<?php
/*
 * Copyright 2005-2013 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * Incapsulates thread api and thread processing functions.
 *
 * Event triggered by the class (see description of the RequestProcessor class
 * for details):
 *  - threadRequestReceived
 *  - threadReceiveRequestError
 *  - threadCallError
 *  - threadFunctionCall
 *
 * WARNING:
 *  threadResponseReceived registered but never called because of asynchronous
 *  nature of Core-to-Window interaction
 *
 * Implements Singleton pattern
 */
class ThreadProcessor extends ClientSideProcessor {

	/**
	 * An instance of the ThreadProcessor class
	 * @var ThreadProcessor
	 */
	protected static $instance = null;

	/**
	 * Return an instance of the ThreadProcessor class.
	 * @return ThreadProcessor
	 */
	public static function getInstance() {
		if (is_null(self::$instance)) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	/**
	 * Loads thread by id and token and checks if thread loaded
	 *
	 * @param int $thread_id Id of the thread
	 * @param int $last_token Last token of the thread
	 * @return Thread
	 * @throws ThreadProcessorException
	 */
	public static function getThread($thread_id, $last_token) {
		// Load thread
		$thread = Thread::load($thread_id, $last_token);
		// Check thread
		if (! $thread) {
			throw new ThreadProcessorException(
				'Wrong thread',
				ThreadProcessorException::ERROR_WRONG_THREAD
			);
		}
		// Return thread
		return $thread;
	}

	/**
	 * Check if arguments exists in $args array
	 *
	 * @param array $args Arguments array
	 * @param array $vars Array of arguments names that must be checked
	 * @throws ThreadProcessorException
	 */
	public static function checkParams($args, $vars) {
		if (empty($vars)) {
			return;
		}
		// Check variables exists
		foreach ($vars as $var) {
			if (! array_key_exists($var, $args)) {
				throw new ThreadProcessorException(
					"There is no '{$var}' variable in arguments list",
					ThreadProcessorException::ERROR_WRONG_ARGUMENTS
				);
			}
		}
	}

	/**
	 * Check if operator logged in
	 *
	 * @return array Operators info array
	 * @throws ThreadProcessorException If operator not logged in.
	 */
	public static function checkOperator() {
		$operator = get_logged_in();
		if (!$operator) {
			throw new ThreadProcessorException(
				"Operator not logged in!",
				ThreadProcessorException::ERROR_AGENT_NOT_LOGGED_IN
			);
		}
		return $operator;
	}

	/**
	 * Class constructor
	 *
	 * Do not use directly __construct method! Use ThreadProcessor::getInstance() instead!
	 */
	public function __construct() {
		parent::__construct(array(
			'signature' => '',
			'trusted_signatures' => array(''),
			'event_prefix' => 'thread'
		));
	}

	/**
	 * Creates and returns an instance of the MibewAPI class.
	 *
	 * @return MibewAPI
	 */
	protected function getMibewAPIInstance() {
		return MibewAPI::getAPI('MibewAPIChatInteraction');
	}

	/**
	 * Sends asynchronous request
	 *
	 * @param array $request The 'request' array. See Mibew API for details
	 * @return boolean true on success or false on failure
	 */
	protected function sendAsyncRequest($request) {
		// Define empty thread id and thread token
		$thread_id = null;
		$token = null;
		$recipient = null;
		foreach ($request['functions'] as $function) {
			// Save thread id and thread token from first function in package
			if (is_null($thread_id)) {
				$thread_id = $function['arguments']['threadId'];
				$token = $function['arguments']['token'];
				$recipient = $function['arguments']['recipient'];
				continue;
			}
			// Check thread id and thread token for the remaining functions
			if ($thread_id != $function['arguments']['threadId']
				|| $token != $function['arguments']['token']) {
				throw new ThreadProcessorException(
					'Various thread id or thread token in different functions in one package!',
					ThreadProcessorException::VARIOUS_THREAD_ID
				);
			}
			// Check request recipient
			if ($recipient !== $function['arguments']['recipient']) {
				throw new ThreadProcessorException(
					'Various recipient in different functions in one package!',
					ThreadProcessorException::VARIOUS_RECIPIENT
				);
			}
		}
		// Store request in buffer
		if ($recipient == 'agent' || $recipient == 'both') {
			$this->addRequestToBuffer('thread_agent_'.$thread_id, $request);
		}
		if ($recipient == 'user' || $recipient == 'both') {
			$this->addRequestToBuffer('thread_user_'.$thread_id, $request);
		}
		return true;
	}

