/*
 * Copyright (c) 2006-2015 DMDirc Developers
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package com.dmdirc.parser.xmpp;

import com.dmdirc.parser.common.AwayState;
import com.dmdirc.parser.common.BaseSocketAwareParser;
import com.dmdirc.parser.common.ChannelJoinRequest;
import com.dmdirc.parser.common.ChildImplementations;
import com.dmdirc.parser.common.CompositionState;
import com.dmdirc.parser.common.DefaultStringConverter;
import com.dmdirc.parser.common.ParserError;
import com.dmdirc.parser.common.QueuePriority;
import com.dmdirc.parser.interfaces.ChannelInfo;
import com.dmdirc.parser.interfaces.ClientInfo;
import com.dmdirc.parser.interfaces.LocalClientInfo;
import com.dmdirc.parser.interfaces.StringConverter;
import com.dmdirc.parser.interfaces.callbacks.AwayStateListener;
import com.dmdirc.parser.interfaces.callbacks.CallbackInterface;
import com.dmdirc.parser.interfaces.callbacks.ChannelSelfJoinListener;
import com.dmdirc.parser.interfaces.callbacks.CompositionStateChangeListener;
import com.dmdirc.parser.interfaces.callbacks.ConnectErrorListener;
import com.dmdirc.parser.interfaces.callbacks.DataInListener;
import com.dmdirc.parser.interfaces.callbacks.DataOutListener;
import com.dmdirc.parser.interfaces.callbacks.NumericListener;
import com.dmdirc.parser.interfaces.callbacks.OtherAwayStateListener;
import com.dmdirc.parser.interfaces.callbacks.PrivateActionListener;
import com.dmdirc.parser.interfaces.callbacks.PrivateMessageListener;
import com.dmdirc.parser.interfaces.callbacks.ServerReadyListener;
import com.dmdirc.parser.interfaces.callbacks.SocketCloseListener;

import java.net.URI;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.jivesoftware.smack.Chat;
import org.jivesoftware.smack.ChatManagerListener;
import org.jivesoftware.smack.ConnectionConfiguration;
import org.jivesoftware.smack.ConnectionListener;
import org.jivesoftware.smack.PacketListener;
import org.jivesoftware.smack.RosterEntry;
import org.jivesoftware.smack.RosterListener;
import org.jivesoftware.smack.XMPPConnection;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.filter.PacketFilter;
import org.jivesoftware.smack.packet.Message;
import org.jivesoftware.smack.packet.Packet;
import org.jivesoftware.smack.packet.Presence;
import org.jivesoftware.smackx.ChatState;
import org.jivesoftware.smackx.ChatStateListener;
import org.jivesoftware.smackx.ChatStateManager;
import org.jivesoftware.smackx.muc.MultiUserChat;
import org.slf4j.LoggerFactory;

/**
 * A parser which can understand the XMPP protocol.
 */
@ChildImplementations({
    XmppClientInfo.class, XmppLocalClientInfo.class, XmppFakeChannel.class,
    XmppChannelClientInfo.class
})
public class XmppParser extends BaseSocketAwareParser {

    private static final org.slf4j.Logger LOG = LoggerFactory.getLogger(XmppParser.class);
    /** Pattern to use to extract priority. */
    private static final Pattern PRIORITY_PATTERN = Pattern.compile(
            "(?i)(?:^|&)priority=([0-9]+)(?:$|&)");
    /** The connection to use. */
    private XMPPConnection connection;
    /** The state manager for the current connection. */
    private ChatStateManager stateManager;
    /** A cache of known chats. */
    private final Map<String, Chat> chats = new HashMap<>();
    /** A cache of known clients. */
    private final Map<String, XmppClientInfo> contacts = new HashMap<>();
    /** Whether or not to use a fake local channel for a buddy list replacement. */
    private final boolean useFakeChannel;
    /** The priority of this endpoint. */
    private final int priority;
    /** The fake channel to use is useFakeChannel is enabled. */
    private XmppFakeChannel fakeChannel;

