import '../models/focus_session.dart';
import '../models/habit.dart';
import '../models/reflection_entry.dart';

String todayKey() => dateKey(DateTime.now());

String dateKey(DateTime date) {
  final local = DateTime(date.year, date.month, date.day);
  return '${local.year.toString().padLeft(4, '0')}-'
      '${local.month.toString().padLeft(2, '0')}-'
      '${local.day.toString().padLeft(2, '0')}';
}

List<String> lastSevenDateKeys() {
  final now = DateTime.now();
  return List.generate(
    7,
    (index) => dateKey(now.subtract(Duration(days: 6 - index))),
  );
}

int minutesForDate(List<FocusSession> sessions, String key) {
  return sessions
      .where((session) => dateKey(session.completedAt) == key)
      .fold<int>(0, (total, session) => total + session.actualMinutes);
}

int currentStreak(
  List<Habit> habits,
  List<FocusSession> sessions,
  List<ReflectionEntry> reflections,
) {
  var streak = 0;
  var cursor = DateTime.now();
  while (true) {
    final key = dateKey(cursor);
    final hasHabit = habits.any((habit) => habit.completedDates.contains(key));
    final hasSession = sessions.any(
      (session) => dateKey(session.completedAt) == key,
    );
    final hasReflection = reflections.any(
      (reflection) => reflection.dateKey == key,
    );
    if (!hasHabit && !hasSession && !hasReflection) {
      return streak;
    }
    streak += 1;
    cursor = cursor.subtract(const Duration(days: 1));
  }
}

String formatSeconds(int seconds) {
  final minutes = seconds ~/ 60;
  final remaining = seconds % 60;
  return '${minutes.toString().padLeft(2, '0')}:'
      '${remaining.toString().padLeft(2, '0')}';
}