	/**
	 * Additional validation for functions that called via call method
	 *
	 * @param Array $function A Function array
	 */
	protected function checkFunction($function) {
		// Check recipient argument existance
		if (! array_key_exists('recipient', $function['arguments'])) {
			throw new ThreadProcessorException(
				"'recipient' argument is not set in function '{function['function]}'!",
				ThreadProcessorException::EMPTY_RECIPIENT
			);
		}
		$recipient = $function['arguments']['recipient'];
		// Check recipient value
		if ($recipient != 'agent'
			&& $recipient != 'both'
			&& $recipient != 'user') {
			throw new ThreadProcessorException(
				"Wrong recipient value '{$recipient}'! It should be one of 'agent', 'user', 'both'",
				ThreadProcessorException::WRONG_RECIPIENT_VALUE
			);
		}
	}

	/**
	 * Update chat window state. API function
	 *
	 * Call periodically by chat window
	 * @param array $args Associative array of arguments. It must contains following keys:
	 *  - 'threadId': Id of the thread related to chat window
	 *  - 'token': last thread token
	 *  - 'user': TRUE if window used by user and FALSE otherwise
	 *  - 'typed': indicates if user(or agent) typed
	 *  - 'lastId': id of the last sent to message
	 * @return array Array of results. It contains following keys:
	 *  - 'typing': indicates if another side of the conversation is typing message
	 *  - 'canPost': indicates if agent(user can post message all the time) can post the message
	 */
	protected function apiUpdate($args) {
		// Load thread
		$thread = self::getThread($args['threadId'], $args['token']);

		// Check variables
		self::checkParams($args, array('user', 'typed'));

		if (! $args['user']) {
			$operator = self::checkOperator();
			$thread->checkForReassign($operator);
		}

		$thread->ping($args['user'], $args['typed']);

		// Create requests key
		$requests_key = false;
		if ($args['user']) {
			$requests_key = 'thread_user_'.$thread->id;
		} else {
			if ($operator['operatorid'] == $thread->agentId) {
				$requests_key = 'thread_agent_'.$thread->id;
			}
		}

		// Load stored requests
		if ($requests_key !== false) {
			$stored_requests = $this->getRequestsFromBuffer($requests_key);
			if ($stored_requests !== false) {
				$this->responses = array_merge($this->responses, $stored_requests);
			}
		}

		// Get status values
		if ($args['user']) {
			$is_typing = abs($thread->lastPingAgent - time()) < Thread::CONNECTION_TIMEOUT && $thread->agentTyping;
		} else {
			$is_typing = abs($thread->lastPingUser - time()) < Thread::CONNECTION_TIMEOUT && $thread->userTyping;
		}
		$can_post = $args['user'] || $operator['operatorid'] == $thread->agentId;

		return array(
			'typing' => $is_typing,
			'canPost' => $can_post
		);
	}

	/**
	 * Send new messages to window. API function
	 *
	 * @param array $args Associative array of arguments. It must contains following keys:
	 *  - 'threadId': Id of the thread related to chat window
	 *  - 'token': last thread token
	 *  - 'user': TRUE if window used by user and FALSE otherwise
	 *  - 'lastId': last sent message id
	 */
	protected function apiUpdateMessages($args) {
		// Load thread
		$thread = self::getThread($args['threadId'], $args['token']);

		// Check variables
		self::checkParams($args, array('user', 'lastId'));

