<?php
/**
 * Admin calendar reschedule (docs/08 §2.3).
 *
 * @package Bookline
 */

declare( strict_types=1 );

namespace Bookline\Application\Booking;

use Bookline\Domain\Booking\Booking;
use Bookline\Domain\Booking\BookingRepository;
use Bookline\Domain\Shared\DomainException;
use DateTimeImmutable;
use DateTimeZone;

/**
 * Maps ISO start/end onto RescheduleBookingHandler, preserving buffers.
 *
 * @since 0.1.0
 */
final class AdminRescheduleBookingHandler {

	/**
	 * Constructor.
	 *
	 * @param BookingRepository        $bookings   Bookings.
	 * @param RescheduleBookingHandler $reschedule Core reschedule use case.
	 */
	public function __construct(
		private readonly BookingRepository $bookings,
		private readonly RescheduleBookingHandler $reschedule,
	) {}

	/**
	 * Reschedule a booking onto a new start (and optional new end).
	 *
	 * @param int    $booking_id Booking id.
	 * @param string $start_iso  Start instant (ISO 8601).
	 * @param string $end_iso    Optional end instant (ISO 8601).
	 *
	 * @throws DomainException When the payload is invalid or policy fails.
	 */
	public function handle( int $booking_id, string $start_iso, string $end_iso = '' ): Booking {
		$booking = $this->bookings->find_by_id( $booking_id );
		if ( null === $booking ) {
			throw new DomainException( 'booking.not_found', 'Booking not found.' );
		}

		$utc = new DateTimeZone( 'UTC' );
		try {
			$start = ( new DateTimeImmutable( $start_iso ) )->setTimezone( $utc );
		} catch ( \Exception $e ) {
			throw new DomainException( 'booking.start_invalid', 'Start date and time are invalid.' );
		}

		$end = null;
		if ( '' !== trim( $end_iso ) ) {
			try {
				$end = ( new DateTimeImmutable( $end_iso ) )->setTimezone( $utc );
			} catch ( \Exception $e ) {
				throw new DomainException( 'booking.end_invalid', 'End date and time are invalid.' );
			}
		}

		$duration = null !== $end
			? $end->getTimestamp() - $start->getTimestamp()
			: $booking->end_utc()->getTimestamp() - $booking->start_utc()->getTimestamp();
		if ( $duration < 1 ) {
			throw new DomainException( 'booking.range', 'End must be after start.' );
		}

		$end_utc      = $start->modify( '+' . $duration . ' seconds' );
		$buf_before   = $booking->start_utc()->getTimestamp() - $booking->buffer_start_utc()->getTimestamp();
		$buf_after    = $booking->buffer_end_utc()->getTimestamp() - $booking->end_utc()->getTimestamp();
		$buffer_start = $start->modify( '-' . max( 0, $buf_before ) . ' seconds' );
		$buffer_end   = $end_utc->modify( '+' . max( 0, $buf_after ) . ' seconds' );

		return $this->reschedule->handle(
			$booking_id,
			$start,
			$end_utc,
			$buffer_start,
			$buffer_end,
			$start
		);
	}
}