const fs = require("fs");
const path = require("path");
const { promisify } = require("util");
const { pipeline } = require("stream");
const archiver = require("archiver");

const streamPipeline = promisify(pipeline);

// Function to extract file ID from Google Drive link
function extractFileId(driveLink) {
    const match = driveLink.match(/[-\w]{25,}/);
    return match ? match[0] : null;
}

// Function to download a single file
async function downloadFile(driveLink, outputDir) {
    const fileId = extractFileId(driveLink);
    if (!fileId) {
        console.error(`Invalid Google Drive link: ${driveLink}`);
        return null;
    }

    const directDownloadURL = `https://drive.google.com/uc?export=download&id=${fileId}`;
    const response = await fetch(directDownloadURL);

    if (!response.ok) {
        console.error(`Failed to download file: ${driveLink}`);
        return null;
    }

    // Get filename from headers, or use default
    let filename = `file_${fileId}`;
    const contentDisposition = response.headers.get("content-disposition");
    if (contentDisposition) {
        const match = contentDisposition.match(/filename="(.+?)"/);
        if (match) filename = match[1];
    }

    // Ensure file has an extension
    if (!path.extname(filename)) filename += ".bin";

    const filePath = path.join(outputDir, filename);
    const fileStream = fs.createWriteStream(filePath);
    await streamPipeline(response.body, fileStream);

    console.log(`Downloaded: ${filename}`);
    return filePath;
}

// Function to zip all downloaded files
function zipFiles(files, outputZipPath) {
    return new Promise((resolve, reject) => {
        const output = fs.createWriteStream(outputZipPath);
        const archive = archiver("zip", { zlib: { level: 9 } });

        output.on("close", () => {
            console.log(`Zipped files: ${outputZipPath}`);
            resolve();
        });

        archive.on("error", (err) => reject(err));

        archive.pipe(output);
        files.forEach((file) => archive.file(file, { name: path.basename(file) }));
        archive.finalize();
    });
}

// Main function to download files and zip them
async function downloadAndZipFiles(links, outputDir, zipFileName) {
    if (!fs.existsSync(outputDir)) fs.mkdirSync(outputDir, { recursive: true });

    const downloadedFiles = [];
    for (const link of links) {
        const filePath = await downloadFile(link, outputDir);
        if (filePath) downloadedFiles.push(filePath);
    }

    if (downloadedFiles.length > 0) {
        const zipPath = path.join(outputDir, zipFileName);
        await zipFiles(downloadedFiles, zipPath);
    } else {
        console.log("No files were downloaded. Skipping zip.");
    }
}

// Example usage
const googleDriveLinks = [
    "https://drive.google.com/file/d/10N5oXw0yKu1QuTcXcPEU9-RIXcw8nisu/view?usp=drive_link",
    "https://drive.google.com/file/d/10N5oXw0yKu1QuTcXcPEU9-RIXcw8nisu/view?usp=drive_link",
];

const outputDir = path.join(__dirname, "downloads");
const zipFileName = "files.zip";

downloadAndZipFiles(googleDriveLinks, outputDir, zipFileName);