		// Check access
		if (! $args['user']) {
			self::checkOperator();
		}

		// Send new messages
		$last_message_id = $args['lastId'];
		$messages = $thread->getMessages($args['user'], $last_message_id);
		if (empty($messages)) {
			$messages = array();
		}

		return array(
			'messages' => $messages,
			'lastId' => $last_message_id
		);
	}

	/**
	 * Post message to thread. API function
	 *
	 * @param array $args Associative array of arguments. It must contains following keys:
	 *  - 'threadId': Id of the thread related to chat window
	 *  - 'token': last thread token
	 *  - 'user': TRUE if window used by user and FALSE otherwise
	 *  - 'message': posted message
	 * @throws ThreadProcessorException
	 */
	protected function apiPost($args) {
		// Load thread
		$thread = self::getThread($args['threadId'], $args['token']);

		// Check variables
		self::checkParams($args, array('user', 'message'));

		// Get operator's array
		if (! $args['user']) {
			$operator = self::checkOperator();
		}

		// Check message can be sent
		if(! $args['user'] && $operator['operatorid'] != $thread->agentId) {
			throw new ThreadProcessorException("Cannot send", ThreadProcessorException::ERROR_CANNOT_SEND);
		}

		// Set fields
		$kind = $args['user'] ? Thread::KIND_USER : Thread::KIND_AGENT;
		if ($args['user']) {
			$msg_options = array('name' => $thread->userName);
		} else {
			$msg_options = array(
				'name' => $thread->agentName,
				'operator_id' => $operator['operatorid']
			);
		}

		// Post message
		$posted_id = $thread->postMessage($kind, $args['message'], $msg_options);

		// Update shownMessageId
		if($args['user'] && $thread->shownMessageId == 0) {
			$thread->shownMessageId = $posted_id;
			$thread->save();
		}
	}

	/**
	 * Rename user in the chat. API function
	 *
	 * @param array $args Associative array of arguments. It must contains following keys:
	 *  - 'threadId': Id of the thread related to chat window
	 *  - 'token': last thread token
	 *  - 'name': new user name
	 * @throws ThreadProcessorException
	 */
	protected function apiRename($args) {
		global $namecookie, $mibew_encoding;

		// Check rename possibility
		if( Settings::get('usercanchangename') != "1" ) {
			throw new ThreadProcessorException(
				'server: forbidden to change name',
				ThreadProcessorException::ERROR_FORBIDDEN_RENAME
			);
		}

		// Load thread
		$thread = self::getThread($args['threadId'], $args['token']);

		// Check if new name exists
		self::checkParams($args, array('name'));

		//Rename user
		$thread->renameUser($args['name']);
		// Update user name in cookies
		$data = strtr(base64_encode(myiconv($mibew_encoding,"utf-8",$args['name'])), '+/=', '-_,');
		setcookie($namecookie, $data, time()+60*60*24*365);
	}

	/**
	 * Close chat thread. API function
	 *
	 * @param array $args Associative array of arguments. It must contains following keys:
	 *  - 'threadId': Id of the thread related to chat window
	 *  - 'token': last thread token
	 *  - 'user': TRUE if window used by user and FALSE otherwise
	 * @return array Array of results. It contains following keys:
	 *  - 'closed': indicates if thread can be closed
	 */
	protected function apiClose($args) {
		// Load thread and check thread's last token
		$thread = self::getThread($args['threadId'], $args['token']);

		// Check if new user variable exists
		self::checkParams($args, array('user'));

		// Load operator
		if (! $args['user']) {
			$operator = self::checkOperator();
		}

		// Close thread
		if( $args['user'] || $thread->agentId == $operator['operatorid']) {
			$thread->close($args['user']);
		}

		return array(
			'closed' => true
		);
	}

	/**
	 * Process submitted prechat survey.
	 *
	 * @global string $namecookie Name of cookie that store visitor name
	 * @param array $args Associative array of arguments. It must contains
	 * following keys:
	 *  - 'threadId': for this function this param equals to null;
	 *  - 'token': for this function this param equals to null;
	 *  - 'name': string, user name;
	 *  - 'email': string, user email;
	 *  - 'message': string, first user message;
	 *  - 'info': string, some info about user;
	 *  - 'referrer': page user came from;
	 *  - 'groupId': selected group id.
	 * @return array Array of results. It contains following keys:
	 *  - 'next': string, indicates what module run next;
	 *  - 'options': options array for next module.
	 */
	protected function apiProcessSurvey($args) {
		global $namecookie;

