<?php
/**
 * Registry of notification channels.
 *
 * @package Bookline
 */

declare( strict_types=1 );

namespace Bookline\Infrastructure\Notification;

use Bookline\Domain\Notification\NotificationChannel;

/**
 * Channel lookup.
 *
 * @since 0.1.0
 */
final class ChannelRegistry {

	/**
	 * Channels keyed by id.
	 *
	 * @var array<string, NotificationChannel>
	 */
	private array $channels = [];

	/**
	 * Register a channel.
	 *
	 * @param NotificationChannel $channel Channel.
	 *
	 * @since 0.1.0
	 */
	public function register( NotificationChannel $channel ): void {
		$this->channels[ $channel->id() ] = $channel;
	}

	/**
	 * Get a channel by id.
	 *
	 * @param string $id Channel id.
	 *
	 * @since 0.1.0
	 */
	public function get( string $id ): ?NotificationChannel {
		$channels = $this->all();
		return $channels[ $id ] ?? null;
	}

	/**
	 * All channels (filterable).
	 *
	 * @return array<string, NotificationChannel>
	 *
	 * @since 0.1.0
	 */
	public function all(): array {
		$channels = $this->channels;
		if ( function_exists( 'apply_filters' ) ) {
			/**
			 * Filter registered notification channels.
			 *
			 * @param array<string, NotificationChannel> $channels Channels.
			 *
			 * @since 0.1.0
			 */
			$filtered = apply_filters( 'bookline/notification/channels', $channels );
			if ( is_array( $filtered ) ) {
				return $filtered;
			}
		}
		return $channels;
	}
}