import fs from 'fs/promises';
import path from 'path';
import { parseFile } from 'music-metadata';
import crypto from 'crypto';
import { run, all } from '../database/db.js';

const AUDIO_EXTENSIONS = ['.mp3', '.m4a', '.flac', '.wav', '.aac', '.ogg'];

export class AudioScanner {
  constructor(libraryPath) {
    this.libraryPath = libraryPath;
  }

  async scanLibrary() {
    console.log(`🔍 Scanning library: ${this.libraryPath}`);
    const files = await this.findAudioFiles(this.libraryPath);
    console.log(`📁 Found ${files.length} audio files`);

    let processed = 0;
    for (const filePath of files) {
      try {
        await this.processAudioFile(filePath);
        processed++;
        if (processed % 10 === 0) {
          console.log(`⏳ Processed ${processed}/${files.length} files`);
        }
      } catch (error) {
        console.error(`❌ Error processing ${filePath}:`, error.message);
      }
    }

    await this.updateAlbums();
    console.log(`✅ Scan complete! Processed ${processed} files`);
  }

  async findAudioFiles(dir, fileList = []) {
    const entries = await fs.readdir(dir, { withFileTypes: true });

    for (const entry of entries) {
      const fullPath = path.join(dir, entry.name);
      
      if (entry.isDirectory()) {
        await this.findAudioFiles(fullPath, fileList);
      } else if (entry.isFile()) {
        const ext = path.extname(entry.name).toLowerCase();
        if (AUDIO_EXTENSIONS.includes(ext)) {
          fileList.push(fullPath);
        }
      }
    }

    return fileList;
  }

  async processAudioFile(filePath) {
    const metadata = await parseFile(filePath);
    const stats = await fs.stat(filePath);
    const relativePath = path.relative(this.libraryPath, filePath);
    const folderPath = path.dirname(relativePath);
    
    const id = this.generateId(filePath);
    const isSingle = this.detectSingle(metadata, folderPath);

    const track = {
      id,
      title: metadata.common.title || path.basename(filePath, path.extname(filePath)),
      artist: metadata.common.artist || 'Unknown Artist',
      album: metadata.common.album || (isSingle ? 'Singles' : 'Unknown Album'),
      album_artist: metadata.common.albumartist || metadata.common.artist,
      track_number: metadata.common.track?.no || null,
      disc_number: metadata.common.disk?.no || null,
      year: metadata.common.year || null,
      genre: metadata.common.genre?.[0] || null,
      duration: metadata.format.duration || 0,
      file_path: relativePath,
      file_size: stats.size,
      format: metadata.format.container || path.extname(filePath).slice(1),
      bitrate: metadata.format.bitrate || null,
      sample_rate: metadata.format.sampleRate || null,
      is_single: isSingle ? 1 : 0,
      folder_path: folderPath,
      artwork_path: null
    };

    await this.saveTrack(track);
    
    // Extract and save artwork if available
    if (metadata.common.picture && metadata.common.picture.length > 0) {
      await this.saveArtwork(id, metadata.common.picture[0]);
    }
  }

  detectSingle(metadata, folderPath) {
    // Check if folder name contains "singles" or "single"
    if (/singles?/i.test(folderPath)) {
      return true;
    }

    // If no album tag, likely a single
    if (!metadata.common.album) {
      return true;
    }

    // Could add more heuristics here
    return false;
  }

  async saveTrack(track) {
    await run(`
      INSERT OR REPLACE INTO tracks (
        id, title, artist, album, album_artist, track_number, disc_number,
        year, genre, duration, file_path, file_size, format, bitrate,
        sample_rate, is_single, folder_path, artwork_path, updated_at
      ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, CURRENT_TIMESTAMP)
    `, [
      track.id, track.title, track.artist, track.album, track.album_artist,
      track.track_number, track.disc_number, track.year, track.genre,
      track.duration, track.file_path, track.file_size, track.format,
      track.bitrate, track.sample_rate, track.is_single, track.folder_path,
      track.artwork_path
    ]);
  }

  async saveArtwork(trackId, picture) {
    const artworkDir = path.join(process.cwd(), 'artwork');
    await fs.mkdir(artworkDir, { recursive: true });
    
    const ext = picture.format.split('/')[1] || 'jpg';
    const filename = `${trackId}.${ext}`;
    const artworkPath = path.join(artworkDir, filename);
    
    await fs.writeFile(artworkPath, picture.data);
    
    await run('UPDATE tracks SET artwork_path = ? WHERE id = ?', [filename, trackId]);
  }

  async updateAlbums() {
    // Group tracks by album and create album entries
    const albums = await all(`
      SELECT 
        album,
        album_artist,
        year,
        genre,
        COUNT(*) as track_count,
        MAX(artwork_path) as artwork_path
      FROM tracks
      WHERE is_single = 0
      GROUP BY album, album_artist
    `);

    for (const album of albums) {
      const albumId = this.generateId(`${album.album}-${album.album_artist}`);
      
      await run(`
        INSERT OR REPLACE INTO albums (
          id, name, artist, year, genre, track_count, artwork_path
        ) VALUES (?, ?, ?, ?, ?, ?, ?)
      `, [
        albumId,
        album.album,
        album.album_artist,
        album.year,
        album.genre,
        album.track_count,
        album.artwork_path
      ]);
    }
  }

  generateId(input) {
    return crypto.createHash('md5').update(input).digest('hex');
  }
}