import '../core/date_keys.dart';
import 'app_state.dart';

class JourneyStats {
  const JourneyStats({
    required this.currentStreakDays,
    required this.weekFocusMinutes,
    required this.activeDaysThisWeek,
    required this.habitCompletionRate,
  });

  final int currentStreakDays;
  final int weekFocusMinutes;
  final int activeDaysThisWeek;
  final double habitCompletionRate;

  static JourneyStats fromState(AppState state) {
    final dateKeys = lastSevenDateKeys();
    final dateKeySet = dateKeys.toSet();
    final weekFocusMinutes = dateKeys.fold<int>(
      0,
      (total, key) => total + minutesForDate(state.sessions, key),
    );
    final activeDays = dateKeys.where((key) => _hasProgress(state, key)).length;
    final habitCompletions = state.habits.fold<int>(
      0,
      (total, habit) =>
          total + habit.completedDates.where(dateKeySet.contains).length,
    );
    final habitOpportunities = state.habits.length * dateKeys.length;

    return JourneyStats(
      currentStreakDays: currentStreak(
        state.habits,
        state.sessions,
        state.reflections,
      ),
      weekFocusMinutes: weekFocusMinutes,
      activeDaysThisWeek: activeDays,
      habitCompletionRate:
          habitOpportunities == 0 ? 0 : habitCompletions / habitOpportunities,
    );
  }

  static bool _hasProgress(AppState state, String key) {
    return state.habits.any((habit) => habit.completedDates.contains(key)) ||
        state.sessions.any((session) => dateKey(session.completedAt) == key) ||
        state.reflections.any((reflection) => reflection.dateKey == key);
  }
}