/**
 *
 * Copyright 2009 Robin Collier.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.jivesoftware.smackx.pubsub;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.ConcurrentHashMap;

import org.jivesoftware.smack.PacketListener;
import org.jivesoftware.smack.SmackException.NoResponseException;
import org.jivesoftware.smack.SmackException.NotConnectedException;
import org.jivesoftware.smack.XMPPConnection;
import org.jivesoftware.smack.XMPPException.XMPPErrorException;
import org.jivesoftware.smack.filter.OrFilter;
import org.jivesoftware.smack.filter.PacketFilter;
import org.jivesoftware.smack.packet.Message;
import org.jivesoftware.smack.packet.Packet;
import org.jivesoftware.smack.packet.PacketExtension;
import org.jivesoftware.smack.packet.IQ.Type;
import org.jivesoftware.smackx.delay.packet.DelayInformation;
import org.jivesoftware.smackx.disco.packet.DiscoverInfo;
import org.jivesoftware.smackx.pubsub.listener.ItemDeleteListener;
import org.jivesoftware.smackx.pubsub.listener.ItemEventListener;
import org.jivesoftware.smackx.pubsub.listener.NodeConfigListener;
import org.jivesoftware.smackx.pubsub.packet.PubSub;
import org.jivesoftware.smackx.pubsub.packet.PubSubNamespace;
import org.jivesoftware.smackx.pubsub.util.NodeUtils;
import org.jivesoftware.smackx.shim.packet.Header;
import org.jivesoftware.smackx.shim.packet.HeadersExtension;
import org.jivesoftware.smackx.xdata.Form;

abstract public class Node
{
        protected XMPPConnection con;
        protected String id;
        protected String to;
        
        protected ConcurrentHashMap<ItemEventListener<Item>, PacketListener> itemEventToListenerMap = new ConcurrentHashMap<ItemEventListener<Item>, PacketListener>();
        protected ConcurrentHashMap<ItemDeleteListener, PacketListener> itemDeleteToListenerMap = new ConcurrentHashMap<ItemDeleteListener, PacketListener>();
        protected ConcurrentHashMap<NodeConfigListener, PacketListener> configEventToListenerMap = new ConcurrentHashMap<NodeConfigListener, PacketListener>();
        
        /**
         * Construct a node associated to the supplied connection with the specified 
         * node id.
         * 
         * @param connection The connection the node is associated with
         * @param nodeName The node id
         */
        Node(XMPPConnection connection, String nodeName)
        {
                con = connection;
                id = nodeName;
        }

        /**
         * Some XMPP servers may require a specific service to be addressed on the 
         * server.
         * 
         *   For example, OpenFire requires the server to be prefixed by <b>pubsub</b>
         */
        void setTo(String toAddress)
        {
                to = toAddress;
        }

        /**
         * Get the NodeId
         * 
         * @return the node id
         */
        public String getId() 
        {
                return id;
        }
        /**
         * Returns a configuration form, from which you can create an answer form to be submitted
         * via the {@link #sendConfigurationForm(Form)}.
         * 
         * @return the configuration form
         * @throws XMPPErrorException 
         * @throws NoResponseException 
         * @throws NotConnectedException 
         */
        public ConfigureForm getNodeConfiguration() throws NoResponseException, XMPPErrorException, NotConnectedException
        {
        PubSub pubSub = createPubsubPacket(Type.GET, new NodeExtension(
                        PubSubElementType.CONFIGURE_OWNER, getId()), PubSubNamespace.OWNER);
                Packet reply = sendPubsubPacket(pubSub);
                return NodeUtils.getFormFromPacket(reply, PubSubElementType.CONFIGURE_OWNER);
        }
        
        /**
         * Update the configuration with the contents of the new {@link Form}
         * 
         * @param submitForm
         * @throws XMPPErrorException 
         * @throws NoResponseException 
         * @throws NotConnectedException 
         */
        public void sendConfigurationForm(Form submitForm) throws NoResponseException, XMPPErrorException, NotConnectedException
        {
        PubSub packet = createPubsubPacket(Type.SET, new FormNode(FormNodeType.CONFIGURE_OWNER,
                        getId(), submitForm), PubSubNamespace.OWNER);
                con.createPacketCollectorAndSend(packet).nextResultOrThrow();
        }
        
