<?php

/*
                    COPYRIGHT

Copyright 2007 Sergio Vaccaro <sergio@inservibile.org>

This file is part of JSON-RPC PHP.

JSON-RPC PHP 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 2 of the License, or
(at your option) any later version.

JSON-RPC PHP 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 JSON-RPC PHP; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

/**
 * The object of this class are generic jsonRPC 1.0 clients
 * http://json-rpc.org/wiki/specification
 *
 * @author sergio <jsonrpcphp@inservibile.org>
 */
class jsonRPCClient
{

    /**
     * Debug state
     *
     * @var boolean
     */
    private $debug;

    /**
     * The server URL
     *
     * @var string
     */
    private $url;
    /**
     * The request id
     *
     * @var integer
     */
    private $id;
    /**
     * If true, notifications are performed instead of requests
     *
     * @var boolean
     */
    private $notification = false;

    /**
     * Takes the connection parameters
     *
     * @param string $url
     * @param boolean $debug
     */
    public function __construct($url, $debug = false)
    {
        // server URL
        $this->url = $url;
        // proxy
        empty($proxy) ? $this->proxy = '' : $this->proxy = $proxy;
        // debug state
        empty($debug) ? $this->debug = false : $this->debug = true;
        // message id
        $this->id = 1;
    }

    /**
     * Sets the notification state of the object. In this state, notifications are performed, instead of requests.
     *
     * @param boolean $notification
     */
    public function setRPCNotification($notification)
    {
        empty($notification) ?
                            $this->notification = false
                            :
                            $this->notification = true;
    }

    /**
     * Performs a jsonRCP request and gets the results as an array
     *
     * @param string $method
     * @param array $params
     * @return array
     */
    public function __call($method, $params)
    {

        // check
        if (!is_scalar($method)) {
            throw new Exception('Method name has no scalar value');
        }

        // check
        if (is_array($params)) {
            // no keys
            $params = array_values($params);
        } else {
            throw new Exception('Params must be given as array');
        }

        // sets notification or request task
        if ($this->notification) {
            $currentId = null;
        } else {
            $currentId = $this->id;
        }

        // prepares the request
        $request = array(
                        'method' => $method,
                        'params' => $params,
                        'id' => $currentId
                        );
        $request = json_encode($request);
        $this->debug && $this->debug .= '***** Request *****' . "\n" . $request . "\n" . '***** End Of request *****' . "\n\n";

        // performs the HTTP POST
        $opts = array('http' => array(
                            'method'  => 'POST',
                            'header'  => 'Content-type: application/json',
                            'content' => $request
                            ));
        $context = stream_context_create($opts);
        if ($fp = fopen($this->url, 'r', false, $context)) {
            stream_set_timeout($fp, 120);
            $response = '';
            while ($row = fgets($fp)) {
                $response .= trim($row) . "\n";
            }
            $this->debug && $this->debug .= '***** Server response *****' . "\n" . $response . '***** End of server response *****' . "\n";
            $response = json_decode($response, true);
        } else {
            throw new Exception('Unable to connect to ' . $this->url);
        }

        // debug output
        if ($this->debug) {
            echo nl2br($this->debug);
            $this->debug = true;
        }

        // final checks and return
        if (!$this->notification) {
            // check
            if ($response['id'] != $currentId) {
                throw new Exception('Incorrect response id (request id: ' . $currentId . ', response id: ' . $response['id'] . ')');
            }
            if (!is_null($response['error'])) {
                throw new Exception('Request error: ' . $response['error']);
            }

            return $response['result'];
        } else {
            return true;
        }
    }

    public function call($method, $params)
    {
        return $this->__call($method, $params);
    }
}