EDIT

/**

* Copyright (C) 2017 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.vaadin.mvp;

import java.util.ArrayList;

import java.util.Collection;

import java.util.EnumSet;

import org.apache.log4j.Logger;

import org.hibernate.HibernateException;

import org.springframework.context.event.EventListener;

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

import eu.etaxonomy.cdm.cache.CdmTransientEntityCacher;

import eu.etaxonomy.cdm.debug.PersistentContextAnalyzer;

import eu.etaxonomy.cdm.model.ICdmCacher;

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

import eu.etaxonomy.cdm.persistence.hibernate.permission.CRUD;

import eu.etaxonomy.cdm.persistence.hibernate.permission.CdmAuthority;

import eu.etaxonomy.cdm.service.CdmStore;

import eu.etaxonomy.cdm.vaadin.event.EntityChangeEvent;

import eu.etaxonomy.cdm.vaadin.security.UserHelper;

import eu.etaxonomy.cdm.vaadin.view.name.CachingPresenter;

import eu.etaxonomy.vaadin.mvp.event.EditorPreSaveEvent;

import eu.etaxonomy.vaadin.mvp.event.EditorSaveEvent;

/**

 * Provides generic save operations of modified cdm entities.

 *

 * @author a.kohlbecker

 * @since Apr 5, 2017

 *

 */

public abstract class AbstractCdmEditorPresenter<DTO extends CdmBase, V extends ApplicationView<?>> extends AbstractEditorPresenter<DTO, V>

    implements CachingPresenter {

    private static final long serialVersionUID = 2218185546277084261L;

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

    /**

     * if not null, this CRUD set is to be used to create a CdmAuthoritiy for the base entity which will be

     * granted to the current use as long this grant is not assigned yet.

     */

    protected EnumSet<CRUD> crud = null;

    private ICdmCacher cache = new CdmTransientEntityCacher(this);

    private java.util.Collection<CdmBase> rootEntities = new ArrayList<>();

    public AbstractCdmEditorPresenter() {

        super();

        logger.trace(this._toString() + " constructor");

    }

    CdmStore<DTO, IService<DTO>> store ;

    protected CdmAuthority newAuthorityCreated;

    protected CdmStore<DTO, IService<DTO>> getStore() {

        if(store == null){

            store = new CdmStore<>(getRepo(), getService());

        }

        return store;

    }

    @Override

    protected DTO loadBeanById(Object identifier) {

        DTO cdmEntitiy;

        if(identifier != null) {

            Integer integerID = (Integer)identifier;

            // CdmAuthority is needed before the bean is loaded into the session.

            // otherwise adding the authority to the user would cause a flush

            guaranteePerEntityCRUDPermissions(integerID);

            cdmEntitiy = loadCdmEntityById(integerID);

        } else {

            cdmEntitiy = loadCdmEntityById(null);

            if(cdmEntitiy != null){

                guaranteePerEntityCRUDPermissions(cdmEntitiy);

            }

        }

        cache.put(cdmEntitiy);

        rootEntities.add(cdmEntitiy);

        return cdmEntitiy;

    }

    /**

     * @param identifier

     * @return

     */

    protected abstract DTO loadCdmEntityById(Integer identifier);

    /**

     * Grant per entity CdmAuthority to the current user <b>for the bean which is not yet loaded</b>

     * into the editor. The <code>CRUD</code> to be granted are stored in the <code>crud</code> field.

     */

    protected abstract void guaranteePerEntityCRUDPermissions(Integer identifier);

    /**

     * Grant per entity CdmAuthority to the current user for the bean which is loaded

     * into the editor. The <code>CRUD</code> to be granted are stored in the <code>crud</code> field.