		$visitor = visitor_from_request();

		// Get form values
		$first_message = $args['message'];
		$info = $args['info'];
		$email = $args['email'];
		$referrer = $args['referrer'];

		// Verify group id
		$group_id = '';
		$group = NULL;
		if(Settings::get('enablegroups') == '1') {
			if (preg_match("/^\d{1,8}$/", $args['groupId']) != 0) {
				$group = group_by_id($args['groupId']);
				if ($group) {
					$group_id = $args['groupId'];
				}
			}
		}

		if(Settings::get('usercanchangename') == "1" && !empty($args['name'])) {
			$newname = $args['name'];
			if($newname != $visitor['name']) {
				$data = strtr(
					base64_encode(myiconv($mibew_encoding,"utf-8",$newname)),
					'+/=',
					'-_,'
				);
				setcookie($namecookie, $data, time()+60*60*24*365);
				$visitor['name'] = $newname;
			}
		}

		// Check if there are online operators
		if(!has_online_operators($group_id)) {
			// Display leave message page
			$client_data = setup_leavemessage(
				$visitor['name'],
				$email,
				$group_id,
				$info,
				$referrer
			);
			$options = $client_data['leaveMessage'];
			$options['page'] += setup_logo($group);
			return array(
				'next' => 'leaveMessage',
				'options' => $options
			);
		}

		// Initialize dialog
		$thread = chat_start_for_user(
			$group_id,
			false,
			$visitor['id'],
			$visitor['name'],
			$referrer,
			$info
		);

		// Send some messages
		if($email) {
			$thread->postMessage(
				Thread::KIND_FOR_AGENT,
				getstring2('chat.visitor.email',array($email))
			);
		}

		if($first_message) {
			$posted_id = $thread->postMessage(
				Thread::KIND_USER,
				$first_message,
				array('name' => $visitor['name'])
			);
			$thread->shownMessageId = $posted_id;
			$thread->save();
		}

		// Prepare chat options
		$client_data = setup_chatview_for_user($thread);
		$options = $client_data['chat'];
		$options['page'] += setup_logo($group);

		return array(
			'next' => 'chat',
			'options' => $options
		);
	}

	/**
	 * Process submitted leave message form.
	 *
	 * Send message to operator email and create special meil thread.
	 * @global string $home_locale Code of the home locale
	 * @global string $current_locale Code of the current locale
	 * @param array $args Associative array of arguments. It must contains
	 * following keys:
	 *  - 'threadId': for this function this param equals to null;
	 *  - 'token': for this function this param equals to null;
	 *  - 'name': string, user name;
	 *  - 'email': string, user email;
	 *  - 'message': string, user message;
	 *  - 'info': string, some info about user;
	 *  - 'referrer': string, page user came from;
	 *  - 'captcha': string, captcha value;
	 *  - 'groupId': selected group id.
	 *
	 * @throws ThreadProcessorException Can throw an exception if captcha or
	 * email is wrong.
	 */
	protected function apiProcessLeaveMessage($args) {
		global $home_locale, $current_locale;

		// Check captcha
		if(Settings::get('enablecaptcha') == '1' && can_show_captcha()) {
			$captcha = $args['captcha'];
			$original = isset($_SESSION["mibew_captcha"])
				? $_SESSION["mibew_captcha"]
				: '';
			unset($_SESSION['mibew_captcha']);
			if(empty($original) || empty($captcha) || $captcha != $original) {
				throw new ThreadProcessorException(
					getlocal('errors.captcha'),
					ThreadProcessorException::ERROR_WRONG_CAPTCHA
				);
			}
		}

