package notification;

import com.amazonaws.regions.Regions;
import com.amazonaws.services.simpleemail.AmazonSimpleEmailService;
import com.amazonaws.services.simpleemail.AmazonSimpleEmailServiceClientBuilder;
import com.amazonaws.services.simpleemail.model.*;
import com.google.common.base.Joiner;
import com.google.common.base.Preconditions;
import com.google.inject.Inject;
import com.typesafe.config.Config;
import exceptions.BadResponseException;
import play.Logger;

import javax.activation.DataHandler;
import javax.activation.DataSource;
import javax.mail.Session;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;
import javax.mail.util.ByteArrayDataSource;
import java.io.ByteArrayOutputStream;
import java.nio.ByteBuffer;
import java.util.List;
import java.util.Properties;
import java.util.stream.Collectors;

/**
 * @author James Lin
 */
public class SESServiceImpl implements EmailService {

    private static final Logger.ALogger logger = Logger.of(SESServiceImpl.class);

    private AmazonSimpleEmailService client;
    private static String SENDER;
    private static final int MAX_RECIPIENTS = 50; // AWS SES 限制每次的有收信者最多 50 人

    @Inject
    public SESServiceImpl(Config config) {
        client = AmazonSimpleEmailServiceClientBuilder.standard().withRegion(Regions.US_EAST_1).build();
        SENDER = config.getString("email.sender");
    }

    @Override
    public void send(Notification notification) {
        Preconditions.checkArgument((notification.users != null && !notification.users.isEmpty()) &&
                (notification.message.type.isPublic() || (notification.users.size() == 1 && notification.message.template != null)));
        try {
            List<String> toAddresses = notification.users.stream().map(user -> user.email).collect(Collectors.toList());
            int fromIndex = 0;
            while(fromIndex < toAddresses.size()) {
                int toIndex = (fromIndex + MAX_RECIPIENTS) < toAddresses.size() ? (fromIndex + MAX_RECIPIENTS) : toAddresses.size();
                SendEmailRequest request = new SendEmailRequest().withDestination(new Destination().withToAddresses(toAddresses.subList(fromIndex, toIndex)))
                        .withSource(SENDER).withMessage(new com.amazonaws.services.simpleemail.model.Message()
                                .withSubject(new Content().withCharset("UTF-8").withData(notification.message.title))
                                .withBody(new Body().withHtml(new Content().withCharset("UTF-8").withData(notification.message.content))));
                client.sendEmail(request);
                fromIndex += MAX_RECIPIENTS;
                if(fromIndex < toAddresses.size()) {
                    Thread.sleep(3000); // 等X秒再寄信，比較不會被擋 ???
                }
            }
        } catch (Throwable e) {
            throw new BadResponseException(String.format("fail to send email %s", notification), e, "AWS-SES");
        }
    }

    @Override
    public void send(EmailMessage myMessage) {
        try {
            Session session = Session.getDefaultInstance(new Properties());
            MimeMessage javaMailMessage = new MimeMessage(session);
            javaMailMessage.setSubject(myMessage.subject, "UTF-8");
            javaMailMessage.setFrom(new InternetAddress(SENDER));
            javaMailMessage.setRecipients(javax.mail.Message.RecipientType.TO, InternetAddress.parse(Joiner.on(",").join(myMessage.addresses)));

            MimeMultipart multipart = new MimeMultipart();
            MimeBodyPart htmlBodyPart = new MimeBodyPart();
            htmlBodyPart.setContent(myMessage.body, "text/html; charset=UTF-8");
            multipart.addBodyPart(htmlBodyPart);

            MimeBodyPart attachmentPart = new MimeBodyPart();
            for(EmailMessage.Attachment attachment: myMessage.attachments) {
                DataSource fds = new ByteArrayDataSource(attachment.content, attachment.mimeType);
                ((ByteArrayDataSource) fds).setName(attachment.fileName);
                attachmentPart.setDataHandler(new DataHandler(fds));
                attachmentPart.setFileName(fds.getName());
                multipart.addBodyPart(attachmentPart);
            }
            javaMailMessage.setContent(multipart);

            ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
            javaMailMessage.writeTo(outputStream);
            RawMessage rawMessage = new RawMessage(ByteBuffer.wrap(outputStream.toByteArray()));
            SendRawEmailRequest request = new SendRawEmailRequest(rawMessage);
            client.sendRawEmail(request);
        } catch (Throwable e) {
            throw new BadResponseException(String.format("fail to send email %s", myMessage), e, "AWS-SES");
        }
    }
}

public class EmailMessage {

    public EmailMessage(String subject, String body, Set<String> addresses) {
        this.subject = subject;
        this.body = body;
        this.addresses = addresses;
    }

    public String subject;

    public String body;

    public Set<String> addresses;

    public List<Attachment> attachments = new ArrayList<>();

    public static class Attachment {

        public String mimeType = "application/vnd.ms-excel";

        public String fileName;

        public InputStream content;

        public Attachment(String fileName, InputStream content) {
            this.fileName = fileName;
            this.content = content;
        }
    }
}

public class Notification {

    public Message message;

    public Set<User> users;

    public Notification(Message message, Set<User> users) {
        this.message = message;
        this.users = users;
    }
}