import { Calendar, CalendarEvent } from '/lib/types.ts';
import { getDaysForWeek } from '/lib/utils.ts';

interface CalendarViewWeekProps {
  startDate: Date;
  visibleCalendars: Pick<Calendar, 'id' | 'name' | 'color'>[];
  calendarEvents: CalendarEvent[];
  onClickAddEvent: (startDate?: Date, isAllDay?: boolean) => void;
  onClickOpenEvent: (calendarEvent: CalendarEvent) => void;
}

export default function CalendarViewWeek(
  { startDate, visibleCalendars, calendarEvents, onClickAddEvent, onClickOpenEvent }: CalendarViewWeekProps,
) {
  const today = new Date().toISOString().substring(0, 10);

  const hourFormat = new Intl.DateTimeFormat('en-GB', { hour12: false, hour: '2-digit', minute: '2-digit' });
  const weekDayFormat = new Intl.DateTimeFormat('en-GB', { weekday: 'short' });

  const days = getDaysForWeek(new Date(startDate));

  return (
    <section class='shadow-md flex flex-auto flex-col rounded-md'>
      <section class='w-full grid gap-px grid-flow-col rounded-md text-white text-xs bg-slate-600 calendar-week-view-days'>
        {days.map((day, dayIndex) => {
          const allDayEvents: CalendarEvent[] = calendarEvents.filter((calendarEvent) => {
            if (!calendarEvent.is_all_day) {
              return false;
            }

            const startDayDate = new Date(day.date);
            const endDayDate = new Date(day.date);
            endDayDate.setHours(23);
            endDayDate.setMinutes(59);
            endDayDate.setSeconds(59);
            endDayDate.setMilliseconds(999);

            const eventStartDate = new Date(calendarEvent.start_date);
            const eventEndDate = new Date(calendarEvent.end_date);

            // Event starts and ends on this day
            if (eventStartDate >= startDayDate && eventEndDate <= endDayDate) {
              return true;
            }

            // Event starts before and ends after this day
            if (eventStartDate <= startDayDate && eventEndDate >= endDayDate) {
              return true;
            }

            // Event starts on and ends after this day
            if (
              eventStartDate >= startDayDate && eventStartDate <= endDayDate && eventEndDate >= endDayDate
            ) {
              return true;
            }

            // Event starts before and ends on this day
            if (
              eventStartDate <= startDayDate && eventEndDate >= startDayDate && eventEndDate <= endDayDate
            ) {
              return true;
            }

            return false;
          });

          const isFirstDay = dayIndex === 0;
          const isLastDay = dayIndex === 6;
          const isToday = new Date(day.date).toISOString().substring(0, 10) === today;

          return (
            <>
              <section
                class={`flex justify-center ${isToday ? 'bg-[#51A4FB]' : 'bg-gray-900'} py-2 ${
                  isFirstDay ? 'rounded-tl-md' : ''
                } ${isLastDay ? 'rounded-tr-md' : ''} text-center text-xs font-semibold text-white`}
              >
                <span>{weekDayFormat.format(day.date)}</span>
              </section>
              <section
                class={`relative bg-slate-700 min-h-8 px-3 py-2 text-slate-100`}
              >
                <time
                  datetime={new Date(startDate).toISOString().substring(0, 10)}
                  onClick={() => onClickAddEvent(new Date(startDate), true)}
                  class='cursor-pointer'
                  title='Add a new all-day event'
                >
                  All-day
                </time>
                {allDayEvents.length > 0
                  ? (
                    <ol class='mt-2'>
                      {allDayEvents.map((calendarEvent) => (
                        <li class='mb-1'>
                          <a
                            href='javascript:void(0);'
                            class={`flex px-2 py-2 rounded-md hover:no-underline hover:opacity-60 ${
                              visibleCalendars.find((calendar) => calendar.id === calendarEvent.calendar_id)
                                ?.color || 'bg-gray-700'
                            }`}
                            onClick={() => onClickOpenEvent(calendarEvent)}
                          >
                            <p class='flex-auto truncate font-medium text-white'>
                              {calendarEvent.title}
                            </p>
                          </a>
                        </li>
                      ))}
                    </ol>
                  )
                  : null}
              </section>
              {day.hours.map((hour, hourIndex) => {
                const shortIsoDate = hour.date.toISOString().substring(0, 10);