		// Get form fields
		$email = $args['email'];
		$name = $args['name'];
		$message = $args['message'];
		$info = $args['info'];
		$referrer = $args['referrer'];

		if( !is_valid_email($email)) {
			throw new ThreadProcessorException(
				wrong_field("form.field.email"),
				ThreadProcessorException::ERROR_WRONG_EMAIL
			);
		}

		// Verify group id
		$group_id = '';
		if(Settings::get('enablegroups') == '1') {
			if (preg_match("/^\d{1,8}$/", $args['groupId']) != 0) {
				$group = group_by_id($args['groupId']);
				if ($group) {
					$group_id = $args['groupId'];
				}
			}
		}

		// Create thread for left message
		$remote_host = get_remote_host();
		$user_browser = $_SERVER['HTTP_USER_AGENT'];
		$visitor = visitor_from_request();

		// Get message locale
		$message_locale = Settings::get('left_messages_locale');
		if(!locale_exists($message_locale)) {
			$message_locale = $home_locale;
		}

		// Create thread
		$thread = Thread::create();
		$thread->groupId = $groupid;
		$thread->userName = $name;
		$thread->remote = $remote_host;
		$thread->referer = $referrer;
		$thread->locale = $current_locale;
		$thread->userId = $visitor['id'];
		$thread->userAgent = $user_browser;
		$thread->state = Thread::STATE_LEFT;
		$thread->closed = time();
		$thread->save();

		// Send some messages
		if ($referrer) {
			$thread->postMessage(
				Thread::KIND_FOR_AGENT,
				getstring2('chat.came.from', array($referrer))
			);
		}
		if($email) {
			$thread->postMessage(
				Thread::KIND_FOR_AGENT,
				getstring2('chat.visitor.email', array($email))
			);
		}
		if($info) {
			$thread->postMessage(
				Thread::KIND_FOR_AGENT,
				getstring2('chat.visitor.info', array($info))
			);
		}
		$thread->postMessage(Thread::KIND_USER, $message, array('name'=>$name));

		// Get email for message
		$inbox_mail = get_group_email($group_id);

		if (empty($inbox_mail)) {
			$inbox_mail = Settings::get('email');
		}

		// Send email
		if($inbox_mail) {
			// Prepare message to send by email
			$subject = getstring2_("leavemail.subject",
				array($args['name']),
				$message_locale
			);
			$body = getstring2_(
				"leavemail.body",
				array(
					$args['name'],
					$email,
					$message,
					$info ? $info."\n" : ""
				),
				$message_locale
			);

			// Send
			mibew_mail($inbox_mail, $email, $subject, $body);
		}
	}
}

class ThreadProcessorException extends RequestProcessorException {
	/**
	 * 'recipient' argument is not set
	 */
	const EMPTY_RECIPIENT = 1;
	/**
	 * Operator is not logged in
	 */
	const ERROR_AGENT_NOT_LOGGED_IN = 2;
	/**
	 * Wrong arguments set for an API function
	 */
	const ERROR_WRONG_ARGUMENTS = 3;
	/**
	 * Thread cannot be loaded
	 */
	const ERROR_WRONG_THREAD = 4;
	/**
	 * Message cannot be send
	 */
	const ERROR_CANNOT_SEND = 5;
	/**
	 * User rename forbidden by system configurations
	 */
	const ERROR_FORBIDDEN_RENAME = 6;
	/**
	 * Various recipient in different functions in one package
	 */
	const VARIOUS_RECIPIENT = 7;
	/**
	 * Various thread ids or thread tokens in different functions in one package
	 */
	const VARIOUS_THREAD_ID = 8;
	/**
	 * Wrong recipient value
	 */
	const WRONG_RECIPIENT_VALUE = 9;
	/**
	 * Wrong captcha value
	 */
	const ERROR_WRONG_CAPTCHA = 10;
	/**
	 * Wrong email address
	 */
	const ERROR_WRONG_EMAIL = 11;
}

?>