/*
 * Copyright (C) 2008-2017, Juick
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.juick.components.s2s;

import com.juick.components.XMPPServer;
import com.juick.xmpp.extensions.StreamError;
import com.juick.xmpp.utils.XmlUtils;
import org.apache.commons.lang3.StringUtils;
import org.xmlpull.v1.XmlPullParser;
import rocks.xmpp.addr.Jid;
import rocks.xmpp.core.session.XmppSessionConfiguration;
import rocks.xmpp.core.stanza.model.Stanza;

import javax.net.ssl.SSLException;
import javax.net.ssl.SSLSocket;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
import java.io.EOFException;
import java.io.IOException;
import java.io.StringReader;
import java.net.Socket;
import java.net.SocketException;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;

/**
 * @author ugnich
 */
public class ConnectionIn extends Connection implements Runnable {

    final public List<String> from = new ArrayList<>();
    public long tsRemoteData = 0;
    public long packetsRemote = 0;
    XmppSessionConfiguration configuration;

    public ConnectionIn(XMPPServer xmpp, Socket socket) throws Exception {
        super(xmpp);
        this.socket = socket;
        restartParser();
    }

    protected Stanza parse(String xml) {
        try {
            Unmarshaller unmarshaller = xmpp.getSession().createUnmarshaller();
            return (Stanza)unmarshaller.unmarshal(new StringReader(xml));
        } catch (JAXBException e) {
            logger.error("JAXB exception", e);
        }
        return null;
    }

    @Override
    public void run() {
        try {
            parser.next(); // stream:stream
            updateTsRemoteData();
            if (!parser.getName().equals("stream")
                    || !parser.getNamespace("stream").equals(NS_STREAM)) {
//                    || !parser.getAttributeValue(null, "version").equals("1.0")
//                    || !parser.getAttributeValue(null, "to").equals(Main.HOSTNAME)) {
                throw new Exception(String.format("stream from %s invalid", socket.getRemoteSocketAddress()));
            }
            streamID = parser.getAttributeValue(null, "id");
            if (streamID == null) {
                streamID = UUID.randomUUID().toString();
            }
            boolean xmppversionnew = parser.getAttributeValue(null, "version") != null;
            String from = parser.getAttributeValue(null, "from");

            if (xmpp.bannedHosts.contains(from)) {
                closeConnection();
                return;
            }
            sendOpenStream(from, xmppversionnew);

            while (parser.next() != XmlPullParser.END_DOCUMENT) {
                updateTsRemoteData();
                if (parser.getEventType() != XmlPullParser.START_TAG) {
                    continue;
                }
                logParser();

                packetsRemote++;

                String tag = parser.getName();
                if (tag.equals("result") && parser.getNamespace().equals(NS_DB)) {
                    String dfrom = parser.getAttributeValue(null, "from");
                    String to = parser.getAttributeValue(null, "to");
                    logger.info("stream from {} to {} {} asking for dialback", dfrom, to, streamID);
                    if (dfrom.endsWith(xmpp.HOSTNAME) && (dfrom.equals(xmpp.HOSTNAME) || dfrom.endsWith("." + xmpp.HOSTNAME))) {
                        logger.warn("stream from {} is invalid", dfrom);
                        break;
                    }
                    if (to != null && to.equals(xmpp.HOSTNAME)) {
                        String dbKey = XmlUtils.getTagText(parser);
                        updateTsRemoteData();
                        xmpp.startDialback(dfrom, streamID, dbKey);
                    } else {
                        logger.warn("stream from " + dfrom + " " + streamID + " invalid to " + to);
                        break;
                    }
                } else if (tag.equals("verify") && parser.getNamespace().equals(NS_DB)) {
                    String vfrom = parser.getAttributeValue(null, "from");
                    String vto = parser.getAttributeValue(null, "to");
                    String vid = parser.getAttributeValue(null, "id");
                    String vkey = XmlUtils.getTagText(parser);
                    updateTsRemoteData();
                    boolean valid = false;
                    if (vfrom != null && vto != null && vid != null && vkey != null) {
                        ConnectionOut c = xmpp.getConnectionOut(vfrom, false);
                        if (c == null) {
                            logger.warn("outgoing connection to {} not found", vfrom);
                        } else {
                            String dialbackKey = c.dbKey;
                            valid = vkey.equals(dialbackKey);
                        }
                    }
                    if (valid) {
                        sendStanza("<db:verify from='" + vto + "' to='" + vfrom + "' id='" + vid + "' type='valid'/>");
                        logger.info("stream from {} {} dialback verify valid", vfrom, streamID);
                    } else {
                        sendStanza("<db:verify from='" + vto + "' to='" + vfrom + "' id='" + vid + "' type='invalid'/>");
                        logger.warn("stream from {} {} dialback verify invalid", vfrom, streamID);
                    }
                } else if (tag.equals("presence") && checkFromTo(parser)) {
                    String xml = XmlUtils.parseToString(parser, false);
                    logger.info("stream {} presence: {}", streamID, xml);
                    xmpp.onStanzaReceived(parse(xml));
                } else if (tag.equals("message") && checkFromTo(parser)) {
                    updateTsRemoteData();
                    String xml = XmlUtils.parseToString(parser, false);
                    logger.info("stream {} message: {}", streamID, xml);
                    xmpp.onStanzaReceived(parse(xml));

