/// 일정 컨트롤러 (MVCS의 Controller 레이어)
///
/// 비즈니스 로직과 상태 관리를 담당합니다.
/// View는 이 Controller를 통해 데이터에 접근합니다.
library;

import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:intl/intl.dart';
import '../models/schedule.dart';
import '../services/schedules_service.dart';

/// 일정 상태
class ScheduleState {
  final DateTime selectedDate;
  final List<Schedule> schedules;
  final bool isLoading;
  final String? error;

  const ScheduleState({
    required this.selectedDate,
    this.schedules = const [],
    this.isLoading = false,
    this.error,
  });

  /// 상태 복사 (불변성 유지)
  ScheduleState copyWith({
    DateTime? selectedDate,
    List<Schedule>? schedules,
    bool? isLoading,
    String? error,
  }) {
    return ScheduleState(
      selectedDate: selectedDate ?? this.selectedDate,
      schedules: schedules ?? this.schedules,
      isLoading: isLoading ?? this.isLoading,
      error: error,
    );
  }

  /// 선택된 날짜의 일정 목록
  List<Schedule> get selectedDateSchedules {
    final dateStr = DateFormat('yyyy-MM-dd').format(selectedDate);
    return schedules.where((s) => s.date.split('T')[0] == dateStr).toList();
  }

  /// 특정 날짜의 일정 (점 표시용, 최대 3개)
  List<Schedule> getDaySchedules(DateTime date) {
    final dateStr = DateFormat('yyyy-MM-dd').format(date);
    return schedules.where((s) => s.date.split('T')[0] == dateStr).take(3).toList();
  }

  /// 해당 달의 모든 날짜 배열
  List<DateTime> get daysInMonth {
    final year = selectedDate.year;
    final month = selectedDate.month;
    final lastDay = DateTime(year, month + 1, 0).day;
    return List.generate(lastDay, (i) => DateTime(year, month, i + 1));
  }
}

/// 일정 컨트롤러
class ScheduleController extends Notifier<ScheduleState> {
  @override
  ScheduleState build() {
    // 초기 상태
    final initialState = ScheduleState(selectedDate: DateTime.now());
    // 초기 데이터 로드
    Future.microtask(() => loadSchedules());
    return initialState;
  }

  /// 월별 일정 로드
  Future<void> loadSchedules() async {
    state = state.copyWith(isLoading: true, error: null);

    try {
      final schedules = await getSchedules(
        state.selectedDate.year,
        state.selectedDate.month,
      );
      state = state.copyWith(schedules: schedules, isLoading: false);
    } catch (e) {
      state = state.copyWith(isLoading: false, error: e.toString());
    }
  }

  /// 날짜 선택
  void selectDate(DateTime date) {
    state = state.copyWith(selectedDate: date);
  }

  /// 월 변경
  void changeMonth(int delta) {
    final newDate = DateTime(
      state.selectedDate.year,
      state.selectedDate.month + delta,
      1,
    );
    final today = DateTime.now();

    // 이번 달이면 오늘 날짜, 다른 달이면 1일 선택
    final selectedDay = (newDate.year == today.year && newDate.month == today.month)
        ? today.day
        : 1;

    state = state.copyWith(
      selectedDate: DateTime(newDate.year, newDate.month, selectedDay),
    );
    loadSchedules();
  }

  /// 오늘 여부
  bool isToday(DateTime date) {
    final today = DateTime.now();
    return date.year == today.year &&
        date.month == today.month &&
        date.day == today.day;
  }

  /// 선택된 날짜 여부
  bool isSelected(DateTime date) {
    return date.year == state.selectedDate.year &&
        date.month == state.selectedDate.month &&
        date.day == state.selectedDate.day;
  }
}

/// 일정 Provider
final scheduleProvider = NotifierProvider<ScheduleController, ScheduleState>(
  ScheduleController.new,
);