<?php
class ParamCleaner {
    function __construct (array $params) {
        $this->sourceParams = $params;
        $this->selectedParams = $params;
        $this->errorCount = 0;
        $this->errorMessage = "";
    }

    function select (string $prop = "") {
        if ($prop == "") {
            $this->selectedParams = $this->sourceParams;
        } else {
            $this->selectedParams = $this->selectedParams[$prop];
        }
    }

    function get (string $prop) {
        if(isset($this->selectedParams[$prop])) {
            return $this->selectedParams[$prop];
        } else {
            $this->errorCount += 1;
            $this->errorMessage .= "Property \"{$prop}\" missing. ";
            return null;
        }
    }

    function exists (array $props) {
        foreach ($props as $prop) {
            if(isset($this->selectedParams[$prop]) == false) {
                return false;
            }
        }
        return true;
    }
    
    function hasErrorOccurred () {
        return $this->errorCount > 0;
    }
    
    function getErrorMessage () {
        return $this->errorMessage;
    }
    
    function resetErrors () {
        $this->errorMessage = "";
        $this->errorCount = 0;
    }
}
?>