<?php

use Reservair\Logger\Logger;

class RsvTimetableService {
    private RsvTimetableRepository $repo;

    public function __construct() {
        $this->repo = new RsvTimetableRepository();
    }

    public function get_all(?int $limit = null, int $skip = 0): array {
        return $this->repo->get_all($limit, $skip);
    }

    public function count_all(): int {
        return $this->repo->count_all();
    }

    public function get(int $id): ?RsvTimetable {
        return $this->repo->get($id);
    }

    public function create(RsvTimetable $timetable): int {
        return $this->repo->create($timetable);
    }

    public function update(int $id, RsvTimetable $timetable): int {
        return $this->repo->update($id, $timetable);
    }

    public function get_all_maintainer_emails(): array {
        return $this->repo->get_all_maintainer_emails();
    }

    public function set_google_calendar_id(int $id, ?string $calendar_id): void {
        $this->repo->set_google_calendar_id($id, $calendar_id);
    }

    public function delete(int $id): int {
        Logger::info('Deleting timetable: ' . $id);
        return $this->repo->delete($id);
    }

    private function datetime_to_minutes(DateTime $dt): int {
        $d = $dt->setTimezone(wp_timezone());
        return (int) $d->format('G') * 60 + (int) $d->format('i');
    }

    /**
     * @return array<int,RsvTimetableAvailability> Availability on date
     */
    public function get_availability_on_date(int $timetable_id, int $block_length, DateTime $date) : array {
        /**
         * Get available seats for the given date
         * Keeps two stacks: capacities & reservations
         *
         * Goes from left to right in reservations and pushes to stack
         */
        $capacities   = (new RsvTimetableCapacityRepository())->get_capacities_for_date($timetable_id, $date);
        $reservations = (new RsvTimetableReservationService())->get_reservations_on_date($timetable_id, $date);

        $capacity_stack = [];
        $reservation_stack = [];

        $capacity_index = 0;
        $reservation_index = 0;

        $blocks_count = 24 * 60 / $block_length;
        $blocks = array_fill(0, $blocks_count, 0);

        $availabilities = [];
        $availability_idx = 0;

        for($i = 0; $i < $blocks_count; $i++) {
            $reservation_stack = array_filter($reservation_stack, fn($reservation) =>
                $this->datetime_to_minutes($reservation->end_utc) > $i * $block_length
            );

            $capacity_stack = array_filter($capacity_stack, fn($capacity) =>
                $capacity->end_time > $i * $block_length
            );

            while($reservation_index < count($reservations) && $this->datetime_to_minutes($reservations[$reservation_index]->start_utc) <= $i * $block_length) {
                $reservation_stack[] = $reservations[$reservation_index];
                $reservation_index++;
            }

            while($capacity_index < count($capacities) && $capacities[$capacity_index]->start_time <= $i * $block_length) {
                $capacity_stack[] = $capacities[$capacity_index];
                $capacity_index++;
            }

            $total_capacity = array_sum(array_map(fn($x) => $x->capacity, $capacity_stack));

            if ($total_capacity > 0) {
                if(count($availabilities) === $availability_idx) {
                    $availabilities[] = new RsvTimetableAvailability($i * $block_length, ($i + 1) * $block_length, $block_length, []);
                }

                $availabilities[$availability_idx]->push_block($total_capacity - count($reservation_stack));
            } else if($total_capacity === 0 && count($availabilities) !== $availability_idx) {
                $availability_idx++;
            }
        }

        return $availabilities;
    }
}