/**
    * Copyright 2005-2012 The Kuali Foundation
    *
    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
    *
   * 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.
   */
  package org.kuali.rice.core.mail;
  
  import org.kuali.rice.core.api.config.property.ConfigContext;
  import org.springframework.beans.factory.config.AbstractFactoryBean;
  import org.springframework.mail.javamail.JavaMailSenderImpl;
  
  import javax.mail.Authenticator;
  import javax.mail.PasswordAuthentication;
  import javax.mail.Session;
  import java.util.Properties;
  
  /**
   * A factory bean which reads mail-related properties from the Configuration system and
   * generates a Spring Java Mail Sender instance for use by services that send e-mail.
   * 
   * @author Kuali Rice Team (rice.collab@kuali.org)
   *
   */
  @SuppressWarnings("unchecked")
  public class MailSenderFactoryBean extends AbstractFactoryBean {
  
  	protected final org.apache.log4j.Logger LOG = org.apache.log4j.Logger.getLogger(MailSenderFactoryBean.class);
  	
      private static final String MAIL_PREFIX = "mail";
      private static final String USERNAME_PROPERTY = "mail.smtp.username";
      private static final String PASSWORD_PROPERTY = "mail.smtp.password";
      private static final String HOST_PROPERTY = "mail.smtp.host";
      private static final String PORT_PROPERTY = "mail.smtp.port";
      
      private Session mailSession;
      
      @Override
  	protected  Object createInstance() throws Exception {
  	    // Retrieve "mail.*" properties from the configuration system and construct a Properties object
  		Properties properties = new Properties();
  		Properties configProps = ConfigContext.getCurrentContextConfig().getProperties();
  		LOG.debug("createInstance(): collecting mail properties.");
  		for (Object keyObj : configProps.keySet()) {
  		    if (keyObj instanceof String) {
  		    	String key = (String)keyObj;
  		    	if (key.startsWith(MAIL_PREFIX)){
  		    		properties.put(key, configProps.get(key));
  		    	}
  		    }
  		}
  		
  		// Construct an appropriate Java Mail Session
  		// If username and password properties are found, construct a Session with SMTP authentication
  		String username = properties.getProperty(USERNAME_PROPERTY);
  		String password = properties.getProperty(PASSWORD_PROPERTY);
  		if (username != null && password != null) {
  			mailSession = Session.getInstance(properties, new SimpleAuthenticator(username, password));
  			LOG.info("createInstance(): Initializing mail session using SMTP authentication.");
  		} else {
  			mailSession = Session.getInstance(properties);
  			LOG.info("createInstance(): Initializing mail session. No SMTP authentication.");
  		}
  		
  		// Construct and return a Spring Java Mail Sender
  		JavaMailSenderImpl mailSender = new JavaMailSenderImpl();
  		LOG.debug("createInstance(): setting SMTP host.");
  		mailSender.setHost(properties.getProperty(HOST_PROPERTY));
  		if (properties.getProperty(PORT_PROPERTY) != null) {
  			LOG.debug("createInstance(): setting SMTP port.");
  			int smtpPort = Integer.parseInt(properties.getProperty(PORT_PROPERTY).trim());
  			mailSender.setPort(smtpPort);
  		}
  		mailSender.setSession(mailSession);
  		
  		LOG.info("createInstance(): Mail Sender Factory Bean initialized.");
  		return mailSender;
      }
      
      private class SimpleAuthenticator extends Authenticator {
      	
      	private final PasswordAuthentication passwordAuthentication;
  
          private SimpleAuthenticator(String username, String password) {
          	this.passwordAuthentication = new PasswordAuthentication(username, password);
          }
  
          public PasswordAuthentication getPasswordAuthentication() {
              return passwordAuthentication;
          }
     }
     
     @SuppressWarnings("unchecked")
 	@Override
     public Class getObjectType() {
 	return JavaMailSenderImpl.class;
     }
 
 }