        /**
         * Discover node information in standard {@link DiscoverInfo} format.
         * 
         * @return The discovery information about the node.
         * @throws XMPPErrorException 
         * @throws NoResponseException if there was no response from the server.
         * @throws NotConnectedException 
         */
        public DiscoverInfo discoverInfo() throws NoResponseException, XMPPErrorException, NotConnectedException
        {
                DiscoverInfo info = new DiscoverInfo();
                info.setTo(to);
                info.setNode(getId());
                return (DiscoverInfo) con.createPacketCollectorAndSend(info).nextResultOrThrow();
        }
        
        /**
         * Get the subscriptions currently associated with this node.
         * 
         * @return List of {@link Subscription}
         * @throws XMPPErrorException 
         * @throws NoResponseException 
         * @throws NotConnectedException 
         * 
         */
        public List<Subscription> getSubscriptions() throws NoResponseException, XMPPErrorException, NotConnectedException
        {
        return getSubscriptions(null, null);
        }

    /**
     * Get the subscriptions currently associated with this node.
     * <p>
     * {@code additionalExtensions} can be used e.g. to add a "Result Set Management" extension.
     * {@code returnedExtensions} will be filled with the packet extensions found in the answer.
     * </p>
     *
     * @param additionalExtensions
     * @param returnedExtensions a collection that will be filled with the returned packet
     *        extensions
     * @return List of {@link Subscription}
     * @throws NoResponseException
     * @throws XMPPErrorException
     * @throws NotConnectedException
     */
    public List<Subscription> getSubscriptions(List<PacketExtension> additionalExtensions, Collection<PacketExtension> returnedExtensions)
                    throws NoResponseException, XMPPErrorException, NotConnectedException {
        PubSub pubSub = createPubsubPacket(Type.GET, new NodeExtension(
                        PubSubElementType.SUBSCRIPTIONS, getId()));
        if (additionalExtensions != null) {
            for (PacketExtension pe : additionalExtensions) {
                pubSub.addExtension(pe);
            }
        }
        PubSub reply = (PubSub) sendPubsubPacket(pubSub);
        if (returnedExtensions != null) {
            returnedExtensions.addAll(reply.getExtensions());
        }
        SubscriptionsExtension subElem = (SubscriptionsExtension) reply.getExtension(PubSubElementType.SUBSCRIPTIONS);
        return subElem.getSubscriptions();
    }

        /**
         * Get the affiliations of this node.
         *
         * @return List of {@link Affiliation}
         * @throws NoResponseException
         * @throws XMPPErrorException
         * @throws NotConnectedException
         */
    public List<Affiliation> getAffiliations() throws NoResponseException, XMPPErrorException,
                    NotConnectedException {
        return getAffiliations(null, null);
    }

    /**
     * Get the affiliations of this node.
     * <p>
     * {@code additionalExtensions} can be used e.g. to add a "Result Set Management" extension.
     * {@code returnedExtensions} will be filled with the packet extensions found in the answer.
     * </p>
     *
     * @param additionalExtensions additional {@code PacketExtensions} add to the request
     * @param returnedExtensions a collection that will be filled with the returned packet
     *        extensions
     * @return List of {@link Affiliation}
     * @throws NoResponseException
     * @throws XMPPErrorException
     * @throws NotConnectedException
     */
    public List<Affiliation> getAffiliations(List<PacketExtension> additionalExtensions, Collection<PacketExtension> returnedExtensions)
                    throws NoResponseException, XMPPErrorException, NotConnectedException {
        PubSub pubSub = createPubsubPacket(Type.GET, new NodeExtension(PubSubElementType.AFFILIATIONS, getId()));
        if (additionalExtensions != null) {
            for (PacketExtension pe : additionalExtensions) {
                pubSub.addExtension(pe);
            }
        }
        PubSub reply = (PubSub) sendPubsubPacket(pubSub);
        if (returnedExtensions != null) {
            returnedExtensions.addAll(reply.getExtensions());
        }
        AffiliationsExtension affilElem = (AffiliationsExtension) reply.getExtension(PubSubElementType.AFFILIATIONS);
        return affilElem.getAffiliations();
    }

