d943771f36
- Introduced PDFMathTranslate converter to handle PDF translations while preserving mathematical formulas. - Updated Dockerfile to include necessary dependencies and pre-download models during build. - Enhanced README.md to document the new converter and its features. - Added tests for PDFMathTranslate to ensure correct functionality and error handling.
326 lines
9.5 KiB
TypeScript
326 lines
9.5 KiB
TypeScript
import { execFile as execFileOriginal } from "node:child_process";
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import { mkdirSync, existsSync, readdirSync, unlinkSync, rmdirSync, copyFileSync } from "node:fs";
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import { join, basename, dirname } from "node:path";
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import { ExecFileFn } from "./types";
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import { getArchiveFileName } from "../transfer";
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/**
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* PDFMathTranslate Content Engine
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*
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* 用於翻譯 PDF 文件同時保留數學公式的引擎。
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*
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* 使用 pdf2zh CLI 工具進行翻譯，支援多種目標語言。
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* 所有輸出一律打包為 .tar 檔案，包含：
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* - original.pdf（原始 PDF）
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* - translated-<lang>.pdf（翻譯後的 PDF）
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*
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* 必須在 Docker build 階段預先下載所需模型，
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* 不允許在 runtime 隱式下載模型。
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*/
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// 支援的目標語言列表
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const SUPPORTED_LANGUAGES = [
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"en", // English
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"zh", // Chinese (Simplified)
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"zh-TW", // Chinese (Traditional)
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"ja", // Japanese
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"ko", // Korean
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"de", // German
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"fr", // French
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"es", // Spanish
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"it", // Italian
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"pt", // Portuguese
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"ru", // Russian
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"ar", // Arabic
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"hi", // Hindi
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"vi", // Vietnamese
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"th", // Thai
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] as const;
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type SupportedLanguage = typeof SUPPORTED_LANGUAGES[number];
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// 模型路徑（Docker 環境中）
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const MODELS_PATH = process.env.PDFMATHTRANSLATE_MODELS_PATH || "/models/pdfmathtranslate";
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// 生成 from/to 格式映射
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function generateLanguageMappings(): { from: Record<string, string[]>; to: Record<string, string[]> } {
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const outputFormats = SUPPORTED_LANGUAGES.map(lang => `pdf-${lang}`);
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return {
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from: {
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document: ["pdf"],
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},
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to: {
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document: outputFormats as unknown as string[],
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},
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};
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}
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export const properties = {
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...generateLanguageMappings(),
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outputMode: "archive" as const,
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};
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/**
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* 從 convertTo 格式中提取目標語言
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* @param convertTo 格式如 "pdf-zh" 或 "pdf-en"
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* @returns 目標語言代碼
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*/
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function extractTargetLanguage(convertTo: string): string {
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// convertTo 格式: pdf-<lang>
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const match = convertTo.match(/^pdf-(.+)$/);
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if (!match || !match[1]) {
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throw new Error(`Invalid convertTo format: ${convertTo}. Expected pdf-<lang>`);
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}
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return match[1];
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}
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/**
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* 檢查模型是否已預先下載
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* @returns 模型是否存在
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*/
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function checkModelsExist(): boolean {
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// 檢查 ONNX 模型目錄是否存在
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if (!existsSync(MODELS_PATH)) {
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console.warn(`[PDFMathTranslate] Models directory not found: ${MODELS_PATH}`);
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console.warn(`[PDFMathTranslate] Models should be pre-downloaded during Docker build.`);
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return false;
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}
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return true;
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}
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/**
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* Helper function to create a .tar archive from a directory (no compression)
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*
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* ⚠️ 重要：僅使用 .tar 格式，禁止 .tar.gz / .tgz / .zip
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*/
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function createTarArchive(
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sourceDir: string,
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outputTar: string,
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execFile: ExecFileFn,
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): Promise<void> {
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return new Promise((resolve, reject) => {
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// Use tar command to create archive (without gzip compression)
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// tar -cf <output.tar> -C <sourceDir> .
