot be parsed, handle this case
        }

        return null;
    }

    public static List<Integer> parsePageList(String pages, int totalPages, boolean oneBased) {
        if (pages == null) {
            return List.of(1); // Default to first page if input is null
        }
        try {
            return parsePageList(pages.split(","), totalPages, oneBased);
        } catch (NumberFormatException e) {
            return List.of(1); // Default to first page if input is invalid
        }
    }

    public static List<Integer> parsePageList(String[] pages, int totalPages) {
        return parsePageList(pages, totalPages, false);
    }

    public static List<Integer> parsePageList(String[] pages, int totalPages, boolean oneBased) {
        List<Integer> result = new ArrayList<>();
        int offset = oneBased ? 1 : 0;
        for (String page : pages) {
            if ("all".equalsIgnoreCase(page)) {

                for (int i = 0; i < totalPages; i++) {
                    result.add(i + offset);
                }
            } else if (page.contains(",")) {
                // Split the string into parts, could be single pages or ranges
                String[] parts = page.split(",");
                for (String part : parts) {
                    result.addAll(handlePart(part, totalPages, offset));
                }
            } else {
                result.addAll(handlePart(page, totalPages, offset));
            }
        }
        return result;
    }

    public static List<Integer> evaluateNFunc(String expression, int maxValue) {
        List<Integer> results = new ArrayList<>();
        DoubleEvaluator evaluator = new DoubleEvaluator();

        // Validate the expression
        if (!expression.matches("[0-9n+\\-*/() ]+")) {
            throw new IllegalArgumentException("Invalid expression");
        }

        for (int n = 1; n <= maxValue; n++) {
            // Replace 'n' with the current value of n, correctly handling numbers before
            // 'n'
            String sanitizedExpression = sanitizeNFunction(expression, n);
            Double result = evaluator.evaluate(sanitizedExpression);

            // Check if the result is null or not within bounds
            if (result == null) break;

            if (result.intValue() > 0 && result.intValue() <= maxValue)
                results.add(result.intValue());
        }

        return results;
    }

    private static String sanitizeNFunction(String expression, int nValue) {
        String sanitizedExpression = expression.replace(" ", "");
        String multiplyByOpeningRoundBracketPattern =
                "([0-9n)])\\("; // example: n(n-1), 9(n-1), (n-1)(n-2)
        sanitizedExpression =
                sanitizedExpression.replaceAll(multiplyByOpeningRoundBracketPattern, "$1*(");

        String multiplyByClosingRoundBracketPattern =
                "\\)([0-9n)])"; // example: (n-1)n, (n-1)9, (n-1)(n-2)
        sanitizedExpression =
                sanitizedExpression.replaceAll(multiplyByClosingRoundBracketPattern, ")*$1");

        sanitizedExpression = insertMultiplicationBeforeN(sanitizedExpression, nValue);
        return sanitizedExpression;
    }

    private static String insertMultiplicationBeforeN(String expression, int nValue) {
        // Insert multiplication between a number and 'n' (e.g., "4n" becomes "4*n")
        String withMultiplication = expression.replaceAll("(\\d)n", "$1*n");
        withMultiplication = formatConsecutiveNsForNFunction(withMultiplication);
        // Now replace 'n' with its current value
        return withMultiplication.replace("n", String.valueOf(nValue));
    }

    private static String formatConsecutiveNsForNFunction(String expression) {
        String text = expression;
        while (text.matches(".*n{2,}.*")) {
            text = text.replaceAll("(?<!n)n{2}", "n*n");
        }
        return text;
    }

    private static List<Integer> handlePart(String part, int totalPages, int offset) {
        List<Integer> partResult = new ArrayList<>();

        // First check for n-syntax because it should not be processed as a range
        if (part.contains("n")) {
            partResult = evaluateNFunc(part, totalPages);
            // Adjust the results according to the offset
            for (int i = 0; i < partResult.size(); i++) {
                int adjustedValue = partResult.get(i) - 1 + offset;
                partResult.set(i, adjustedValue);
            }
        } else if (part.contains("-")) {
            // Process ranges only if it's not n-syntax
            String[] rangeParts = part.split("-");
            try {
                int start = Integer.parseInt(rangeParts[0]);
                int end =
                        (rangeParts.length > 1 && !rangeParts[1].isEmpty())
                                ? Integer.parseInt(rangeParts[1])
                                : totalPages;
                for (int i = start; i <= end; i++) {
                    if (i >= 1 && i <= totalPages) {
                        partResult.add(i - 1 + offset);
                    }
                }
            } catch (NumberFormatException e) {
                // Range is invalid, ignore this part
            }
        } else {
            // This is a single page number
            try {
                int pageNum = Integer.parseInt(part.trim());
                if (pageNum >= 1 && pageNum <= totalPages) {
                    partResult.add(pageNum - 1 + offset);
                }
            } catch (NumberFormatException ignored) {
                // Ignore invalid numbers
            }
        }
        return partResult;
    }

    public static boolean createDir(String path) {
        Path folder = Paths.get(path);
        if (!Files.exists(folder)) {
            try {
                Files.createDirectories(folder);
            } catch (IOException e) {
                log.error("exception", e);
                return false;
            }
        }
        return true;
    }

