/**
 * @license
 * Copyright 2025 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */
import fs from 'node:fs';
import fsPromises from 'node:fs/promises';
import path from 'node:path';
// eslint-disable-next-line import/no-internal-modules
import mime from 'mime/lite';
import { ToolErrorType } from '../tools/tool-error.js';
import { BINARY_EXTENSIONS } from './ignorePatterns.js';
import { createRequire as createModuleRequire } from 'node:module';
import { debugLogger } from './debugLogger.js';
const requireModule = createModuleRequire(import.meta.url);
export async function readWasmBinaryFromDisk(specifier) {
    const resolvedPath = requireModule.resolve(specifier);
    const buffer = await fsPromises.readFile(resolvedPath);
    return new Uint8Array(buffer);
}
export async function loadWasmBinary(dynamicImport, fallbackSpecifier) {
    try {
        const module = await dynamicImport();
        if (module?.default instanceof Uint8Array) {
            return module.default;
        }
    }
    catch (error) {
        try {
            return await readWasmBinaryFromDisk(fallbackSpecifier);
        }
        catch {
            throw error;
        }
    }
    try {
        return await readWasmBinaryFromDisk(fallbackSpecifier);
    }
    catch (error) {
        throw new Error('WASM binary module did not provide a Uint8Array export', {
            cause: error,
        });
    }
}
// Constants for text file processing
const DEFAULT_MAX_LINES_TEXT_FILE = 2000;
const MAX_LINE_LENGTH_TEXT_FILE = 2000;
// Default values for encoding and separator format
export const DEFAULT_ENCODING = 'utf-8';
/**
 * Detect a Unicode BOM (Byte Order Mark) if present.
 * Reads up to the first 4 bytes and returns encoding + BOM length, else null.
 */
export function detectBOM(buf) {
    if (buf.length >= 4) {
        // UTF-32 LE: FF FE 00 00
        if (buf[0] === 0xff &&
            buf[1] === 0xfe &&
            buf[2] === 0x00 &&
            buf[3] === 0x00) {
            return { encoding: 'utf32le', bomLength: 4 };
        }
        // UTF-32 BE: 00 00 FE FF
        if (buf[0] === 0x00 &&
            buf[1] === 0x00 &&
            buf[2] === 0xfe &&
            buf[3] === 0xff) {
            return { encoding: 'utf32be', bomLength: 4 };
        }
    }
    if (buf.length >= 3) {
        // UTF-8: EF BB BF
        if (buf[0] === 0xef && buf[1] === 0xbb && buf[2] === 0xbf) {
            return { encoding: 'utf8', bomLength: 3 };
        }
    }
    if (buf.length >= 2) {
        // UTF-16 LE: FF FE  (but not UTF-32 LE already matched above)
        if (buf[0] === 0xff &&
            buf[1] === 0xfe &&
            (buf.length < 4 || buf[2] !== 0x00 || buf[3] !== 0x00)) {
            return { encoding: 'utf16le', bomLength: 2 };
        }
        // UTF-16 BE: FE FF
        if (buf[0] === 0xfe && buf[1] === 0xff) {
            return { encoding: 'utf16be', bomLength: 2 };
        }
    }
    return null;
}
/**
 * Convert a UTF-16 BE buffer to a JS string by swapping to LE then using Node's decoder.
 * (Node has 'utf16le' but not 'utf16be'.)
 */
function decodeUTF16BE(buf) {
    if (buf.length === 0)
        return '';
    const swapped = Buffer.from(buf); // swap16 mutates in place, so copy
    swapped.swap16();
    return swapped.toString('utf16le');
}
/**
 * Decode a UTF-32 buffer (LE or BE) into a JS string.
 * Invalid code points are replaced with U+FFFD, partial trailing bytes are ignored.
