<?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
 */
 
if (!class_exists('TwitterAPIExchange')) {
     
    class TwitterAPIExchange 
    {
        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 \TwitterAPIExchange 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.'); 
            }
            $this->postfields = $array;
            return $this;
        }
        
        /**
         * Set getfield string, example: '?screen_name=J7mbo'
         * 
         * @param string $string Get key and value pairs as string
         * @return \TwitterAPIExchange Instance of self for method chaining
         */
        public function setGetfield($string)
        {
            if (!is_null($this->getPostfields())) 
            { 
                throw new Exception('You can only choose get OR post fields.'); 
            }
            
            $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 $requestMethod Either POST or GET
         * @return \TwitterAPIExchange Instance of self for method chaining
         */
        public function buildOauth($url, $requestMethod)
        {
            if (strtolower($requestMethod) !== 'post' && strtolower($requestMethod) !== '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 optional $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;
        }
    
    }
}