EDIT

/**

* Copyright (C) 2016 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.ui.combo;

import java.util.ArrayList;

import java.util.Collections;

import org.eclipse.equinox.internal.p2.ui.misc.StringMatcher;

import org.eclipse.jface.fieldassist.ComboContentAdapter;

import org.eclipse.jface.fieldassist.ContentProposalAdapter;

import org.eclipse.jface.fieldassist.IContentProposal;

import org.eclipse.jface.fieldassist.IContentProposalListener;

import org.eclipse.jface.fieldassist.IContentProposalProvider;

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.ui.forms.widgets.TableWrapData;

import eu.etaxonomy.cdm.common.CdmUtils;

import eu.etaxonomy.taxeditor.preference.PreferencesUtil;

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

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;

/**

 * @author pplitzner

 * @date Aug 11, 2016

 */

public abstract class AbstractComboElement<T>

		extends AbstractRelevanceFormElement

		implements SelectionListener, IEnableableFormElement,

			ISelectable, DisposeListener {

    protected static final int DEFAULT_VISIBLE_ITEMS = 10;

    protected T selection;

    protected Label label;

    protected Combo combo;

    public boolean hasNullValue;

    public AbstractComboElement(CdmFormFactory formFactory, ICdmFormElement formElement, boolean hasNullValue) {

        super(formFactory, formElement);

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

        addControl(label);

        // create combo

        combo = new Combo(getLayoutComposite(), SWT.BORDER);

        addControl(combo);

        TableWrapData fill_HORIZONTALLY = LayoutConstants.FILL_HORIZONTALLY();

        combo.setLayoutData(fill_HORIZONTALLY);

        fill_HORIZONTALLY.maxWidth = 50;

//        combo.setVisibleItemCount(DEFAULT_VISIBLE_ITEMS);

        //disable mouse-wheel selection

        combo.addListener(SWT.MouseWheel, e->e.doit=false);

        this.hasNullValue = hasNullValue;

    }

    public AbstractComboElement(CdmFormFactory formFactory, ICdmFormElement formElement){

        this(formFactory, formElement, false);

    }

    @Override

    public void setBackground(Color color) {

        if (label != null && !label.isDisposed()) {

            label.setBackground(color);

        }

    }

    @Override

    public void updateCacheRelevance() {

        Color color = cacheRelevance().getColor();

        combo.setBackground(color);

    }

    public void setVisibleItemCount(int count){

        combo.setVisibleItemCount(count);

    }

    @Override

    public void setSelected(boolean selected) {

        setBackground(selected ? SELECTED : getPersistentBackground());

    }

    public T getSelection() {

        return selection;

    }

    public void addSelectionListener(SelectionListener listener) {

        combo.addSelectionListener(listener);

    }

    public void removeSelectionListener(SelectionListener listener) {

        combo.removeSelectionListener(listener);

    }

    @Override

    public void widgetDisposed(DisposeEvent e) {

        PreferencesUtil.getPreferenceStore().removePropertyChangeListener(this);

    }

    @Override

    public void widgetDefaultSelected(SelectionEvent e) {

    }

    @Override

    public boolean isEnabled() {

        return combo.isEnabled();

    }

    @Override

    public void setEnabled(boolean enabled) {

        combo.setEnabled(enabled);

    }

    public abstract void setSelection(T selection);

    private AbstractComboElement<T> getComboElement(){

        return this;

    }

    protected void addContentProposalAdapter() {

        ContentProposalAdapter adapter;

        adapter = new ContentProposalAdapter(combo, new ComboContentAdapter(), getProposalProvider(), null, null);

        adapter.setPropagateKeys(true);

        adapter.setProposalAcceptanceStyle(ContentProposalAdapter.PROPOSAL_REPLACE);

        adapter.addContentProposalListener(new IContentProposalListener() {

            @SuppressWarnings("unchecked")

            @Override

            public void proposalAccepted(IContentProposal proposal) {

                setSelection((T)combo.getData(proposal.getContent()));

                firePropertyChangeEvent(new CdmPropertyChangeEvent(getComboElement(), null));

            }

        });

    }

    IContentProposalProvider getProposalProvider() {

        return new IContentProposalProvider() {

            @Override

            public IContentProposal[] getProposals(String contents, int position) {

                String[] items = combo.getItems();

                if (contents.length() == 0 || items.length == 0) {

                    return new IContentProposal[0];

                }

                StringMatcher matcher = new StringMatcher("*" + contents + "*", true, false); //$NON-NLS-1$ //$NON-NLS-2$

                ArrayList<String> matches = new ArrayList<>();

                for (int i = 0; i < items.length; i++) {

                    if (matcher.match(items[i])) {

                        matches.add(items[i]);

                    }

                }

                Collections.sort(matches);

                // We don't want to autoactivate if the only proposal exactly matches

                // what is in the combo.  This prevents the popup from

                // opening when the user is merely scrolling through the combo values or

                // has accepted a combo value.

                if (matches.size() == 1 && matches.get(0).equals(combo.getText())) {

                    return new IContentProposal[0];

                }

                if (matches.isEmpty()) {

                    return new IContentProposal[0];

                }

                // Make the proposals

                IContentProposal[] proposals = new IContentProposal[matches.size()];

                for (int i = 0; i < matches.size(); i++) {

                    final String proposal = matches.get(i);

                    proposals[i] = new IContentProposal() {

                        @Override

                        public String getContent() {

                            return proposal;

                        }

                        @Override

                        public int getCursorPosition() {

                            return proposal.length();

                        }

                        @Override

                        public String getDescription() {

                            return null;

                        }

                        @Override

                        public String getLabel() {

                            return null;

                        }

                    };

                }

                return proposals;

            }

        };

    }

    @Override

    public String toString() {

        if (label != null){

            return CdmUtils.concat("", "ComboElement[", label.getText(),"]");

        }else{

            return super.toString();

        }

    }

}