EDIT

// $Id$

/**

 * Copyright (C) 2014 EDIT

 * European Distributed Institute of Taxonomy

 * http://www.e-taxonomy.eu

 *

 * The contents of this file are subject to the Mozilla Public License Version 1.1

 * See LICENSE.TXT at the top of this package for the full license terms.

 */

package eu.etaxonomy.taxeditor.session;

import java.util.ArrayList;

import java.util.Collection;

import java.util.HashMap;

import java.util.HashSet;

import java.util.List;

import java.util.Map;

import java.util.Set;

import org.apache.log4j.Logger;

import org.springframework.stereotype.Component;

import eu.etaxonomy.cdm.api.service.UpdateResult;

import eu.etaxonomy.cdm.model.common.CdmBase;

import eu.etaxonomy.cdm.persistence.dto.MergeResult;

/**

 * @author cmathew

 * @date 16 Oct 2014

 *

 */

@Component

public class CdmEntitySessionManager implements ICdmEntitySessionManager {

    private static final Logger logger = Logger.getLogger(CdmEntitySessionManager.class);

    private final Map<ICdmEntitySessionEnabled, ICdmEntitySession> ownerSessionMap =

            new HashMap<ICdmEntitySessionEnabled, ICdmEntitySession>();

    private final List<ICdmEntitySessionManagerObserver> sessionObservers = new ArrayList<ICdmEntitySessionManagerObserver>();

    //private ICdmEntitySession activeSession;

    private final InheritableThreadLocal<ICdmEntitySession> tlActiveSession = new InheritableThreadLocal<ICdmEntitySession>();

    private  NullSession nullSession;

    @Override

    public ICdmEntitySession getNullSession() {

        return nullSession;

    }

    @Override

    public ICdmEntitySession newSession(ICdmEntitySessionEnabled sessionOwner, boolean setAsActive) {

        ICdmEntitySession session = ownerSessionMap.get(sessionOwner);

        if(session == null) {

            session = new CdmEntitySession(sessionOwner, this);

            addToOwnerSessionMap(sessionOwner, session);

        }

        if(setAsActive) {

            setActiveSession(session);

        }

        return session;

    }

    @Override

    public ICdmEntitySession bindNullSession() {

        if(nullSession == null) {

            nullSession = new NullSession(null, this);

        }

        setActiveSession(nullSession);

        return nullSession;

    }

    @Override

    public ICdmEntitySession getActiveSession() {

        return tlActiveSession.get();

    }

    private void setActiveSession(ICdmEntitySession activeSession) {

       this. tlActiveSession.set(activeSession);

        notifyObservers();

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySessionManager#getSessions()

     */

    @Override

    public Collection<ICdmEntitySession> getSessions() {

        return ownerSessionMap.values();

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySessionManager#bind(eu.etaxonomy.taxeditor.session.ISessionEventListener)

     */

    @Override

    public void bind(ICdmEntitySessionEnabled sessionOwner) {

        if(sessionOwner == null) {

            setActiveSession(null);

            return;

        }

        ICdmEntitySession session  = ownerSessionMap.get(sessionOwner);

        if(session == null) {

            throw new CdmClientSessionException("Trying to bind session which does not exist");

        }

        setActiveSession(session);

    }

    @Override

    public boolean contains(ICdmEntitySessionEnabled sessionOwner) {

        return ownerSessionMap.containsKey(sessionOwner);

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySessionManager#load(T)

     */

    @Override

    public <T extends Object> T load(T obj, boolean update) {

        if(tlActiveSession.get() == null) {

            return obj;

        } else {

            return tlActiveSession.get().load(obj, update);

        }

    }

    @Override

    public <T extends CdmBase> void update() {

        if(tlActiveSession.get() != null) {

            tlActiveSession.get().update();

        }

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySessionManager#load(T)

     */

    @Override

    public <T extends CdmBase> T load(T cdmBase, boolean update) {

        if(tlActiveSession.get() == null) {

            return cdmBase;

        }

        return tlActiveSession.get().load(cdmBase, update);

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySessionManager#load(eu.etaxonomy.cdm.api.service.UpdateResult, boolean)

     */

    @Override

    public UpdateResult load(UpdateResult updateResult, boolean update) {

        if(tlActiveSession.get() == null) {

            return updateResult;

        }

        return tlActiveSession.get().load(updateResult, update);

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySessionManager#load(eu.etaxonomy.cdm.persistence.dto.MergeResult, boolean)

     */

    @Override

    public MergeResult load(MergeResult mergeResult, boolean update) {

        if(tlActiveSession.get() == null) {

            return mergeResult;

        }

        return tlActiveSession.get().load(mergeResult, update);

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySessionManager#load(java.util.Collection)

     */

    @Override

    public <T extends CdmBase> Collection<T> load(Collection<T> cdmBaseList, boolean update) {

        if(tlActiveSession.get() == null) {

            return cdmBaseList;

        }

        return tlActiveSession.get().load(cdmBaseList, update);

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySessionManager#dispose(eu.etaxonomy.taxeditor.session.ISessionEventListener)

     */

    void remove(ICdmEntitySessionEnabled owner) {

        ICdmEntitySession session = ownerSessionMap.get(owner);

        if(session == null) {

            logger.info("No Session connected to owner, nothing to do");

            return;

        }

        if(session == tlActiveSession.get()) {

            setActiveSession(null);

        }

        ownerSessionMap.remove(owner);

        notifyObservers();

    }

    @Override

    public void dispose(ICdmEntitySessionEnabled owner) {

        ICdmEntitySession session = ownerSessionMap.get(owner);

        if(session != null) {

            session.dispose();

        }

        if(nullSession != null && nullSession.getOwner() == owner) {

            nullSession = null;

        }

    }

    @Override

    public void disposeAll() {

        Set<ICdmEntitySessionEnabled> owners =

                new HashSet<ICdmEntitySessionEnabled>(ownerSessionMap.keySet());

        for(ICdmEntitySessionEnabled owner : owners) {

            ICdmEntitySession session = ownerSessionMap.get(owner);

            if(session != null) {

                session.dispose();

            }

        }

    }

    void addToOwnerSessionMap(ICdmEntitySessionEnabled owner, ICdmEntitySession session) {

        ownerSessionMap.put(owner, session);

        notifyObservers();

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySessionManager#addSessionListener()

     */

    @Override

    public void addSessionObserver(ICdmEntitySessionManagerObserver sessionObserver) {

        sessionObservers.add(sessionObserver);

    }

    public void notifyObservers() {

        for(ICdmEntitySessionManagerObserver sessionObserver : sessionObservers) {

            sessionObserver.changed();

        }

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySessionManager#isRemoting()

     */

    @Override

    public boolean isRemoting() {

        // FIXME:Remoting stupid method to check whether we are in remoting

        return true;

    }

}