/**************************************************************************
 * EntityProxyFactory.java
 *
 * $Revision: 1.45 $
 * $Date: 2005/05/10 11:40:09 $
 *
 * Copyright (C) 2001 CERN - European Organization for Nuclear Research
 * All rights reserved.
 **************************************************************************/

package com.c2kernel.entity.proxy;

import java.util.ArrayList;
import java.util.ConcurrentModificationException;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;

import com.c2kernel.common.InvalidDataException;
import com.c2kernel.common.ObjectNotFoundException;
import com.c2kernel.lookup.AgentPath;
import com.c2kernel.lookup.DomainPath;
import com.c2kernel.lookup.Path;
import com.c2kernel.persistency.ClusterStorage;
import com.c2kernel.process.Gateway;
import com.c2kernel.property.Property;
import com.c2kernel.utils.Logger;
import com.c2kernel.utils.SoftCache;
import com.c2kernel.utils.server.SimpleTCPIPServer;


public class EntityProxyManager
{
    SoftCache<Integer, EntityProxy>       proxyPool     = new SoftCache<Integer, EntityProxy>(50);
    HashMap<DomainPathSubscriber, DomainPath>         treeSubscribers = new HashMap<DomainPathSubscriber, DomainPath>();
    HashMap<String, ProxyServerConnection>         connections = new HashMap<String, ProxyServerConnection>();

    // server objects
    static ArrayList<ProxyClientConnection> proxyClients      = new ArrayList<ProxyClientConnection>();
    static SimpleTCPIPServer proxyServer = null;
    static String serverName = null;

    /**
     * Create an entity proxy manager to listen for proxy events and reap unused proxies
     */
    public EntityProxyManager()
    {
        Logger.msg(5, "EntityProxyManager - Starting.....");

        Enumeration<Path> servers = Gateway.getLDAPLookup().searchEntities(new DomainPath("/servers"));
        while(servers.hasMoreElements()) {
            Path thisServerPath = servers.nextElement();
            try {
                int syskey = thisServerPath.getSysKey();
                String remoteServer = ((Property)Gateway.getStorage().get(syskey, ClusterStorage.PROPERTY+"/Name", null)).getValue();
                String portStr = ((Property)Gateway.getStorage().get(syskey, ClusterStorage.PROPERTY+"/ProxyPort", null)).getValue();
                int remotePort = Integer.parseInt(portStr);
                connectToProxyServer(remoteServer, remotePort);

            } catch (Exception ex) {
                Logger.error("Exception retrieving proxy server connection data for "+thisServerPath);
                Logger.error(ex);
            }
        }
    }

    public void connectToProxyServer(String name, int port) {
        ProxyServerConnection oldConn = connections.get(name);
        if (oldConn != null)
            oldConn.shutdown();
        connections.put(name, new ProxyServerConnection(name, port, this));
    }


    protected void resubscribe(ProxyServerConnection conn) {
        synchronized (proxyPool) {
            for (Integer key : proxyPool.keySet()) {
                ProxyMessage sub = new ProxyMessage(key.intValue(), ProxyMessage.ADDPATH, false);
                Logger.msg(5, "Subscribing to entity "+key);
                conn.sendMessage(sub);
            }
        }
    }

    /**
     * @param sub
     */
    private void sendMessage(ProxyMessage sub) {
        for (ProxyServerConnection element : connections.values()) {
            element.sendMessage(sub);
        }

    }

    public void shutdown() {
        Logger.msg("EntityProxyManager.shutdown() - flagging shutdown of server connections");
        for (ProxyServerConnection element : connections.values()) {
            element.shutdown();
        }
    }

    protected void processMessage(ProxyMessage thisMessage) throws InvalidDataException {
        if (Logger.doLog(9)) Logger.msg(9, thisMessage.toString());

        if (thisMessage.getPath().equals(ProxyMessage.PINGPATH)) // ping response
            return;

        if (thisMessage.getSysKey() == ProxyMessage.NA) // must be domain path info
            informTreeSubscribers(thisMessage.getState(), thisMessage.getPath());
        else {
            // proper proxy message
            Logger.msg(5, "Received proxy message: "+thisMessage.toString());
            Integer key = new Integer(thisMessage.getSysKey());
            EntityProxy relevant = proxyPool.get(key);
            if (relevant == null)
                Logger.warning("Received proxy message for sysKey "+thisMessage.getSysKey()+" which we don't have a proxy for.");
            else
                try {
                    relevant.notify(thisMessage);
                } catch (Throwable ex) {
                    Logger.error("Error caught notifying proxy listener "+relevant.toString()+" of "+thisMessage.toString());
                    Logger.error(ex);
                }
        }
    }

    private void informTreeSubscribers(boolean state, String path) {
        DomainPath last = new DomainPath(path);
        DomainPath parent; boolean first = true;
        synchronized(treeSubscribers) {
            while((parent = last.getParent()) != null) {
            	ArrayList<DomainPathSubscriber> currentKeys = new ArrayList<DomainPathSubscriber>();
            	currentKeys.addAll(treeSubscribers.keySet());
                for (DomainPathSubscriber sub : currentKeys) {
                    DomainPath interest = treeSubscribers.get(sub);
                    if (interest!= null && interest.equals(parent)) {
                        if (state == ProxyMessage.ADDED)
                            sub.pathAdded(last);
                        else if (first)
                            sub.pathRemoved(last);
                    }
                }
            last = parent;
            first = false;
            }
        }
    }

    public void subscribeTree(DomainPathSubscriber sub, DomainPath interest) {
        synchronized(treeSubscribers) {
            treeSubscribers.put(sub, interest);
        }
    }

    public void unsubscribeTree(DomainPathSubscriber sub) {
        synchronized(treeSubscribers) {
            treeSubscribers.remove(sub);
        }
    }

