<?php

namespace Aby\Telegram;

class Notification
{
    private $api_url = 'https://api.telegram.org/bot';

    /**
     * @param $token
     * @param $chats
     * @param $text
     * @return bool
     */
    public function send($token, $chats, $text){
        if($token && $chats && count($chats) && $text){
            $text = $this->convertEncoding($text);
            $text = htmlspecialchars_decode($text);

            if($text) {
                $send_result = false;

                foreach ($chats as $chat_id) {
                    $send_result = $this->apiRequest("sendMessage", $token, array('chat_id' => $chat_id, "parse_mode" => 'HTML', "text" => $text));
                }

                return $send_result;
            }
        }

        return false;
    }

    /**
     * @param $text
     * @return null|string
     */
    private function convertEncoding($text){
        if (function_exists('mb_convert_encoding')) {
            if(mb_detect_encoding($text) != 'UTF-8') {
                return mb_convert_encoding($text, 'UTF-8', ['Windows-1251', 'UTF-8', mb_detect_encoding($text)]);
            }
        }

        return $text;
    }

    /**
     * @param $handle
     * @return bool
     */
    private function exec_curl_request($handle) {
        $log_class = new Log();

        $response = curl_exec($handle);

        if ($response === false) {
            $errno = curl_errno($handle);
            $error = curl_error($handle);
            $log_class->write_log("Curl returned error $errno: $error", __FILE__, __LINE__);
            curl_close($handle);
            return false;
        }

        $http_code = intval(curl_getinfo($handle, CURLINFO_HTTP_CODE));
        curl_close($handle);

        if ($http_code >= 500) {
            // do not want to DDOS server if something goes wrong
            sleep(1);
            return false;
        } else if ($http_code != 200) {
            $response = json_decode($response, true);
            $log_class->write_log("Request has failed with error {$response['error_code']}: {$response['description']}", __FILE__, __LINE__);
            if ($http_code == 401) {
                $log_class->write_log("Invalid access token provided", __FILE__, __LINE__);
            }
            return false;
        } else {
			$response = json_decode($response, true);
            $response = $response['result'];
        }

        return true;
    }

    /**
     * @param $method
     * @param $token
     * @param $parameters
     * @return bool
     */
    private function apiRequest($method, $token, $parameters): bool
    {
        foreach ($parameters as $key => &$val) {
            // encoding to JSON array parameters, for example reply_markup
            if (!is_numeric($val) && !is_string($val)) {
                $val = json_encode($val);
            }
        }
        $url = $this->api_url . $token . '/' . $method . '?' . http_build_query($parameters);

        $handle = curl_init($url);
        curl_setopt($handle, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($handle, CURLOPT_CONNECTTIMEOUT, 5);
        curl_setopt($handle, CURLOPT_TIMEOUT, 10);

        return $this->exec_curl_request($handle);
    }
}