<?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
{
    public $table;
    public $columns = array('id', 'from_user', 'to_user', 'message', 'sent', 'recd');
    public $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'];
        }
        $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;
                    }
                }
            }
        }
        $sql = "UPDATE ".$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;
    }
}
