EDIT

/**

 *

 */

package eu.etaxonomy.taxeditor.ui.element;

import java.util.ConcurrentModificationException;

import java.util.HashSet;

import java.util.Iterator;

import java.util.List;

import java.util.Set;

import org.eclipse.core.runtime.Assert;

import org.eclipse.jface.util.IPropertyChangeListener;

import org.eclipse.jface.util.PropertyChangeEvent;

import org.eclipse.jface.viewers.ISelectionChangedListener;

import org.eclipse.jface.viewers.ISelectionProvider;

import org.eclipse.jface.viewers.IStructuredSelection;

import org.eclipse.jface.viewers.SelectionChangedEvent;

import org.eclipse.jface.viewers.StructuredSelection;

import org.eclipse.swt.SWT;

import org.eclipse.swt.events.SelectionEvent;

import org.eclipse.swt.events.SelectionListener;

import org.eclipse.swt.graphics.Color;

import org.eclipse.swt.widgets.Composite;

import org.eclipse.swt.widgets.Control;

import org.eclipse.swt.widgets.Display;

import org.eclipse.swt.widgets.TypedListener;

import org.eclipse.swt.widgets.Widget;

import org.eclipse.ui.forms.events.ExpansionEvent;

import org.eclipse.ui.forms.events.IExpansionListener;

import org.eclipse.ui.forms.widgets.Section;

import org.eclipse.ui.forms.widgets.TableWrapLayout;

import org.eclipse.ui.forms.widgets.ToggleHyperlink;

import eu.etaxonomy.cdm.api.conversation.ConversationHolder;

import eu.etaxonomy.cdm.api.conversation.IConversationEnabled;

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

import eu.etaxonomy.taxeditor.model.AbstractUtility;

import eu.etaxonomy.taxeditor.model.MessagingUtils;

import eu.etaxonomy.taxeditor.preference.PreferencesUtil;

/**

 * <p>

 * Abstract super class for a {@link Section} GUI element that visualizes a CDM

 * entity, manages a conversation and listens to selections

 * </p>

 *

 * @param <ENTITY> A CDM entity which should be visualized by this section.

 *

 * @author n.hoffmann

 * @created Feb 22, 2010

 * @param <T>

 */

//TODO shouldn't ENTITY be bound with super class ICdmBase for example (AbstractFormSection<ENTITY extends ICdmBase>)?

public abstract class AbstractFormSection<ENTITY> extends Section implements ISelectionChangedListener, IEntityElement<ENTITY>, IConversationEnabled {

    /**

     * The default number of columns in detail sections

     */

    public static final int DEFAULT_NUM_COLUMNS = 2;

	private ISelectionProvider selectionProvider;

	private ENTITY entity;

	private final Set<ICdmFormElement> elements = new HashSet<>();

	protected CdmFormFactory formFactory;

	private List<IPropertyChangeListener> propertyChangeListeners;

	private ICdmFormElement parentElement;

	private Color persistentBackgroundColor;

	/**

	 * <p>

	 * Constructor for AbstractFormSection.

	 * </p>

	 *

	 * @param conversation

	 *            TODO

	 * @param style

	 *            a int.

	 * @param formFactory

	 *            a {@link eu.etaxonomy.taxeditor.ui.element.CdmFormFactory}

	 *            object.

	 * @param parentElement

	 *            a {@link eu.etaxonomy.taxeditor.ui.element.ICdmFormElement}

	 *            object.

	 * @param <ENTITY>

	 *            a ENTITY object.

	 */

    protected AbstractFormSection(CdmFormFactory formFactory, ICdmFormElement parentElement, int style) {

		super(parentElement.getLayoutComposite(), style);

		this.parentElement = parentElement;

		this.formFactory = formFactory;

		this.setLayoutData(LayoutConstants.FILL());

		Composite client = formFactory.createComposite(this, SWT.WRAP);

		client.setBackgroundMode(SWT.INHERIT_DEFAULT);

		TableWrapLayout layout = LayoutConstants.LAYOUT();

		layout.bottomMargin = 10;

		layout.rightMargin = 5;

		layout.horizontalSpacing = 5;

		client.setLayout(layout);

		this.setClient(client);

	}

	    /**

     * <p>

     * Constructor for AbstractFormSection.

     * </p>

     *

     * @param formFactory

     *            a {@link eu.etaxonomy.taxeditor.ui.element.CdmFormFactory}

     *            object.

