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.Arrays;

import java.util.Collection;

import java.util.List;

import java.util.Set;

import java.util.UUID;

import net.sf.ehcache.statistics.LiveCacheStatistics;

import org.apache.log4j.Logger;

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

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

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

import eu.etaxonomy.cdm.persistence.hibernate.CdmDataChangeEvent;

import eu.etaxonomy.cdm.persistence.hibernate.CdmDataChangeEvent.EventType;

import eu.etaxonomy.cdm.persistence.hibernate.CdmPostDataChangeObservableListener;

import eu.etaxonomy.taxeditor.remoting.cache.CdmTransientEntityCacher;

import eu.etaxonomy.taxeditor.remoting.cache.EntityCacherDebugResult;

/**

 *

 * NOTE : It would be nice to have this class performing merge / delete operations

 * using services, but this is only possible if we can 'intelligently'

 * get from a model class to the correspoding service class

 * @author cmathew

 * @date 20 Oct 2014

 *

 */

public class CdmEntitySession implements ICdmEntitySession  {

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

    private final CdmEntitySessionManager cdmEntitySessionManager;

    private final ICdmEntitySessionEnabled sessionOwner;

    private final CdmTransientEntityCacher cdmTransientEntityCacher;

    private final List<ICdmEntitySessionEnabled> changeObservers;

    public CdmEntitySession(ICdmEntitySessionEnabled sessionOwner, CdmEntitySessionManager cdmEntitySessionManager) {

        this.sessionOwner = sessionOwner;

        this.cdmTransientEntityCacher = new CdmTransientEntityCacher(sessionOwner, cdmEntitySessionManager);

        this.cdmEntitySessionManager = cdmEntitySessionManager;

        this.changeObservers = new ArrayList<ICdmEntitySessionEnabled>();

        cdmEntitySessionManager.addToOwnerSessionMap(sessionOwner, this);

    }

    /* (non-Javadoc)

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

     */

    @Override

    public  <O extends Object> O load(O obj) {

        return cdmTransientEntityCacher.load(obj,true);

    }

    /* (non-Javadoc)

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

     */

    @Override

    public  <T extends CdmBase> T load(T cdmBase) {

        return (T)cdmTransientEntityCacher.load(cdmBase,true);

    }

    @Override

    public <T extends ICdmBase> void update(T cdmBase, Set<CdmBase> affectedObjects) {

        load(cdmBase);

        addEvent(cdmBase, affectedObjects, EventType.UPDATE);

    }

    @Override

    public <T extends ICdmBase> void delete(T cdmBase, Set<CdmBase> affectedObjects) {

        for(CdmBase cb : affectedObjects) {

            load(cb);

        }

        addEvent(cdmBase, affectedObjects, EventType.DELETE);

    }

    @Override

    public <T extends ICdmBase> void delete(Set<T> cdmBases, Set<CdmBase> affectedObjects) {

        for(CdmBase cb : affectedObjects) {

            load(cb);

        }

        addEvent(cdmBases, affectedObjects, EventType.DELETE);

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySession#debug(eu.etaxonomy.cdm.model.common.CdmBase)

     */

    @Override

    public <T extends CdmBase> EntityCacherDebugResult debug(T cdmBase) {

        return debug(Arrays.asList(cdmBase));

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySession#debug(java.util.List)

     */

    @Override

    public <T extends CdmBase> EntityCacherDebugResult debug(List<T> cdmBases) {

        EntityCacherDebugResult entityCacherDebugResult =

                new EntityCacherDebugResult(cdmTransientEntityCacher, cdmBases);

        return entityCacherDebugResult;

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySession#debug()

     */

    @Override

    public <T extends CdmBase> EntityCacherDebugResult debug() {

        return debug(getRootEntities());

    }

    /* (non-Javadoc)

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

     */

    @Override

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

        return cdmTransientEntityCacher.load(cdmBaseList,true);

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySession#setEntitiesAsLatest()

     */

    @Override

    public void setEntitiesAsLatest() {

        //FIXME:Remoting need to think more about whether we really need this

        //		List<CdmBase> entities = cdmTransientEntityCacher.getAllEntities();

        //		for(CdmBase entity : entities) {

        //			cdmEntitySessionManager.setEntityAsLatest(entity);