 */
function decodeUTF32(buf, littleEndian) {
    if (buf.length < 4)
        return '';
    const usable = buf.length - (buf.length % 4);
    let out = '';
    for (let i = 0; i < usable; i += 4) {
        const cp = littleEndian
            ? (buf[i] |
                (buf[i + 1] << 8) |
                (buf[i + 2] << 16) |
                (buf[i + 3] << 24)) >>>
                0
            : (buf[i + 3] |
                (buf[i + 2] << 8) |
                (buf[i + 1] << 16) |
                (buf[i] << 24)) >>>
                0;
        // Valid planes: 0x0000..0x10FFFF excluding surrogates
        if (cp <= 0x10ffff && !(cp >= 0xd800 && cp <= 0xdfff)) {
            out += String.fromCodePoint(cp);
        }
        else {
            out += '\uFFFD';
        }
    }
    return out;
}
/**
 * Read a file as text, honoring BOM encodings (UTF‑8/16/32) and stripping the BOM.
 * Falls back to utf8 when no BOM is present.
 */
export async function readFileWithEncoding(filePath) {
    // Read the file once; detect BOM and decode from the single buffer.
    const full = await fs.promises.readFile(filePath);
    if (full.length === 0)
        return '';
    const bom = detectBOM(full);
    if (!bom) {
        // No BOM → treat as UTF‑8
        return full.toString('utf8');
    }
    // Strip BOM and decode per encoding
    const content = full.subarray(bom.bomLength);
    switch (bom.encoding) {
        case 'utf8':
            return content.toString('utf8');
        case 'utf16le':
            return content.toString('utf16le');
        case 'utf16be':
            return decodeUTF16BE(content);
        case 'utf32le':
            return decodeUTF32(content, true);
        case 'utf32be':
            return decodeUTF32(content, false);
        default:
            // Defensive fallback; should be unreachable
            return content.toString('utf8');
    }
}
/**
 * Looks up the specific MIME type for a file path.
 * @param filePath Path to the file.
 * @returns The specific MIME type string (e.g., 'text/python', 'application/javascript') or undefined if not found or ambiguous.
 */
export function getSpecificMimeType(filePath) {
    const lookedUpMime = mime.getType(filePath);
    return typeof lookedUpMime === 'string' ? lookedUpMime : undefined;
}
/**
 * Checks if a path is within a given root directory.
 * @param pathToCheck The absolute path to check.
 * @param rootDirectory The absolute root directory.
 * @returns True if the path is within the root directory, false otherwise.
 */
export function isWithinRoot(pathToCheck, rootDirectory) {
    const normalizedPathToCheck = path.resolve(pathToCheck);
    const normalizedRootDirectory = path.resolve(rootDirectory);
    // Ensure the rootDirectory path ends with a separator for correct startsWith comparison,
    // unless it's the root path itself (e.g., '/' or 'C:\').
    const rootWithSeparator = normalizedRootDirectory === path.sep ||
        normalizedRootDirectory.endsWith(path.sep)
        ? normalizedRootDirectory
        : normalizedRootDirectory + path.sep;
    return (normalizedPathToCheck === normalizedRootDirectory ||
        normalizedPathToCheck.startsWith(rootWithSeparator));
}
/**
 * Heuristic: determine if a file is likely binary.
 * Now BOM-aware: if a Unicode BOM is detected, we treat it as text.
 * For non-BOM files, retain the existing null-byte and non-printable ratio checks.
 */
export async function isBinaryFile(filePath) {
    let fh = null;
    try {
        fh = await fs.promises.open(filePath, 'r');
        const stats = await fh.stat();
        const fileSize = stats.size;
        if (fileSize === 0)
            return false; // empty is not binary
        // Sample up to 4KB from the head (previous behavior)
        const sampleSize = Math.min(4096, fileSize);
        const buf = Buffer.alloc(sampleSize);
        const { bytesRead } = await fh.read(buf, 0, sampleSize, 0);
        if (bytesRead === 0)
            return false;
        // BOM → text (avoid false positives for UTF‑16/32 with nulls)
        const bom = detectBOM(buf.subarray(0, Math.min(4, bytesRead)));
        if (bom)
            return false;
        let nonPrintableCount = 0;
        for (let i = 0; i < bytesRead; i++) {
            if (buf[i] === 0)
                return true; // strong indicator of binary when no BOM
            if (buf[i] < 9 || (buf[i] > 13 && buf[i] < 32)) {
                nonPrintableCount++;
            }
        }
        // If >30% non-printable characters, consider it binary
        return nonPrintableCount / bytesRead > 0.3;
    }
    catch (error) {
        debugLogger.warn(`Failed to check if file is binary: ${filePath}`, error instanceof Error ? error.message : String(error));
        return false;
    }
    finally {
        if (fh) {
            try {
                await fh.close();
            }
            catch (closeError) {
                debugLogger.warn(`Failed to close file handle for: ${filePath}`, closeError instanceof Error ? closeError.message : String(closeError));
            }
        }
    }
}
/**
 * Detects the type of file based on extension and content.