   /**************************************************************************
    *
    **************************************************************************/
    private EntityProxy createProxy( org.omg.CORBA.Object ior,
                                              int systemKey,
                                              boolean isItem )
        throws ObjectNotFoundException
    {

        EntityProxy newProxy = null;

        Logger.msg(5, "EntityProxyFactory::creating proxy on entity " + systemKey);

        if( isItem )
        {
            newProxy = new ItemProxy(ior, systemKey);
        }
        else
        {
            newProxy = new AgentProxy(ior, systemKey);
        }

        // subscribe to changes from server
        ProxyMessage sub = new ProxyMessage(systemKey, ProxyMessage.ADDPATH, false);
        sendMessage(sub);
        reportCurrentProxies(9);
        return ( newProxy );
   }

   protected void removeProxy( int systemKey )
   {
       ProxyMessage sub = new ProxyMessage(systemKey, ProxyMessage.DELPATH, true);
       Logger.msg(5,"EntityProxyManager.removeProxy() - Unsubscribing to proxy informer for "+systemKey);
       sendMessage(sub);
   }


   /**************************************************************************
    * EntityProxy getProxy( ManageableEntity, SystemKey)
    *
    * Called by the other GetProxy methods. Fills in either the ior or the
    * SystemKey
    **************************************************************************/
    private EntityProxy getProxy( org.omg.CORBA.Object ior,
                                           int systemKey,
                                           boolean isItem )
        throws ObjectNotFoundException
    {
        Integer key = new Integer(systemKey);

        synchronized(proxyPool) {
            EntityProxy newProxy;
            // return it if it exists
            newProxy = proxyPool.get(key);
            if (newProxy == null) {
                // create a new one
                newProxy = createProxy(ior, systemKey, isItem );
                proxyPool.put(key, newProxy);
            }
            return newProxy;

        }
    }

   /**************************************************************************
    * EntityProxy getProxy( String )
    *
    * Proxy from Alias
    **************************************************************************/
    public EntityProxy getProxy( Path path )
        throws ObjectNotFoundException
    {

        //convert namePath to dn format
        Logger.msg(8,"EntityProxyFactory::getProxy(" + path.toString() + ")");
        boolean isItem = !(path.getEntity() instanceof AgentPath);
        return getProxy( Gateway.getLDAPLookup().getIOR(path),
                            path.getSysKey(),
                            isItem );

    }

   /**************************************************************************
    * void reportCurrentProxies()
    *
    * A utility to Dump the current proxies loaded
    **************************************************************************/
    public void reportCurrentProxies(int logLevel)
    {
        if (!Logger.doLog(logLevel)) return;
        Logger.msg(logLevel, "Current proxies: ");
        try {
            synchronized(proxyPool) {
                Iterator<Integer> i = proxyPool.keySet().iterator();

                for( int count=0; i.hasNext(); count++ )
                {
                    Integer nextProxy = i.next();
                    EntityProxy thisProxy = proxyPool.get(nextProxy);
                    if (thisProxy != null)
                        Logger.msg(logLevel,
                            "" + count + ": "
                            + proxyPool.get(nextProxy).getClass().getName()
                            + ": " + nextProxy);
                }
            }
        } catch (ConcurrentModificationException ex) {
            Logger.msg(logLevel, "Proxy cache modified. Aborting.");
        }
    }


    /**************************************************************************
     * Static Proxy Server methods
     **************************************************************************/

    /**
     * Initialises the Proxy event UDP server listening on 'Host.Proxy.port' from c2kprops
     * @param c2kProps
     */
    public static void initServer()
    {
        Logger.msg(5, "EntityProxyFactory::initServer - Starting.....");
        String port = Gateway.getProperty("ItemServer.Proxy.port");
        serverName = Gateway.getProperty("ItemServer.name");
        if (port == null) {
            Logger.error("ItemServer.Proxy.port not defined in connect file. Remote proxies will not be informed of entity changes.");
            return;
        }

        // set up the proxy server
        try {
            int portNo = Integer.parseInt(port);
            Logger.msg(5, "EntityProxyFactory::initServer - Initialising proxy informer on port "+port);
            proxyServer = new SimpleTCPIPServer(portNo, ProxyClientConnection.class, 200);
            proxyServer.startListening();
        } catch (Exception ex) {
            Logger.error("Error setting up Proxy Server. Remote proxies will not be informed of entity changes.");
            Logger.error(ex);
        }
    }

    public static void sendProxyEvent(ProxyMessage message) {
        if (proxyServer != null && message.getPath() != null)
            synchronized(proxyClients) {
                for (ProxyClientConnection client : proxyClients) {
                    client.sendMessage(message);
                }
            }
    }

    public static void reportConnections(int logLevel) {
        synchronized(proxyClients) {
            Logger.msg(logLevel, "Currently connected proxy clients:");
            for (ProxyClientConnection client : proxyClients) {
                Logger.msg(logLevel, "   "+client);
            }
        }
    }

    public static void shutdownServer() {
        if (proxyServer != null) {
            Logger.msg(1, "EntityProxyManager: Closing Server.");
            proxyServer.stopListening();
        }
    }

    public static void registerProxyClient(ProxyClientConnection client) {
        synchronized(proxyClients) {
            proxyClients.add(client);
        }
    }

    public static void unRegisterProxyClient(ProxyClientConnection client) {
        synchronized(proxyClients) {
            proxyClients.remove(client);
        }
    }
}