EDIT

/**

 *

 */

package eu.etaxonomy.taxeditor.ui.combo;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Comparator;

import java.util.List;

import org.eclipse.jface.util.PropertyChangeEvent;

import org.eclipse.swt.SWT;

import org.eclipse.swt.events.DisposeEvent;

import org.eclipse.swt.events.DisposeListener;

import org.eclipse.swt.events.SelectionEvent;

import org.eclipse.swt.events.SelectionListener;

import org.eclipse.swt.graphics.Color;

import org.eclipse.swt.widgets.Combo;

import org.eclipse.swt.widgets.Label;

import org.eclipse.swt.widgets.Listener;

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

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

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

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

import eu.etaxonomy.taxeditor.model.MessagingUtils;

import eu.etaxonomy.taxeditor.preference.PreferencesUtil;

import eu.etaxonomy.taxeditor.preference.Resources;

import eu.etaxonomy.taxeditor.store.CdmStore;

import eu.etaxonomy.taxeditor.store.StoreUtil;

import eu.etaxonomy.taxeditor.store.TermManager;

import eu.etaxonomy.taxeditor.ui.element.AbstractCdmFormElement;

import eu.etaxonomy.taxeditor.ui.element.CdmFormFactory;

import eu.etaxonomy.taxeditor.ui.element.CdmPropertyChangeEvent;

import eu.etaxonomy.taxeditor.ui.element.ICdmFormElement;

import eu.etaxonomy.taxeditor.ui.element.IEnableableFormElement;

import eu.etaxonomy.taxeditor.ui.element.ISelectable;

import eu.etaxonomy.taxeditor.ui.element.LayoutConstants;

/**

 * <p>

 * Abstract AbstractTermComboElement class.

 * </p>

 *

 * @author n.hoffmann

 * @created Nov 5, 2009

 * @version 1.0

 * @param <T>

 */

public class TermComboElement<T extends DefinedTermBase>

		extends AbstractCdmFormElement implements SelectionListener,

		DisposeListener, IEnableableFormElement, ISelectable {

	private static final int DEFAULT_VISIBLE_ITEMS = 10;

	private T selection;

	private T emptyElement;

	private static String EMPTY_ELEMENT_LABEL = "";

	protected Label label;

	private final Combo combo;

	private ArrayList<T> terms;

	private Comparator<T> termComparator;

	private final Class<T> termClass;

	private List<T> customPreferredTerms;

	private boolean addEmptyElement;

	public TermComboElement(CdmFormFactory formFactory,

			ICdmFormElement parentElement, TermType termType, String labelString, T selection, boolean addEmptyElement,

			int style) {

		this(formFactory, parentElement, null, termType, null, labelString, selection, addEmptyElement, style);

	}

	public TermComboElement(CdmFormFactory formFactory,

	        ICdmFormElement parentElement, TermVocabulary<?> termVocabulary, String labelString, T selection, boolean addEmptyElement,

	        int style) {

	    this(formFactory, parentElement, null, null, termVocabulary, labelString, selection, addEmptyElement, style);

	}

    public TermComboElement(CdmFormFactory formFactory,

            ICdmFormElement parentElement, Class<T> termClass, String labelString, T selection, boolean addEmptyElement,

            int style) {

        this(formFactory, parentElement, termClass, null, null, labelString, selection, addEmptyElement, style);

    }

	private TermComboElement(CdmFormFactory formFactory,

	        ICdmFormElement parentElement, Class<T> termClass, TermType termType, TermVocabulary<?> termVocabulary, String labelString, T selection, boolean addEmptyElement,

	        int style) {

        super(formFactory, parentElement);

        if(termClass!=null){

            this.termClass = termClass;

        }

        else{

            this.termClass =  (Class<T>) DefinedTerm.class;

        }

        this.addEmptyElement = addEmptyElement;

        if (labelString != null) {

            label = formFactory.createLabel(getLayoutComposite(), labelString);

            addControl(label);

