const express = require("express");
const multer = require("multer");
const { spawn, execSync } = require("child_process");
const fs = require("fs");

const app = express();
const upload = multer({ dest: "uploads/" });

app.post("/convert", upload.fields([{ name: "audio" }, { name: "image" }]), async (req, res) => {
  if (!req.files?.audio || !req.files?.image) {
    return res.status(400).send("Missing audio or image file.");
  }

  const audioPath = req.files.audio[0].path;
  const imagePath = req.files.image[0].path;
  const output = `output-${Date.now()}.mp4`;

  let durationSec = 0;
  try {
    const durationStr = execSync(
      `ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 ${audioPath}`
    ).toString().trim();
    durationSec = parseFloat(durationStr);
    console.log(`🎧 Audio duration: ${durationSec.toFixed(2)} sec`);
  } catch (err) {
    console.error("❌ Could not determine audio duration");
    return res.status(500).send("Failed to analyze audio.");
  }

  const args = [
    "-loop", "1",
    "-i", imagePath,
    "-i", audioPath,
    "-c:v", "libx264",
    "-preset", "ultrafast",
    "-tune", "stillimage",
    "-crf", "23",
    "-c:a", "aac",
    "-shortest",
    "-pix_fmt", "yuv420p",
    "-movflags", "+faststart",
    output
  ];

  console.log(`🚀 Starting conversion to ${output}`);
  const ffmpeg = spawn("ffmpeg", args);

  ffmpeg.stderr.on("data", (data) => {
    const line = data.toString().trim();
    const timeMatch = line.match(/time=(\d+):(\d+):([\d.]+)/);

    if (timeMatch) {
      const [, h, m, s] = timeMatch;
      const timeSec = parseInt(h) * 3600 + parseInt(m) * 60 + parseFloat(s);
      const percent = Math.min(100, ((timeSec / durationSec) * 100).toFixed(1));
      console.log(`${line} | 📊 ${percent}%`);
    } else {
      console.log(line);
    }
  });

  ffmpeg.on("exit", (code) => {
    if (code !== 0) {
      console.error(`❌ FFmpeg exited with code ${code}`);
      return res.status(500).send("Conversion failed");
    }

    console.log("✅ Conversion complete. Sending file...");
    res.download(output, () => {
      fs.unlinkSync(audioPath);
      fs.unlinkSync(imagePath);
      fs.unlinkSync(output);
    });
  });
});

app.get("/", (req, res) => {
  res.send("🎧 FileConvert API is running.");
});

app.listen(3000, () => console.log("✅ Listening on http://0.0.0.0:3000"));