/**
 * Download Spotify playlist - converts tracks to Deezer via ISRC, adds to queue, and creates m3u8 file
 */

import { addToQueue } from '$lib/stores/downloadQueue';
import { trackExists } from '$lib/services/deezer/downloader';
import { writeM3U8, makeRelativePath, type M3U8Track } from '$lib/library/m3u8';
import { generateTrackPath } from '$lib/services/deezer/paths';
import { settings } from '$lib/stores/settings';
import { deezerAuth } from '$lib/stores/deezer';
import { deezerAPI } from '$lib/services/deezer';
import { setInfo, setSuccess, setWarning } from '$lib/stores/status';
import { get } from 'svelte/store';
import { mkdir } from '@tauri-apps/plugin-fs';
import { convertSpotifyTrackToDeezer, type SpotifyTrackInput } from './converter';
import type { DeezerTrack } from '$lib/types/deezer';

export interface SpotifyPlaylistTrack {
  id: number | string;
  track_id: string;
  name: string;
  artist_name: string;
  album_name: string;
  duration_ms: number;
  isrc?: string | null;
}

/**
 * Download a Spotify playlist by converting tracks to Deezer equivalents
 * - Converts all tracks via ISRC matching
 * - Adds converted tracks to the download queue (respects overwrite setting)
 * - Creates an m3u8 playlist file with relative paths
 *
 * @param playlistName - Name of the playlist
 * @param spotifyTracks - Array of Spotify track objects
 * @param playlistsFolder - Path to playlists folder
 * @param musicFolder - Path to music folder
 * @returns Object with m3u8 path and statistics
 */
export async function downloadSpotifyPlaylist(
  playlistName: string,
  spotifyTracks: SpotifyPlaylistTrack[],
  playlistsFolder: string,
  musicFolder: string
): Promise<{
  m3u8Path: string;
  stats: {
    total: number;
    queued: number;
    skipped: number;
    failed: number;
  };
}> {
  const appSettings = get(settings);
  const authState = get(deezerAuth);

  // Ensure Deezer is authenticated
  if (!authState.loggedIn || !authState.arl) {
    throw new Error('Deezer authentication required for downloads');
  }

  deezerAPI.setArl(authState.arl);

  console.log(`[SpotifyPlaylistDownloader] Starting download for playlist: ${playlistName}`);
  console.log(`[SpotifyPlaylistDownloader] Tracks: ${spotifyTracks.length}`);

  // Ensure playlists folder exists
  try {
    await mkdir(playlistsFolder, { recursive: true });
  } catch (error) {
    // Folder might already exist
  }

  // Track statistics
  let queuedCount = 0;
  let skippedCount = 0;
  let failedCount = 0;

  // Track successful conversions for m3u8 generation
  const successfulTracks: Array<{
    deezerTrack: DeezerTrack;
    spotifyTrack: SpotifyPlaylistTrack;
  }> = [];

  // Convert and queue each track
  for (const spotifyTrack of spotifyTracks) {
    try {
      // Convert Spotify track to Deezer
      const conversionInput: SpotifyTrackInput = {
        id: spotifyTrack.track_id,
        name: spotifyTrack.name,
        artists: [spotifyTrack.artist_name],
        album: spotifyTrack.album_name,
        duration_ms: spotifyTrack.duration_ms,
        isrc: spotifyTrack.isrc
      };

      const conversionResult = await convertSpotifyTrackToDeezer(conversionInput);

      if (!conversionResult.success || !conversionResult.deezerTrack) {
        console.warn(
          `[SpotifyPlaylistDownloader] Failed to convert: ${spotifyTrack.name} - ${conversionResult.error}`
        );
        failedCount++;
        continue;
      }

      const deezerPublicTrack = conversionResult.deezerTrack;

      // Fetch full track data from Deezer GW API (needed for download)
      const deezerTrackId = deezerPublicTrack.id.toString();
      const deezerFullTrack = await deezerAPI.getTrack(deezerTrackId);

      if (!deezerFullTrack || !deezerFullTrack.SNG_ID) {
        console.warn(`[SpotifyPlaylistDownloader] Could not fetch full Deezer track data for ID: ${deezerTrackId}`);
        failedCount++;
        continue;
      }

