import express from 'express';
import path from 'path';
import fs from 'fs/promises';
import * as mm from 'music-metadata';
import cors from 'cors';

const app = express();
app.use(cors()); // adjust for production if needed

// Base music directory
const MUSIC_DIR = path.resolve(__dirname, 'music');
const SUPPORTED = ['.flac', '.mp3', '.wav', '.m4a', '.ogg'];

// Serve static music files
app.use('/music', express.static(MUSIC_DIR, {
  setHeaders: (res) => {
    res.setHeader('Cache-Control', 'public, max-age=86400');
  }
}));

// Recursive scan for all music files
async function scanDir(dir) {
  let results = [];
  const files = await fs.readdir(dir, { withFileTypes: true });

  for (const file of files) {
    const fullPath = path.join(dir, file.name);
    if (file.isDirectory()) {
      results = results.concat(await scanDir(fullPath));
    } else if (SUPPORTED.includes(path.extname(file.name).toLowerCase())) {
      results.push(fullPath);
    }
  }
  return results;
}

// Parse filename into metadata
function parseFilename(filename) {
  // Expected: Title__Movie__Genre__YYYY-MM-DD.ext
  const base = path.basename(filename);
  const noExt = base.replace(/\.[^.]+$/, '');
  const parts = noExt.split('__');

  return {
    title: parts[0] || 'Unknown',
    movie: parts[1] && parts[1] !== 'None' ? parts[1] : null,
    genre: parts[2] || null,
    date: parts[3] || null,
    filename: base,
  };
}

// API endpoint: list all tracks
app.get('/api/tracks', async (req, res) => {
  try {
    const files = await scanDir(MUSIC_DIR);
    const tracks = [];

    for (const f of files) {
      const stat = await fs.stat(f);
      const metadata = parseFilename(f);

      metadata.path = `/music/${encodeURIComponent(path.relative(MUSIC_DIR, f))}`;
      metadata.size = stat.size;
      metadata.ext = path.extname(f).toLowerCase();
      metadata.duration = null;
      metadata.tags = {};

      // Try reading embedded metadata (optional)
      try {
        const mmData = await mm.parseFile(f, { duration: true });
        if (mmData.format.duration) metadata.duration = Math.round(mmData.format.duration);
        if (mmData.common) {
          metadata.tags = mmData.common;
          metadata.title = mmData.common.title || metadata.title;
          metadata.movie = mmData.common.album || metadata.movie;
          if (!metadata.genre && mmData.common.genre) {
            metadata.genre = Array.isArray(mmData.common.genre) ? mmData.common.genre.join(', ') : mmData.common.genre;
          }
          if (!metadata.date && mmData.common.date) metadata.date = mmData.common.date;
        }
      } catch (err) {
        // ignore metadata errors
      }

      tracks.push(metadata);
    }

    // Sort: first by date (desc), then by filename
    tracks.sort((a, b) => {
      if (a.date && b.date) return String(b.date).localeCompare(String(a.date));
      return a.filename.localeCompare(b.filename);
    });

    res.json({ tracks });
  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'Failed to read music folder' });
  }
});

// Start server
const PORT = process.env.PORT || 3001;
app.listen(PORT, () => console.log(`Music API server running at http://localhost:${PORT}`));