package kr.wisestone.owl.monitor;

import com.google.common.collect.Lists;
import kr.wisestone.owl.util.WebAppUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;

import javax.mail.*;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeUtility;
import javax.mail.search.FlagTerm;
import java.io.*;
import java.util.List;
import java.util.Properties;

/**
 * Created by jeong on 2018-02-08.
 */
public class MailMonitor {
    private static final Logger log = LoggerFactory.getLogger(MailMonitor.class);

    private volatile static MailMonitor uniqueInstance;
    private Store store;
    private String downloadDirectory = "";
    private String userName = "";
    private String password = "";

    private MailMonitor() {
        //  시스템 프로퍼티를 읽어 다운로드 경로를 지정
        this.initMailProperties();
        this.connectEmail();
    }

    public static MailMonitor getInstance() {
        if (uniqueInstance == null) {
            synchronized (MailMonitor.class) {
                if (uniqueInstance == null) {
                    uniqueInstance = new MailMonitor();
                }
            }
        }

        return uniqueInstance;
    }

    private void initMailProperties() {
        Properties properties = new Properties();
        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
        InputStream inputStream = classLoader.getResourceAsStream("system.properties");

        try {
            properties.load(inputStream);
            this.downloadDirectory = properties.getProperty("mail.file.path");
            this.userName = properties.getProperty("mail.account");
            this.password = properties.getProperty("mail.password");
        } catch (IOException e) {
            log.debug("initMailProperties() : " + e.getMessage());
        }
    }

    private void connectEmail() {
        Properties properties = new Properties();
        properties.setProperty("mail.host", "imap.gmail.com");
        properties.setProperty("mail.port", "995");
        properties.setProperty("mail.transport.protocol", "imaps");

        Session session = Session.getInstance(properties,
                new javax.mail.Authenticator() {
                    protected PasswordAuthentication getPasswordAuthentication() {
                        return new PasswordAuthentication(userName, password);
                    }
                });

        try {
            this.store = session.getStore("imaps");
            this.store.connect();
        } catch (MessagingException e) {
            log.debug("connectEmail() : " + e.getMessage());
        }
    }

    //  TODO - 이메일 연동 시스템에서 추가적으로 사용자가 이메일을 보내고 싶은 프로젝트를 선택하는 설정 화면 개발이 필요하다.
    public List<Email> readMails() {
        Folder inbox = null;
        List<Email> emails = Lists.newArrayList();

        try {
            inbox = store.getFolder("INBOX");
            inbox.open(Folder.READ_WRITE);

            Message messages[] = inbox.search(new FlagTerm(new Flags(Flags.Flag.SEEN), false));

            System.out.println("Number of mails = " + messages.length);

            for (Message message : messages) {
                Email email = new Email();
                Address[] from = message.getFrom();

                /*System.out.println("-------------------------------");
                System.out.println("Date : " + message.getSentDate());
                System.out.println("From : " + MimeUtility.decodeText(from[0].toString()));
                System.out.println("Subject: " + MimeUtility.decodeText(message.getSubject()));
                System.out.println("Content :");*/

                String contentType = message.getContentType();
                String messageContent = "";
                List<EmailAttachment> emailAttachments = Lists.newArrayList();

                if (contentType.contains("multipart")) {
                    Multipart multiPart = (Multipart) message.getContent();
                    int numberOfParts = multiPart.getCount();

                    for (int partCount = 0; partCount < numberOfParts; partCount++) {
                        MimeBodyPart part = (MimeBodyPart) multiPart.getBodyPart(partCount);
                        if (Part.ATTACHMENT.equalsIgnoreCase(part.getDisposition())) {
                            // 첨부 파일
                            String fileName = MimeUtility.decodeText(part.getFileName());
                            EmailAttachment emailAttachment = new EmailAttachment();
                            emailAttachment.setName(fileName);
                            emailAttachment.setPath(this.downloadDirectory + fileName);
                            emailAttachments.add(emailAttachment);

                            part.saveFile(this.downloadDirectory + fileName);
                        }
                        else {
                            // 본문 텍스트
                            messageContent = this.getText(part);
                        }
                    }
                }
                else if (contentType.contains("text/plain") || contentType.contains("text/html")) {
                    Object content = message.getContent();
                    if (content != null) {
                        // 본문 텍스트
                        messageContent = content.toString();
                    }
                }

                /*System.out.println("\t Message: " + messageContent);
                System.out.println("--------------------------------");*/

                email.setSubject(message.getSubject());
                email.setFrom(MimeUtility.decodeText(from[0].toString()));
                email.setBody(messageContent);
                email.setAttachments(emailAttachments);
                emails.add(email);
            }

            //inbox.setFlags(messages, new Flags(Flags.Flag.SEEN), true);

            /*inbox.close(true);
            this.store.close();*/
        } catch (NoSuchProviderException e) {
            log.debug("readMails() : "+ e.getMessage());
            e.printStackTrace();
        } catch (MessagingException e) {
            log.debug("readMails() : "+ e.getMessage());
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            log.debug("readMails() : "+ e.getMessage());
            e.printStackTrace();
        } catch (IOException e) {
            log.debug("readMails() : "+ e.getMessage());
            e.printStackTrace();
        }
        finally{
            this.closeFolder(inbox);
        }

        return emails;
    }

    private String getText(Part part) throws MessagingException, IOException {
        if (part.isMimeType("text/*")) {
            return (String) part.getContent();
        }

        if (part.isMimeType("multipart/alternative")) {
            // prefer html text over plain text
            Multipart mp = (Multipart) part.getContent();
            String text = null;
            for (int i = 0; i < mp.getCount(); i++) {
                Part bp = mp.getBodyPart(i);
                if (bp.isMimeType("text/plain")) {
                    if (text == null) {
                        text = this.getText(bp);
                    }
                    continue;
                }
                else if (bp.isMimeType("text/html")) {
                    String content = this.getText(bp);
                    if (content != null) {
                        return content;
                    }
                }
                else {
                    return this.getText(bp);
                }
            }
            return text;
        }
        else if (part.isMimeType("multipart/*")) {
            Multipart mp = (Multipart) part.getContent();
            for (int i = 0; i < mp.getCount(); i++) {
                String content = this.getText(mp.getBodyPart(i));
                if (content != null) {
                    return content;
                }
            }
        }

        return null;
    }

    private void closeFolder(Folder inbox) {
        try {
            if (inbox != null) {
                inbox.close(false);
            }

        } catch (MessagingException e) {
            log.debug("closeFolder() : "+ e.getMessage());
        }
    }
}