    public static boolean isValidUUID(String uuid) {
        if (uuid == null) {
            return false;
        }
        try {
            UUID.fromString(uuid);
            return true;
        } catch (IllegalArgumentException e) {
            return false;
        }
    }

    public static void saveKeyToConfig(String id, String key) throws IOException {
        saveKeyToConfig(id, key, true);
    }

    public static void saveKeyToConfig(String id, boolean key) throws IOException {
        saveKeyToConfig(id, key, true);
    }

    public static void saveKeyToConfig(String id, String key, boolean autoGenerated)
            throws IOException {
        doSaveKeyToConfig(id, (key == null ? "" : key), autoGenerated);
    }

    public static void saveKeyToConfig(String id, boolean key, boolean autoGenerated)
            throws IOException {
        doSaveKeyToConfig(id, String.valueOf(key), autoGenerated);
    }

    /*------------------------------------------------------------------------*
     *                  Internal Implementation Details                       *
     *------------------------------------------------------------------------*/

    /**
     * Actually performs the line-based update for the given path (e.g. "security.csrfDisabled") to
     * a new string value (e.g. "true"), possibly marking it as auto-generated.
     */
    private static void doSaveKeyToConfig(String fullPath, String newValue, boolean autoGenerated)
            throws IOException {
        // 1) Load the file (settings.yml)
        Path settingsPath = Paths.get(InstallationPathConfig.getSettingsPath());
        if (!Files.exists(settingsPath)) {
            log.warn("Settings file not found at {}, creating a new empty file...", settingsPath);
            Files.createDirectories(settingsPath.getParent());
            Files.createFile(settingsPath);
        }
        List<String> lines = Files.readAllLines(settingsPath);

        // 2) Build a map of "nestedKeyPath -> lineIndex" by parsing indentation
        //    Also track each line's indentation so we can preserve it when rewriting.
        Map<String, LineInfo> pathToLine = parseNestedYamlKeys(lines);

        // 3) If the path is found, rewrite its line. Else, append at the bottom (no indentation).
        boolean changed = false;
        if (pathToLine.containsKey(fullPath)) {
            // Rewrite existing line
            LineInfo info = pathToLine.get(fullPath);
            String oldLine = lines.get(info.lineIndex);
            String newLine =
                    rewriteLine(oldLine, info.indentSpaces, fullPath, newValue, autoGenerated);
            if (!newLine.equals(oldLine)) {
                lines.set(info.lineIndex, newLine);
                changed = true;
            }
        } else {
            // Append a new line at the bottom, with zero indentation
            String appended = fullPath + ": " + newValue;
            if (autoGenerated) {
                appended += " # Automatically Generated Settings (Do Not Edit Directly)";
            }
            lines.add(appended);
            changed = true;
        }

        // 4) If changed, write back to file
        if (changed) {
            Files.write(settingsPath, lines);
            log.info(
                    "Updated '{}' to '{}' (autoGenerated={}) in {}",
                    fullPath,
                    newValue,
                    autoGenerated,
                    settingsPath);
        } else {
            log.info("No changes for '{}' (already set to '{}').", fullPath, newValue);
        }
    }

    /** A small record-like class that holds: - lineIndex - indentSpaces */
    private static class LineInfo {
        int lineIndex;
        int indentSpaces;

        public LineInfo(int lineIndex, int indentSpaces) {
            this.lineIndex = lineIndex;
            this.indentSpaces = indentSpaces;
        }
    }

    /**
     * Parse the YAML lines to build a map: "full.nested.key" -> (lineIndex, indentSpaces). We do a
     * naive indentation-based path stacking: - 2 spaces = 1 indent level - lines that start with
     * fewer or equal indentation pop the stack - lines that look like "key:" or "key: value" cause
     * a push
     */
    private static Map<String, LineInfo> parseNestedYamlKeys(List<String> lines) {
        Map<String, LineInfo> result = new HashMap<>();

        // We'll maintain a stack of (keyName, indentLevel).
        // Each line that looks like "myKey:" or "myKey: value" is a new "child" of the top of the
        // stack if indent is deeper.
        Deque<String> pathStack = new ArrayDeque<>();
        Deque<Integer> indentStack = new ArrayDeque<>();
        indentStack.push(-1); // sentinel

        for (int i = 0; i < lines.size(); i++) {
            String line = lines.get(i);
            String trimmed = line.trim();

            // skip blank lines, comment lines, or list items
            if (trimmed.isEmpty() || trimmed.startsWith("#") || trimmed.startsWith("-")) {
                continue;
            }
            // check if there's a colon
            int colonIdx = trimmed.indexOf(':');
            if (colonIdx <= 0) { // must have at least one char before ':'
                continue;
            }
            // parse out key
            String keyPart = trimmed.substring(0, colonIdx).trim();
            if (keyPart.isEmpty()) {
                continue;
            }

            // count leading spaces for indentation
            int leadingSpaces = countLeadingSpaces(line);
            int indentLevel = leadingSpaces / 2; // assume 2 spaces per level

