<?php

/**
 * CodeIgniter library to interface with the Akismet API.
 * @author Peter Goodman
 */
class Akismet {
    
    protected $api_key,
              $key_verified = FALSE,
              $blog_url,
              $user_ip,
              $user_agent;
    
    /**
     * Constructor.
     */
    public function __construct() {
        
        $ci = get_instance();
        
        $this->blog_url = $ci->config->slash_item('base_url');
        $this->user_ip = $ci->input->ip_address();
        $this->user_agent = $ci->input->user_agent();
    }
    
    /**
     * Verify the API key.
     */
    public function verify($key) {
        
        $this->api_key = $key;
        $key = urlencode($key);
        $url = urlencode($this->blog_url);
        
        return $this->key_verified = $this->query(
            'rest.akismet.com/1.1/verify-key',
            "key={$key}&blog={$url}"
        );
    }
    
    /**
     * Validate some content with akismet.
     */
    public function validate(array $content) {
        
        if(!$this->key_verified)
            return FALSE;
        
        // build up the content to send to akismet
        $content = array_merge($_SERVER, array(
            'blog' => $this->blog_url,
            'user_ip' => $this->user_ip,
            'user_agent' => $this->user_agent,
            'referrer' => NULL,
            'permalink' => NULL,
            'comment_type' => 'comment',
            'comment_author' => 'viagra-test-123',
            'comment_author_email' => NULL,
            'comment_author_url' => NULL,
            'comment_content' => NULL,
        ), $content);
        
        // clear out useless values
        foreach($content as $key => $val) {
            if(empty($val))
                unset($content[$key]);
        }
        
        // is this spam?
        return !$this->query(
            "{$this->api_key}.rest.akismet.com/1.1/comment-check",
            http_build_query($content)
        );
    }
    
    /**
     * Get a response from akismet for something.
     * @internal
     */
    protected function query($url, $data) {
        
        $ch = curl_init();
        
        curl_setopt_array($ch, array(
            CURLOPT_URL => $url,
            CURLOPT_HEADER => FALSE,
            CURLOPT_RETURNTRANSFER => TRUE,
            CURLOPT_FAILONERROR => TRUE,
            CURLOPT_FOLLOWLOCATION => TRUE,
            CURLOPT_FRESH_CONNECT => TRUE, // don't allow caching
            CURLOPT_FORBID_REUSE => TRUE,
            CURLOPT_POST => TRUE,
            CURLOPT_CONNECTTIMEOUT => 30,
            CURLOPT_POSTFIELDS => $data,
        ));
        
        // if it fails the response will be false
        $response = curl_exec($ch);
        curl_close($ch);
        
        // this goes for the key being valid or the comment being spam :P
        if($response == 'valid' || $response == 'true')
            return TRUE;
        
        return FALSE;
    }
}