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// 注意：使用 -cf 而非 -czf，避免 gzip 壓縮
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execFile(
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"tar",
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["-cf", outputTar, "-C", sourceDir, "."],
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(error, stdout, stderr) => {
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if (error) {
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reject(`tar error: ${error}`);
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return;
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}
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if (stdout) {
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console.log(`tar stdout: ${stdout}`);
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}
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if (stderr) {
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console.error(`tar stderr: ${stderr}`);
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}
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resolve();
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},
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);
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});
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}
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/**
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* Helper function to remove a directory recursively
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*/
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function removeDir(dirPath: string): void {
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if (existsSync(dirPath)) {
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const files = readdirSync(dirPath, { withFileTypes: true });
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for (const file of files) {
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const filePath = join(dirPath, file.name);
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if (file.isDirectory()) {
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removeDir(filePath);
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} else {
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unlinkSync(filePath);
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}
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}
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rmdirSync(dirPath);
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}
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}
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/**
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* 執行 pdf2zh 命令進行 PDF 翻譯
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*
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* @param inputPath 輸入 PDF 路徑
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* @param outputDir 輸出目錄
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* @param targetLang 目標語言
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* @param execFile 執行函數
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*/
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function runPdf2zh(
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inputPath: string,
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outputDir: string,
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targetLang: string,
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execFile: ExecFileFn,
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): Promise<{ monoPath: string; dualPath: string }> {
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return new Promise((resolve, reject) => {
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// pdf2zh CLI 參數：
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// -lo <lang>: 目標語言
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// -o <dir>: 輸出目錄
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// -s google: 使用 Google 翻譯（預設，免費）
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//
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// 輸出檔案：
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// - <filename>-mono.pdf: 純翻譯版本
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// - <filename>-dual.pdf: 雙語對照版本
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const args = [
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inputPath,
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"-lo", targetLang,
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"-o", outputDir,
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"-s", process.env.PDFMATHTRANSLATE_SERVICE || "google",
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];
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// 如果設定了自訂模型路徑，使用 --onnx 參數
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if (existsSync(MODELS_PATH)) {
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const onnxModelPath = join(MODELS_PATH, "model.onnx");
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if (existsSync(onnxModelPath)) {
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args.push("--onnx", onnxModelPath);
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}
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}
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console.log(`[PDFMathTranslate] Running: pdf2zh ${args.join(" ")}`);
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execFile("pdf2zh", args, (error, stdout, stderr) => {
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if (error) {
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reject(`pdf2zh error: ${error}\nstderr: ${stderr}`);
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return;
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}
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if (stdout) {
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console.log(`[PDFMathTranslate] stdout: ${stdout}`);
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}
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if (stderr) {
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console.log(`[PDFMathTranslate] stderr: ${stderr}`);
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}
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// 找到輸出的 PDF 檔案
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const inputFileName = basename(inputPath, ".pdf");
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const monoPath = join(outputDir, `${inputFileName}-mono.pdf`);
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const dualPath = join(outputDir, `${inputFileName}-dual.pdf`);
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// 檢查輸出檔案是否存在
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if (!existsSync(monoPath) && !existsSync(dualPath)) {
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// 嘗試在 outputDir 下尋找任何 PDF 檔案
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const files = readdirSync(outputDir);
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const pdfFiles = files.filter(f => f.endsWith(".pdf"));
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console.log(`[PDFMathTranslate] Found PDF files: ${pdfFiles.join(", ")}`);
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if (pdfFiles.length === 0) {
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reject(`No output PDF files found in ${outputDir}`);
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return;
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}
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}
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resolve({ monoPath, dualPath });
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});
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});
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}
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/**
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* 主要轉換函數
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*
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* @param filePath 輸入 PDF 檔案路徑
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* @param fileType 檔案類型（應為 "pdf"）
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* @param convertTo 目標格式（如 "pdf-zh"）
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* @param targetPath 輸出路徑
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* @param options 額外選項
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* @param execFile 執行函數覆寫
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*/
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export async function convert(
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filePath: string,
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fileType: string,
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convertTo: string,
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targetPath: string,
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options?: unknown,
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execFile: ExecFileFn = execFileOriginal,
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): Promise<string> {
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return new Promise(async (resolve, reject) => {
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try {
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// 1. 檢查模型（警告但不阻止，因為 pdf2zh 可能會自動下載）
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checkModelsExist();
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// 2. 提取目標語言
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const targetLang = extractTargetLanguage(convertTo);
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console.log(`[PDFMathTranslate] Translating to: ${targetLang}`);
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// 3. 建立臨時輸出目錄
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const outputDir = dirname(targetPath);
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const inputFileName = basename(filePath, `.${fileType}`);
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const tempDir = join(outputDir, `${inputFileName}_pdfmathtranslate_${Date.now()}`);
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if (!existsSync(tempDir)) {
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mkdirSync(tempDir, { recursive: true });
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}
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// 4. 建立封裝用目錄
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const archiveDir = join(tempDir, "archive");
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mkdirSync(archiveDir, { recursive: true });
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// 5. 執行 pdf2zh 翻譯
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const { monoPath, dualPath } = await runPdf2zh(filePath, tempDir, targetLang, execFile);
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// 6. 複製原始檔案到封裝目錄
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const originalDest = join(archiveDir, "original.pdf");
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copyFileSync(filePath, originalDest);
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// 7. 複製翻譯後的檔案（優先使用 mono，因為它是純翻譯版本）
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const translatedDest = join(archiveDir, `translated-${targetLang}.pdf`);
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// 檢查各種可能的輸出檔案名稱
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const possibleOutputs = [
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monoPath,
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dualPath,
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join(tempDir, `${inputFileName}-mono.pdf`),
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join(tempDir, `${inputFileName}-dual.pdf`),
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];
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let foundOutput = false;
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for (const outputPath of possibleOutputs) {
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if (existsSync(outputPath)) {
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copyFileSync(outputPath, translatedDest);
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foundOutput = true;
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console.log(`[PDFMathTranslate] Using output: ${outputPath}`);
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break;
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}
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}
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// 如果找不到預期的輸出檔案，嘗試找任何 PDF
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if (!foundOutput) {
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const allFiles = readdirSync(tempDir);
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const pdfFiles = allFiles.filter(f => f.endsWith(".pdf") && f !== basename(filePath));
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const firstPdfName = pdfFiles[0];
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if (firstPdfName) {
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const firstPdf = join(tempDir, firstPdfName);
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copyFileSync(firstPdf, translatedDest);
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foundOutput = true;
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console.log(`[PDFMathTranslate] Using fallback output: ${firstPdf}`);
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}
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}
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if (!foundOutput) {
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throw new Error("No translated PDF output found");
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}
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// 8. 建立 .tar 封裝
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const tarPath = getArchiveFileName(targetPath);
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const tarDir = dirname(tarPath);
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if (!existsSync(tarDir)) {
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mkdirSync(tarDir, { recursive: true });
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}
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await createTarArchive(archiveDir, tarPath, execFile);
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console.log(`[PDFMathTranslate] Created archive: ${tarPath}`);
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// 9. 清理臨時目錄
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removeDir(tempDir);
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resolve("Done");
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} catch (error) {
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reject(`PDFMathTranslate error: ${error}`);
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}
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});
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}
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