            // pop from stack until we get to a shallower indentation
            while (indentStack.peek() != null && indentStack.peek() >= indentLevel) {
                indentStack.pop();
                pathStack.pop();
            }

            // push the new key
            pathStack.push(keyPart);
            indentStack.push(indentLevel);

            // build the full path
            String[] arr = pathStack.toArray(new String[0]);
            List<String> reversed = Arrays.asList(arr);
            Collections.reverse(reversed);
            String fullPath = String.join(".", reversed);

            // store line info
            result.put(fullPath, new LineInfo(i, leadingSpaces));
        }

        return result;
    }

    /**
     * Rewrite a single line to set a new value, preserving indentation and (optionally) the
     * existing or auto-generated inline comment.
     *
     * <p>For example, oldLine might be: " csrfDisabled: false # set to 'true' to disable CSRF
     * protection" newValue = "true" autoGenerated = false
     *
     * <p>We'll produce something like: " csrfDisabled: true # set to 'true' to disable CSRF
     * protection"
     */
    private static String rewriteLine(
            String oldLine, int indentSpaces, String path, String newValue, boolean autoGenerated) {
        // We'll keep the exact leading indentation (indentSpaces).
        // Then "key: newValue". We'll try to preserve any existing inline comment unless
        // autoGenerated is true.

        // 1) Extract leading spaces from the old line (just in case they differ from indentSpaces).
        int actualLeadingSpaces = countLeadingSpaces(oldLine);
        String leading = oldLine.substring(0, actualLeadingSpaces);

        // 2) Remove leading spaces from the rest
        String trimmed = oldLine.substring(actualLeadingSpaces);

        // 3) Check for existing comment
        int hashIndex = trimmed.indexOf('#');
        String lineWithoutComment =
                (hashIndex >= 0) ? trimmed.substring(0, hashIndex).trim() : trimmed.trim();
        String oldComment = (hashIndex >= 0) ? trimmed.substring(hashIndex).trim() : "";

        // 4) Rebuild "key: newValue"
        // The "key" here is everything before ':' in lineWithoutComment
        int colonIdx = lineWithoutComment.indexOf(':');
        String existingKey =
                (colonIdx >= 0)
                        ? lineWithoutComment.substring(0, colonIdx).trim()
                        : path; // fallback if line is malformed

        StringBuilder sb = new StringBuilder();
        sb.append(leading); // restore original leading spaces

        // "key: newValue"
        sb.append(existingKey).append(": ").append(newValue);

        // 5) If autoGenerated, add/replace comment
        if (autoGenerated) {
            sb.append(" # Automatically Generated Settings (Do Not Edit Directly)");
        } else {
            // preserve the old comment if it exists
            if (!oldComment.isEmpty()) {
                sb.append(" ").append(oldComment);
            }
        }
        return sb.toString();
    }

    private static int countLeadingSpaces(String line) {
        int count = 0;
        for (char c : line.toCharArray()) {
            if (c == ' ') count++;
            else break;
        }
        return count;
    }

    public static String generateMachineFingerprint() {
        try {
            // Get the MAC address
            StringBuilder sb = new StringBuilder();
            InetAddress ip = InetAddress.getLocalHost();
            NetworkInterface network = NetworkInterface.getByInetAddress(ip);

            if (network == null) {
                Enumeration<NetworkInterface> networks = NetworkInterface.getNetworkInterfaces();
                while (networks.hasMoreElements()) {
                    NetworkInterface net = networks.nextElement();
                    byte[] mac = net.getHardwareAddress();
                    if (mac != null) {
                        for (int i = 0; i < mac.length; i++) {
                            sb.append(String.format("%02X", mac[i]));
                        }
                        break; // Use the first network interface with a MAC address
                    }
                }
            } else {
                byte[] mac = network.getHardwareAddress();
                if (mac != null) {
                    for (int i = 0; i < mac.length; i++) {
                        sb.append(String.format("%02X", mac[i]));
                    }
                }
            }

            // Hash the MAC address for privacy and consistency
            MessageDigest md = MessageDigest.getInstance("SHA-256");
            byte[] hash = md.digest(sb.toString().getBytes(StandardCharsets.UTF_8));
            StringBuilder fingerprint = new StringBuilder();
            for (byte b : hash) {
                fingerprint.append(String.format("%02x", b));
            }
            return fingerprint.toString();
        } catch (Exception e) {
            return "GenericID";
        }
    }

    public static boolean isVersionHigher(String currentVersion, String compareVersion) {
        if (currentVersion == null || compareVersion == null) {
            return false;
        }

        // Split versions into components
        String[] current = currentVersion.split("\\.");
        String[] compare = compareVersion.split("\\.");

        // Get the length of the shorter version array
        int length = Math.min(current.length, compare.length);

        // Compare each component
        for (int i = 0; i < length; i++) {
            int currentPart = Integer.parseInt(current[i]);
            int comparePart = Integer.parseInt(compare[i]);

            if (currentPart > comparePart) {
                return true;
            }
            if (currentPart < comparePart) {
                return false;
            }
        }

        // If all components so far are equal, the longer version is considered higher
        return current.length > compare.length;
    }
}