        }

        // create combo

        combo = new Combo(getLayoutComposite(), SWT.BORDER | SWT.READ_ONLY );//FIXME: removed this parameter seems break windows version: | style

        addControl(combo);

        combo.setLayoutData(LayoutConstants.FILL_HORIZONTALLY());

        combo.setVisibleItemCount(DEFAULT_VISIBLE_ITEMS);

        if(termType!=null){

            //TODO try to remove generic T and avoid classes to be used

            populateTerms((List<T>) getTermManager().getPreferredTerms(termType));

        }

        else if(termVocabulary!=null){

            populateTerms((List<T>) getTermManager().getPreferredTerms(termVocabulary));

        }

        else if(this.termClass!=null){

            populateTerms(getPreferredTerms());

        }

        combo.addSelectionListener(this);

        combo.addDisposeListener(this);

        PreferencesUtil.getPreferenceStore().addPropertyChangeListener(this);

        if (selection != null) {

            setSelection(selection);

        }

	}

	/**

	 * <p>

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

	 * </p>

	 *

	 * @return a T object.

	 */

	public T getSelection() {

		return selection;

	}

	/**

	 * <p>Sets the selection of the combo to the given T object.</p>

	 * <p>Passing <code>null</code> to this method will set the selection to

	 * the empty element and effectively clear the selection</p>

	 *

	 * @param selection

	 *            a T object or <code>null</code> to clear the selection

	 */

	public void setSelection(T selection) {

		this.selection = selection;

		this.selection = selection;

		Listener[] listeners = combo.getListeners(SWT.Selection);

		for (Listener listener : listeners) {

			combo.removeListener(SWT.Selection, listener);

		}

		int selectedIndex;

		if(selection == null){

			// set selection to the emptyElement

			selectedIndex = 0;

		}else{

			selectedIndex = terms.indexOf(selection);

			if (selectedIndex == -1) {

				createTermNotInPreferredTerms(selection);

				selectedIndex = terms.indexOf(selection);

			}

		}

		combo.select(selectedIndex);

		for (Listener listener : listeners) {

			combo.addListener(SWT.Selection, listener);

		}

	}

	/**

	 * Fills the combo with elements and sets up the convenience functions

	 * for selection index

	 *

	 * @param preferredTerms

	 */

	private void populateTerms(List<T> preferredTerms) {

		combo.removeAll();

		terms = new ArrayList<T>();

		int i = 1;

		int index = 0;

		if(addEmptyElement){

		    // Add an empty element for when nothing was selected yet

		    combo.add(EMPTY_ELEMENT_LABEL);

		    terms.add(emptyElement);

		}

		if (termComparator != null) {

			Collections.sort(preferredTerms, termComparator);

		}

		for (T term : preferredTerms) {

			String label = getLabel(term);

			if (label == null) {

				if (term.getTitleCache() != null) {

					label = term.getTitleCache();

					MessagingUtils.warn(getClass(),

							"Term does not have a default language representation: " + label

									+ ", " + term.getUuid());

				} else {

					label = "Unknown";

					MessagingUtils.warn(getClass(),

							"Representation Label and TitleCache empty for term: "

									+ term + ", " + term.getUuid());

				}

			}

			combo.add(label);

			terms.add(term);

			i++;

			if (selection != null) {

				if (selection.equals(term)) {

					index = i;

				}

			}

		}

		if (selection != null && index == 0) {

			createTermNotInPreferredTerms(selection);

		}

		combo.select(index);

	}

	/*

	 * (non-Javadoc)

	 * @see eu.etaxonomy.taxeditor.forms.IEnableableFormElement#setEnabled(boolean)

	 */

	/** {@inheritDoc} */

	@Override

    public void setEnabled(boolean enabled) {

		combo.setEnabled(enabled);

	}

	/* (non-Javadoc)

	 * @see eu.etaxonomy.taxeditor.ui.element.IEnableableFormElement#isEnabled()

	 */

	@Override

	public boolean isEnabled() {

	    return combo.isEnabled();

	}

	/**

	 * <p>

	 * preferredTerms

	 * </p>

	 *

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

	 */

	protected List<T> getPreferredTerms(){

		if (customPreferredTerms != null){

			return customPreferredTerms;

		}

		return getTermManager().getPreferredTerms(termClass);

	}

	/**

	 * May be overridden by derived classes if the desired label string does not

	 * reside in term.getLabel();

	 *

	 * @param term

	 *            a T object.

