<?php
namespace RR;

/*
 *
 *
 */
class Response{

    private static $_instance;

    /*
     *
     */
    public $_headers = Array();

    /*
     *
     */
    public $_body = Array();

    /*
     *
     */
    public $_code = 200;

    //SINGLETON==============================================

    private function __construct(){
    }

    private static function newObj() : Response {
        if (!isset( self::$_instance )) {
            self::$_instance = new Response();
        }
        return self::$_instance;
    }

    public function getInstance() : Response {
        if (!isset(self::$_instance)) {
            return self::newObj();
        }
        return self::$_instance;
    }

    //=======================================================

    /**
     *
     * @ctag Response::header($key, $value);
     *
     */
    public static function header($key, $value){
        $istance = self::getInstance();
        $istance->_headers[$key] = $value;
        return $istance;
    }

    /**
     *
     * @ctag Response::bodyPrepend($value);
     *
     */
    public static function bodyPrepend($body = null){
        $instance = self::getInstance();
        if (null !== $body) {
            $instance->_body = (string) $body . $instance->_body;
            return $instance;
        }
        return $instance;
    }

    /**
     *
     * @ctag Response::body($value);
     *
     */
    public static function body($body = null){
        $instance = self::getInstance();
        if (null !== $body) {
            $instance->_body = (string) $body;
            return $instance;
        }
        return $instance;
    }

    /**
     *
     * @ctag Response::bodyAppend($value);
     *
     */
    public static function bodyAppend($body = null){
        $instance = self::getInstance();
        if (null !== $body) {
            $instance->_body .= (string) $body;
            return $instance;
        }
        return $instance;
    }

    private function sendHeaders(){
        foreach ($this->_headers as $key => $value) {
            header($key .': '. $value, true);
        }
        return $this;
    }

    private function sendBody(){
        if(!empty($this->_body)){
            echo (string) $this->_body;
        }

        return $this;
    }

    /**
     *
     * @ctag Response::bodySend();
     *
     */
    public static function send(){
        $instance = self::getInstance();
        $instance->sendHeaders();
        $instance->sendBody();
        http_response_code($instance->_code);
        return $instance;
    }

    /**
     *
     * @ctag Response::json($object);
     * @ctag Response::json($object, $prefix);
     *
     */
    public static function json($object, $jsonPrefix = null): Response{
        $instance = self::getInstance();

        $instance->body('');

        $json = $object;
        if(!is_string($object)){
            $json = json_encode($object);
        }

        if (null !== $jsonPrefix) {
            $instance->header('Content-Type', 'text/javascript');
            $instance->body("$jsonPrefix($json);");
        } else {
            $instance->header('Content-Type', 'application/json');
            $instance->body($json);
        }

        return $instance;
    }

    /**
     *
     * @ctag Response::redirect($url);
     * @ctag Response::redirect($url, $code);
     *
     */
    public static function redirect($url, $code = 302){
        $instance = self::getInstance();

        if(is_ajax_request()){
            return $instance->json(['location' => $url])->send();
        }

        ## TODO
        header("Location: $url");
        die;

        $instance->header('Location: ', $url)->send();

        return $instance->send()->done();

    }

    /**
     *
     * @ctag Response::back();
     *
     */
    public static function back(){
        $instance = self::getInstance();

        $instance->header('Location: ', $_SERVER['HTTP_REFERER']);

        $instance->body('');
        $instance->send();
    }

    public function done(){
        die;
    }
}