<?php

    /**
    * Twitter-API-PHP : Simple PHP wrapper for the v1.1 API
    * 
    * PHP version 5.3.10
    * 
    * @category Awesomeness
    * @package  Twitter-API-PHP
    * @author   James Mallison <me@j7mbo.co.uk>
    * @license  http://opensource.org/licenses/gpl-license.php GNU Public License
    * @link     http://github.com/j7mbo/twitter-api-php
    * How to use
    * $settings = array(
    *     'oauth_access_token' => "",
    *     'oauth_access_token_secret' => "",
    *     'consumer_key' => "",
    *     'consumer_secret' => ""
    * );
    * 
    * ///  https://dev.twitter.com/console
    * 
    * $url = 'https://api.twitter.com/1.1/statuses/user_timeline.json';
    * $getfield = '?count=1&screen_name=joomshaper';
    * $requestMethod = 'GET';
    * $twitter = new SPTwitterAPIExchange($settings);
    * echo $twitter->setGetfield($getfield)->buildOauth($url, $requestMethod)->performRequest();
    */
    
    // no direct access
    defined('_JEXEC') or die('Restricted access');

    class SPTwitterAPIExchange 
    {
        private $oauth_access_token;
        private $oauth_access_token_secret;
        private $consumer_key;
        private $consumer_secret;
        private $postfields;
        private $getfield;
        protected $oauth;
        public $url;

        /**
        * Create the API access object. Requires an array of settings::
        * oauth access token, oauth access token secret, consumer key, consumer secret
        * These are all available by creating your own application on dev.twitter.com
        * Requires the cURL library
        * 
        * @param array $settings
        */
        public function __construct(array $settings)
        {
            if (!in_array('curl', get_loaded_extensions())) 
            {
                throw new Exception('You need to install cURL, see: http://curl.haxx.se/docs/install.html');
            }

            if (!isset($settings['oauth_access_token'])
                || !isset($settings['oauth_access_token_secret'])
                || !isset($settings['consumer_key'])
                || !isset($settings['consumer_secret']))
            {
                throw new Exception('Make sure you are passing in the correct parameters');
            }

            $this->oauth_access_token = $settings['oauth_access_token'];
            $this->oauth_access_token_secret = $settings['oauth_access_token_secret'];
            $this->consumer_key = $settings['consumer_key'];
            $this->consumer_secret = $settings['consumer_secret'];
        }

        /**
        * Set postfields array, example: array('screen_name' => 'J7mbo')
        * 
        * @param array $array Array of parameters to send to API
        * 
        * @return SPTwitterAPIExchange Instance of self for method chaining
        */
        public function setPostfields(array $array)
        {
            if (!is_null($this->getGetfield())) 
            { 
                throw new Exception('You can only choose get OR post fields.'); 
            }

            if (isset($array['status']) && substr($array['status'], 0, 1) === '@')
            {
                $array['status'] = sprintf(" %s", $array['status']);
            }

            $this->postfields = $array;

            return $this;
        }

        /**
        * Set getfield string, example: '?screen_name=J7mbo'
        * 
        * @param string $string Get key and value pairs as string
        * 
        * @return \SPTwitterAPIExchange Instance of self for method chaining
        */
        public function setGetfield($string)
        {
            if (!is_null($this->getPostfields())) 
            { 
                throw new Exception('You can only choose get OR post fields.'); 
            }

            $search = array('#', ',', '+', ':');
            $replace = array('%23', '%2C', '%2B', '%3A');
            $string = str_replace($search, $replace, $string);  

            $this->getfield = $string;

            return $this;
        }

        /**
        * Get getfield string (simple getter)
        * 
        * @return string $this->getfields
        */
        public function getGetfield()
        {
            return $this->getfield;
        }

        /**
        * Get postfields array (simple getter)
        * 
        * @return array $this->postfields
        */
        public function getPostfields()
        {
            return $this->postfields;
        }

