<?php
/* For licensing terms, see /license.txt */
/**
*    This is the Chat library for Chamilo.
*    Include/require it in your code to use its functionality.
*
*    @package chamilo.library.chat
*/
/**
 * Chat class
 */
class Chat extends Model {
    
    var $table;
    var $columns = array('id', 'from_user','to_user','message','sent','recd');    
    var $window_list = array();

    /**
     * The contructor sets the chat table name and the window_list attribute
     * @return object Object reference
     */
    public function __construct() {
        $this->table =  Database::get_main_table(TABLE_MAIN_CHAT);
        $this->window_list = $_SESSION['window_list'] = isset($_SESSION['window_list']) ? $_SESSION['window_list'] : array();
    }    
    
    /**
     * Get user chat status
     * @return int 0 if disconnected, 1 if connected
     */
    function get_user_status() {
        $status = UserManager::get_extra_user_data_by_field(api_get_user_id(), 'user_chat_status', false, true);
        return $status['user_chat_status'];
    }
    
    /*
     * Set user chat status
     * @param int 0 if disconnected, 1 if connected
     * @return void
     */
    function set_user_status($status) {
        UserManager::update_extra_field_value(api_get_user_id(), 'user_chat_status', $status);
    }
    
    /* 
     * Starts a chat session and returns JSON array of status and chat history
     * @return void (prints output in JSON format)
     */
    public function start_session() {                
        $items = array();        
        if (isset($_SESSION['chatHistory'])) {
            $items = $_SESSION['chatHistory'];
        }             
        //print_r($items);
        $return = array('user_status' => $this->get_user_status(), 'me' => get_lang('Me'), 'items' => $items);        
        echo json_encode($return);           
        exit;
    }
    
    /**
     * Refreshes the chat windows (usually called every x seconds through AJAX)
     * @return void (prints JSON array of chat windows)
     */
    public function heartbeat() {
        $to_user_id    = api_get_user_id();                
        $minutes    = 60;
        $now        = time() - $minutes*60;
        $now        = api_get_utc_datetime($now);    
        
        //OR  sent > '$now'
        $sql = "SELECT * FROM ".$this->table." 
                WHERE to_user = '".intval($to_user_id)."' AND ( recd  = 0 ) ORDER BY id ASC";
        $result = Database::query($sql);
        
        $chat_list = array();
        
        while ($chat = Database::fetch_array($result,'ASSOC')) {    
            $chat_list[$chat['from_user']]['items'][] = $chat;
        }                
        
        $items = array();
        
        foreach ($chat_list as $from_user_id => $rows) {
            $rows = $rows['items'];
            $user_info = api_get_user_info($from_user_id, true);
            
            //Cleaning tsChatBoxes
            unset($_SESSION['tsChatBoxes'][$from_user_id]);
            
            foreach ($rows as $chat) {
                $chat['message'] = Security::remove_XSS($chat['message']);
                
                $item = array(  's'        => '0', 
                                'f'        => $from_user_id, 
                                'm'        => $chat['message'],                                 
                                'username' => $user_info['complete_name'],                            
                                'id'       => $chat['id']                                
                            );
                $items[$from_user_id]['items'][] = $item;                
                $items[$from_user_id]['user_info']['user_name'] = $user_info['complete_name'];
                $items[$from_user_id]['user_info']['online'] = $user_info['user_is_online'];
                $_SESSION['openChatBoxes'][$from_user_id] = api_strtotime($chat['sent'],'UTC');                
            }
            $_SESSION['chatHistory'][$from_user_id]['items'][] = $item;                    
            $_SESSION['chatHistory'][$from_user_id]['user_info']['user_name'] = $user_info['complete_name'];    
            $_SESSION['chatHistory'][$from_user_id]['user_info']['online'] = $user_info['user_is_online'];            
        }
        
        if (!empty($_SESSION['openChatBoxes'])) {
            foreach ($_SESSION['openChatBoxes'] as $user_id => $time) {
                if (!isset($_SESSION['tsChatBoxes'][$user_id])) {
                    $now = time() - $time;
                    $time = api_convert_and_format_date($time, DATE_TIME_FORMAT_SHORT_TIME_FIRST);
                    $message = sprintf(get_lang('SentAtX'), $time);
                    
                    if ($now > 180) {        
                        $item = array('s' => '2', 'f' => $user_id, 'm' => $message);            
                        
