<?php
/*
 * PHP Telegram API implementation
 * Daniele Callari
 * Daxtech.net
 *
*/
class TelegramBot 
{
	#
	# version
	#
	const Version = '1.3';
  
  	#
  	# limit of http retry
  	#
  	const RetryMax = 5;
      
	#
	# Bot token
	#
	private $Token = null;
	
	#
	# bool param - TODO
	#
	private $Async = false;
	
	#
	# messages methods collection
	#
	private $actions = array();
	
	#
	# debug mode
	#
	public $debug = false;

	#
	# ids whitelist
	#
	private $PermittedSenders = array();

	#
	# init class
	#
	function __construct($token)
    {
      	#
		# set token as private
		#
		$this->Token = $token;
      
      	#
		# check curl module
		#
		if( !function_exists ('curl_init') )
		{
			header("Content-type:application/json");
			die(json_encode(array('error' => true, 'message' => 'php-curl module not installed/enabled')));
		}
	}
	
	#
	# Set async calls
	#
	public function SetAsync($bool)
	{
		$this->Async = $bool;
	}

	#
	# add id to whitelist
	#
	public function PermitFromId($userId)
	{
		$this->PermittedSenders[] = $userId;
	}

	#
	# do http call
	#
	private function _httpSend($method, $data)
	{
		#
		# init curl
		#
		$ch = curl_init("https://api.telegram.org/bot$this->Token/$method");
		
		#
		# set options
		#
		curl_setopt($ch, CURLOPT_POST, 1);
		curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($data) );
		curl_setopt($ch, CURLOPT_VERBOSE, 0);
		curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

		#
		# do http call with retry
		#
		$TryCounter = 0;
		$Result = false;
		
		while( $TryCounter < self::RetryMax )
		{
			#
			# do call
			#
			$Result = curl_exec($ch);

			#
			# manage retry
			#
			if($Result === false) $TryCounter++;
			else $TryCounter = self::RetryMax;
		}

		#
		# parse response
		#
		$j = @json_decode($Result, true);

		#
		# output if debug
		#
		if($this->debug) print_r($j);

		#
		# return response from api.telegram
		#
		return ($Result)?$j:json_encode([]);
	}
	
	#
	# https://core.telegram.org/bots/api#sendChatAction
	#  
	public function SendChatAction($destination, $action)
	{
		return $this->_httpSend('sendChatAction', array(
			'chat_id'	=> $destination,
			'action'	=> $action
		));
	}
	
	#
	# https://core.telegram.org/bots/api#sendMessage
	#
	public function SendMessage($destination, $textMessage)
	{
		$base = array
		(
			'text'		=> $textMessage,
			'chat_id'	=> $destination,
			'parse_mode'=> 'HTML'
		);
		
		
		
		return $this->_httpSend('sendMessage', $base);
	}

	#
	# ReplyKeyboardMarkup
	#
	public function ReplyKeyboardMarkup($destination, $textMessage, $keyboard, $resize = false, $oneTime = false, $selective = false)
	{
		return $this->_httpSend('sendMessage', 
		[
			'text'			=> $textMessage,
			'chat_id'		=> $destination,
			'parse_mode'	=> 'HTML',
			'reply_markup'	=> json_encode(
			[
						 'keyboard' => $keyboard,
				  'resize_keyboard' => $resize,
				'one_time_keyboard' => $oneTime,
						'selective' => $selective
			])
		]);
	}

	#
	# InlineKeyboardMarkup
	#
	public function InlineKeyboardMarkup($destination, $textMessage, $keyboard)
	{
		return $this->_httpSend('sendMessage',
		[
			'text'			=> $textMessage,
			'chat_id'		=> $destination,
			'parse_mode'	=> 'HTML',
			'reply_markup'	=> json_encode(['inline_keyboard' => $keyboard])
		]);
	}
	