 * @param filePath Path to the file.
 * @returns Promise that resolves to 'text', 'image', 'pdf', 'audio', 'video', 'binary' or 'svg'.
 */
export async function detectFileType(filePath) {
    const ext = path.extname(filePath).toLowerCase();
    // The mimetype for various TypeScript extensions (ts, mts, cts, tsx) can be
    // MPEG transport stream (a video format), but we want to assume these are
    // TypeScript files instead.
    if (['.ts', '.mts', '.cts'].includes(ext)) {
        return 'text';
    }
    if (ext === '.svg') {
        return 'svg';
    }
    const lookedUpMimeType = mime.getType(filePath); // Returns null if not found, or the mime type string
    if (lookedUpMimeType) {
        if (lookedUpMimeType.startsWith('image/')) {
            return 'image';
        }
        if (lookedUpMimeType.startsWith('audio/')) {
            return 'audio';
        }
        if (lookedUpMimeType.startsWith('video/')) {
            return 'video';
        }
        if (lookedUpMimeType === 'application/pdf') {
            return 'pdf';
        }
    }
    // Stricter binary check for common non-text extensions before content check
    // These are often not well-covered by mime-types or might be misidentified.
    if (BINARY_EXTENSIONS.includes(ext)) {
        return 'binary';
    }
    // Fall back to content-based check if mime type wasn't conclusive for image/pdf
    // and it's not a known binary extension.
    if (await isBinaryFile(filePath)) {
        return 'binary';
    }
    return 'text';
}
/**
 * Reads and processes a single file, handling text, images, and PDFs.
 * @param filePath Absolute path to the file.
 * @param rootDirectory Absolute path to the project root for relative path display.
 * @param offset Optional offset for text files (0-based line number).
 * @param limit Optional limit for text files (number of lines to read).
 * @returns ProcessedFileReadResult object.
 */
export async function processSingleFileContent(filePath, rootDirectory, fileSystemService, offset, limit) {
    try {
        if (!fs.existsSync(filePath)) {
            // Sync check is acceptable before async read
            return {
                llmContent: 'Could not read file because no file was found at the specified path.',
                returnDisplay: 'File not found.',
                error: `File not found: ${filePath}`,
                errorType: ToolErrorType.FILE_NOT_FOUND,
            };
        }
        const stats = await fs.promises.stat(filePath);
        if (stats.isDirectory()) {
            return {
                llmContent: 'Could not read file because the provided path is a directory, not a file.',
                returnDisplay: 'Path is a directory.',
                error: `Path is a directory, not a file: ${filePath}`,
                errorType: ToolErrorType.TARGET_IS_DIRECTORY,
            };
        }
        const fileSizeInMB = stats.size / (1024 * 1024);
        if (fileSizeInMB > 20) {
            return {
                llmContent: 'File size exceeds the 20MB limit.',
                returnDisplay: 'File size exceeds the 20MB limit.',
                error: `File size exceeds the 20MB limit: ${filePath} (${fileSizeInMB.toFixed(2)}MB)`,
                errorType: ToolErrorType.FILE_TOO_LARGE,
            };
        }
        const fileType = await detectFileType(filePath);
        const relativePathForDisplay = path
            .relative(rootDirectory, filePath)
            .replace(/\\/g, '/');
        switch (fileType) {
            case 'binary': {
                return {
                    llmContent: `Cannot display content of binary file: ${relativePathForDisplay}`,
                    returnDisplay: `Skipped binary file: ${relativePathForDisplay}`,
                };
            }
            case 'svg': {
                const SVG_MAX_SIZE_BYTES = 1 * 1024 * 1024;
                if (stats.size > SVG_MAX_SIZE_BYTES) {
                    return {
                        llmContent: `Cannot display content of SVG file larger than 1MB: ${relativePathForDisplay}`,
                        returnDisplay: `Skipped large SVG file (>1MB): ${relativePathForDisplay}`,
                    };
                }
                const content = await readFileWithEncoding(filePath);
                return {
                    llmContent: content,
                    returnDisplay: `Read SVG as text: ${relativePathForDisplay}`,
