EDIT

/**

 *

 */

package eu.etaxonomy.taxeditor.ui.combo;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collections;

import java.util.Comparator;

import java.util.List;

import org.apache.commons.lang.StringUtils;

import org.eclipse.jface.util.PropertyChangeEvent;

import org.eclipse.swt.SWT;

import org.eclipse.swt.events.SelectionEvent;

import org.eclipse.swt.widgets.Listener;

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

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

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

import eu.etaxonomy.taxeditor.model.MessagingUtils;

import eu.etaxonomy.taxeditor.preference.IPreferenceKeys;

import eu.etaxonomy.taxeditor.preference.PreferencesUtil;

import eu.etaxonomy.taxeditor.store.CdmStore;

import eu.etaxonomy.taxeditor.store.TermManager;

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

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

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

/**

 * @author n.hoffmann

 * @created Nov 5, 2009

 * @version 1.0

 * @param <T>

 */

public class TermComboElement<T extends DefinedTermBase>

		extends AbstractComboElement<T> {

	private T emptyElement;

	private static String EMPTY_ELEMENT_LABEL = "";

	private ArrayList<T> terms;

	private Comparator<T> termComparator;

	public Comparator<T> getTermComparator() {

		return termComparator;

	}

	public void setTermComparator(Comparator<T> termComparator) {

		this.termComparator = termComparator;

		List<T> termsWithoutNull = terms.subList(1, terms.size());

		populateTerms(termsWithoutNull);

	}

	private final TermType termType;

	private final TermVocabulary termVocabulary;

	private final Class<T> termClass;

	private List<T> customPreferredTerms;

	private boolean useAbbrevLabel = false;

	private boolean addEmptyElement;

	public TermComboElement(CdmFormFactory formFactory,

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

			int style, boolean useAbbrevLabel, Comparator<T> comparator) {

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

	}

	public TermComboElement(CdmFormFactory formFactory,

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

	        int style, boolean useAbbrevLabel, Comparator<T> comparator) {

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

	}

    public TermComboElement(CdmFormFactory formFactory,

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

            int style) {

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

    }

    public TermComboElement(CdmFormFactory formFactory,

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

            int style, boolean useAbbrevLabel) {

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

    }

    public TermComboElement(CdmFormFactory formFactory,

            ICdmFormElement parentElement, List<T> terms, String labelString, T selection, boolean addEmptyElement,

            int style, boolean useAbbrevLabel) {

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

    }

	private TermComboElement(CdmFormFactory formFactory,

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

	        int style, boolean useAbbrevLabel, Comparator<T> comparator) {

        super(formFactory, parentElement);

        this.termType = termType;

        this.termVocabulary = termVocabulary;

        this.termClass = termClass;

        this.addEmptyElement = addEmptyElement;

        this.useAbbrevLabel = useAbbrevLabel;

        this.termComparator = comparator;

        if (labelString != null) {

            label.setText(labelString);

        }

        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());

        }else if (terms != null){

            populateTerms(terms);

        }

        combo.addSelectionListener(this);

        combo.addDisposeListener(this);

        PreferencesUtil.getPreferenceStore().addPropertyChangeListener(this);

        if (selection != null) {

            setSelection(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

	 */

	@Override

    public void setSelection(T 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

	 */

	protected 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);

	}

	protected List<T> getPreferredTerms(){

	    List<T> preferredTerms = new ArrayList<T>();

		if (customPreferredTerms != null){

			return customPreferredTerms;

		}

		else if(termType!=null){

		    preferredTerms = getTermManager().getPreferredTerms(termType);

		}

		else if(termVocabulary!=null){

		    preferredTerms = getTermManager().getPreferredTerms(termVocabulary);

		}

		if(termClass!=null){

		    preferredTerms = getTermManager().getPreferredTerms(termClass);

		}

		return preferredTerms;

	}

	/**

	 * 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{

			String termLabel = null;

			if (useAbbrevLabel){

			    if (!StringUtils.isBlank(term.getIdInVocabulary())){

			        termLabel = term.getIdInVocabulary();

			    }

			}

			if (termLabel == null){

				termLabel = term.getLabel(CdmStore.getDefaultLanguage());

			}

			if (termLabel == null){

			    termLabel = term.getLabel();

			}

			if(PreferencesUtil.getBooleanValue(IPreferenceKeys.SHOW_VOCABULARY_ID_FOR_TERM_LABELS)

			    && term.getVocabulary()!=null){

			    String vocLabel = term.getVocabulary().getLabel(CdmStore.getDefaultLanguage());

			    if (vocLabel == null){

			        vocLabel = term.getVocabulary().getLabel();

			    }

			    termLabel += " ["+vocLabel+"]";

			}

            return termLabel;

		}

	}

	/**

	 *

	 *

	 * @param term

	 */

	private void createTermNotInPreferredTerms(T term) {

		List<T> preferredTerms = getPreferredTerms();

		preferredTerms.add(term);

		populateTerms(preferredTerms);

	}

	/** {@inheritDoc} */

	@Override

    public void widgetSelected(SelectionEvent e) {

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

		firePropertyChangeEvent(new CdmPropertyChangeEvent(this, e));

	}

	/** {@inheritDoc} */

	@Override

    public void propertyChange(PropertyChangeEvent event) {

		super.propertyChange(event);

		if (event != null

				&& PreferencesUtil.PREFERRED_TERMS_CHANGE.equals(event

						.getProperty())) {

			populateTerms(getPreferredTerms());

		}

	}

	protected TermManager getTermManager() {

		return CdmStore.getTermManager();

	}

	public int getVisibleItemCount(){

		return combo.getVisibleItemCount();

	}

	/**

	 * <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);

	}

	public void removeEmptyElement(){

	    if(addEmptyElement){

	        if(terms.contains(emptyElement)){

	            terms.remove(emptyElement);

	        }

	        if(Arrays.asList(combo.getItems()).contains(EMPTY_ELEMENT_LABEL)){

	            combo.remove(EMPTY_ELEMENT_LABEL);

	        }

	    }

	}

}