<?php
/**
 * Chooses a request signer.
 *
 * @package AdPix\Analytics
 */

declare( strict_types = 1 );

namespace AdPix\Analytics\Http;

use AdPix\Analytics\Contracts\SignerInterface;
use AdPix\Analytics\Model\Settings;

defined( 'ABSPATH' ) || exit;

/**
 * Builds the signer the current configuration calls for.
 *
 * A factory rather than a constructor argument because the answer depends on settings that can
 * change during a request — the connection test runs immediately after a save — and a signer chosen
 * once at boot would still be holding the previous key.
 */
final class SignerFactory {

	/**
	 * The signer for a configuration.
	 *
	 * @param Settings $settings Current configuration.
	 * @return SignerInterface
	 */
	public function for_settings( Settings $settings ): SignerInterface {
		$secret = $settings->str( 'server_key' );

		if ( ! $settings->flag( 'use_hmac' ) || '' === $secret ) {
			return new NullSigner();
		}

		// The server key is the shared secret; there is no second credential to configure.
		return new HmacSigner( $secret );
	}
}