package com.ots.project.tool.email.utils;
import lombok.extern.slf4j.Slf4j;
import javax.mail.*;
import javax.mail.Message.RecipientType;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeUtility;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.text.SimpleDateFormat;
import java.util.*;

@Slf4j
public class EmailUtil {
    private String username = null; 
    private String password = null; 
    
    public EmailUtil(String username, String password) {
        this.username = username;
        this.password = password;
    }
    
    public static boolean isSeen(MimeMessage msg) throws MessagingException {
        return msg.getFlags().contains(Flags.Flag.SEEN);
    }
    
    public static String getReceiveAddress(MimeMessage msg, Message.RecipientType type) throws MessagingException {
        StringBuffer receiveAddress = new StringBuffer();
        Address[] addresss = null;
        if (type == null) {
            addresss = msg.getAllRecipients();
        } else {
            addresss = msg.getRecipients(type);
        }
        if (addresss == null || addresss.length < 1)
            throw new MessagingException("没有收件人!");
        for (Address address : addresss) {
            InternetAddress internetAddress = (InternetAddress) address;
            receiveAddress.append(internetAddress.toUnicodeString()).append(",");
        }
        receiveAddress.deleteCharAt(receiveAddress.length() - 1); 
        return receiveAddress.toString();
    }
    
    public static void getMailTextContent(Part part, StringBuffer content) throws MessagingException, IOException {
        
        boolean isContainTextAttach = part.getContentType().indexOf("name") > 0;
        if (part.isMimeType("text/*") && !isContainTextAttach) {
            content.append(part.getContent().toString());
        } else if (part.isMimeType("message/rfc822")) {
            getMailTextContent((Part) part.getContent(), content);
        } else if (part.isMimeType("multipart/*")) {
            Multipart multipart = (Multipart) part.getContent();
            int partCount = multipart.getCount();
            for (int i = 0; i < partCount; i++) {
                BodyPart bodyPart = multipart.getBodyPart(i);
                getMailTextContent(bodyPart, content);
            }
        }
    }
    
    public Session createSession(Properties props) {
        Session session = Session.getInstance(props, new Authenticator() {

            @Override
            public PasswordAuthentication getPasswordAuthentication() {
                PasswordAuthentication pa = new PasswordAuthentication(username, password);
                return pa;
            }
        });
        return session;
    }
    
    public void sendMail(Properties props, SendEmailMessage sem) throws Exception {
        Session session = createSession(props);
        
        Message msg = new MimeMessage(session);
        msg.setFrom(InternetAddress.parse(MimeUtility.decodeText(sem.getFrom()))[0]);
        
        msg.setRecipients(RecipientType.TO, InternetAddress.parse(sem.getRecipient()));
        msg.setSubject(sem.getSubject());
        msg.setText(sem.getText());
        msg.setSentDate(new Date());
        
        Transport.send(msg);
    }
    
    public List<BouncedUser> receiveMail(Properties props, String protocol) {
        Store store = null;
        List<BouncedUser> bouncedUserList = new ArrayList<>();
        try {
            Session session = createSession(props);
            store = session.getStore(protocol);
            store.connect(); 
            Folder inbox = store.getFolder("INBOX"); 
            inbox.open(Folder.READ_WRITE); 
            FetchProfile profile = new FetchProfile();
            profile.add(FetchProfile.Item.ENVELOPE); 
            Message[] msgs = inbox.getMessages(); 
            inbox.fetch(msgs, profile); 
            for (int i = 0; i < msgs.length; i++) {
                MimeMessage msg = (MimeMessage) msgs[i];
                String sender = decodeText(msgs[i].getFrom()[0].toString());
                if (isSeen(msg)) { 
                    continue;
                }
                if (countStr(sender, "PostMaster") > 0) {
                    StringBuffer content = new StringBuffer(30);
                    getMailTextContent(msg, content);
                    String head = "收件人（";
                    int start = content.indexOf(head);
                    int end = content.indexOf("）", start);
                    String realSender = content.substring(start + head.length(), end);
                    String message = content.substring(end, end + 30);
                    BouncedUser bouncedUser = new BouncedUser();
                    bouncedUser.setRealsender(realSender);
                    bouncedUser.setSentDateExtend(getSentDate(msg, "yyyy-MM-dd HH:mm:ss"));
                    bouncedUser.setReason(message);
                    int len = content.length();
                    if (len > 3000) {
                        len = 3000;
                    }
                    bouncedUser.setContent(content.toString().substring(0, len));
                    bouncedUser.setTitle(msgs[i].getSubject());
                    bouncedUser.setReceiveaddress(getReceiveAddress(msg, null));
                    bouncedUser.setSenddate(msg.getSentDate());
                    bouncedUser.setSender(sender);
                    bouncedUserList.add(bouncedUser);
                    log.error("----------------------------------------------------------------------");
                    log.error("发送时间：{}", msgs[i].getSentDate());
                    log.error("发送时间：{}", getSentDate(msg, "yyyy-MM-dd HH:mm:ss"));
                    log.error("发送人：{}", sender);
                    log.error("收件人：{}", getReceiveAddress(msg, null));
                    log.error("大小：{}", msgs[i].getSize());
                    log.error("是否已读：{}", isSeen(msg));
                    log.error("标题：{}", msgs[i].getSubject());
                    log.error("内容:{}", msgs[i].getContent());
                    log.error("退信邮箱地址:{}", realSender);
                    log.error("退信原因：{}", message);
                    log.error("----------------------------------------------------------------------");
                }
            }
        } catch (Exception ex) {
            log.error("接收邮件拉取失败：{}" + ex.getMessage(), ex);
        } finally {
            if (Objects.isNull(store)) {
                try {
                    store.close();
                } catch (MessagingException e) {
                    log.error("关闭邮箱拉取连接通道失败：{}", e.getMessage(), e);
                }
            }
        }
        return bouncedUserList;
    }
    
    private int countStr(String str, String sToFind) {
        int num = 0;
        while (str.contains(sToFind)) {
            str = str.substring(str.indexOf(sToFind) + sToFind.length());
            num++;
        }
        return num;
    }
    
    public String getSentDate(MimeMessage msg, String pattern) throws MessagingException {
        Date receivedDate = msg.getSentDate();
        if (receivedDate == null)
            return "";
        if (pattern == null || "".equals(pattern))
            pattern = "yyyy年MM月dd日 E HH:mm ";
        Calendar cal = Calendar.getInstance();
        cal.setTime(receivedDate);
        cal.add(Calendar.MINUTE, 10);
        return new SimpleDateFormat(pattern).format(cal.getTime());
    }
    
    private String decodeText(String text) throws UnsupportedEncodingException {
        if (text == null) {
            return null;
        }
        if (text.startsWith("=?GB") || text.startsWith("=?gb"))
            text = MimeUtility.decodeText(text);
        else
            text = new String(text.getBytes("ISO8859_1"));
        return text;
    }
}