<?php
namespace RR;

class Flash{

    private static $_instance;

    // Message types and shortcuts
    const FLASH_INFO    = 'i';
    const FLASH_SUCCESS = 's';
    const FLASH_WARNING = 'w';
    const FLASH_ERROR   = 'e';

    const FLASH_SESSION_NAME   = 'flashes';

    const defaultType = self::INFO;

    protected $msgTypes = [
        self::ERROR   => 'error',
        self::WARNING => 'warning',
        self::SUCCESS => 'success',
        self::INFO    => 'info',
    ];

    public $oldMessages = Array();
    public $newMessages = Array();
    public $_flashes = Array();

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

    private function __construct(){
        if(session_id() == '' || !isset($_SESSION)) {
            session_start();
        }
        if( isset($_SESSION['flashes']) ){
            $this->oldMessages = $_SESSION['flashes'];
        }
        unset( $_SESSION[self::SESSION_NAME] );
    }

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

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

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

    public function merge(){
        $this->_flashes = array_merge_recursive($this->newMessages, $this->oldMessages);
    }

    public function loadToSession(){
        $_SESSION[self::SESSION_NAME] = $this->newMessages;
    }

    /*
     *
     * @ctag Flash:addMessage();
     * @ctag Flash:addMessage(Flash::FLASH_INFO, '');
     * @ctag Flash:addMessage(Flash::FLASH_SUCCESS, '');
     * @ctag Flash:addMessage(Flash::FLASH_WARNING, '');
     * @ctag Flash:addMessage(Flash::FLASH_ERROR, '');
     *
     */
    public static function addMessage($type = self::defaultType, $message){
        $instance = self::getInstance();
        $instance->newMessages[$type] = $message;
        $instance->loadToSession();
    }
    
    /**
     *
     * @ctag Flash::addInfo('');
     *
     */
    public static function addInfo($message){
        $instance = self::getInstance();
        $instance->newMessages[self::INFO] = $message;
        $instance->loadToSession();
    }

    /**
     *
     * @ctag Flash::addError('');
     *
     */
    public static function addError($message){
        $instance = self::getInstance();
        $instance->newMessages[self::ERROR] = $message;
        $instance->loadToSession();
    }

    /**
     *
     * @ctag Flash::getErrors();
     *
     */
    public static function getErrors(){
        if(!self::hasErrors()){
            return Array();
        }
        return self::getInstance()->_flashes[self::ERROR];
    }

    /**
     *
     * @ctag Flash::addInfos();
     *
     */
    public static function getInfos(){
        if(!self::hasInfo()){
            return Array();
        }
        return self::getInstance()->_flashes[self::INFO];
    }

    /**
     *
     * @ctag Flash::addErrors();
     *
     */
    public static function hasErrors(){
        $instance = self::getInstance();
        $instance->merge();
        if( array_key_exists(self::ERROR, $instance->_flashes ) ){
            return true;
        }else{
            return false;
        }
    }

    /**
     *
     * @ctag Flash::hasInfo();
     *
     */
    public static function hasInfo(){
        $instance = self::getInstance();
        $instance->merge();
        if( array_key_exists(self::INFO, $instance->_flashes ) ){
            return true;
        }else{
            return false;
        }
    }

}