import 'package:dio/dio.dart';
import '../../../core/network/api_client.dart';
import '../models/backtest_history_entry_model.dart';
import '../models/backtest_report_model.dart';

/// Backend endpoint contract: `FinlyticBackend/Controllers/SimulationController.cs`
/// (`POST /api/v1/simulation/run`, body shape `BacktestRequestDto` in
/// `FinlyticCore/Dtos/Simulation/SimulationDtos.cs`).
class SimulationRepository {
  final ApiClient apiClient;

  const SimulationRepository({required this.apiClient});

  Future<BacktestReportModel> runBacktest({
    required String isin,
    required String symbol,
    required String strategyKey,
    required String timeframe,
    DateTime? startDateUtc,
    DateTime? endDateUtc,
    double startingCapital = 10000.0,
    double riskPerTradePercent = 1.0,
    bool includeFeesAndSlippage = true,
    bool simulateKnockOutDerivatives = false,
    double? targetLeverage,
    Map<String, double>? strategyParameters,
  }) async {
    final now = DateTime.now().toUtc();
    final start = (startDateUtc ?? now.subtract(const Duration(days: 180))).toUtc();
    final end = (endDateUtc ?? now).toUtc();

    final response = await apiClient.post('/api/v1/simulation/run', data: {
      'isin': isin,
      'symbol': symbol,
      'strategyKey': strategyKey,
      'timeframe': timeframe,
      'startDateUtc': start.toIso8601String(),
      'endDateUtc': end.toIso8601String(),
      'startingCapital': startingCapital,
      'riskPerTradePercent': riskPerTradePercent,
      'includeFeesAndSlippage': includeFeesAndSlippage,
      'simulateKnockOutDerivatives': simulateKnockOutDerivatives,
      if (targetLeverage != null) 'targetLeverage': targetLeverage,
      if (strategyParameters != null && strategyParameters.isNotEmpty) 'strategyParameters': strategyParameters,
    });

    if (response.statusCode == 200 && response.data is Map) {
      return BacktestReportModel.fromJson(Map<String, dynamic>.from(response.data as Map));
    }

    throw Exception('Simulation fehlgeschlagen: Status ${response.statusCode}');
  }

  /// Lightweight history of past backtest runs for an asset (`GET /api/v1/simulation/history/{isin}`).
  Future<List<BacktestHistoryEntryModel>> getBacktestHistory({
    required String isin,
    String? strategyKey,
    int limit = 20,
  }) async {
    final response = await apiClient.get(
      '/api/v1/simulation/history/$isin',
      queryParameters: {
        if (strategyKey != null && strategyKey.isNotEmpty) 'strategyKey': strategyKey,
        'limit': limit,
      },
    );

    if (response.statusCode == 200 && response.data is List) {
      return (response.data as List)
          .whereType<Map>()
          .map((e) => BacktestHistoryEntryModel.fromJson(Map<String, dynamic>.from(e)))
          .toList();
    }

    throw Exception('Backtest-Verlauf konnte nicht geladen werden: Status ${response.statusCode}');
  }

  /// Full report (trades + equity curve) for one specific past run (`GET /api/v1/simulation/history/run/{runId}`).
  Future<BacktestReportModel> getBacktestRunDetail(String runId) async {
    final response = await apiClient.get('/api/v1/simulation/history/run/$runId');

    if (response.statusCode == 200 && response.data is Map) {
      return BacktestReportModel.fromJson(Map<String, dynamic>.from(response.data as Map));
    }

    throw Exception('Backtest-Lauf konnte nicht geladen werden: Status ${response.statusCode}');
  }

  /// Saved indicator-parameter profile for one (isin, strategyKey) pair
  /// (`GET /api/v1/simulation/parameters/{isin}/{strategyKey}`). Returns `null` when none was ever saved -
  /// an expected, legitimate empty state (the server responds 404), not an error to surface to the user.
  Future<Map<String, double>?> getStrategyParameters({
    required String isin,
    required String strategyKey,
  }) async {
    try {
      final response = await apiClient.get('/api/v1/simulation/parameters/$isin/$strategyKey');
      if (response.statusCode == 200 && response.data is Map) {
        final raw = Map<String, dynamic>.from(response.data as Map)['parameters'];
        if (raw is Map) {
          return raw.map((key, value) => MapEntry(key.toString(), (value as num).toDouble()));
        }
      }
      return null;
    } on DioException catch (e) {
      if (e.response?.statusCode == 404) return null;
      rethrow;
    }
  }

  /// Saves/updates a per-asset/per-strategy indicator-parameter profile (`POST /api/v1/simulation/parameters`).
  Future<void> saveStrategyParameters({
    required String isin,
    required String strategyKey,
    required Map<String, double> parameters,
  }) async {
    final response = await apiClient.post('/api/v1/simulation/parameters', data: {
      'isin': isin,
      'strategyKey': strategyKey,
      'parameters': parameters,
    });

    if (response.statusCode != 200) {
      throw Exception('Parameter-Profil konnte nicht gespeichert werden: Status ${response.statusCode}');
    }
  }
}