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

import '../models/app_settings.dart';
import 'supabase_provider.dart';

/// Fetches the Ramadan configuration from app_settings.
final ramadanConfigProvider = FutureProvider<RamadanConfig>((ref) async {
  final client = ref.watch(supabaseClientProvider);
  final data = await client
      .from('app_settings')
      .select()
      .eq('key', 'ramadan_mode')
      .maybeSingle();
  if (data == null) return RamadanConfig(enabled: false, autoDetect: true);
  final setting = AppSetting.fromMap(data);
  return RamadanConfig.fromJson(setting.value);
});

/// Whether Ramadan mode is currently active.
/// Combines manual toggle with auto-detection via Hijri calendar approximation.
final isRamadanActiveProvider = Provider<bool>((ref) {
  final config = ref.watch(ramadanConfigProvider).valueOrNull;
  if (config == null) return false;

  // Manual override takes priority
  if (config.enabled) return true;

  // Auto-detect based on approximate Hijri calendar
  if (config.autoDetect) {
    return isApproximateRamadan(DateTime.now());
  }

  return false;
});

/// Approximate Ramadan detection using a simplified Hijri calendar calculation.
/// Ramadan moves ~11 days earlier each Gregorian year.
/// This provides a reasonable approximation; for exact dates, a Hijri calendar
/// package could be used.
bool isApproximateRamadan(DateTime now) {
  // Known Ramadan start dates (approximate):
  // 2025: Feb 28 - Mar 30
  // 2026: Feb 17 - Mar 19
  // 2027: Feb 7 - Mar 8
  // 2028: Jan 27 - Feb 25
  final ramadanWindows = {
    2025: (start: DateTime(2025, 2, 28), end: DateTime(2025, 3, 30)),
    2026: (start: DateTime(2026, 2, 17), end: DateTime(2026, 3, 19)),
    2027: (start: DateTime(2027, 2, 7), end: DateTime(2027, 3, 8)),
    2028: (start: DateTime(2028, 1, 27), end: DateTime(2028, 2, 25)),
  };

  final window = ramadanWindows[now.year];
  if (window != null) {
    return !now.isBefore(window.start) && !now.isAfter(window.end);
  }
  return false;
}

final ramadanControllerProvider = Provider<RamadanController>((ref) {
  final client = ref.watch(supabaseClientProvider);
  return RamadanController(client);
});

class RamadanController {
  RamadanController(this._client);

  final SupabaseClient _client;

  Future<void> setEnabled(bool enabled) async {
    final current = await _client
        .from('app_settings')
        .select()
        .eq('key', 'ramadan_mode')
        .maybeSingle();

    final value = current != null
        ? Map<String, dynamic>.from(current['value'] as Map)
        : <String, dynamic>{'auto_detect': true};
    value['enabled'] = enabled;

    await _client.from('app_settings').upsert({
      'key': 'ramadan_mode',
      'value': value,
    });
  }

  Future<void> setAutoDetect(bool autoDetect) async {
    final current = await _client
        .from('app_settings')
        .select()
        .eq('key', 'ramadan_mode')
        .maybeSingle();

    final value = current != null
        ? Map<String, dynamic>.from(current['value'] as Map)
        : <String, dynamic>{'enabled': false};
    value['auto_detect'] = autoDetect;

    await _client.from('app_settings').upsert({
      'key': 'ramadan_mode',
      'value': value,
    });
  }
}