                } else if (tag.equals("iq") && checkFromTo(parser)) {
                    updateTsRemoteData();
                    String type = parser.getAttributeValue(null, "type");
                    String xml = XmlUtils.parseToString(parser, false);
                    if (type == null || !type.equals("error")) {
                        logger.info("stream {} iq: {}", streamID, xml);
                        xmpp.getRouter().sendStanza(parse(xml));
                    }
                } else if (sc != null && !isSecured() && tag.equals("starttls")) {
                    logger.info("stream {} securing", streamID);
                    sendStanza("<proceed xmlns=\"" + NS_TLS + "\" />");
                    try {
                        socket = sc.getSocketFactory().createSocket(socket, socket.getInetAddress().getHostAddress(),
                                socket.getPort(), true);
                        ((SSLSocket) socket).setUseClientMode(false);
                        ((SSLSocket) socket).startHandshake();
                        setSecured(true);
                        logger.info("stream {} secured", streamID);
                        restartParser();
                    } catch (SSLException sex) {
                        logger.warn("stream {} ssl error {}", streamID, sex);
                        sendStanza("<failed xmlns\"" + NS_TLS + "\" />");
                        xmpp.removeConnectionIn(this);
                        closeConnection();
                    }
                } else if (isSecured() && tag.equals("stream") && parser.getNamespace().equals(NS_STREAM)) {
                    sendOpenStream(null, true);
                } else if (tag.equals("error")) {
                    StreamError streamError = StreamError.parse(parser);
                    logger.warn("Stream error from {}: {}", streamID, streamError.getCondition());
                    xmpp.removeConnectionIn(this);
                    closeConnection();
                } else {
                    String unhandledStanza = XmlUtils.parseToString(parser, true);
                    logger.warn("Unhandled stanza from {}: {}", streamID, unhandledStanza);
                }
            }
            logger.warn("stream {} finished", streamID);
            xmpp.removeConnectionIn(this);
            closeConnection();
        } catch (EOFException | SocketException ex) {
            logger.info("stream {} closed (dirty)", streamID);
            xmpp.removeConnectionIn(this);
            closeConnection();
        } catch (Exception e) {
            logger.warn("stream {} error {}", streamID, e);
            xmpp.removeConnectionIn(this);
            closeConnection();
        }
    }

    void updateTsRemoteData() {
        tsRemoteData = System.currentTimeMillis();
    }

    void sendOpenStream(String from, boolean xmppversionnew) throws IOException {
        String openStream = "<?xml version='1.0'?><stream:stream xmlns='jabber:server' " +
                "xmlns:stream='http://etherx.jabber.org/streams' xmlns:db='jabber:server:dialback' from='" +
                xmpp.HOSTNAME + "' id='" + streamID + "' version='1.0'>";
        if (xmppversionnew) {
            openStream += "<stream:features>";
            if (sc != null && !isSecured() && !xmpp.brokenSSLhosts.contains(from)) {
                openStream += "<starttls xmlns=\"" + NS_TLS + "\"><optional/></starttls>";
            }
            openStream += "</stream:features>";
        }
        sendStanza(openStream);
    }

    public void sendDialbackResult(String sfrom, String type) {
        sendStanza("<db:result from='" + xmpp.HOSTNAME + "' to='" + sfrom + "' type='" + type + "'/>");
        if (type.equals("valid")) {
            from.add(sfrom);
            logger.info("stream from {} {} ready", sfrom, streamID);
        }
    }

    boolean checkFromTo(XmlPullParser parser) throws Exception {
        String cfrom = parser.getAttributeValue(null, "from");
        String cto = parser.getAttributeValue(null, "to");
        if (StringUtils.isNotEmpty(cfrom) &&  StringUtils.isNotEmpty(cto)) {
            Jid jidto = Jid.of(cto);
            if (jidto.getDomain().equals(xmpp.HOSTNAME)) {
                Jid jidfrom = Jid.of(cfrom);
                int size = from.size();
                for (int i = 0; i < size; i++) {
                    if (from.get(i).equals(jidfrom.getDomain())) {
                        return true;
                    }
                }
            }
        }
        return false;
    }
}