        /**
        * Build the Oauth object using params set in construct and additionals
        * passed to this method. For v1.1, see: https://dev.twitter.com/docs/api/1.1
        * 
        * @param string $url The API url to use. Example: https://api.twitter.com/1.1/search/tweets.json
        * @param string $requestMethod Either POST or GET
        * @return \SPTwitterAPIExchange Instance of self for method chaining
        */
        public function buildOauth($url, $requestMethod)
        {
            if (!in_array(strtolower($requestMethod), array('post', 'get')))
            {
                throw new Exception('Request method must be either POST or GET');
            }

            $consumer_key = $this->consumer_key;
            $consumer_secret = $this->consumer_secret;
            $oauth_access_token = $this->oauth_access_token;
            $oauth_access_token_secret = $this->oauth_access_token_secret;

            $oauth = array( 
                'oauth_consumer_key' => $consumer_key,
                'oauth_nonce' => time(),
                'oauth_signature_method' => 'HMAC-SHA1',
                'oauth_token' => $oauth_access_token,
                'oauth_timestamp' => time(),
                'oauth_version' => '1.0'
            );

            $getfield = $this->getGetfield();

            if (!is_null($getfield))
            {
                $getfields = str_replace('?', '', explode('&', $getfield));
                foreach ($getfields as $g)
                {
                    $split = explode('=', $g);
                    $oauth[$split[0]] = $split[1];
                }
            }

            $base_info = $this->buildBaseString($url, $requestMethod, $oauth);
            $composite_key = rawurlencode($consumer_secret) . '&' . rawurlencode($oauth_access_token_secret);
            $oauth_signature = base64_encode(hash_hmac('sha1', $base_info, $composite_key, true));
            $oauth['oauth_signature'] = $oauth_signature;

            $this->url = $url;
            $this->oauth = $oauth;

            return $this;
        }

        /**
        * Perform the acual data retrieval from the API
        * 
        * @param boolean $return If true, returns data.
        * 
        * @return json If $return param is true, returns json data.
        */
        public function performRequest($return = true)
        {
            if (!is_bool($return)) 
            { 
                throw new Exception('performRequest parameter must be true or false'); 
            }

            $header = array($this->buildAuthorizationHeader($this->oauth), 'Expect:');

            $getfield = $this->getGetfield();
            $postfields = $this->getPostfields();

            $options = array( 
                CURLOPT_HTTPHEADER => $header,
                CURLOPT_HEADER => false,
                CURLOPT_URL => $this->url,
                CURLOPT_RETURNTRANSFER => true,
                CURLOPT_SSL_VERIFYPEER => false
            );

            if (!is_null($postfields))
            {
                $options[CURLOPT_POSTFIELDS] = $postfields;
            }
            else
            {
                if ($getfield !== '')
                {
                    $options[CURLOPT_URL] .= $getfield;
                }
            }

            $feed = curl_init();
            curl_setopt_array($feed, $options);
            $json = curl_exec($feed);
            curl_close($feed);

            if ($return) { return $json; }
        }

        /**
        * Private method to generate the base string used by cURL
        * 
        * @param string $baseURI
        * @param string $method
        * @param string $params
        * 
        * @return string Built base string
        */
        private function buildBaseString($baseURI, $method, $params) 
        {
            $return = array();
            ksort($params);

            foreach($params as $key=>$value)
            {
                $return[] = "$key=" . $value;
            }

            return $method . "&" . rawurlencode($baseURI) . '&' . rawurlencode(implode('&', $return)); 
        }

        /**
        * Private method to generate authorization header used by cURL
        * 
        * @param array $oauth Array of oauth data generated by buildOauth()
        * 
        * @return string $return Header used by cURL for request
        */    
        private function buildAuthorizationHeader($oauth) 
        {
            $return = 'Authorization: OAuth ';
            $values = array();

            foreach($oauth as $key => $value)
            {
                $values[] = "$key=\"" . rawurlencode($value) . "\"";
            }

            $return .= implode(', ', $values);
            return $return;
        }

    }
