<?php

class FirebaseApi {

    private $urlEndpoint = 'https://fcm.googleapis.com/fcm/send/';
    private $serverKey = 'some_sort_of_servey_key';

    private function headerInitialization () {

        $header = array(
                'Authorization: key=' . $this->serverKey,
                'Content-Type: application/json'
            );

        return $header;


    }

    public function init ( $message = false ) {

        $ch = curl_init();

        $message = array(
                // this is the token received when refreshtoken function was called
                // from client side(android)
                'to'           => 'alphanumeric_value:alphanumeric_value',
                'priority'     => "high",
                'notification' => array( "tag"=>"chat", "body" => 'testing...' ),
            );

        echo json_encode( $message, TRUE );

        $options = array(
                CURLOPT_URL            => $this->urlEndpoint,
                CURLOPT_HTTPHEADER     => $this->headerInitialization(),
                CURLOPT_POST           => 1,
                CURLOPT_RETURNTRANSFER => true,
                CURLOPT_SSL_VERIFYPEER => 0,
                CURLOPT_POSTFIELDS     => json_encode( $message )
            );

        curl_setopt_array( $ch, $options );
        $response = curl_exec( $ch );
        curl_close( $ch );

        return $response;
    }


}