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.taxeditor.databaseAdmin.preferencePage;

import java.awt.Toolkit;

import javax.swing.event.DocumentEvent;

import org.apache.commons.lang.StringUtils;

import org.eclipse.swt.SWT;

import org.eclipse.swt.events.MouseEvent;

import org.eclipse.swt.events.MouseListener;

import org.eclipse.swt.graphics.Rectangle;

import org.eclipse.swt.layout.GridData;

import org.eclipse.swt.widgets.Button;

import org.eclipse.swt.widgets.Composite;

import org.eclipse.swt.widgets.List;

import org.eclipse.swt.widgets.Text;

import eu.etaxonomy.cdm.model.metadata.CdmPreference;

import eu.etaxonomy.cdm.model.metadata.PreferencePredicate;

import eu.etaxonomy.taxeditor.preference.PreferencesUtil;

/**

 * @author k.luther

 * @date 20.04.2017

 *

 */

public class ListComponent

                      {

    private List list;

    private static final String addString = "Add Provider";

    private static final String removeString = "Remove Provider";

    private static final String noProvider = "No Providers available";

    private Button removeButton;

    private Text providerURI;

    public ListComponent(Composite parent, int style) {

         list = new List(parent, SWT.BORDER |  SWT.V_SCROLL);

        GridData gridData = new GridData(SWT.FILL, SWT.CENTER, true, true, 2, 3);

        gridData.grabExcessHorizontalSpace = true;

        list.setLayoutData(gridData);

        Rectangle clientArea = parent.getShell().getClientArea ();

        list.setBounds (clientArea.x, clientArea.y, 100, 500);

        CdmPreference providerListPreference = PreferencesUtil.getPreferenceFromDB(PreferencePredicate.BioCaseProvider);

        String allProviderString = "";

        if (providerListPreference != null){

            allProviderString  = providerListPreference.getValue();

        }

//         = PreferencesUtil.getPreferenceStore().getString(IPreferenceKeys.BIOCASE_PROVIDER_LIST);

        //the string is structured like this: http://ww3.bgbm.org/biocase/pywrapper.cgi?dsa=DNA_Bank;http:...;

        String[] providerArray = allProviderString.split(";");

        for (String providerString : providerArray){

            if (!StringUtils.isBlank(providerString)){

                list.add(providerString);

            }

        }

        if (list.getItemCount() == 0){

            list.add(noProvider);

        }

        list.add("");

//        list.setSelection(0);

        GridData dataList = new GridData();

        dataList.horizontalAlignment = GridData.FILL;

        dataList.horizontalSpan = 3;

//        dataList.grabExcessVerticalSpace = true;

        list.setLayoutData(dataList);

        providerURI = new Text(parent, SWT.BORDER | SWT.SINGLE | SWT.FULL_SELECTION);

        GridData dataProviderUri = new GridData();

        dataProviderUri.horizontalAlignment = GridData.FILL;

        dataProviderUri.horizontalSpan = 3;

        providerURI.setLayoutData(dataProviderUri);

        Button addButton = new Button(parent, SWT.NULL);

        AddListener addListener = new AddListener(addButton);

        addButton.setText(addString);

        addButton.addMouseListener(addListener);

        removeButton = new Button(parent, SWT.NULL);

        removeButton.setText(removeString);

        removeButton.addMouseListener(new RemoveListener());

    }

    class RemoveListener implements MouseListener {

        @Override

        public void mouseUp(MouseEvent e)  {

            //This method can be called only if

            //there's a valid selection

            //so go ahead and remove whatever's selected.

            int index = list.getSelectionIndex();

            list.remove(index);

            int size = list.getItemCount();

            if (size == 0) { //Nothing's left, disable removing.

                removeButton.setEnabled(false);

            } else { //Select an index.

                if (index == size) {

                    //removed item in last position

                    index--;

                }

                list.setSelection(index-1);

            }

        }

        /**

         * {@inheritDoc}

         */

        @Override

        public void mouseDoubleClick(MouseEvent e) {

            // TODO Auto-generated method stub

        }

        /**

         * {@inheritDoc}

         */

        @Override

        public void mouseDown(MouseEvent e) {

            // TODO Auto-generated method stub

        }

    }

    //This listener is shared by the text field and the add button.

    class AddListener implements MouseListener {

        private boolean alreadyEnabled = false;

        private Button button;

        public AddListener(Button button) {

            this.button = button;

        }

        protected boolean alreadyInList(String name) {

            return list.getData(name) != null;

        }

        private void enableButton() {

            if (!alreadyEnabled) {

                button.setEnabled(true);

            }

        }

        private boolean handleEmptyTextField(DocumentEvent e) {

            if (e.getDocument().getLength() <= 0) {

                button.setEnabled(false);

                alreadyEnabled = false;

                return true;

            }

            return false;

        }

        /**

         * {@inheritDoc}

         */

        @Override

        public void mouseDoubleClick(MouseEvent e) {

            // TODO Auto-generated method stub

        }

        /**

         * {@inheritDoc}

         */

        @Override

        public void mouseDown(MouseEvent e) {

            // TODO Auto-generated method stub

        }

        /**

         * {@inheritDoc}

         */

        @Override

        public void mouseUp(MouseEvent event) {

            String name = providerURI.getText();

            //User didn't type in a unique name...

            if (name.equals("") || alreadyInList(name)) {

                Toolkit.getDefaultToolkit().beep();

                providerURI.selectAll();

                return;

            }

            int index = list.getSelectionIndex(); //get selected index

            if (index == -1) { //no selection, so insert at beginning

                index = 0;

            } else {           //add after the selected item

                index++;

            }

            if(list.getItemCount() == 0){

                index = 0;

            }else if (list.getItem(0).equals(noProvider)){

                list.remove(noProvider);

            }

            int itemCount = list.getItemCount();

            list.add(providerURI.getText(), index);

            list.setSelection(index);

            list.update();

            list.redraw();

            //Select the new item

            providerURI.setText("");

        }

    }

    public String createAllProviderString(){

        String allProviderString = null;

        boolean first = true;

        for (String item: list.getItems()){

            if (first || allProviderString == null || allProviderString == ""){

                allProviderString = item.trim();

                first = false;

            }else{

                allProviderString +=";"+ item.trim();

            }

        }

        return allProviderString;

    }

}