<?php
// Hoplite
// Copyright (c) 2016 Blue Static
//
// This program is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation, either version 3 of the License, or any later version.
//
// This program is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
// more details.
//
// You should have received a copy of the GNU General Public License along with
// this program.  If not, see <http://www.gnu.org/licenses/>.

namespace hoplite\http2;

require_once HOPLITE_ROOT . '/http2/middleware.php';
require_once HOPLITE_ROOT . '/http2/request.php';
require_once HOPLITE_ROOT . '/http2/response.php';

class Pipeline {
  private $middleware = [];

  public function add($middleware) {
    /*
    if (!($middleware instanceof Middleware ||
          $middleware instanceof \Closure ||
          is_array($middleware))) {
      // TODO(php7): TypeError
      throw new \Exception(__FUNCTION__ . ' requires a Middleware or Closure');
    }
     */
    $this->middleware[] = $middleware;
    return $this;
  }

  public function build() {
    $chain = new Sentinel(new NotFoundResponse());
    for ($i = count($this->middleware) - 1; $i >= 0; --$i) {
      $args = $this->middleware[$i];
      if ($args instanceof \Closure) {
        $chain = new ClosureMiddleware($this, $chain, $args);
      } else if (is_array($args)) {
        $class = array_shift($args);
        array_unshift($args, $this, $chain);
        $chain = new $class(...$args);
      } else {
        $chain = new $args($this, $chain);
      }
    }

    return $chain;
  }

  public function run(Middleware $chain) {
    $response = $chain->execute(new Request());
    $response->generate();
  }

  public function buildAndRun() {
    $this->run($this->build());
  }
}

class SubPipeline extends Middleware {
  public function __construct(Pipeline $subpipe) {
    // Skip calling super since this is a new pipeline and the
    // next middleware will be selected by building the subpipe.
    // It would be possible to build the middleware chain here, but
    // doing it lazily on execution is more efficient, since SubPipeline
    // should be used to partition applications.
    $this->subpipe = $subpipe;
  }

  public function execute(Request $request) {
    return $this->subpipe->build()->execute($request);
  }
}