<?php
namespace RR;

class Flash{

    private static $_instance;

    // Message types and shortcuts
    const INFO    = 'i';
    const SUCCESS = 's';
    const WARNING = 'w';
    const ERROR   = 'e';

    const SESSION_NAME   = 'flashes';

    const defaultType = self::INFO;

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

    public $old_messages = Array();
    public $new_messages = Array();
    public $_flashes = Array();

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

    private function __construct(){
        if(session_id() == '' || !isset($_SESSION)) {
            session_start();
        }
        if( isset($_SESSION['flashes']) ){
            $this->old_messages = $_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->new_messages, $this->old_messages);
    }

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

    public static function add_message($type = self::defaultType, $message){
        $instance = self::getInstance();
        $instance->new_messages[$type] = $message;
        $instance->load_to_session();
    }

    public static function add_info($message){
        $instance = self::getInstance();
        $instance->new_messages[self::INFO] = $message;
        $instance->load_to_session();
    }

    public static function add_error($message){
        $instance = self::getInstance();
        $instance->new_messages[self::ERROR] = $message;
        $instance->load_to_session();
    }

    public static function get_errors(){
        if(!self::has_errors()){
            return Array();
        }
        return self::getInstance()->_flashes[self::ERROR];
    }

    public static function get_infos(){
        if(!self::has_info()){
            return Array();
        }
        return self::getInstance()->_flashes[self::INFO];
    }

    public static function has_errors(){
        $instance = self::getInstance();
        $instance->merge();
        if( array_key_exists(self::ERROR, $instance->_flashes ) ){
            return true;
        }else{
            return false;
        }
    }

    public static function has_info(){
        $instance = self::getInstance();
        $instance->merge();
        if( array_key_exists(self::INFO, $instance->_flashes ) ){
            return true;
        }else{
            return false;
        }
    }

}