     * @param conversation

     *            a {@link eu.etaxonomy.cdm.api.conversation.ConversationHolder}

     *            object.

     * @param parentElement

     *            a {@link eu.etaxonomy.taxeditor.ui.element.ICdmFormElement}

     *            object.

     * @param selectionProvider

     *            a {@link org.eclipse.jface.viewers.ISelectionProvider} object.

     * @param style

     *            a int.

     */

    protected AbstractFormSection(CdmFormFactory formFactory, ICdmFormElement parentElement, ISelectionProvider selectionProvider, int style) {

        this(formFactory, parentElement, style);

        this.selectionProvider = selectionProvider;

    }

	/**

	 * <p>

	 * Getter for the field <code>propertyChangeListeners</code>.

	 * </p>

	 *

	 * @return a {@link java.util.Set} object.

	 */

	@Override

    public List<IPropertyChangeListener> getPropertyChangeListeners() {

		return propertyChangeListeners;

	}

	/** {@inheritDoc} */

	@Override

    public void setPropertyChangeListeners(

			List<IPropertyChangeListener> propertyChangeListeners) {

		this.propertyChangeListeners = propertyChangeListeners;

	}

	/**

	 * <p>

	 * Setter for the field <code>entity</code>.

	 * </p>

	 *

	 * @param entity

	 *            a ENTITY object.

	 */

	public void setEntity(ENTITY entity) {

		this.entity = entity;

		addExpandListener();

	}

	/**

	 * <p>

	 * Getter for the field <code>entity</code>.

	 * </p>

	 *

	 * @return a ENTITY object.

	 */

	@Override

    public ENTITY getEntity() {

		return entity;

	}

	/**

	 * <p>

	 * getToggle

	 * </p>

	 *

	 * @return a {@link org.eclipse.ui.forms.widgets.ToggleHyperlink} object.

	 */

	public ToggleHyperlink getToggle() {

		return this.toggle;

	}

	/**

	 * <p>

	 * getSection

	 * </p>

	 *

	 * @return a {@link eu.etaxonomy.taxeditor.ui.element.AbstractFormSection}

	 *         object.

	 */

	public AbstractFormSection<ENTITY> getSection() {

		return this;

	}

	/*

	 * (non-Javadoc)

	 *

	 * @see

	 * eu.etaxonomy.taxeditor.forms.IPropertyChangeEmitter#firePropertyChangeEvent

	 * ()

	 */

	/** {@inheritDoc} */

	@Override

    public void firePropertyChangeEvent(CdmPropertyChangeEvent event) {

        Assert.isNotNull(propertyChangeListeners, "No property change listeners.");

        try {

            for (Object listener : propertyChangeListeners) {

                ((IPropertyChangeListener) listener).propertyChange(event);

            }

        } catch (ConcurrentModificationException e) {

            MessagingUtils.warn(getClass(), "ConcurrentModificationException while handling PropertyChangeEvents."

                    + " It seems like this is not critical");

        }

	}

	/**

	 * Fires a {@link CdmPropertyChangeEvent} with the given object as source.

	 *

	 * @param object

	 *            the object on which the property changed

	 */

	public void firePropertyChangeEvent(Object object) {

		firePropertyChangeEvent(object, null);

	}

	/**

	 * Fires a {@link CdmPropertyChangeEvent} with the given object as source

	 * also containing the originating event

	 *

	 * @param object

	 *            the object on which the property changed

	 * @param originatingEvent

	 *            the originating event

	 */

	public void firePropertyChangeEvent(Object object,

			PropertyChangeEvent originatingEvent) {

		firePropertyChangeEvent(new CdmPropertyChangeEvent(object,

				originatingEvent));

	}

	/*

	 * (non-Javadoc)

	 *

	 * @see org.eclipse.swt.widgets.Composite#setFocus()

	 */

	/** {@inheritDoc} */

	@Override

	public boolean setFocus() {

		return getClient().setFocus();

	}

	/*

	 * (non-Javadoc)

	 *

	 * @see

	 * org.eclipse.jface.util.IPropertyChangeListener#propertyChange(org.eclipse

	 * .jface.util.PropertyChangeEvent)

	 */

	/** {@inheritDoc} */

	@Override

    public void propertyChange(PropertyChangeEvent event) {

		firePropertyChangeEvent(new CdmPropertyChangeEvent(this, event));

	}

	/*

	 * (non-Javadoc)