    /**
     * Creates a new XMPP parser for the specified address.
     *
     * @param address The address to connect to
     */
    public XmppParser(final URI address) {
        super(address);

        if (address.getQuery() == null) {
            useFakeChannel = false;
            priority = 0;
        } else {
            final Matcher matcher = PRIORITY_PATTERN.matcher(address.getQuery());

            useFakeChannel = address.getQuery().matches("(?i).*(^|&)showchannel($|&).*");
            priority = matcher.find() ? Integer.parseInt(matcher.group(1)) : 0;
        }

        LOG.debug(
                "XMPP parser created with query string {}, parsed fake channel = {}, priority = {}",
                address.getQuery(), useFakeChannel, priority);
    }

    @Override
    public void disconnect(final String message) {
        super.disconnect(message);
        // TODO: Pass quit message on as presence?
        connection.disconnect();
    }

    @Override
    public void joinChannels(final ChannelJoinRequest... channels) {
        for (ChannelJoinRequest request : channels) {
            final MultiUserChat muc = new MultiUserChat(connection, request.getName().substring(1));

            try {
                if (request.getPassword() == null) {
                    muc.join(getLocalClient().getNickname());
                } else {
                    muc.join(getLocalClient().getNickname(), request.getPassword());
                }

                // TODO: Send callbacks etc
            } catch (XMPPException ex) {
                // TODO: handle
            }
        }
    }

    @Override
    public ChannelInfo getChannel(final String channel) {
        // TODO: Implement
        throw new UnsupportedOperationException("Not supported yet.");
    }

    @Override
    public Collection<? extends ChannelInfo> getChannels() {
        return Collections.<ChannelInfo>emptyList();
    }

    @Override
    public int getMaxLength(final String type, final String target) {
        return Integer.MAX_VALUE;
    }

    @Override
    public int getMaxLength() {
        return Integer.MAX_VALUE;
    }

    @Override
    public LocalClientInfo getLocalClient() {
        final String[] parts = parseHostmask(connection.getUser());

        // TODO: Cache this
        return new XmppLocalClientInfo(this, parts[0], parts[2], parts[1]);
    }

    @Override
    public XmppClientInfo getClient(final String details) {
        final String[] parts = parseHostmask(details);

        if (!contacts.containsKey(parts[0])) {
            contacts.put(parts[0], new XmppClientInfo(this, parts[0], parts[2], parts[1]));
        }

        return contacts.get(parts[0]);
    }

    @Override
    public void sendRawMessage(final String message) {
        // Urgh, hacky horrible rubbish. These commands should call methods.
        if (message.toUpperCase().startsWith("WHOIS ")) {
            handleWhois(message.split(" ")[1]);
        } else if (!message.isEmpty() && message.charAt(0) == '<') {
            // Looks vaguely like XML, let's send it.
            connection.sendPacket(new Packet() {

                @Override
                public String toXML() {
                    return message;
                }
            });
        }
    }

    /**
     * Handles a whois request for the specified target.
     *
     * @param target The user being WHOIS'd
     */
    private void handleWhois(final String target) {
        // Urgh, hacky horrible rubbish. This should be abstracted.
        if (contacts.containsKey(target)) {
            final XmppClientInfo client = contacts.get(target);
            final String[] userParts = client.getNickname().split("@", 2);

            callNumericCallback(311, target, userParts[0], userParts[1], "*", client.getRealname());

            for (Map.Entry<String, XmppEndpoint> endpoint : client.getEndpoints().entrySet()) {
                callNumericCallback(399, target, endpoint.getKey(),
                        "(" + endpoint.getValue().getPresence() + ")", "has endpoint");
            }
        } else {
            callNumericCallback(401, target, "No such contact found");
        }

        callNumericCallback(318, target, "End of /WHOIS.");
    }

    private void callNumericCallback(final int numeric, final String... args) {
        final String[] newArgs = new String[args.length + 3];
        newArgs[0] = ":xmpp.server";
        newArgs[1] = (numeric < 100 ? "0" : "") + (numeric < 10 ? "0" : "") + numeric;
        newArgs[2] = getLocalClient().getNickname();
        System.arraycopy(args, 0, newArgs, 3, args.length);

        getCallback(NumericListener.class).onNumeric(this, new Date(), numeric, newArgs);
    }