	#
	# Send a contact
	#
	public function SendContact($destination, $number, $firstName, $lastName=null)
	{
		return $this->_httpSend('sendContact', array(
			'chat_id'		=> $destination,
			'phone_number'	=> $number,
			'first_name'	=> $firstName,
			'last_name'		=> $lastName
		));
	}
	
	#
	# Send location
	#
	public function SendLocation($destination, $lat, $long)
	{
		return $this->_httpSend('sendLocation', array(
			'chat_id'  	=> $destination,
			'latitude' 	=> $lat,
			'longitude'	=> $long
		));
	}
	
	#
	# send document
	#
	public function SendDocument($destination, $url)
	{
		if( strpos('http', $url) === 0 )
		{
			return $this->_httpSend('sendDocument', array(
				'chat_id'	=> $destination,
				'photo'		=> $url
			));
		}else{
			return $this->_httpSend('sendDocument', array(
				'chat_id'	=> $destination,
				'photo'		=> new CURLFile($url)
			));
		}
	}
	
	#
	# send image
	#
	public function SendImage($destination, $url)
	{
		if( strpos('http', $url) === 0 )
		{
			return $this->_httpSend('sendPhoto', array(
				'chat_id'	=> $destination,
				'photo'		=> $url
			));
		}else{
				return $this->_httpSend('sendPhoto', array(
					'chat_id'	=> $destination,
					'photo'		=> new CURLFile($url)
			));
		}
	}
	
	#
	# add method in queue
	#
	public function AddMessageHandler($x)
	{
		$this->actions[] = $x;
	}
	
	#
	# listen recevied messages 4 bot
	#
	public function Listen()
	{
		#
		# last message readed cache
		#
		$offset = 0;
		
		#
		# infinite loop
		#
		while(true)
		{
			try
			{
				#
				# build query
				#
				$ApiCall = "https://api.telegram.org/bot$this->Token/getUpdates?".http_build_query(array(
					'offset' => $offset
				));
	
				#
				# do query
				#
				$result = @file_get_contents($ApiCall);
	
				#
				# parse response
				#
				$x = @json_decode($result);
	
				#
				# length
				#
				$count = @count((array)$x->result);
	
				if( $count )
				{
					#
					# each messages
					#
					foreach( $x->result as &$message )
					{
						#
						# message type helpers
						#
						$message->message->IsText = isset($message->message->text);
						$message->message->IsDocument = isset($message->message->document);
						$message->message->IsPhoto = isset($message->message->photo);
						$message->message->IsVoice = isset($message->message->voice);
	
						#
						# check whitelist
						#
						if( count($this->PermittedSenders))
						{
							if(!in_array($message->message->from->id, $this->PermittedSenders))
							{
								#
								# debug
								#
								if($this->debug) echo "*** Discarded message from ".$message->message->from->id." ***\n";
								
								#
								# set as read
								#
								$offset = $message->update_id+1;
								
								#
								# jump
								#
								continue;
							}
						}
		
						#
						# debug
						#
						if($this->debug) print_r($message);

						#
						# update offset 4 next http call - we comunicate at api.telegram that we have readed the message
						#
						$offset = $message->update_id+1;

						#
						# discard old messages
						#
						if( (time() - $message->message->date) > 10*60 ) continue;
						
						#
						# iterate actions
						#
						foreach( $this->actions as $action )
						{
							#
							# execute anonymous action (as function)
							#
							$action($message->message, $this);
						}
					}
				}
			}
			catch(Exception $e) 
			{
			    if($this->debug) echo $e->getMessage()."\n";
			}
			finally {
			    #
				# loop standby
				#
				usleep(1000);
			}
		}
	}
	
	public static function Contains($x,$y)
	{
		return strpos( strtolower($y), strtolower($x) ) !== false;
	}
	
	public static function KeyboardButton($text, $requestContact = false, $requestLocation = false)
	{
		return [
			'text' => $text,
			'request_contact' => $requestContact,
			'request_location' => $requestLocation,
			
		];
	}
	
	public static function InlineKeyboardButton($text)
	{
		return [
			'text' => $text
			// todo....
		];
	}
	
}

?>