        /**
         * The user subscribes to the node using the supplied jid.  The
         * bare jid portion of this one must match the jid for the connection.
         * 
         * Please note that the {@link Subscription.State} should be checked 
         * on return since more actions may be required by the caller.
         * {@link Subscription.State#pending} - The owner must approve the subscription 
         * request before messages will be received.
         * {@link Subscription.State#unconfigured} - If the {@link Subscription#isConfigRequired()} is true, 
         * the caller must configure the subscription before messages will be received.  If it is false
         * the caller can configure it but is not required to do so.
         * @param jid The jid to subscribe as.
         * @return The subscription
         * @throws XMPPErrorException 
         * @throws NoResponseException 
         * @throws NotConnectedException 
         */
        public Subscription subscribe(String jid) throws NoResponseException, XMPPErrorException, NotConnectedException
        {
            PubSub pubSub = createPubsubPacket(Type.SET, new SubscribeExtension(jid, getId()));
                PubSub reply = (PubSub)sendPubsubPacket(pubSub);
                return (Subscription)reply.getExtension(PubSubElementType.SUBSCRIPTION);
        }
        
        /**
         * The user subscribes to the node using the supplied jid and subscription
         * options.  The bare jid portion of this one must match the jid for the 
         * connection.
         * 
         * Please note that the {@link Subscription.State} should be checked 
         * on return since more actions may be required by the caller.
         * {@link Subscription.State#pending} - The owner must approve the subscription 
         * request before messages will be received.
         * {@link Subscription.State#unconfigured} - If the {@link Subscription#isConfigRequired()} is true, 
         * the caller must configure the subscription before messages will be received.  If it is false
         * the caller can configure it but is not required to do so.
         * @param jid The jid to subscribe as.
         * @return The subscription
         * @throws XMPPErrorException 
         * @throws NoResponseException 
         * @throws NotConnectedException 
         */
        public Subscription subscribe(String jid, SubscribeForm subForm) throws NoResponseException, XMPPErrorException, NotConnectedException
        {
            PubSub request = createPubsubPacket(Type.SET, new SubscribeExtension(jid, getId()));
                request.addExtension(new FormNode(FormNodeType.OPTIONS, subForm));
                PubSub reply = (PubSub)PubSubManager.sendPubsubPacket(con, request);
                return (Subscription)reply.getExtension(PubSubElementType.SUBSCRIPTION);
        }

        /**
         * Remove the subscription related to the specified JID.  This will only 
         * work if there is only 1 subscription.  If there are multiple subscriptions,
         * use {@link #unsubscribe(String, String)}.
         * 
         * @param jid The JID used to subscribe to the node
         * @throws XMPPErrorException 
         * @throws NoResponseException 
         * @throws NotConnectedException 
         * 
         */
        public void unsubscribe(String jid) throws NoResponseException, XMPPErrorException, NotConnectedException
        {
                unsubscribe(jid, null);
        }
        
        /**
         * Remove the specific subscription related to the specified JID.
         * 
         * @param jid The JID used to subscribe to the node
         * @param subscriptionId The id of the subscription being removed
         * @throws XMPPErrorException 
         * @throws NoResponseException 
         * @throws NotConnectedException 
         */
        public void unsubscribe(String jid, String subscriptionId) throws NoResponseException, XMPPErrorException, NotConnectedException
        {
                sendPubsubPacket(createPubsubPacket(Type.SET, new UnsubscribeExtension(jid, getId(), subscriptionId)));
        }

        /**
         * Returns a SubscribeForm for subscriptions, from which you can create an answer form to be submitted
         * via the {@link #sendConfigurationForm(Form)}.
         * 
         * @return A subscription options form
         * @throws XMPPErrorException 
         * @throws NoResponseException 
         * @throws NotConnectedException 
         */
        public SubscribeForm getSubscriptionOptions(String jid) throws NoResponseException, XMPPErrorException, NotConnectedException
        {
                return getSubscriptionOptions(jid, null);
        }


        /**
         * Get the options for configuring the specified subscription.
         * 
         * @param jid JID the subscription is registered under
         * @param subscriptionId The subscription id
         * 
         * @return The subscription option form
         * @throws XMPPErrorException 
         * @throws NoResponseException 
         * @throws NotConnectedException 
         * 
         */
        public SubscribeForm getSubscriptionOptions(String jid, String subscriptionId) throws NoResponseException, XMPPErrorException, NotConnectedException
        {
                PubSub packet = (PubSub)sendPubsubPacket(createPubsubPacket(Type.GET, new OptionsExtension(jid, getId(), subscriptionId)));
                FormNode ext = (FormNode)packet.getExtension(PubSubElementType.OPTIONS);
                return new SubscribeForm(ext.getForm());
        }

