/**
 * The contents of this file are subject to the OpenMRS Public License
 * Version 1.0 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://license.openmrs.org
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
 * License for the specific language governing rights and limitations
 * under the License.
 *
 * Copyright (C) OpenMRS, LLC.  All Rights Reserved.
 */
package org.openmrs.notification.mail;

import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.openmrs.api.context.Context;
import org.openmrs.notification.Message;
import org.openmrs.notification.MessageException;
import org.openmrs.notification.MessageSender;
import org.springframework.util.StringUtils;

public class MailMessageSender implements MessageSender {
	
	protected static final Log log = LogFactory.getLog(MailMessageSender.class);
	
	/**
	 * JavaMail session
	 */
	private Session session;
	
	/**
	 * Default public constructor.
	 */
	public MailMessageSender() {
	}
	
	/**
	 * Public constructor.
	 * 
	 * @param session
	 */
	public MailMessageSender(Session session) {
		this.session = session;
	}
	
	/**
	 * Set javamail session.
	 * 
	 * @param session
	 */
	public void setMailSession(Session session) {
		this.session = session;
	}
	
	/**
	 * Send the message.
	 * 
	 * @param message the message to be sent
	 */
	public void send(Message message) throws MessageException {
		try {
			MimeMessage mimeMessage = createMimeMessage(message);
			Transport.send(mimeMessage);
		}
		catch (Exception e) {
			log.error("failed to send message", e);
			
			// catch mail-specific exception and re-throw it as app-specific exception
			throw new MessageException(e);
		}
	}
	
	/**
	 * Converts the message object to a mime message in order to prepare it to be sent.
	 * 
	 * @param message
	 * @return MimeMessage
	 */
	public MimeMessage createMimeMessage(Message message) throws Exception {
		
		if (message.getRecipients() == null)
			throw new MessageException("Message must contain at least one recipient");
		
		// set the content-type to the default if it isn't defined in Message
		if (!StringUtils.hasText(message.getContentType())) {
			String contentType = Context.getAdministrationService().getGlobalProperty("mail.default_content_type");
			message.setContentType(StringUtils.hasText(contentType) ? contentType : "text/plain");
		}
		
		MimeMessage mimeMessage = new MimeMessage(session);
		
		// TODO Need to test the null case.  
		// Transport should use default mail.from value defined in properties.
		if (message.getSender() != null)
			mimeMessage.setSender(new InternetAddress(message.getSender()));
		
		mimeMessage
		        .setRecipients(javax.mail.Message.RecipientType.TO, InternetAddress.parse(message.getRecipients(), false));
		mimeMessage.setSubject(message.getSubject());
		
		if (!message.hasAttachment())
			mimeMessage.setContent(message.getContent(), message.getContentType());
		else
			mimeMessage.setContent(createMultipart(message));
		
		return mimeMessage;
	}
	
	/**
	 * Creates a MimeMultipart, so that we can have an attachment.
	 * 
	 * @param message
	 * @return
	 */
	private MimeMultipart createMultipart(Message message) throws Exception {
		MimeMultipart toReturn = new MimeMultipart();
		
		MimeBodyPart textContent = new MimeBodyPart();
		textContent.setContent(message.getContent(), message.getContentType());
		
		MimeBodyPart attachment = new MimeBodyPart();
		attachment.setContent(message.getAttachment(), message.getAttachmentContentType());
		attachment.setFileName(message.getAttachmentFileName());
		
		toReturn.addBodyPart(textContent);
		toReturn.addBodyPart(attachment);
		
		return toReturn;
	}
	
}