	 *

	 * @see

	 * org.eclipse.swt.widgets.Control#setBackground(org.eclipse.swt.graphics

	 * .Color)

	 */

	/** {@inheritDoc} */

	@Override

	public void setBackground(Color color) {

		for (ICdmFormElement element : getElements()) {

			element.setBackground(color);

		}

		getLayoutComposite().setBackground(color);

		super.setBackground(color);

	}

	@Override

	public void setPersistentBackground(Color color) {

		persistentBackgroundColor = color;

		setBackground(color);

	}

	@Override

	public Color getPersistentBackground() {

		return persistentBackgroundColor;

	}

	/**

	 * <p>

	 * widgetSelected

	 * </p>

	 *

	 * @param e

	 *            a {@link org.eclipse.swt.events.SelectionEvent} object.

	 */

	public void widgetSelected(SelectionEvent e) {

        Widget widget = e.widget;

        if (widget instanceof Control) {

            Control control = (Control) widget;

            if (checkControlAncestryForWidget(control)) {

                if (getEntity() != null) {

                    IStructuredSelection selection = new StructuredSelection(getEntity());

                    if (selectionProvider != null) {

                        selectionProvider.setSelection(selection);

                    }

                }

            }

        }

	}

	private boolean checkControlAncestryForWidget(Control control) {

		if (control.equals(this)) {

			return true;

		} else {

			Control parent = control.getParent();

			if (parent == null) {

				return false;

			} else {

				return checkControlAncestryForWidget(parent);

			}

		}

	}

	/** {@inheritDoc} */

	@Override

    public void setSelected(boolean selected) {

		if (selected) {

			setBackground(Display.getCurrent().getSystemColor(

					SWT.COLOR_LIST_SELECTION));

		} else {

			setBackground(Display.getCurrent().getSystemColor(SWT.COLOR_WHITE));

		}

	}

	/** {@inheritDoc} */

	@Override

    public void selectionChanged(SelectionChangedEvent event) {

		if (event.getSelection() == CdmFormFactory.EMPTY_SELECTION) {

			return;

		}

		IStructuredSelection selection = (IStructuredSelection) event

				.getSelection();

		setSelected(false);

		Object selectedObject = selection.getFirstElement();

		if (selectedObject != null && selectedObject.equals(getEntity())) {

			setSelected(true);

		}

	}

	/**

	 * <p>

	 * addSelectionListener

	 * </p>

	 *

	 * @param listener

	 *            a {@link org.eclipse.swt.events.SelectionListener} object.

	 */

	public void addSelectionListener(SelectionListener listener) {

		addListener(SWT.Selection, new TypedListener(listener));

	}

	/**

	 * <p>

	 * removeSelectionListener

	 * </p>

	 *

	 * @param listener

	 *            a {@link org.eclipse.swt.events.SelectionListener} object.

	 */

	public void removeSelectionListener(SelectionListener listener) {

		removeListener(SWT.Selection, listener);

	}

	/** {@inheritDoc} */

	@Override

    public void addElement(ICdmFormElement element) {

		elements.add(element);

	}

	/**

	 * <p>

	 * removeElement

	 * </p>

	 *

	 * @param element

	 *            a {@link eu.etaxonomy.taxeditor.ui.element.ICdmFormElement}

	 *            object.

	 */

	protected void removeElement(ICdmFormElement element) {

		elements.remove(element);

	}

	/**

	 * <p>

	 * removeElements

	 * </p>

	 */

	@Override

    public void removeElements() {

		for (Iterator<ICdmFormElement> formElementIterator = getElements().iterator();formElementIterator.hasNext();) {

		    ICdmFormElement childElement = formElementIterator.next();

			// recursion

			childElement.removeElements();

			// unregister selection arbitrator

			if (childElement instanceof ISelectableElement) {

				ISelectableElement selectableElement = (ISelectableElement) childElement;

				if (selectableElement.getSelectionArbitrator() != null) {

					formFactory.destroySelectionArbitrator(selectableElement

							.getSelectionArbitrator());

				}

			}

			// unregister propertyChangeListener

			formFactory.removePropertyChangeListener(childElement);

			// dispose of the controls

			for (Iterator<Control> controlIterator = childElement.getControls().iterator();controlIterator.hasNext();) {

			    Control control = controlIterator.next();

				// we added the layoutComposite of the parental element as the

				// layout composite to this formElement

				// but we do not want to destroy it.

				if (control.equals(childElement.getLayoutComposite())) {

					continue;

				} else {

					control.dispose();

					control = null;

				}

			}

		}

		elements.clear();

	}

	/**

	 * <p>

	 * Getter for the field <code>parentElement</code>.