                };
            }
            case 'text': {
                // Use BOM-aware reader to avoid leaving a BOM character in content and to support UTF-16/32 transparently
                const content = await readFileWithEncoding(filePath);
                const lines = content.split('\n');
                const originalLineCount = lines.length;
                const startLine = offset || 0;
                const effectiveLimit = limit === undefined ? DEFAULT_MAX_LINES_TEXT_FILE : limit;
                // Ensure endLine does not exceed originalLineCount
                const endLine = Math.min(startLine + effectiveLimit, originalLineCount);
                // Ensure selectedLines doesn't try to slice beyond array bounds if startLine is too high
                const actualStartLine = Math.min(startLine, originalLineCount);
                const selectedLines = lines.slice(actualStartLine, endLine);
                let linesWereTruncatedInLength = false;
                const formattedLines = selectedLines.map((line) => {
                    if (line.length > MAX_LINE_LENGTH_TEXT_FILE) {
                        linesWereTruncatedInLength = true;
                        return (line.substring(0, MAX_LINE_LENGTH_TEXT_FILE) + '... [truncated]');
                    }
                    return line;
                });
                const contentRangeTruncated = startLine > 0 || endLine < originalLineCount;
                const isTruncated = contentRangeTruncated || linesWereTruncatedInLength;
                const llmContent = formattedLines.join('\n');
                // By default, return nothing to streamline the common case of a successful read_file.
                let returnDisplay = '';
                if (contentRangeTruncated) {
                    returnDisplay = `Read lines ${actualStartLine + 1}-${endLine} of ${originalLineCount} from ${relativePathForDisplay}`;
                    if (linesWereTruncatedInLength) {
                        returnDisplay += ' (some lines were shortened)';
                    }
                }
                else if (linesWereTruncatedInLength) {
                    returnDisplay = `Read all ${originalLineCount} lines from ${relativePathForDisplay} (some lines were shortened)`;
                }
                return {
                    llmContent,
                    returnDisplay,
                    isTruncated,
                    originalLineCount,
                    linesShown: [actualStartLine + 1, endLine],
                };
            }
            case 'image':
            case 'pdf':
            case 'audio':
            case 'video': {
                const contentBuffer = await fs.promises.readFile(filePath);
                const base64Data = contentBuffer.toString('base64');
                return {
                    llmContent: {
                        inlineData: {
                            data: base64Data,
                            mimeType: mime.getType(filePath) || 'application/octet-stream',
                        },
                    },
                    returnDisplay: `Read ${fileType} file: ${relativePathForDisplay}`,
                };
            }
            default: {
                // Should not happen with current detectFileType logic
                const exhaustiveCheck = fileType;
                return {
                    llmContent: `Unhandled file type: ${exhaustiveCheck}`,
                    returnDisplay: `Skipped unhandled file type: ${relativePathForDisplay}`,
                    error: `Unhandled file type for ${filePath}`,
                };
            }
        }
    }
    catch (error) {
        const errorMessage = error instanceof Error ? error.message : String(error);
        const displayPath = path
            .relative(rootDirectory, filePath)
            .replace(/\\/g, '/');
        return {
            llmContent: `Error reading file ${displayPath}: ${errorMessage}`,
            returnDisplay: `Error reading file ${displayPath}: ${errorMessage}`,
            error: `Error reading file ${filePath}: ${errorMessage}`,
            errorType: ToolErrorType.READ_CONTENT_FAILURE,
        };
    }
}
export async function fileExists(filePath) {
    try {
        await fsPromises.access(filePath, fs.constants.F_OK);
        return true;
    }
    catch (_) {
        return false;
    }
}
//# sourceMappingURL=fileUtils.js.map