    @Override
    public void sendRawMessage(final String message, final QueuePriority priority) {
        sendRawMessage(message);
    }

    @Override
    public StringConverter getStringConverter() {
        return new DefaultStringConverter();
    }

    @Override
    public boolean isValidChannelName(final String name) {
        return false; // TODO: Implement
    }

    @Override
    public boolean compareURI(final URI uri) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    @Override
    public Collection<? extends ChannelJoinRequest> extractChannels(final URI uri) {
        return Collections.<ChannelJoinRequest>emptyList();
    }

    @Override
    public String getNetworkName() {
        return "XMPP"; // TODO
    }

    @Override
    public String getServerSoftware() {
        return "Unknown"; // TODO
    }

    @Override
    public String getServerSoftwareType() {
        return "XMPP"; // TODO
    }

    @Override
    public List<String> getServerInformationLines() {
        return Collections.emptyList(); // TODO
    }

    @Override
    public int getMaxTopicLength() {
        return 0; // TODO
    }

    @Override
    public String getBooleanChannelModes() {
        return ""; // TODO
    }

    @Override
    public String getListChannelModes() {
        return ""; // TODO
    }

    @Override
    public int getMaxListModes(final char mode) {
        return 0; // TODO
    }

    @Override
    public boolean isUserSettable(final char mode) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    @Override
    public String getParameterChannelModes() {
        return ""; // TODO
    }

    @Override
    public String getDoubleParameterChannelModes() {
        return ""; // TODO
    }

    @Override
    public String getUserModes() {
        return ""; // TODO
    }

    @Override
    public String getChannelUserModes() {
        return ""; // TODO
    }

    @Override
    public String getChannelPrefixes() {
        return "#";
    }

    @Override
    public long getServerLatency() {
        return 1000L; // TODO
    }

    @Override
    public void sendCTCP(final String target, final String type, final String message) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    @Override
    public void sendCTCPReply(final String target, final String type, final String message) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    @Override
    public void sendMessage(final String target, final String message) {
        if (!chats.containsKey(target)) {
            LOG.debug("Creating new chat for {}", target);
            chats.put(target, connection.getChatManager().createChat(target,
                    new MessageListenerImpl()));
        }

        try {
            chats.get(target).sendMessage(message);
        } catch (XMPPException ex) {
            // TODO: Handle this
        }
    }

    @Override
    public void sendNotice(final String target, final String message) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    @Override
    public void sendAction(final String target, final String message) {
        sendMessage(target, "/me " + message);
    }

    @Override
    public void sendInvite(final String channel, final String user) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    @Override
    public void sendWhois(final String nickname) {
        // TODO: Implement this
    }

    @Override
    public String getLastLine() {
        return "TODO: Implement me";
    }

    @Override
    public String[] parseHostmask(final String hostmask) {
        return new XmppProtocolDescription().parseHostmask(hostmask);
    }

    @Override
    public long getPingTime() {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    @Override
    public void run() {
        if (getURI().getUserInfo() == null || !getURI().getUserInfo().contains(":")) {
            getCallback(ConnectErrorListener.class).onConnectError(this,
                    new Date(), new ParserError(ParserError.ERROR_USER,
                            "User name and password must be specified in URI", ""));
            return;
        }
        final String[] userInfoParts = getURI().getUserInfo().split(":", 2);
        final String[] userParts = userInfoParts[0].split("@", 2);

        final ConnectionConfiguration config = new ConnectionConfiguration(getURI().getHost(),
                getURI().getPort(), userParts[0]);
        config.setSecurityMode(getURI().getScheme().equalsIgnoreCase("xmpps")
                ? ConnectionConfiguration.SecurityMode.required
                : ConnectionConfiguration.SecurityMode.disabled);
        config.setSASLAuthenticationEnabled(true);
        config.setReconnectionAllowed(false);
        config.setRosterLoadedAtLogin(true);
        config.setSocketFactory(getSocketFactory());
        connection = new FixedXmppConnection(config);

        try {
            connection.connect();