                        if (isset($_SESSION['chatHistory'][$user_id])) {
                            $_SESSION['chatHistory'][$user_id]['items'][] = $item;                                                            
                        }                        
                        $_SESSION['tsChatBoxes'][$user_id] = 1;
                    }
                }
            }
        }
        
        //print_r($_SESSION['chatHistory']);
        
        /*
        var_dump($_SESSION['openChatBoxes']);
        var_dump($_SESSION['tsChatBoxes']);
        var_dump($_SESSION['chatHistory']);
        var_dump($items);
        */
        //print_r($_SESSION['chatHistory']);
        $sql = "UPDATE ".$this->table." SET recd = 1 WHERE to_user = '".$to_user_id."' AND recd = 0";
        Database::query($sql);
        
        if ($items != '') {
            //$items = substr($items, 0, -1);
        }        
        echo json_encode(array('items' => $items));
    }

    /* 
     * Returns an array of messages inside a chat session with a specific user
     * @param int The ID of the user with whom the current user is chatting
     * @return array Messages list
     */
    function box_session($user_id) {
        $items = array();
        if (isset($_SESSION['chatHistory'][$user_id])) {
            $items = $_SESSION['chatHistory'][$user_id];
        }
        return $items;
    }

    /**
     * Saves into session the fact that a chat window exists with the given user
     * @param int The ID of the user with whom the current user is chatting
     * @return void
     */
    function save_window($user_id){
        $this->window_list[$user_id] = true; 
        $_SESSION['window_list']  = $this->window_list;
    }
    /**
     * Sends a message from one user to another user
     * @param int The ID of the user sending the message
     * @param int The ID of the user receiving the message
     * @param string Message
     * @return void Prints "1"
     */
    function send($from_user_id, $to_user_id, $message) {
        
        $user_friend_relation = SocialManager::get_relation_between_contacts($from_user_id, $to_user_id);
        if ($user_friend_relation == USER_RELATION_TYPE_FRIEND) {
        
            $user_info = api_get_user_info($to_user_id, true);
            $this->save_window($to_user_id);

            $_SESSION['openChatBoxes'][$to_user_id] = api_get_utc_datetime();
            $messagesan = self::sanitize($message);

            if (!isset($_SESSION['chatHistory'][$to_user_id])) {
                $_SESSION['chatHistory'][$to_user_id] = array();
            }
            $item = array ( "s"            => "1", 
                            "f"            => $from_user_id,
                            "m"            => $messagesan,
                            "username"     => get_lang('Me')
                        );
            $_SESSION['chatHistory'][$to_user_id]['items'][] = $item;    
            $_SESSION['chatHistory'][$to_user_id]['user_info']['user_name'] = $user_info['complete_name'];    
            $_SESSION['chatHistory'][$to_user_id]['user_info']['online'] = $user_info['user_is_online'];    

            unset($_SESSION['tsChatBoxes'][$to_user_id]);

            $params = array();
            $params['from_user']    = intval($from_user_id);
            $params['to_user']        = intval($to_user_id);
            $params['message']        = $message;
            $params['sent']            = api_get_utc_datetime();

            if (!empty($from_user_id) && !empty($to_user_id)) {        
                $this->save($params);
            }
            //print_r($_SESSION['chatHistory']);
            echo "1";
            exit;
        } else {
            echo "0";
            exit;
        }
    }
    /**
     * Close a specific chat box (user ID taken from $_POST['chatbox'])
     * @return void Prints "1"
     */
    function close() {
        unset($_SESSION['openChatBoxes'][$_POST['chatbox']]);
        unset($_SESSION['chatHistory'][$_POST['chatbox']]);        
        echo "1";
        exit;
    }
    
    /**
     * Filter chat messages to avoid XSS or other JS
     * @param string Unfiltered message
     * @return string Filterd mssage
     */
    function sanitize($text) {
        $text = htmlspecialchars($text, ENT_QUOTES);
        $text = str_replace("\n\r","\n",$text);
        $text = str_replace("\r\n","\n",$text);
        $text = str_replace("\n","<br>",$text);
        return $text;
    }
    
    function is_chat_blocked_by_exercises() {
        if (isset($_SESSION['current_exercises'])) {
            foreach ($_SESSION['current_exercises'] as $attempt_status) {
                if ($attempt_status == true) {
                    return true;
                }
            }
        }
        return false;
    }
}