<?php
  error_reporting(-1);
  ini_set('display_errors', 'On');
  ini_set("allow_url_fopen", 1);

  class postXML{
    protected $file;
    protected $oldRate;
    protected $name;
    protected $loc;

    public function getFile(){
      $this->file = new SimpleXMLElement('currencies.xml', NULL, TRUE);
    }

    public function postCurr(){
      $code = $this->file->xpath("currency[@code='".$_POST["code"]."']");
      $this->oldRate = $code[0]->attributes()->rate;
      $this->name = $code[0]->children('name');
      foreach($code[0]->children('location') as $child){
        $this->loc = $this->loc.",".$child;
      }
      $code[0]->attributes()->time = date("l, d m Y h:i:sa");
      $code[0]->attributes()->rate = $_POST['rate'];
      $this->file->asXML('currencies.xml');
    }

    public function responseXML(){
      $xml = new SimpleXMLElement('<method/>');
      $xml->addAttribute('type', 'post');
      $xml->addChild('at', date('l, d m Y h:i:sa'));
      $prev = $xml->addChild('previous');
      $prev->addChild('rate', $this->oldRate);
      $pCurr = $prev->addChild('curr');
      $pCurr->addChild('code', $_POST['code']);
      $pCurr->addChild('name', $this->name);
      $pCurr->addChild('loc', $this->loc);
      $new = $xml->addChild('new');
      $new->addChild('rate', $_POST['rate']);
      $nCurr = $new->addChild('curr');
      $nCurr->addChild('code', $_POST['code']);
      $nCurr->addChild('name', $this->name);
      $nCurr->addChild('loc', $this->loc);
      echo $xml->asXML();
      header('Content-Type: text/xml');
    }
  }

  $postXML = new postXML;
  $postXML->getFile();
  $postXML->postCurr();
  $postXML->responseXML();
?>