        /**
         * Register a listener for item publication events.  This 
         * listener will get called whenever an item is published to 
         * this node.
         * 
         * @param listener The handler for the event
         */
        @SuppressWarnings("unchecked")
    public void addItemEventListener(@SuppressWarnings("rawtypes") ItemEventListener listener)
        {
                PacketListener conListener = new ItemEventTranslator(listener); 
                itemEventToListenerMap.put(listener, conListener);
                con.addPacketListener(conListener, new EventContentFilter(EventElementType.items.toString(), "item"));
        }

        /**
         * Unregister a listener for publication events.
         * 
         * @param listener The handler to unregister
         */
        public void removeItemEventListener(@SuppressWarnings("rawtypes") ItemEventListener listener)
        {
                PacketListener conListener = itemEventToListenerMap.remove(listener);
                
                if (conListener != null)
                        con.removePacketListener(conListener);
        }

        /**
         * Register a listener for configuration events.  This listener
         * will get called whenever the node's configuration changes.
         * 
         * @param listener The handler for the event
         */
        public void addConfigurationListener(NodeConfigListener listener)
        {
                PacketListener conListener = new NodeConfigTranslator(listener); 
                configEventToListenerMap.put(listener, conListener);
                con.addPacketListener(conListener, new EventContentFilter(EventElementType.configuration.toString()));
        }

        /**
         * Unregister a listener for configuration events.
         * 
         * @param listener The handler to unregister
         */
        public void removeConfigurationListener(NodeConfigListener listener)
        {
                PacketListener conListener = configEventToListenerMap .remove(listener);
                
                if (conListener != null)
                        con.removePacketListener(conListener);
        }
        
        /**
         * Register an listener for item delete events.  This listener
         * gets called whenever an item is deleted from the node.
         * 
         * @param listener The handler for the event
         */
        public void addItemDeleteListener(ItemDeleteListener listener)
        {
                PacketListener delListener = new ItemDeleteTranslator(listener); 
                itemDeleteToListenerMap.put(listener, delListener);
                EventContentFilter deleteItem = new EventContentFilter(EventElementType.items.toString(), "retract");
                EventContentFilter purge = new EventContentFilter(EventElementType.purge.toString());
                
                con.addPacketListener(delListener, new OrFilter(deleteItem, purge));
        }

        /**
         * Unregister a listener for item delete events.
         * 
         * @param listener The handler to unregister
         */
        public void removeItemDeleteListener(ItemDeleteListener listener)
        {
                PacketListener conListener = itemDeleteToListenerMap .remove(listener);
                
                if (conListener != null)
                        con.removePacketListener(conListener);
        }

        @Override
        public String toString()
        {
                return super.toString() + " " + getClass().getName() + " id: " + id;
        }
        
        protected PubSub createPubsubPacket(Type type, PacketExtension ext)
        {
                return createPubsubPacket(type, ext, null);
        }
        
        protected PubSub createPubsubPacket(Type type, PacketExtension ext, PubSubNamespace ns)
        {
                return PubSub.createPubsubPacket(to, type, ext, ns);
        }

        protected Packet sendPubsubPacket(PubSub packet) throws NoResponseException, XMPPErrorException, NotConnectedException
        {
                return PubSubManager.sendPubsubPacket(con, packet);
        }


        private static List<String> getSubscriptionIds(Packet packet)
        {
                HeadersExtension headers = (HeadersExtension)packet.getExtension("headers", "http://jabber.org/protocol/shim");
                List<String> values = null;
                
                if (headers != null)
                {
                        values = new ArrayList<String>(headers.getHeaders().size());
                        
                        for (Header header : headers.getHeaders())
                        {
                                values.add(header.getValue());
                        }
                }
                return values;
        }

        /**
         * This class translates low level item publication events into api level objects for 
         * user consumption.
         * 
         * @author Robin Collier
         */
        public class ItemEventTranslator implements PacketListener
        {
                @SuppressWarnings("rawtypes")
        private ItemEventListener listener;

                public ItemEventTranslator(@SuppressWarnings("rawtypes") ItemEventListener eventListener)
                {
                        listener = eventListener;
                }
                
