import 'dart:convert';

import 'package:hooks_riverpod/hooks_riverpod.dart';

import '../../../common/domain/metal_type.dart';
import '../../../common/storage/preferences_storage.dart';
import '../../../common/storage/storage_keys.dart';
import 'asset_models.dart';

final mockAssetRepositoryProvider = Provider<MockAssetRepository>(
  (ref) => MockAssetRepository(ref.watch(preferencesStorageProvider)),
);

class MockAssetRepository {
  MockAssetRepository(this._preferences);

  static const guestAccountScope = 'guest';

  final PreferencesStorage _preferences;
  Future<void> _operationTail = Future<void>.value();

  static String accountScope({String? userId, String? phone}) {
    final normalizedUserId = userId?.trim() ?? '';
    if (normalizedUserId.isNotEmpty) return 'id:$normalizedUserId';
    final normalizedPhone = phone?.trim() ?? '';
    if (normalizedPhone.isNotEmpty) return 'phone:$normalizedPhone';
    return guestAccountScope;
  }

  static String holdingsStorageKey(String accountScope) =>
      '$storageJinzhiHoldings:${Uri.encodeComponent(accountScope)}';

  static String deletedStorageKey(String accountScope) =>
      '$storageJinzhiHoldingsDeleted:${Uri.encodeComponent(accountScope)}';

  List<GoldAssetHolding> loadHoldings(String accountScope) {
    if (_preferences.getBool(deletedStorageKey(accountScope))) return [];
    final encoded = _preferences.getString(holdingsStorageKey(accountScope));
    if (encoded == null || encoded.isEmpty) return _seedHoldings();
    try {
      final decoded = jsonDecode(encoded);
      if (decoded is! List) return _seedHoldings();
      return [
        for (final item in decoded)
          GoldAssetHolding.fromJson(Map<String, Object?>.from(item as Map)),
      ];
    } catch (_) {
      return _seedHoldings();
    }
  }

  Future<void> saveHoldings(
    String accountScope,
    List<GoldAssetHolding> holdings,
  ) async {
    final encoded = jsonEncode([
      for (final holding in holdings) holding.toJson(),
    ]);
    await _serialize(() async {
      await _preferences.setString(holdingsStorageKey(accountScope), encoded);
      await _preferences.remove(deletedStorageKey(accountScope));
    });
  }

  Future<void> deleteAccountHoldings(String accountScope) async {
    await _serialize(() async {
      final scopes = {accountScope, guestAccountScope};
      await Future.wait([
        for (final scope in scopes) ...[
          _preferences.remove(holdingsStorageKey(scope)),
          _preferences.setBool(deletedStorageKey(scope), true),
        ],
        // Remove the pre-account-scoping key left by earlier builds.
        _preferences.remove(storageJinzhiHoldings),
      ]);
    });
  }

  Future<T> _serialize<T>(Future<T> Function() operation) {
    final result = _operationTail.then((_) => operation());
    _operationTail = result.then<void>(
      (_) {},
      onError: (Object _, StackTrace _) {},
    );
    return result;
  }

  List<GoldAssetHolding> _seedHoldings() {
    final now = DateTime(2026, 6, 18, 16, 11);
    return [
      GoldAssetHolding(
        id: 'holding_gold_bar_001',
        name: '投资金条',
        metal: MetalType.gold,
        category: AssetCategory.bar,
        purity: 0.9999,
        purityLabel: '足金9999',
        weightGram: 50,
        costAmount: 43200,
        purchaseDate: DateTime(2025, 10, 12),
        channel: '银行',
        createdAt: now.subtract(const Duration(days: 249)),
        updatedAt: now,
      ),
      GoldAssetHolding(
        id: 'holding_gold_ring_001',
        name: '素圈戒指',
        metal: MetalType.gold,
        category: AssetCategory.ring,
        purity: 0.999,
        purityLabel: '足金999',
        weightGram: 8.6,
        costAmount: 7820,
        purchaseDate: DateTime(2024, 12, 4),
        channel: '金店',
        createdAt: now.subtract(const Duration(days: 196)),
        updatedAt: now,
      ),
      GoldAssetHolding(
        id: 'holding_platinum_001',
        name: 'PT950 项链',
        metal: MetalType.platinum,
        category: AssetCategory.platinumPiece,
        purity: 0.95,
        purityLabel: 'PT950',
        weightGram: 12.3,
        costAmount: 5200,
        purchaseDate: DateTime(2023, 8, 21),
        channel: '金店',
        createdAt: now.subtract(const Duration(days: 667)),
        updatedAt: now,
      ),
      GoldAssetHolding(
        id: 'holding_silver_001',
        name: '银手镯',
        metal: MetalType.silver,
        category: AssetCategory.bracelet,
        purity: 0.999,
        purityLabel: '999银',
        weightGram: 31.8,
        costAmount: 980,
        purchaseDate: DateTime(2024, 4, 7),
        channel: '金店',
        note: '材料价值偏低',
        createdAt: now.subtract(const Duration(days: 802)),
        updatedAt: now,
      ),
    ];
  }
}