     */

     protected abstract void guaranteePerEntityCRUDPermissions(DTO bean);

    /**

     * @return

     */

    protected abstract IService<DTO> getService();

    @SuppressWarnings("unchecked")

    @Override

    @EventListener // the generic type parameter <DTO> must not be used here otherwise events will not be received

    public void onEditorPreSaveEvent(EditorPreSaveEvent preSaveEvent){

        if(!isFromOwnView(preSaveEvent)){

            return;

        }

        super.onEditorPreSaveEvent(preSaveEvent);

    }

    @SuppressWarnings("unchecked")

    @Override

    @EventListener // the generic type parameter <DTO> must not be used here otherwise events will not be received

    public void onEditorSaveEvent(EditorSaveEvent saveEvent){

        if(!isFromOwnView(saveEvent)){

            return;

        }

        // the bean is now updated with the changes made by the user

        DTO bean = (DTO) saveEvent.getBean();

        if(logger.isTraceEnabled()){

            PersistentContextAnalyzer pca = new PersistentContextAnalyzer(bean);

            pca.printEntityGraph(System.err);

            pca.printCopyEntities(System.err);

        }

        bean = handleTransientProperties(bean);

        if(logger.isTraceEnabled()){

            PersistentContextAnalyzer pca = new PersistentContextAnalyzer(bean);

            pca.printEntityGraph(System.err);

            pca.printCopyEntities(System.err);

        }

        try {

            EntityChangeEvent changeEvent = getStore().saveBean(bean);

            if(changeEvent != null){

                eventBus.publishEvent(changeEvent);

            }

        } catch (HibernateException e){

            if(newAuthorityCreated != null){

                UserHelper.fromSession().removeAuthorityForCurrentUser(newAuthorityCreated);

            }

        }

    }

    /**

     * EditorPresneters for beans with transient properties should overwrite this method to

     * update the beanItem with the changes made to the transient properties.

     * <p>

     * This is necessary because Vaadin MethodProperties are readonly when no setter is

     * available. This can be the case with transient properties. Automatic updating

     * of the property during the fieldGroup commit does not work in this case.

     *

     * @deprecated editors should operate on DTOs instead, remove this method if unused.

     */

    @Deprecated

    protected DTO handleTransientProperties(DTO bean) {

        // no need to handle transient properties in the generic case

        return bean;

    }

//    @Override

//    protected DTO prepareAsFieldGroupDataSource(DTO bean){

//        DTO mergedBean = getStore().mergedBean(bean);

//        // DTO mergedBean = bean;

//        return mergedBean;

//    }

    /**

     * If the bean is contained in the session it is being updated by

     * doing an evict and merge. The fieldGroup is updated with the merged bean.

     *

     * @param bean

     *

     * @return The bean merged to the session or original bean in case a merge was not necessary.

     */

    private DTO mergedBean(DTO bean) {

        DTO mergedBean = getStore().mergedBean(bean);

        ((AbstractPopupEditor<DTO, AbstractCdmEditorPresenter<DTO, V>>)getView()).updateItemDataSource(mergedBean);

        return mergedBean;

    }

    @Override

    protected

    final void saveBean(DTO bean){

        // blank implementation, since this is not needed in this or any sub class

        // see onEditorSaveEvent() instead

    }

    @Override

    protected final void deleteBean(DTO bean){

        EntityChangeEvent changeEvent = getStore().deleteBean(bean);

        if(changeEvent != null){

            eventBus.publishEvent(changeEvent);

        }

    }

    /**

     * @param crud

     */

    public void setGrantsForCurrentUser(EnumSet<CRUD> crud) {

        this.crud = crud;

    }

    /**

     * {@inheritDoc}

     */

    @Override

    public ICdmCacher getCache() {

        return cache;

    }

    /**

     * {@inheritDoc}

     */

    @Override

    public Collection<CdmBase> getRootEntities() {

        return rootEntities;

    }

    /**

     * Returns true only after the view method {@link AbstractPopupEditor#loadInEditor()}

     * has completed.

     *

     */

    @Override

    public boolean isCacheInitialized() {

        return ((AbstractPopupEditor)getView()).isBeanLoaded();

    }

}