                @SuppressWarnings({ "rawtypes", "unchecked" })
        public void processPacket(Packet packet)
                {
                EventElement event = (EventElement)packet.getExtension("event", PubSubNamespace.EVENT.getXmlns());
                        ItemsExtension itemsElem = (ItemsExtension)event.getEvent();
                        DelayInformation delay = (DelayInformation)packet.getExtension("delay", "urn:xmpp:delay");
                        
                        // If there was no delay based on XEP-0203, then try XEP-0091 for backward compatibility
                        if (delay == null)
                        {
                                delay = (DelayInformation)packet.getExtension("x", "jabber:x:delay");
                        }
            ItemPublishEvent eventItems = new ItemPublishEvent(itemsElem.getNode(), (List<Item>)itemsElem.getItems(), getSubscriptionIds(packet), (delay == null ? null : delay.getStamp()));
                        listener.handlePublishedItems(eventItems);
                }
        }

        /**
         * This class translates low level item deletion events into api level objects for 
         * user consumption.
         * 
         * @author Robin Collier
         */
        public class ItemDeleteTranslator implements PacketListener
        {
                private ItemDeleteListener listener;

                public ItemDeleteTranslator(ItemDeleteListener eventListener)
                {
                        listener = eventListener;
                }
                
                public void processPacket(Packet packet)
                {
                EventElement event = (EventElement)packet.getExtension("event", PubSubNamespace.EVENT.getXmlns());
                
                List<PacketExtension> extList = event.getExtensions();
                
                if (extList.get(0).getElementName().equals(PubSubElementType.PURGE_EVENT.getElementName()))
                {
                        listener.handlePurge();
                }
                else
                {
                                ItemsExtension itemsElem = (ItemsExtension)event.getEvent();
                                @SuppressWarnings("unchecked")
                Collection<RetractItem> pubItems = (Collection<RetractItem>) itemsElem.getItems();
                                List<String> items = new ArrayList<String>(pubItems.size());

                                for (RetractItem item : pubItems)
                                {
                                        items.add(item.getId());
                                }

                                ItemDeleteEvent eventItems = new ItemDeleteEvent(itemsElem.getNode(), items, getSubscriptionIds(packet));
                                listener.handleDeletedItems(eventItems);
                }
                }
        }
        
        /**
         * This class translates low level node configuration events into api level objects for 
         * user consumption.
         * 
         * @author Robin Collier
         */
        public class NodeConfigTranslator implements PacketListener
        {
                private NodeConfigListener listener;

                public NodeConfigTranslator(NodeConfigListener eventListener)
                {
                        listener = eventListener;
                }
                
                public void processPacket(Packet packet)
                {
                EventElement event = (EventElement)packet.getExtension("event", PubSubNamespace.EVENT.getXmlns());
                        ConfigurationEvent config = (ConfigurationEvent)event.getEvent();

                        listener.handleNodeConfiguration(config);
                }
        }

        /**
         * Filter for {@link PacketListener} to filter out events not specific to the 
         * event type expected for this node.
         * 
         * @author Robin Collier
         */
        class EventContentFilter implements PacketFilter
        {
                private String firstElement;
                private String secondElement;
                
                EventContentFilter(String elementName)
                {
                        firstElement = elementName;
                }

                EventContentFilter(String firstLevelEelement, String secondLevelElement)
                {
                        firstElement = firstLevelEelement;
                        secondElement = secondLevelElement;
                }

                public boolean accept(Packet packet)
                {
                        if (!(packet instanceof Message))
                                return false;

                        EventElement event = (EventElement)packet.getExtension("event", PubSubNamespace.EVENT.getXmlns());
                        
                        if (event == null)
                                return false;

                        NodeExtension embedEvent = event.getEvent();
                        
                        if (embedEvent == null)
                                return false;
                        
                        if (embedEvent.getElementName().equals(firstElement))
                        {
                                if (!embedEvent.getNode().equals(getId()))
                                        return false;
                                
                                if (secondElement == null)
                                        return true;
                                
                                if (embedEvent instanceof EmbeddedPacketExtension)
                                {
                                        List<PacketExtension> secondLevelList = ((EmbeddedPacketExtension)embedEvent).getExtensions();
                                        
                                        if (secondLevelList.size() > 0 && secondLevelList.get(0).getElementName().equals(secondElement))
                                                return true;
                                }
                        }
                        return false;
                }
        }
}