        //		}

    }

    /**

     * Register to get updated after any interaction with the datastore

     */

    @Override

    public void registerForDataStoreChanges(ICdmEntitySessionEnabled observer) {

        CdmPostDataChangeObservableListener.getDefault().register(observer);

    }

    /**

     * Register to get updated after any interaction with the datastore

     */

    @Override

    public void unregisterForDataStoreChanges(ICdmEntitySessionEnabled observer) {

        CdmPostDataChangeObservableListener.getDefault().unregister(observer);

    }

    @Override

    public void bind() {

        logger.info("Binding session with owner " + sessionOwner.toString());

        cdmEntitySessionManager.bind(sessionOwner);

        cdmEntitySessionManager.notifyObservers();

    }

    /* (non-Javadoc)

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

     */

    @Override

    public void dispose() {

        cdmTransientEntityCacher.dispose();

        for(ICdmEntitySessionEnabled observer : changeObservers) {

            CdmPostDataChangeObservableListener.getDefault().unregister(observer);

        }

        changeObservers.clear();

        cdmEntitySessionManager.dispose(sessionOwner);

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySession#commit()

     */

    @Override

    public void addEvent(ICdmBase cdmBase, Set<CdmBase> affectedObjects, EventType eventType) {

        CdmDataChangeEvent cdce = CdmDataChangeEvent.NewInstance((CdmBase)cdmBase, affectedObjects, eventType);

        CdmPostDataChangeObservableListener.getDefault().notifyObservers(cdce);

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySession#notify(java.util.Collection, eu.etaxonomy.cdm.persistence.hibernate.CdmDataChangeEvent.EventType)

     */

    @Override

    public  <T extends ICdmBase>  void addEvent(Collection <T> cdmBases, Set<CdmBase> affectedObjects, EventType eventType) {

        for(ICdmBase cdmBase : cdmBases) {

            CdmDataChangeEvent cdce = CdmDataChangeEvent.NewInstance((CdmBase)cdmBase, affectedObjects, eventType);

            CdmPostDataChangeObservableListener.getDefault().notifyObservers(cdce);

        }

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySession#commit()

     */

    @Override

    public void fireNotifications() {

        CdmPostDataChangeObservableListener.getDefault().delayedNotify();

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySession#load(java.util.UUID, java.lang.Class)

     */

    @Override

    public  <T extends CdmBase>  T remoteLoad(IService<T> service, UUID uuid) {

        T cdmBase = service.load(uuid);

        return load(cdmBase);

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySession#load(eu.etaxonomy.cdm.api.service.IService, java.util.UUID, java.util.List)

     */

    @Override

    public <T extends CdmBase>  T remoteLoad(IService<T> service, UUID uuid, List<String> propertyPaths) {

        T cdmBase = service.load(uuid, propertyPaths);

        return load(cdmBase);

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySession#save(eu.etaxonomy.cdm.api.service.IService, eu.etaxonomy.cdm.model.common.CdmBase)

     */

    @Override

    public <T extends CdmBase> UUID remoteSave(IService<T> service, T cdmBase) {

        UUID uuid = service.save(cdmBase);

        load(cdmBase);

        return uuid;

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySession#update(eu.etaxonomy.cdm.api.service.IService, eu.etaxonomy.cdm.model.common.CdmBase)

     */

    @Override

    public <T extends CdmBase> T remoteUpdate(IService<T> service, T cdmBase) {

        debug(cdmBase);

        T mergedCdmBase = service.merge(cdmBase);

        //cdmTransientEntityCacher.clear();

        // FIXME:Remoting not really sure if we need to reload the new

        // merged object or can we keep using the old one

        //return load(mergedCdmBase);

        return mergedCdmBase;

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySession#isActive()

     */

    @Override

    public boolean isActive() {

        return cdmEntitySessionManager.getActiveSession() == this;

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySession#getOwner()

     */

    @Override

    public ICdmEntitySessionEnabled getOwner() {

        return sessionOwner;

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySession#getNoOfObjectsInCache()

     */

    @Override

    public LiveCacheStatistics getCacheStatistics() {

        return cdmTransientEntityCacher.getCacheStatistics();

    }

    /* (non-Javadoc)

     * @see eu.etaxonomy.taxeditor.session.ICdmEntitySession#getRootEntities()

     */

    @Override

    public <T extends CdmBase> List<T> getRootEntities() {

        return sessionOwner.getRootEntities();

    }

}