package de.srsoftware.widerhall.mail;

import com.sun.mail.imap.IMAPFolder;
import de.srsoftware.widerhall.Constants;
import org.json.simple.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.mail.*;
import java.util.HashSet;
import java.util.Properties;

public class ImapClient {

    private static final Logger LOG = LoggerFactory.getLogger(ImapClient.class);
    private final int port;
    private final String host, username, password, folderName;
    private boolean stopped = true;
    private IMAPFolder inbox;
    private HashSet<MessageHandler> listeners = new HashSet<>();

    private class ListeningThread extends Thread {

        private static final Logger LOG = LoggerFactory.getLogger(ListeningThread.class);

        @Override
        public void run() {
            while (!stopped) {
                try {
                    openInbox();
                } catch (MessagingException e){
                    LOG.warn("Connection problem:",e);
                    try {
                        sleep(1000);
                    } catch (InterruptedException interruptedException) {
                        interruptedException.printStackTrace();
                    }
                }
            }
        }

        private void openInbox() throws MessagingException {
            LOG.debug("Connecting and logging in…");
            Properties props = imapProps();
            Session session = Session.getInstance(props);
            Store store = session.getStore(Constants.IMAPS);
            store.connect(host,username,password);
            LOG.debug("Connected, opening {}:",folderName);
            inbox = (IMAPFolder)store.getFolder(folderName);
            inbox.open(IMAPFolder.READ_WRITE);

            while (!stopped){
                handleMessages();
                LOG.debug("Idling.");
                inbox.idle(true);
            }
        }

        private void handleMessages() throws MessagingException {
            LOG.debug("reading email:");
            if (!inbox.isOpen()){
                inbox.open(IMAPFolder.READ_WRITE);
            }
            for (Message message : inbox.getMessages()){
                if (message.isSet(Flags.Flag.SEEN)) continue;
                handle(message);
                message.setFlag(Flags.Flag.SEEN,true);
            }
        }

        private void handle(Message message) throws MessagingException {
            LOG.debug("Handling {}",message.getSubject());
            for (MessageHandler listener : listeners) listener.onMessageReceived(message);
        }

        private Properties imapProps() {
            Properties props = new Properties();
            props.put(Constants.PROTOCOL,Constants.IMAPS);
            return props;
        }
    }

    private class Heartbeat extends Thread{

        private static final Logger LOG = LoggerFactory.getLogger(Heartbeat.class);
        @Override
        public void run() {
            while (!stopped){
                try {
                    sleep(300034);
                    if (inbox != null) continue;
                    LOG.debug("sending NOOP");
                    inbox.doCommand(protocol -> {
                            protocol.simpleCommand("NOOP",null);
                            return null;
                    });
                } catch (InterruptedException | MessagingException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    public ImapClient(String host, int port, String username, String password, String folderName) {
        this.host = host;
        this.port = port;
        this.username = username;
        this.password = password;
        this.folderName = folderName;
    }


    public ImapClient addListener(MessageHandler messageHandler) {
        listeners.add(messageHandler);
        return this;
    }

    public String host(){
        return host;
    }

    public String username(){
        return username;
    }

    public String password(){
        return password;
    }

    public int port(){
        return port;
    }

    public String folderName(){
        return folderName;
    }

    public void start() {
        stopped = false;
        LOG.debug("Creating ListeningThread…");
        new ListeningThread().start();
        LOG.debug("Creating Heartbeat…");
        new Heartbeat().start();
    }

    public void stop(){
        stopped = true;
    }
}