import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../features/scan/recognition_service.dart';
import '../../shared/models/home_summary.dart';
import '../../shared/models/menu.dart';
import '../menu/menu_provider.dart';
import 'home_service.dart';

// ── Selected date (persists while app is open) ────────────────

/// The date currently viewed on the home screen.
/// Defaults to today; can be changed via the date selector.
final selectedDateProvider = StateProvider<DateTime>((ref) => DateTime.now());

/// Formats a [DateTime] to the 'YYYY-MM-DD' string expected by the diary API.
String formatDateForDiary(DateTime date) =>
    '${date.year}-${date.month.toString().padLeft(2, '0')}-'
    '${date.day.toString().padLeft(2, '0')}';

// ── Home summary ──────────────────────────────────────────────

class HomeNotifier extends StateNotifier<AsyncValue<HomeSummary>> {
  final HomeService _service;

  HomeNotifier(this._service) : super(const AsyncValue.loading()) {
    load();
  }

  Future<void> load() async {
    state = const AsyncValue.loading();
    state = await AsyncValue.guard(() => _service.getSummary());
  }
}

final homeProvider =
    StateNotifierProvider<HomeNotifier, AsyncValue<HomeSummary>>(
  (ref) => HomeNotifier(ref.read(homeServiceProvider)),
);

// ── Today's unlinked recognition jobs ─────────────────────────

class TodayJobsNotifier
    extends StateNotifier<AsyncValue<List<DishJobSummary>>> {
  final RecognitionService _service;

  TodayJobsNotifier(this._service) : super(const AsyncValue.loading()) {
    load();
  }

  Future<void> load() async {
    state = const AsyncValue.loading();
    state =
        await AsyncValue.guard(() => _service.listTodayUnlinkedJobs());
  }
}

final todayJobsProvider =
    StateNotifierProvider<TodayJobsNotifier, AsyncValue<List<DishJobSummary>>>(
  (ref) => TodayJobsNotifier(ref.read(recognitionServiceProvider)),
);

// ── All recognition jobs (history screen) ─────────────────────

class AllJobsNotifier extends StateNotifier<AsyncValue<List<DishJobSummary>>> {
  final RecognitionService _service;

  AllJobsNotifier(this._service) : super(const AsyncValue.loading()) {
    load();
  }

  Future<void> load() async {
    state = const AsyncValue.loading();
    state = await AsyncValue.guard(() => _service.listAllJobs());
  }
}

final allJobsProvider =
    StateNotifierProvider<AllJobsNotifier, AsyncValue<List<DishJobSummary>>>(
  (ref) => AllJobsNotifier(ref.read(recognitionServiceProvider)),
);

// ── Planned meals from menu ────────────────────────────────────

/// Returns planned [MealSlot]s from the menu plan for [dateString].
/// Derives from the already-cached weekly menu — no extra network call.
/// Returns an empty list when no plan exists for that week.
final plannedMealsProvider =
    Provider.family<List<MealSlot>, String>((ref, dateString) {
  final date = DateTime.parse(dateString);
  final weekString = isoWeekString(date);
  final menuState = ref.watch(menuProvider(weekString));
  final plan = menuState.valueOrNull;
  if (plan == null) return [];
  for (final day in plan.days) {
    if (day.date == dateString) return day.meals;
  }
  return [];
});