<?php
namespace DayTidy;

use DayTidy\Data\RepeatTypes;
use DayTidy\Sessions\Adapters\Custom;
use DayTidy\Sessions\Adapters\Recurring;
use DayTidy\Interfaces\Session as SessionInterface;
use DayTidy\Recurrence\Factory;
use DayTidy\Recurrence\Recurrence;
use Carbon\Carbon;
use DayTidy\Interfaces\Advent as AdventInterface;
use DateTime;
use Exception;

class Sessions
{
    /**
     * @param AdventInterface $entity
     * @param int $maximum
     * @param string|null $start
     * @return SessionInterface[]
     * @throws Exception
     */
    public static function getByRecurrence(AdventInterface $entity, int $maximum = 50, ?string $start = null): array
    {
        // Sessions
        $sessions = [];

        // Offering Frequency
        $frequency = $entity->meta_get('daytidy_freq', RepeatTypes::CUSTOM);

        // Custom Frequency
        if ($frequency === RepeatTypes::CUSTOM)
        {
            $custom_sessions = $entity->meta_get('daytidy_sessions', []);
            foreach ($custom_sessions as $session)
            {
                $sessions[] = [
                    'start' => new DateTime($session['start'], $entity->getTimeZone()),
                    'end' => new DateTime($session['end'], $entity->getTimeZone()),
                ];
            }

            // Convert PHP DateTime[] to Session[]
            return (new Custom($entity))->collection($sessions);
        }

        // Recurring Offering

        // Get Recurrence
        $recurrence = self::recurrence($entity);

        // Auto Populate Start Date
        if (!$start) $start = $entity->meta_get('daytidy_schedule_start', Carbon::now()->format('Y-m-d H:i:s'));

        // Sessions
        $sessions = $recurrence->getSessionsAfter($start, false, $maximum);

        // Convert PHP DateTime[] to Session[]
        return (new Recurring($entity))->collection($sessions);
    }

    /**
     * Get Recurrence by RFC
     *
     * @param AdventInterface $entity
     * @return Recurrence<\DateTime>
     */
    public static function recurrence(AdventInterface $entity)
    {
        // RFC Rule
        $rule = $entity->meta_get('daytidy_recurrence_rule', '');

        // Recurrence
        return Factory::recurrenceByRFCString($rule);
    }
}