	 * </p>

	 *

	 * @return a {@link eu.etaxonomy.taxeditor.ui.element.ICdmFormElement} object.

	 */

	@Override

    public ICdmFormElement getParentElement() {

		return parentElement;

	}

	/**

	 * <p>

	 * Getter for the field <code>elements</code>.

	 * </p>

	 *

	 * @return a {@link java.util.Set} object.

	 */

	@Override

    public Set<ICdmFormElement> getElements() {

		return elements;

	}

	/**

	 * <p>

	 * getControls

	 * </p>

	 *

	 * @return a {@link java.util.Set} object.

	 */

	@Override

    public Set<Control> getControls() {

		Set<Control> controls = new HashSet<>();

		for (Control control : getChildren()) {

			controls.add(control);

		}

		return controls;

	}

	/** {@inheritDoc} */

	@Override

	public void dispose() {

		removeElements();

		super.dispose();

	}

	/**

	 * <p>

	 * getLayoutComposite

	 * </p>

	 *

	 * @return a {@link org.eclipse.swt.widgets.Composite} object.

	 */

	@Override

    public Composite getLayoutComposite() {

		return (Composite) getClient();

	}

	/** {@inheritDoc} */

	@Override

    public boolean containsFormElement(ICdmFormElement formElement) {

		if (formElement == this) {

			return true;

		} else {

			for (ICdmFormElement element : getElements()) {

				boolean contains = element.containsFormElement(formElement);

				if (contains == true) {

					return true;

				}

			}

			return false;

		}

	}

	/**

	 * <p>

	 * Getter for the field <code>formFactory</code>.

	 * </p>

	 *

	 * @return a {@link eu.etaxonomy.taxeditor.ui.element.CdmFormFactory} object.

	 */

	@Override

    public CdmFormFactory getFormFactory() {

		return formFactory;

	}

	/*

	 * (non-Javadoc)

	 *

	 * @see eu.etaxonomy.taxeditor.forms.ICdmFormElement#refresh()

	 */

	@Override

    public void refresh() {

		// empty default implementation

	}

	/**

	 * <p>

	 * getConversationHolder

	 * </p>

	 *

	 * @return a {@link eu.etaxonomy.cdm.api.conversation.ConversationHolder}

	 *         object.

	 */

	@Override

    public ConversationHolder getConversationHolder() {

	    if(AbstractUtility.getActivePart() instanceof IConversationEnabled){

            return ((IConversationEnabled) AbstractUtility.getActivePart()).getConversationHolder();

        }

	    if(getParentElement() instanceof RootElement || getParentElement() == null){

	        Object activeEditor = AbstractUtility.getActiveEditor();

	        if(activeEditor instanceof IConversationEnabled){

	            ConversationHolder conversation = ((IConversationEnabled) AbstractUtility.getActiveEditor()).getConversationHolder();

	            return conversation;

	        }

	    }else if(getParentElement() instanceof IConversationEnabled){

	        return ((IConversationEnabled) getParentElement()).getConversationHolder();

	    }

		MessagingUtils.error(getClass(), "Could not get conversation for AbstractFormSection. There is an error in the implementation. There should have been an active editor but it wasn't",

				new IllegalArgumentException());

		return null;

	}

	/** {@inheritDoc} */

	@Override

    public void update(CdmDataChangeMap changeEvents) {

	}

    public class ExpandListener implements IExpansionListener{

		@Override

		public void expansionStateChanging(ExpansionEvent e) {

		}

		@Override

		public void expansionStateChanged(ExpansionEvent e) {

			PreferencesUtil.getPreferenceStore().setValue(getPrefKey(), e.getState());

		}

    }

    /**

     * Adds a custom implementation of IExpansionListener to this section

     * which stores the expansion state in the preferences

     */

	protected void addExpandListener() {

		PreferencesUtil.getPreferenceStore().setDefault(getPrefKey(), isExpanded());

		setExpanded(PreferencesUtil.getPreferenceStore().getBoolean(getPrefKey()));

		addExpansionListener(new ExpandListener());

	}

	private String getPrefKey() {

		return this.getClass().getCanonicalName()+";"+entity.getClass().getCanonicalName();

	}

}