<?php
/**
 * IANA timezone identifier value object.
 *
 * @package Bookline
 */

declare( strict_types=1 );

namespace Bookline\Domain\Shared;

use DateTimeZone;
use Exception;

/**
 * Validates against the IANA timezone database.
 *
 * @since 0.1.0
 */
final class TimeZoneId {

	/**
	 * IANA identifier (e.g. Europe/London).
	 *
	 * @var string
	 */
	private string $value;

	/**
	 * Constructor.
	 *
	 * @param string $value IANA timezone id.
	 *
	 * @throws DomainException When the identifier is unknown.
	 */
	public function __construct( string $value ) {
		$value = trim( $value );
		if ( '' === $value ) {
			throw new DomainException( 'timezone.empty', 'Timezone identifier must not be empty.' );
		}
		try {
			new DateTimeZone( $value );
		} catch ( Exception $e ) {
			throw new DomainException( 'timezone.invalid', 'Unknown IANA timezone identifier.' );
		}
		$this->value = $value;
	}

	/**
	 * String representation.
	 *
	 * @since 0.1.0
	 */
	public function to_string(): string {
		return $this->value;
	}

	/**
	 * To date time zone.
	 *
	 * @since 0.1.0
	 */
	public function to_date_time_zone(): DateTimeZone {
		return new DateTimeZone( $this->value );
	}

	/**
	 * Equals.
	 *
	 * @param self $other Parameter.
	 * @since 0.1.0
	 */
	public function equals( self $other ): bool {
		return $this->value === $other->value;
	}

	/**
	 * String cast.
	 *
	 * @since 0.1.0
	 */
	public function __toString(): string {
		return $this->value;
	}
}