import 'dart:convert';

import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:supabase_flutter/supabase_flutter.dart';

import '../core/env.dart';
import '../core/models.dart';
import '../core/search_normalize.dart';

class Catalog {
  Catalog({required List<Track> tracks, required List<Artist> artists, List<Album> albums = const []})
      : tracks = List.unmodifiable(tracks),
        artistsById = {for (final a in artists) a.id: a},
        albumsById = {for (final a in albums) a.id: a};

  /// Newest first.
  final List<Track> tracks;
  final Map<String, Artist> artistsById;
  final Map<String, Album> albumsById;

  /// Albums with songs, biggest first.
  late final List<Album> albums = albumsById.values.where((a) => byAlbum(a.id).isNotEmpty).toList()
    ..sort((a, b) => byAlbum(b.id).length.compareTo(byAlbum(a.id).length));

  late final Map<String, List<Track>> _byAlbum = () {
    final map = <String, List<Track>>{};
    // Oldest first, so an album plays in the order it was imported (its track order).
    for (final t in tracks.reversed) {
      if (t.albumId != null) map.putIfAbsent(t.albumId!, () => []).add(t);
    }
    return map;
  }();

  List<Track> byAlbum(String albumId) => _byAlbum[albumId] ?? const [];

  Album? albumOf(Track t) => t.albumId == null ? null : albumsById[t.albumId];

  List<Artist> get artists => artistsById.values.toList();

  List<Artist> artistsOf(Track t) =>
      t.artistIds.map((id) => artistsById[id]).whereType<Artist>().toList();

  String artistLine(Track t) => artistsOf(t).map((a) => a.name).join(', ');

  /// For display: many legacy songs have no singer credited yet.
  String creditLine(Track t) {
    final line = artistLine(t);
    return line.isEmpty ? 'Singer not credited yet' : line;
  }

  List<Track> byOccasion(Occasion o) => tracks.where((t) => t.occasion == o).toList();

  List<Track> byArtist(String artistId) =>
      tracks.where((t) => t.artistIds.contains(artistId)).toList();

  Track? trackById(String id) {
    for (final t in tracks) {
      if (t.id == id) return t;
    }
    return null;
  }

  List<Track> searchTracks(String query) => tracks
      .where((t) => matchesSearch(query, [
            t.titleLatin,
            t.titleTamil,
            t.meaning,
            t.occasion.label,
            artistLine(t),
            albumOf(t)?.title,
          ]))
      .toList();

  List<Album> searchAlbums(String query) =>
      albums.where((a) => matchesSearch(query, [a.title])).toList();

  List<Artist> searchArtists(String query) =>
      artists.where((a) => matchesSearch(query, [a.name, a.hatti])).toList();
}

abstract interface class CatalogRepository {
  Future<Catalog> load();
}

/// Reads the bundled demo catalog. Used until Supabase is configured.
class AssetCatalogRepository implements CatalogRepository {
  const AssetCatalogRepository([this.path = 'assets/catalog/demo_catalog.json']);

  final String path;

  @override
  Future<Catalog> load() async => parseCatalogJson(await rootBundle.loadString(path));
}

Catalog parseCatalogJson(String raw) {
  final json = jsonDecode(raw) as Map<String, dynamic>;
  return Catalog(
    tracks: (json['tracks'] as List).map((e) => Track.fromJson(e as Map<String, dynamic>)).toList(),
    artists: (json['artists'] as List).map((e) => Artist.fromJson(e as Map<String, dynamic>)).toList(),
  );
}

/// Reads approved songs from Supabase (schema: supabase/migrations/0001_init.sql).
/// Row-level security already hides anything that is not approved.
class SupabaseCatalogRepository implements CatalogRepository {
  SupabaseCatalogRepository(this.client);

  final SupabaseClient client;

  @override
  Future<Catalog> load() async {
    final artistRows = await client.from('artists').select('id, name_latin, hatti:hattis(name_latin), photo_url, bio');
    final albumRows = await client.from('albums').select('id, title_latin, year, cover_url');
    final trackRows = await client
        .from('tracks')
        .select('id, title_latin, title_tamil, title_en_meaning, album_id, occasion, duration_ms, '
            'audio_key_128, cover_url, tier, track_artists(artist_id, position, role)')
        // Admins may read unapproved songs too; the app only ever lists approved ones.
        .eq('status', 'approved')
        .order('created_at', ascending: false);

    final artists = [
      for (final r in artistRows)
        Artist(
          id: r['id'] as String,
          name: r['name_latin'] as String,
          hatti: (r['hatti'] as Map?)?['name_latin'] as String?,
          photoUrl: r['photo_url'] as String?,
          bio: r['bio'] as String?,
        ),
    ];
    final tracks = [
      for (final r in trackRows)
        Track(
          id: r['id'] as String,
          titleLatin: r['title_latin'] as String,
          titleTamil: r['title_tamil'] as String?,
          meaning: r['title_en_meaning'] as String?,
          artistIds: ([...(r['track_artists'] as List).where((ta) => ta['role'] == 'singer')]
                ..sort((a, b) => (a['position'] as int).compareTo(b['position'] as int)))
              .map((ta) => ta['artist_id'] as String)
              .toList(),
          albumId: r['album_id'] as String?,
          occasion: Occasion.fromId(r['occasion'] as String?),
          duration: Duration(milliseconds: (r['duration_ms'] as num?)?.toInt() ?? 0),
          audioUrl: '${Env.mediaBaseUrl}/${r['audio_key_128']}',
          coverUrl: r['cover_url'] as String?,
          tier: r['tier'] == 'premium' ? Tier.premium : Tier.free,
        ),
    ];
    final albums = [
      for (final r in albumRows)
        Album(
          id: r['id'] as String,
          title: r['title_latin'] as String,
          year: (r['year'] as num?)?.toInt(),
          coverUrl: r['cover_url'] as String?,
        ),
    ];
    return Catalog(tracks: tracks, artists: artists, albums: albums);
  }
}

final catalogRepositoryProvider = Provider<CatalogRepository>((ref) {
  if (Env.hasSupabase) return SupabaseCatalogRepository(Supabase.instance.client);
  return const AssetCatalogRepository();
});

final catalogProvider = FutureProvider<Catalog>((ref) => ref.watch(catalogRepositoryProvider).load());