<?php
class Api
{

    private static $instance;
    private static $httpAuthToken;
    private static $encryptionAlg;
    private static $encryptionKey;
    private static $encryptionIV;
    private static $baseURL;

    public function __construct()
    {
    }

    public static function initConfig()
    {
        global $savvyext;
        self::$httpAuthToken = $savvyext->cfgReadChar('system.oauth2_token');
        self::$encryptionAlg = $savvyext->cfgReadChar('encryption.algorithm');
        self::$encryptionKey = $savvyext->cfgReadChar('encryption.key');
        self::$encryptionIV = $savvyext->cfgReadChar('encryption.iv');
        self::$baseURL = $savvyext->cfgReadChar('system.api_url');
    }

    public static function getInstance()
    {
        if (null === static::$instance) {
            static::$instance = new static;
            self::initConfig();
            return static::$instance;
        }
        return static::$instance;
    }

    public static function postData($endpoint, $payload)
    {
        self::getInstance();
        $encrypted_payload = bin2hex(
            openssl_encrypt(
                $payload,
                self::$encryptionAlg,
                self::$encryptionKey,
                OPENSSL_RAW_DATA,
                self::$encryptionIV
            ));
        $postdata = "{\"encrypted_payload\": \"${encrypted_payload}\"}";
        $url = self::$baseURL . $endpoint;
        $ch = curl_init($url);
        curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
        curl_setopt($ch, CURLOPT_POSTFIELDS, $postdata);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($ch, CURLOPT_VERBOSE, false);
        curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
        curl_setopt($ch, CURLOPT_HTTPHEADER, array(
                'Content-Type: application/json',
                'Content-Length: ' . strlen($postdata),
                'Authorization: Server-Token ' . self::$httpAuthToken,
                "client_id: BATCH"
            )
        );

        $body = curl_exec($ch);
        $result = json_decode($body, true);

        $decrypted = openssl_decrypt(
            hex2bin(
                $result['payload']
            ),
            self::$encryptionAlg,
            self::$encryptionKey,
            OPENSSL_RAW_DATA,
            self::$encryptionIV
        );
        $payload = json_decode($decrypted, true);
        return $payload;
    }

    public static function getData($endpoint)
    {
        self::getInstance();
        if ($endpoint != "") { // minimal sanity
            sleep(1);
            $url = self::$baseURL . $endpoint;
            $ch = curl_init($url);
            curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "GET");
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
            curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
            curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
            curl_setopt($ch, CURLOPT_VERBOSE, false);
            curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
            curl_setopt($ch, CURLOPT_HTTPHEADER, array(
                    'Content-Type: application/json',
                    'Authorization: Server-Token ' . self::$httpAuthToken,
                    "client_id: BATCH"
                )
            );

            $body = curl_exec($ch);
            $result = json_decode($body, true);
            $decrypted = openssl_decrypt(
                hex2bin(
                    $result['payload']
                ),
                self::$encryptionAlg,
                self::$encryptionKey,
                OPENSSL_RAW_DATA,
                self::$encryptionIV
            );
            $payload = json_decode($decrypted, true);
            return [$payload, $decrypted, $result, $body];
        }
        return [null, null, null, null];
    }
}