      // Build DeezerTrack object
      const deezerTrack: DeezerTrack = {
        id: parseInt(deezerFullTrack.SNG_ID, 10),
        title: deezerFullTrack.SNG_TITLE,
        artist: deezerFullTrack.ART_NAME,
        artistId: parseInt(deezerFullTrack.ART_ID, 10),
        artists: [deezerFullTrack.ART_NAME],
        album: deezerFullTrack.ALB_TITLE,
        albumId: parseInt(deezerFullTrack.ALB_ID, 10),
        albumArtist: deezerFullTrack.ART_NAME,
        albumArtistId: parseInt(deezerFullTrack.ART_ID, 10),
        trackNumber:
          typeof deezerFullTrack.TRACK_NUMBER === 'number'
            ? deezerFullTrack.TRACK_NUMBER
            : parseInt(deezerFullTrack.TRACK_NUMBER, 10),
        discNumber:
          typeof deezerFullTrack.DISK_NUMBER === 'number'
            ? deezerFullTrack.DISK_NUMBER
            : parseInt(deezerFullTrack.DISK_NUMBER, 10),
        duration:
          typeof deezerFullTrack.DURATION === 'number'
            ? deezerFullTrack.DURATION
            : parseInt(deezerFullTrack.DURATION, 10),
        explicit: deezerFullTrack.EXPLICIT_LYRICS === 1,
        md5Origin: deezerFullTrack.MD5_ORIGIN,
        mediaVersion: deezerFullTrack.MEDIA_VERSION,
        trackToken: deezerFullTrack.TRACK_TOKEN
      };

      // Check if track already exists (if overwrite is disabled)
      if (!appSettings.deezerOverwrite && appSettings.musicFolder) {
        const exists = await trackExists(deezerTrack, appSettings.musicFolder, appSettings.deezerFormat);
        if (exists) {
          console.log(`[SpotifyPlaylistDownloader] Skipping "${deezerTrack.title}" - already exists`);
          skippedCount++;
          // Still add to successful tracks for m3u8 generation
          successfulTracks.push({ deezerTrack, spotifyTrack });
          continue;
        }
      }

      // Queue track for download
      await addToQueue({
        source: 'deezer',
        type: 'track',
        title: deezerTrack.title,
        artist: deezerTrack.artist,
        totalTracks: 1,
        downloadObject: deezerTrack
      });

      queuedCount++;
      successfulTracks.push({ deezerTrack, spotifyTrack });

      console.log(
        `[SpotifyPlaylistDownloader] Queued: ${deezerTrack.title} (matched via ${conversionResult.matchMethod})`
      );
    } catch (error) {
      console.error(`[SpotifyPlaylistDownloader] Error processing track ${spotifyTrack.name}:`, error);
      failedCount++;
    }
  }

  console.log(
    `[SpotifyPlaylistDownloader] Queued ${queuedCount} tracks, skipped ${skippedCount}, failed ${failedCount}`
  );

  // Show queue status message
  if (queuedCount > 0) {
    const parts = [`Queued ${queuedCount} track${queuedCount !== 1 ? 's' : ''}`];
    if (skippedCount > 0) parts.push(`${skippedCount} skipped`);
    if (failedCount > 0) parts.push(`${failedCount} not found`);
    setInfo(parts.join(', '));
  } else if (skippedCount > 0) {
    setWarning(`All ${skippedCount} tracks already exist`);
  } else if (failedCount > 0) {
    setWarning(`Could not find ${failedCount} tracks on Deezer`);
  }

  // Generate m3u8 file using Deezer track paths
  const m3u8Tracks: M3U8Track[] = successfulTracks.map(({ deezerTrack, spotifyTrack }) => {
    // Generate expected path for this Deezer track
    const paths = generateTrackPath(deezerTrack, musicFolder, appSettings.deezerFormat, false);
    const absolutePath = `${paths.filepath}/${paths.filename}`;

    // Convert to relative path from playlists folder
    const relativePath = makeRelativePath(absolutePath, 'Music');

    return {
      duration: deezerTrack.duration,
      artist: deezerTrack.artist,
      title: deezerTrack.title,
      path: relativePath
    };
  });

  // Write m3u8 file
  const m3u8Path = await writeM3U8(playlistName, m3u8Tracks, playlistsFolder);

  console.log(`[SpotifyPlaylistDownloader] Playlist saved to: ${m3u8Path}`);

  // Show success message for playlist creation
  setSuccess(`Playlist created: ${playlistName} (${successfulTracks.length} tracks)`);

  return {
    m3u8Path,
    stats: {
      total: spotifyTracks.length,
      queued: queuedCount,
      skipped: skippedCount,
      failed: failedCount
    }
  };
}