<?php

/*

 * This file is part of the Symfony package.

 *

 * (c) Fabien Potencier <fabien@symfony.com>

 *

 * For the full copyright and license information, please view the LICENSE

 * file that was distributed with this source code.

 */

namespace Symfony\Component\Console;

use Symfony\Component\Console\Application;

use Symfony\Component\Console\Input\StringInput;

use Symfony\Component\Console\Output\ConsoleOutput;

/**

 * A Shell wraps an Application to add shell capabilities to it.

 *

 * This class only works with a PHP compiled with readline support

 * (either --with-readline or --with-libedit)

 *

 * @author Fabien Potencier <fabien@symfony.com>

 */

class Shell

{

    private $application;

    private $history;

    private $output;

    /**

     * Constructor.

     *

     * If there is no readline support for the current PHP executable

     * a \RuntimeException exception is thrown.

     *

     * @param Application $application An application instance

     *

     * @throws \RuntimeException When Readline extension is not enabled

     */

    public function __construct(Application $application)

    {

        if (!function_exists('readline')) {

            throw new \RuntimeException('Unable to start the shell as the Readline extension is not enabled.');

        }

        $this->application = $application;

        $this->history = getenv('HOME').'/.history_'.$application->getName();

        $this->output = new ConsoleOutput();

    }

    /**

     * Runs the shell.

     */

    public function run()

    {

        $this->application->setAutoExit(false);

        $this->application->setCatchExceptions(true);

        readline_read_history($this->history);

        readline_completion_function(array($this, 'autocompleter'));

        $this->output->writeln($this->getHeader());

        while (true) {

            $command = readline($this->application->getName().' > ');

            if (false === $command) {

                $this->output->writeln("\n");

                break;

            }

            readline_add_history($command);

            readline_write_history($this->history);

            if (0 !== $ret = $this->application->run(new StringInput($command), $this->output)) {

                $this->output->writeln(sprintf('<error>The command terminated with an error status (%s)</error>', $ret));

            }

        }

    }

    /**

     * Tries to return autocompletion for the current entered text.

     *

     * @param string  $text     The last segment of the entered text

     * @param integer $position The current position

     */

    private function autocompleter($text, $position)

    {

        $info = readline_info();

        $text = substr($info['line_buffer'], 0, $info['end']);

        if ($info['point'] !== $info['end']) {

            return true;

        }

        // task name?

        if (false === strpos($text, ' ') || !$text) {

            return array_keys($this->application->all());

        }

        // options and arguments?

        try {

            $command = $this->application->find(substr($text, 0, strpos($text, ' ')));

        } catch (\Exception $e) {

            return true;

        }

        $list = array('--help');

        foreach ($command->getDefinition()->getOptions() as $option) {

            $list[] = '--'.$option->getName();

        }

        return $list;

    }

    /**

     * Returns the shell header.

     *

     * @return string The header string

     */

    protected function getHeader()

    {

        return <<<EOF

Welcome to the <info>{$this->application->getName()}</info> shell (<comment>{$this->application->getVersion()}</comment>).

At the prompt, type <comment>help</comment> for some help,

or <comment>list</comment> to get a list available commands.

To exit the shell, type <comment>^D</comment>.

EOF;

    }

}