            connection.addConnectionListener(new ConnectionListenerImpl());
            connection.addPacketListener(new PacketListenerImpl(DataInListener.class),
                    new AcceptAllPacketFilter());
            connection.addPacketSendingListener(new PacketListenerImpl(DataOutListener.class),
                    new AcceptAllPacketFilter());
            connection.getChatManager().addChatListener(new ChatManagerListenerImpl());

            try {
                connection.login(userInfoParts[0], userInfoParts[1], "DMDirc.");
            } catch (XMPPException ex) {
                getCallback(ConnectErrorListener.class).onConnectError(this,
                        new Date(), new ParserError(ParserError.ERROR_USER,
                                ex.getMessage(), ""));
                return;
            }

            connection.sendPacket(new Presence(Presence.Type.available, null, priority,
                    Presence.Mode.available));
            connection.getRoster().addRosterListener(new RosterListenerImpl());

            stateManager = ChatStateManager.getInstance(connection);

            setServerName(connection.getServiceName());

            getCallback(ServerReadyListener.class).onServerReady(this, new Date());

            for (RosterEntry contact : connection.getRoster().getEntries()) {
                getClient(contact.getUser()).setRosterEntry(contact);
            }

            if (useFakeChannel) {
                fakeChannel = new XmppFakeChannel(this, "&contacts");
                getCallback(ChannelSelfJoinListener.class).
                        onChannelSelfJoin(null, null, fakeChannel);
                fakeChannel.updateContacts(contacts.values());

                contacts.values().stream().filter(XmppClientInfo::isAway).forEach(client ->
                        getCallback(OtherAwayStateListener.class).onAwayStateOther(this, new Date(),
                                client, AwayState.UNKNOWN, AwayState.AWAY));
            }
        } catch (XMPPException ex) {
            LOG.debug("Go an XMPP exception", ex);

            connection = null;

            final ParserError error = new ParserError(ParserError.ERROR_ERROR, "Unable to connect",
                    "");

            if (ex.getWrappedThrowable() instanceof Exception) {
                // Pass along the underlying exception instead of an XMPP
                // specific one
                error.setException((Exception) ex.getWrappedThrowable());
            } else {
                error.setException(ex);
            }

            getCallback(ConnectErrorListener.class).onConnectError(this, new Date(), error);
        }
    }

    /**
     * Handles a client's away state changing.
     *
     * @param client The client whose state is changing
     * @param isBack True if the client is coming back, false if they're going away
     */
    public void handleAwayStateChange(final ClientInfo client, final boolean isBack) {
        LOG.debug("Handling away state change for {} to {}", client.getNickname(), isBack);

        if (useFakeChannel) {
            getCallback(OtherAwayStateListener.class)
                    .onAwayStateOther(null, null, client,
                            isBack ? AwayState.AWAY : AwayState.HERE,
                            isBack ? AwayState.HERE : AwayState.AWAY);
        }
    }

    /**
     * Marks the local user as away with the specified reason.
     *
     * @param reason The away reason
     */
    public void setAway(final String reason) {
        connection.sendPacket(new Presence(Presence.Type.available, reason,
                priority, Presence.Mode.away));

        getCallback(AwayStateListener.class).onAwayState(this, new Date(),
                AwayState.HERE, AwayState.AWAY, reason);
    }

    /**
     * Marks the local user as back.
     */
    public void setBack() {
        connection.sendPacket(new Presence(Presence.Type.available, null,
                priority, Presence.Mode.available));

        getCallback(AwayStateListener.class).onAwayState(this, new Date(),
                AwayState.AWAY, AwayState.HERE, null);
    }

    @Override
    public void setCompositionState(final String host, final CompositionState state) {
        LOG.debug("Setting composition state for {} to {}", host, state);

        final Chat chat = chats.get(parseHostmask(host)[0]);

        final ChatState newState;

        switch (state) {
            case ENTERED_TEXT:
                newState = ChatState.paused;
                break;
            case TYPING:
                newState = ChatState.composing;
                break;
            case IDLE:
            default:
                newState = ChatState.active;
                break;
        }

        if (chat != null && stateManager != null) {
            try {
                stateManager.setCurrentState(newState, chat);
            } catch (XMPPException ex) {
                // Can't set chat state... Oh well?
                LOG.info("Couldn't set composition state", ex);
            }
        }
    }

