package com.c2kernel.persistency;
import java.util.HashMap;
import java.util.StringTokenizer;

import com.c2kernel.entity.AgentHelper;
import com.c2kernel.entity.C2KLocalObject;
import com.c2kernel.entity.ItemHelper;
import com.c2kernel.entity.ManageableEntity;
import com.c2kernel.lookup.EntityPath;
import com.c2kernel.lookup.LDAPLookup;
import com.c2kernel.persistency.outcome.Outcome;
import com.c2kernel.process.Gateway;
import com.c2kernel.utils.CastorXMLUtility;
import com.c2kernel.utils.Logger;

/** Used by proxies to load clusters by queryData from the Entity.
*   Last client storage - only used if not cached elsewhere
*/

public class ProxyLoader extends ClusterStorage {
    HashMap<Integer, ManageableEntity> entities = new HashMap<Integer, ManageableEntity>();
    LDAPLookup lookup;

    @Override
	public void open() throws ClusterStorageException {
        lookup = Gateway.getLDAPLookup();
    }

    @Override
	public void close() throws ClusterStorageException {
    }
    // introspection
    @Override
	public short queryClusterSupport(String clusterType) {
        return READ;
    }

    @Override
	public String getName() {
        return "Proxy Cluster Loader";
    }

    @Override
	public String getId() {
        return "CORBA";
    }

    // retrieve object by path
    @Override
	public C2KLocalObject get(Integer sysKey, String path) throws ClusterStorageException {
        try {
            ManageableEntity thisEntity = getIOR(sysKey);
            String type = getClusterType(path);

            // fetch the xml from the item
            String queryData = thisEntity.queryData(path);

            if (queryData != null) {
                if (type.equals(OUTCOME))
                    return new Outcome(path, queryData);
                else
                    return (C2KLocalObject)CastorXMLUtility.unmarshall(queryData);
            }
        } catch (Exception e) {
            //Logger.error(e);
            throw new ClusterStorageException(e.getMessage());
        }
        return null;
    }

    // store object by path
    @Override
	public void put(Integer sysKey, C2KLocalObject obj) throws ClusterStorageException {
        // not supported
        throw new ClusterStorageException("Cannot write to items through the ProxyLoader");
    }
    // delete cluster
    @Override
	public void delete(Integer sysKey, String path) throws ClusterStorageException {
        // not supported
        throw new ClusterStorageException("Cannot write to items through the ProxyLoader");
    }

    /* navigation */

    // directory listing
    @Override
	public String[] getClusterContents(Integer sysKey, String path) throws ClusterStorageException {
        try {
            ManageableEntity thisEntity = getIOR(sysKey);
            String contents = thisEntity.queryData(path+"/all");
            StringTokenizer tok = new StringTokenizer(contents, ",");
            String[] result = new String[tok.countTokens()];
            for (int i=0; i<result.length; i++)
                result[i] = tok.nextToken();

            return result;
        } catch (Exception e) {
            throw new ClusterStorageException(e.getMessage());
        }
    }

    private ManageableEntity getIOR(Integer sysKey) throws ClusterStorageException {
        if (entities.containsKey(sysKey)) {
            // check the cache
            Logger.msg(7, "ProxyLoader.getIOR() - "+sysKey+" cached.");
            return entities.get(sysKey);
        }

        try {
            Logger.msg(7, "ProxyLoader.getIOR() - Resolving "+sysKey+".");

            org.omg.CORBA.Object ior = lookup.getIOR(new EntityPath(sysKey.intValue()));

            ManageableEntity thisEntity = null;
            try {
                thisEntity = ItemHelper.narrow(ior);
            } catch (org.omg.CORBA.BAD_PARAM ex) {
                try {
                    thisEntity =  AgentHelper.narrow(ior);
                } catch (org.omg.CORBA.BAD_PARAM ex2) {
                    throw new ClusterStorageException ("Could not narrow "+sysKey+" as a known Entity type");
                }
            }

            Logger.msg(7, "ProxyLoader.getIOR() - Found "+sysKey+".");
            entities.put(sysKey, thisEntity);
            return thisEntity;
        } catch (Exception e) {
            throw new ClusterStorageException("Error narrowing "+sysKey+": "+e.getMessage());
        }
    }
}