                const startHourDate = new Date(shortIsoDate);
                startHourDate.setHours(hour.date.getHours());
                const endHourDate = new Date(shortIsoDate);
                endHourDate.setHours(hour.date.getHours());
                endHourDate.setMinutes(59);
                endHourDate.setSeconds(59);
                endHourDate.setMilliseconds(999);

                const isLastHourOfFirstDay = hourIndex === 23 && dayIndex === 0;
                const isLastHourOfLastDay = hourIndex === 23 && dayIndex === 6;

                const hourEvents = calendarEvents.filter((calendarEvent) => {
                  if (calendarEvent.is_all_day) {
                    return false;
                  }

                  const eventStartDate = new Date(calendarEvent.start_date);
                  const eventEndDate = new Date(calendarEvent.end_date);
                  eventEndDate.setSeconds(eventEndDate.getSeconds() - 1); // Take one second back so events don't bleed into the next hour

                  // Event starts and ends on this hour
                  if (eventStartDate >= startHourDate && eventEndDate <= endHourDate) {
                    return true;
                  }

                  // Event starts before and ends after this hour
                  if (eventStartDate <= startHourDate && eventEndDate >= endHourDate) {
                    return true;
                  }

                  // Event starts on and ends after this hour
                  if (
                    eventStartDate >= startHourDate && eventStartDate <= endHourDate &&
                    eventEndDate >= endHourDate
                  ) {
                    return true;
                  }

                  // Event starts before and ends on this hour
                  if (
                    eventStartDate <= startHourDate && eventEndDate >= startHourDate &&
                    eventEndDate <= endHourDate
                  ) {
                    return true;
                  }

                  return false;
                });

                return (
                  <section
                    class={`relative ${hour.isCurrentHour ? 'bg-slate-600' : 'bg-slate-700'} min-h-8 px-3 py-2 ${
                      hour.isCurrentHour ? '' : 'text-slate-100'
                    } ${isLastHourOfFirstDay ? 'rounded-bl-md' : ''} ${isLastHourOfLastDay ? 'rounded-br-md' : ''}`}
                  >
                    <time
                      datetime={startHourDate.toISOString()}
                      onClick={() => onClickAddEvent(startHourDate)}
                      class='cursor-pointer'
                      title='Add a new event'
                    >
                      {hourFormat.format(startHourDate)}
                    </time>
                    {hourEvents.length > 0
                      ? (
                        <ol class='mt-2'>
                          {hourEvents.map((hourEvent) => (
                            <li class='mb-1'>
                              <a
                                href='javascript:void(0);'
                                class={`flex px-2 py-2 rounded-md hover:no-underline hover:opacity-60 ${
                                  visibleCalendars.find((calendar) => calendar.id === hourEvent.calendar_id)
                                    ?.color || 'bg-gray-700'
                                }`}
                                onClick={() => onClickOpenEvent(hourEvent)}
                              >
                                <time
                                  datetime={new Date(hourEvent.start_date).toISOString()}
                                  class='mr-2 flex-none text-slate-100 block'
                                >
                                  {hourFormat.format(new Date(hourEvent.start_date))}
                                </time>
                                <p class='flex-auto truncate font-medium text-white'>
                                  {hourEvent.title}
                                </p>
                              </a>
                            </li>
                          ))}
                        </ol>
                      )
                      : null}
                  </section>
                );
              })}
            </>
          );
        })}
      </section>
    </section>
  );
}