    @Override
    public void requestGroupList(final String searchTerms) {
        // Do nothing
    }

    private class ConnectionListenerImpl implements ConnectionListener {

        @Override
        public void connectionClosed() {
            getCallback(SocketCloseListener.class).onSocketClosed(XmppParser.this, new Date());
        }

        @Override
        public void connectionClosedOnError(final Exception excptn) {
            // TODO: Handle exception
            getCallback(SocketCloseListener.class).onSocketClosed(XmppParser.this, new Date());
        }

        @Override
        public void reconnectingIn(final int i) {
            throw new UnsupportedOperationException("Not supported yet.");
        }

        @Override
        public void reconnectionSuccessful() {
            throw new UnsupportedOperationException("Not supported yet.");
        }

        @Override
        public void reconnectionFailed(final Exception excptn) {
            throw new UnsupportedOperationException("Not supported yet.");
        }

    }

    private class RosterListenerImpl implements RosterListener {

        @Override
        public void entriesAdded(final Collection<String> clctn) {
            // Do nothing, yet
        }

        @Override
        public void entriesUpdated(final Collection<String> clctn) {
            // Do nothing, yet
        }

        @Override
        public void entriesDeleted(final Collection<String> clctn) {
            // Do nothing, yet
        }

        @Override
        public void presenceChanged(final Presence prsnc) {
            getClient(prsnc.getFrom()).setPresence(prsnc);
        }

    }

    private class ChatManagerListenerImpl implements ChatManagerListener {

        @Override
        public void chatCreated(final Chat chat, final boolean bln) {
            if (!bln) {
                // Only add chats that weren't created locally
                chats.put(parseHostmask(chat.getParticipant())[0], chat);
                chat.addMessageListener(new MessageListenerImpl());
            }
        }

    }

    private class MessageListenerImpl implements ChatStateListener {

        @Override
        public void processMessage(final Chat chat, final Message msg) {
            if (msg.getType() == Message.Type.error) {
                getCallback(NumericListener.class).onNumeric(XmppParser.this, new Date(),
                        404, new String[]{
                            ":xmpp", "404", getLocalClient().getNickname(),
                            msg.getFrom(),
                            "Cannot send message: " + msg.getError().toString()
                        });
                return;
            }

            if (msg.getBody() != null) {
                if (msg.getBody().startsWith("/me ")) {
                    getCallback(PrivateActionListener.class).onPrivateAction(XmppParser.this,
                            new Date(), msg.getBody().substring(4), msg.getFrom());
                } else {
                    getCallback(PrivateMessageListener.class).onPrivateMessage(XmppParser.this,
                            new Date(), msg.getBody(), msg.getFrom());
                }
            }
        }

        @Override
        public void stateChanged(final Chat chat, final ChatState cs) {
            final CompositionState state;

            switch (cs) {
                case paused:
                    state = CompositionState.ENTERED_TEXT;
                    break;
                case composing:
                    state = CompositionState.TYPING;
                    break;
                case active:
                case gone:
                case inactive:
                default:
                    state = CompositionState.IDLE;
                    break;
            }

            getCallback(CompositionStateChangeListener.class)
                    .onCompositionStateChanged(XmppParser.this, new Date(), state,
                            chat.getParticipant());
        }

    }

    private class PacketListenerImpl implements PacketListener {

        private final Class<? extends CallbackInterface> callback;

        public PacketListenerImpl(final Class<? extends CallbackInterface> callback) {
            this.callback = callback;
        }

        @Override
        public void processPacket(final Packet packet) {
            if (callback.equals(DataOutListener.class)) {
                getCallback(DataOutListener.class).onDataOut(XmppParser.this, new Date(),
                        packet.toXML(), true);
            } else {
                getCallback(DataInListener.class).onDataIn(XmppParser.this, new Date(),
                        packet.toXML());
            }
        }

    }

    private static class AcceptAllPacketFilter implements PacketFilter {

        @Override
        public boolean accept(final Packet packet) {
            return true;
        }

    }

}