	 * @return a {@link java.lang.String} object.

	 */

	protected String getLabel(T term) {

		if (term == null){

			return "";

		}else{

			return term.getLabel(CdmStore.getDefaultLanguage());

		}

	}

	/**

	 *

	 *

	 * @param term

	 */

	private void createTermNotInPreferredTerms(T term) {

		List<T> preferredTerms = getPreferredTerms();

		preferredTerms.add(term);

		populateTerms(preferredTerms);

	}

	/**

	 * <p>

	 * addSelectionListener

	 * </p>

	 *

	 * @param listener

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

	 */

	public void addSelectionListener(SelectionListener listener) {

		combo.addSelectionListener(listener);

	}

	/**

	 * <p>

	 * removeSelectionListener

	 * </p>

	 *

	 * @param listener

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

	 */

	public void removeSelectionListener(SelectionListener listener) {

		combo.removeSelectionListener(listener);

	}

	/*

	 * (non-Javadoc)

	 *

	 * @see

	 * org.eclipse.swt.events.SelectionListener#widgetSelected(org.eclipse.swt

	 * .events.SelectionEvent)

	 */

	/** {@inheritDoc} */

	@Override

    public void widgetSelected(SelectionEvent e) {

		selection = terms.get(combo.getSelectionIndex());

		firePropertyChangeEvent(new CdmPropertyChangeEvent(this, e));

	}

	/*

	 * (non-Javadoc)

	 *

	 * @see java.beans.PropertyChangeListener#propertyChange(java.beans.

	 * PropertyChangeEvent)

	 */

	/** {@inheritDoc} */

	@Override

    public void propertyChange(PropertyChangeEvent event) {

		super.propertyChange(event);

		if (event != null

				&& PreferencesUtil.PREFERRED_TERMS_CHANGE.equals(event

						.getProperty())) {

			populateTerms(getPreferredTerms());

		}

	}

	/** {@inheritDoc} */

	@Override

    public void setSelected(boolean selected) {

		setBackground(selected ? SELECTED : getPersistentBackground());

	}

	/** {@inheritDoc} */

	@Override

    public void widgetDisposed(DisposeEvent e) {

		PreferencesUtil.getPreferenceStore().removePropertyChangeListener(this);

	}

	// not used

	/** {@inheritDoc} */

	@Override

    public void widgetDefaultSelected(SelectionEvent e) {

	}

	/** {@inheritDoc} */

	@Override

    public void setIrrelevant(boolean irrelevant) {

		String colorId = irrelevant ? Resources.COLOR_COMPOSITE_IRRELEVANT

				: Resources.COLOR_COMPOSITE_BACKGROUND;

		Color color = StoreUtil.getColor(colorId);

		combo.setBackground(color);

	}

	/** {@inheritDoc} */

	@Override

	public void setBackground(Color color) {

		if (label != null) {

            label.setBackground(color);

        }

	}

	/**

	 *

	 */

	protected TermManager getTermManager() {

		return CdmStore.getTermManager();

	}

	/**

	 *

	 * @return

	 */

	public int getVisibleItemCount(){

		return combo.getVisibleItemCount();

	}

	/**

	 *

	 * @param count

	 */

	public void setVisibleItemCount(int count){

		combo.setVisibleItemCount(count);

	}

	/**

	 * <p>A {@link List} of term objects may be passed to this combo box. In this case, the default behaviour

	 * of displaying the preferred terms for the T type will be overridden and the combo will only display the

	 * given terms. Also, any previous selection will be reseted.</p>

	 *

	 * <p>To return to the default of displaying the preferred terms, simply pass <code>null</code>.</p>

	 *

	 * @param terms a {@link List} of T objects or <code>null</code> for default preferred terms

	 */

	public void setTerms(List<T> terms) {

		setSelection(null);

		customPreferredTerms = terms;

		populateTerms(customPreferredTerms);

	}

}