const express = require("express");
const fs = require("fs");
const path = require("path");
const { exec } = require("child_process");

const app = express();
const PORT = 7860;
const DOWNLOAD_DIR = path.join(__dirname, "downloads");

// Ensure the downloads directory exists
if (!fs.existsSync(DOWNLOAD_DIR)) {
    fs.mkdirSync(DOWNLOAD_DIR, { recursive: true });
}

// Function to extract filename from URL
const getFileName = (fileUrl) => path.basename(new URL(fileUrl).pathname);

// Function to delete file after a delay (default: 10 minutes)
const scheduleFileDeletion = (filePath, delay = 600000) => {
    setTimeout(() => {
        fs.unlink(filePath, (err) => {
            if (!err) {
                console.log(`✅ Deleted file: ${filePath}`);
            }
        });
    }, delay);
};

// Function to download file using aria2c (super fast)
const downloadFile = (fileUrl, filePath) => {
    return new Promise((resolve, reject) => {
        const aria2Cmd = `aria2c -x 16 -s 16 -k 1M -o "${filePath}" "${fileUrl}"`;
        console.log(`🚀 Starting fast download: ${aria2Cmd}`);

        exec(aria2Cmd, (error, stdout, stderr) => {
            if (error) {
                console.error(`❌ Download Error: ${error.message}`);
                return reject(error);
            }
            console.log(`✅ Download Complete: ${filePath}`);
            resolve(filePath);
        });
    });
};

// Function to convert MKV to MP4 using FFmpeg (Fast Conversion)
const convertToMp4 = (inputPath, outputPath) => {
    return new Promise((resolve, reject) => {
        const ffmpegCmd = `ffmpeg -i "${inputPath}" -c:v copy -c:a aac -b:a 192k -y "${outputPath}"`;
        console.log(`🚀 Running FFmpeg: ${ffmpegCmd}`);

        exec(ffmpegCmd, (error, stdout, stderr) => {
            if (error) {
                console.error(`❌ FFmpeg Error: ${error.message}`);
                return reject(error);
            }
            console.log(`✅ FFmpeg Output: ${stdout || stderr}`);
            resolve(outputPath);
        });
    });
};

// API Route to download, convert, and serve .mp4 files
app.get("/download", async (req, res) => {
    const fileUrl = req.query.url;
    if (!fileUrl) {
        return res.status(400).json({ error: "❌ Missing URL parameter" });
    }

    try {
        console.log(`⬇️ Downloading: ${fileUrl}`);

        const originalFilename = getFileName(fileUrl);
        const originalFilePath = path.join(DOWNLOAD_DIR, originalFilename);

        const isMkv = originalFilename.toLowerCase().endsWith(".mkv");
        const mp4Filename = isMkv ? originalFilename.replace(/\.mkv$/, ".mp4") : originalFilename;
        const mp4FilePath = path.join(DOWNLOAD_DIR, mp4Filename);

        // Start fast download with aria2c
        await downloadFile(fileUrl, originalFilePath);

        // Dynamically get the host URL from request headers
        const hostUrl = `${req.protocol}://${req.get("host")}`;

        if (isMkv) {
            // Convert MKV to MP4
            try {
                await convertToMp4(originalFilePath, mp4FilePath);
                fs.unlinkSync(originalFilePath); // Remove original MKV after conversion
            } catch (error) {
                return res.status(500).json({ error: "❌ Conversion failed" });
            }
        }

        const servedUrl = `${hostUrl}/files/${mp4Filename}`;
        scheduleFileDeletion(mp4FilePath); // Auto-delete after 10 minutes

        console.log(`✅ Download & conversion complete: ${servedUrl}`);
        return res.json({ message: "Download & conversion complete", fileUrl: servedUrl });

    } catch (error) {
        console.error("❌ Error:", error.message);
        return res.status(500).json({ error: "Download or conversion failed" });
    }
});

// Serve files from downloads directory (publicly accessible)
app.use("/files", express.static(DOWNLOAD_DIR));

// Start the server
app.listen(PORT, () => {
    console.log(`🚀 Server running on port ${PORT}`);
});