import 'package:flutter/material.dart';
import 'package:syncfusion_flutter_calendar/calendar.dart';

import '../../../../api/webuntis/queries/getHolidays/getHolidaysResponse.dart';
import '../../../../extensions/date_time.dart';
import '../data/calendar_layout.dart';
import '../data/lesson_period_schedule.dart';
import '../data/webuntis_time.dart';
import 'time_region_tile.dart';

class SpecialRegionsBuilder {
  final GetHolidaysResponse holidays;
  final LessonPeriodSchedule schedule;
  final ColorScheme colorScheme;
  final Color disabledColor;

  SpecialRegionsBuilder({
    required this.holidays,
    required this.schedule,
    required this.colorScheme,
    required this.disabledColor,
  });

  List<TimeRegion> build() {
    final lastMonday = DateTime.now().subtract(const Duration(days: 14)).nextWeekday(DateTime.monday);

    final holidayRegions = _buildHolidayRegions().toList();
    bool isInHoliday(DateTime time) => holidayRegions.any((region) => region.startTime.isSameDay(time));

    final breakRegions = schedule.periods.where((p) => p.isBreak).map((p) {
      final start = lastMonday.copyWith(hour: p.start.hour, minute: p.start.minute);
      return _breakRegion(start, p.duration);
    }).where((region) => !isInHoliday(region.startTime));

    return [
      ...holidayRegions,
      ...breakRegions,
    ];
  }

  Iterable<TimeRegion> _buildHolidayRegions() => holidays.result.expand((holiday) {
        final startDay = WebuntisTime.parse(holiday.startDate, 0);
        final dayCount = WebuntisTime.parse(holiday.endDate, 0).difference(startDay).inDays;
        final days = List<DateTime>.generate(dayCount, (i) => startDay.add(Duration(days: i)));
        final gridStartHour = kCalendarStartHour.floor();
        final gridStartMinute = ((kCalendarStartHour - gridStartHour) * 60).round();
        final gridEndHour = kCalendarEndHour.floor();
        final gridEndMinute = ((kCalendarEndHour - gridEndHour) * 60).round();
        return days.map((day) => TimeRegion(
              startTime: day.copyWith(hour: gridStartHour, minute: gridStartMinute),
              endTime: day.copyWith(hour: gridEndHour, minute: gridEndMinute),
              text: '$kTimeRegionHolidayPrefix${holiday.name}',
              color: disabledColor.withAlpha(50),
              iconData: Icons.holiday_village_outlined,
            ));
      });

  TimeRegion _breakRegion(DateTime start, Duration duration) => TimeRegion(
        startTime: start,
        endTime: start.add(duration),
        recurrenceRule: 'FREQ=DAILY;INTERVAL=1',
        text: kTimeRegionCenterIcon,
        color: colorScheme.primary.withAlpha(50),
        iconData: Icons.restaurant,
      );
}