package com.juick.server.xmpp.router;

import com.juick.server.XMPPServer;
import com.juick.server.xmpp.s2s.BasicXmppSession;
import com.juick.server.xmpp.s2s.CacheEntry;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import org.xmlpull.v1.XmlPullParserException;
import rocks.xmpp.addr.Jid;
import rocks.xmpp.core.stanza.model.IQ;
import rocks.xmpp.core.stanza.model.Message;
import rocks.xmpp.core.stanza.model.Presence;
import rocks.xmpp.core.stanza.model.Stanza;
import rocks.xmpp.core.stanza.model.server.ServerIQ;
import rocks.xmpp.core.stanza.model.server.ServerMessage;
import rocks.xmpp.core.stanza.model.server.ServerPresence;
import rocks.xmpp.util.XmppUtils;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.inject.Inject;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamWriter;
import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.time.Instant;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.ExecutorService;

@Component
public class XMPPRouter implements StreamHandler {
    private static final Logger logger = LoggerFactory.getLogger("com.juick.server.xmpp");

    @Inject
    private ExecutorService service;

    private final List<StreamComponentServer> connections = Collections.synchronizedList(new ArrayList<>());
    private final List<CacheEntry> outCache = new CopyOnWriteArrayList<>();

    private ServerSocket listener;

    @Inject
    private BasicXmppSession session;

    @Value("${router_port:5347}")
    private int routerPort;

    @Inject
    private XMPPServer xmppServer;

    @PostConstruct
    public void init() {
        logger.info("component router initialized");
        service.submit(() -> {
            try {
                listener = new ServerSocket(routerPort);
                logger.info("component router listening on {}", routerPort);
                while (!listener.isClosed()) {
                    if (Thread.currentThread().isInterrupted()) break;
                    Socket socket = listener.accept();
                    service.submit(() -> {
                        try {
                            StreamComponentServer client = new StreamComponentServer(socket.getInputStream(), socket.getOutputStream(), "secret");
                            addConnectionIn(client);
                            client.setHandler(this);
                            client.connect();
                        } catch (IOException e) {
                            logger.error("component error", e);
                        } catch (XmlPullParserException e) {
                            e.printStackTrace();
                        }
                    });
                }
            } catch (SocketException e) {
                // shutdown
            } catch (IOException e) {
                logger.warn("io exception", e);
            }
        });
    }

    @PreDestroy
    public void close() throws Exception {
        if (!listener.isClosed()) {
            listener.close();
        }
        synchronized (getConnections()) {
            for (Iterator<StreamComponentServer> i = getConnections().iterator(); i.hasNext(); ) {
                StreamComponentServer c = i.next();
                c.logoff();
                i.remove();
            }
        }
        service.shutdown();
        logger.info("XMPP router destroyed");
    }

    private void addConnectionIn(StreamComponentServer c) {
        synchronized (getConnections()) {
            getConnections().add(c);
        }
    }

    private void sendOut(Stanza s) {
        try {
            StringWriter stanzaWriter = new StringWriter();
            XMLStreamWriter xmppStreamWriter = XmppUtils.createXmppStreamWriter(
                    session.getConfiguration().getXmlOutputFactory().createXMLStreamWriter(stanzaWriter));
            session.createMarshaller().marshal(s, xmppStreamWriter);
            xmppStreamWriter.flush();
            xmppStreamWriter.close();
            String xml = stanzaWriter.toString();
            logger.info("XMPPRouter (out): {}", xml);
            sendOut(s.getTo().getDomain(), xml);
        } catch (XMLStreamException | JAXBException e1) {
            logger.info("jaxb exception", e1);
        }
    }

    private void sendOut(String hostname, String xml) {
        boolean haveAnyConn = false;

        StreamComponentServer connOut = null;
        synchronized (getConnections()) {
            for (StreamComponentServer c : getConnections()) {
                if (c.to != null && c.to.getDomain().equals(hostname)) {
                    if (c.isLoggedIn()) {
                        connOut = c;
                        break;
                    } else {
                        logger.info("bouncing stanza to {} component until it will be ready", hostname);
                        boolean haveCache = false;
                        for (CacheEntry entry : outCache) {
                            if (entry.hostname != null && entry.hostname.equals(hostname)) {
                                entry.xml += xml;
                                entry.updated = Instant.now();
                                haveCache = true;
                                break;
                            }
                        }
                        if (!haveCache) {
                            outCache.add(new CacheEntry(Jid.of(hostname), xml));
                        }
                    }
                }
            }
        }
        if (connOut != null) {
            connOut.send(xml);
            return;
        }
        xmppServer.sendOut(Jid.of(hostname), xml);

    }

    public List<StreamComponentServer> getConnections() {
        return connections;
    }

    private Stanza parse(String xml) {
        try {
            Unmarshaller unmarshaller = session.createUnmarshaller();
            return (Stanza)unmarshaller.unmarshal(new StringReader(xml));
        } catch (JAXBException e) {
            logger.error("JAXB exception", e);
        }
        return null;
    }
    @Override
    public void stanzaReceived(String stanza) {
        Stanza input = parse(stanza);
        if (input instanceof Message) {
            sendOut(ServerMessage.from((Message)input));
        } else if (input instanceof IQ) {
            sendOut(ServerIQ.from((IQ)input));
        } else {
            sendOut(ServerPresence.from((Presence) input));
        }
    }

    public String getFromCache(Jid to) {
        final String[] cache = new String[1];
        outCache.stream().filter(c -> c.hostname != null && c.hostname.equals(to)).findFirst().ifPresent(c -> {
            cache[0] = c.xml;
            outCache.remove(c);
        });
        return cache[0];
    }

    @Override
    public void ready(StreamComponentServer componentServer) {
        logger.info("component {} ready", componentServer.to);
        String cache = getFromCache(componentServer.to);
        if (cache != null) {
            logger.debug("sending cache to {}", componentServer.to);
            componentServer.send(cache);
        }
    }

    @Override
    public void fail(Exception e) {

    }

    @Override
    public boolean filter(Jid jid, Jid jid1) {
        return false;
    }
}