<?php

namespace authkit2\Oidc\Authentication;

/**
 * Abstract provider for signing/authenticating http requests
 */
abstract class Authentication
{
	/**
	 * Authenticate the passed in HTTP request
	 *
	 * @param \Psr\Http\Message\RequestInterface $request request to authenticate
	 * @return \Psr\Http\Message\RequestInterface authenticated request
	 */
	public abstract function authenticate(\Psr\Http\Message\RequestInterface $request): \Psr\Http\Message\RequestInterface;

	/**
	 * Wrap this provider up as a middleware appropriate for use directly with
	 * Guzzle's handler stack.
	 *
	 * @return callable
	 */
	public function getMiddleware(): callable
	{
		$auth = $this;
		return function(callable $handler) use ($auth) : callable {
			/**
			 * @param \Psr\Http\Message\RequestInterface $request
			 * @param mixed[] $options
			 * @return mixed
			 */
			return function(\Psr\Http\Message\RequestInterface $request, array $options) use ($handler, $auth) {
				return $handler(
					$auth->authenticate($request),
					$options
				);
			};
		};
	}

	/**
	 * Fetch a guzzle client with the authentication middleware included
	 *
	 * @param mixed[] $options options to pass through to the guzzle client
	 * @return \GuzzleHttp\Client
	 */
	public function getClient(array $options = []): \GuzzleHttp\Client
	{
		$stack = new \GuzzleHttp\HandlerStack();
		$stack->setHandler(new \GuzzleHttp\Handler\CurlHandler());
		$stack->push($this->getMiddleware());
		return new \GuzzleHttp\Client(array_merge($options, ['handler' => $stack]));
	}
}