<?php
/**
 * Copyright 2014 Openstack Foundation
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 **/
class EmailValidator {

      	/**
		Validate an email address.
		Provide email address (raw input)
		Returns true if the email address has the email 
		address format and the domain exists.
		*/

		public function validEmail($email)
		{
		   $isValid = true;
		   $atIndex = strrpos($email, "@");
		   if (is_bool($atIndex) && !$atIndex)
		   {
		      $isValid = false;
		   }
		   else
		   {
		      $domain = substr($email, $atIndex+1);
		      $local = substr($email, 0, $atIndex);
		      $localLen = strlen($local);
		      $domainLen = strlen($domain);
		      if ($localLen < 1 || $localLen > 64)
		      {
		         // local part length exceeded
		         $isValid = false;
		      }
		      else if ($domainLen < 1 || $domainLen > 255)
		      {
		         // domain part length exceeded
		         $isValid = false;
		      }
		      else if ($local[0] == '.' || $local[$localLen-1] == '.')
		      {
		         // local part starts or ends with '.'
		         $isValid = false;
		      }
		      else if (preg_match('/\\.\\./', $local))
		      {
		         // local part has two consecutive dots
		         $isValid = false;
		      }
		      else if (!preg_match('/^[A-Za-z0-9\\-\\.]+$/', $domain))
		      {
		         // character not valid in domain part
		         $isValid = false;
		      }
		      else if (preg_match('/\\.\\./', $domain))
		      {
		         // domain part has two consecutive dots
		         $isValid = false;
		      }
		      else if
		(!preg_match('/^(\\\\.|[A-Za-z0-9!#%&`_=\\/$\'*+?^{}|~.-])+$/',
		                 str_replace("\\\\","",$local)))
		      {
		         // character not valid in local part unless 
		         // local part is quoted
		         if (!preg_match('/^"(\\\\"|[^"])+"$/',
		             str_replace("\\\\","",$local)))
		         {
		            $isValid = false;
		         }
		      }
		      if ($isValid && !(checkdnsrr($domain,"MX") || checkdnsrr($domain,"A")))
		      {
		         // domain not found in DNS
		         $isValid = false;
		      }
		   }
		   return $isValid;
		}

}