import '../models/closed_tab_item.dart';

class ClosedTabItemDayGroup {
  final DateTime day;
  final List<ClosedTabItem> items;

  const ClosedTabItemDayGroup({required this.day, required this.items});

  int get itemCount => items.fold(
    0,
    (total, item) => total + (item.isRemoved ? 0 : item.quantity),
  );
}

List<ClosedTabItemDayGroup> groupClosedTabItemsByDay(
  Iterable<ClosedTabItem> items, {
  required DateTime fallbackDate,
}) {
  final groups = <DateTime, List<ClosedTabItem>>{};

  for (final item in items) {
    final localPurchasedAt = (item.purchasedAt ?? fallbackDate).toLocal();
    final day = DateTime(
      localPurchasedAt.year,
      localPurchasedAt.month,
      localPurchasedAt.day,
    );
    groups.putIfAbsent(day, () => []).add(item);
  }

  for (final group in groups.values) {
    group.sort((a, b) {
      final aTime = (a.purchasedAt ?? fallbackDate).toLocal();
      final bTime = (b.purchasedAt ?? fallbackDate).toLocal();
      final byTime = bTime.compareTo(aTime);
      if (byTime != 0) return byTime;

      return b.id.compareTo(a.id);
    });
  }

  final sortedGroups = groups.entries.toList()
    ..sort((a, b) => b.key.compareTo(a.key));

  return sortedGroups
      .map((entry) => ClosedTabItemDayGroup(day: entry.key, items: entry.value))
      .toList();
}