import 'package:flutter/material.dart';
import 'package:health/health.dart';
import 'package:collection/collection.dart';
import '../models/cycle_entry.dart';

class HealthService {
  static final HealthService _instance = HealthService._internal();
  factory HealthService() => _instance;
  HealthService._internal();

  final Health _health = Health();
  List<HealthDataType> _requestedTypes = [];

  // Define data types for menstruation
  static const List<HealthDataType> _menstruationDataTypes = [
    HealthDataType.menstruation,
  ];

  Future<bool> requestAuthorization(List<HealthDataType> types) async {
    _requestedTypes = types;
    try {
      final bool authorized = await _health.requestAuthorization(types);
      return authorized;
    } catch (e) {
      debugPrint("Error requesting authorization: $e");
      return false;
    }
  }

  Future<bool> hasPermissions(List<HealthDataType> types) async {
    return await _health.hasPermissions(types);
  }

  Future<bool> writeMenstruationData(List<CycleEntry> entries) async {
    // Filter for period days
    final periodEntries = entries.where((entry) => entry.isPeriodDay).toList();

    if (periodEntries.isEmpty) {
      debugPrint("No period entries to write.");
      return true; // Nothing to write is not an error
    }

    // Check if authorized for menstruation data
    final hasAuth = await hasPermissions([HealthDataType.menstruation]);
    if (!hasAuth) {
      debugPrint("Authorization not granted for menstruation data.");
      return false;
    }

    bool allWrittenSuccessfully = true;
    for (var entry in periodEntries) {
      try {
        final success = await _health.writeHealthData(
          entry.date, // Start date
          entry.date.add(const Duration(days: 1)), // End date (inclusive of start, so +1 day for all-day event)
          HealthDataType.menstruation,
          // HealthKit menstruation type often doesn't need a value,
          // it's the presence of the event that matters.
          // For other types, a value would be required.
          Platform.isIOS ? 0.0 : 0.0, // Value depends on platform and data type
        );
        if (!success) {
          allWrittenSuccessfully = false;
          debugPrint("Failed to write menstruation data for ${entry.date}");
        }
      } catch (e) {
        allWrittenSuccessfully = false;
        debugPrint("Error writing menstruation data for ${entry.date}: $e");
      }
    }
    return allWrittenSuccessfully;
  }

  List<HealthDataType> get mensturationDataTypes => _menstruationDataTypes;
}