import 'package:flutter_riverpod/flutter_riverpod.dart';
import '../../data/models/scan_item.dart';
import '../../domain/usecases/get_scan_history_usecase.dart';
import 'dependency_injection.dart';

/// State for the scanner functionality
class ScannerState {
  final String? currentBarcode;
  final List<ScanItem> history;
  final bool isLoading;
  final String? error;

  const ScannerState({
    this.currentBarcode,
    this.history = const [],
    this.isLoading = false,
    this.error,
  });

  ScannerState copyWith({
    String? currentBarcode,
    List<ScanItem>? history,
    bool? isLoading,
    String? error,
  }) {
    return ScannerState(
      currentBarcode: currentBarcode ?? this.currentBarcode,
      history: history ?? this.history,
      isLoading: isLoading ?? this.isLoading,
      error: error ?? this.error,
    );
  }

  @override
  bool operator ==(Object other) =>
      identical(this, other) ||
      other is ScannerState &&
          runtimeType == other.runtimeType &&
          currentBarcode == other.currentBarcode &&
          history == other.history &&
          isLoading == other.isLoading &&
          error == other.error;

  @override
  int get hashCode =>
      currentBarcode.hashCode ^
      history.hashCode ^
      isLoading.hashCode ^
      error.hashCode;
}

/// Scanner state notifier
class ScannerNotifier extends StateNotifier<ScannerState> {
  final GetScanHistoryUseCase _getScanHistoryUseCase;

  ScannerNotifier(this._getScanHistoryUseCase) : super(const ScannerState()) {
    _loadHistory();
  }

  /// Load scan history from local storage
  Future<void> _loadHistory() async {
    state = state.copyWith(isLoading: true, error: null);

    final result = await _getScanHistoryUseCase();
    result.fold(
      (failure) => state = state.copyWith(
        isLoading: false,
        error: failure.message,
      ),
      (history) => state = state.copyWith(
        isLoading: false,
        history: history.map((entity) => ScanItem.fromEntity(entity)).toList(),
      ),
    );
  }

  /// Update current scanned barcode
  void updateBarcode(String barcode) {
    if (barcode.trim().isEmpty) return;

    state = state.copyWith(currentBarcode: barcode);

    // Add to history if not already present
    final existingIndex = state.history.indexWhere((item) => item.barcode == barcode);
    if (existingIndex == -1) {
      final newScanItem = ScanItem(
        barcode: barcode,
        timestamp: DateTime.now(),
      );

      final updatedHistory = [newScanItem, ...state.history];
      state = state.copyWith(history: updatedHistory);
    } else {
      // Move existing item to top
      final existingItem = state.history[existingIndex];
      final updatedHistory = List<ScanItem>.from(state.history);
      updatedHistory.removeAt(existingIndex);
      updatedHistory.insert(0, existingItem.copyWith(timestamp: DateTime.now()));
      state = state.copyWith(history: updatedHistory);
    }
  }

  /// Clear current barcode
  void clearBarcode() {
    state = state.copyWith(currentBarcode: null);
  }

  /// Refresh history from storage
  Future<void> refreshHistory() async {
    await _loadHistory();
  }

  /// Add or update scan item in history
  void updateScanItem(ScanItem scanItem) {
    final existingIndex = state.history.indexWhere(
      (item) => item.barcode == scanItem.barcode,
    );

    List<ScanItem> updatedHistory;
    if (existingIndex != -1) {
      // Update existing item
      updatedHistory = List<ScanItem>.from(state.history);
      updatedHistory[existingIndex] = scanItem;
    } else {
      // Add new item at the beginning
      updatedHistory = [scanItem, ...state.history];
    }

    state = state.copyWith(history: updatedHistory);
  }

  /// Clear error message
  void clearError() {
    state = state.copyWith(error: null);
  }
}

/// Provider for scanner state
final scannerProvider = StateNotifierProvider<ScannerNotifier, ScannerState>(
  (ref) => ScannerNotifier(
    ref.watch(getScanHistoryUseCaseProvider),
  ),
);

/// Provider for current barcode (for easy access)
final currentBarcodeProvider = Provider<String?>((ref) {
  return ref.watch(scannerProvider).currentBarcode;
});

/// Provider for scan history (for easy access)
final scanHistoryProvider = Provider<List<ScanItem>>((ref) {
  return ref.watch(scannerProvider).history;
});

/// Provider for scanner loading state
final scannerLoadingProvider = Provider<bool>((ref) {
  return ref.watch(scannerProvider).isLoading;
});

/// Provider for scanner error state
final scannerErrorProvider = Provider<String?>((ref) {
  return ref.watch(scannerProvider).error;
});