/*******************************************************************************
 * Copyright (c) 2000, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.ui.internal.ide;

import java.text.Collator;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Locale;

import org.eclipse.jface.viewers.DoubleClickEvent;
import org.eclipse.jface.viewers.IDoubleClickListener;
import org.eclipse.jface.viewers.ISelectionChangedListener;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.jface.viewers.ListViewer;
import org.eclipse.jface.viewers.SelectionChangedEvent;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.dialogs.SelectionDialog;
import org.eclipse.ui.internal.ide.dialogs.SimpleListContentProvider;

/**
 * Dialog to allow the user to select a feature from a list.
 */
public class FeatureSelectionDialog extends SelectionDialog {
    /**
     * List width in characters.
     */
    private final static int LIST_WIDTH = 60;

    /**
     * List height in characters.
     */
    private final static int LIST_HEIGHT = 10;

    /**
     * The feature about infos.
     */
    private AboutInfo[] features;

    /**
     * List to display the resolutions.
     */
    private ListViewer listViewer;

    /**
     * The help context id
     */
    private String helpContextId;

    /**
     * Creates an instance of this dialog to display
     * the given features.
     * <p>
     * There must be at least one feature.
     * </p>
     * 
     * @param shell  the parent shell
     * @param features  the features to display
     * @param primaryFeatureId  the id of the primary feature or null if none
     * @param shellTitle  shell title
     * @param shellMessage  shell message
     * @param helpContextId  help context id
     */
    public FeatureSelectionDialog(Shell shell, AboutInfo[] features,
            String primaryFeatureId, String shellTitle, String shellMessage,
            String helpContextId) {

        super(shell);
        if (features == null || features.length == 0) {
            throw new IllegalArgumentException();
        }
        this.features = features;
        this.helpContextId = helpContextId;
        setTitle(shellTitle);
        setMessage(shellMessage);

        // Sort ascending
        Arrays.sort(features, new Comparator() {
            Collator coll = Collator.getInstance(Locale.getDefault());

            public int compare(Object a, Object b) {
                AboutInfo i1, i2;
                String name1, name2;
                i1 = (AboutInfo) a;
                name1 = i1.getFeatureLabel();
                i2 = (AboutInfo) b;
                name2 = i2.getFeatureLabel();
                if (name1 == null) {
					name1 = ""; //$NON-NLS-1$
				}
                if (name2 == null) {
					name2 = ""; //$NON-NLS-1$
				}
                return coll.compare(name1, name2);
            }
        });

        // Find primary feature
        for (int i = 0; i < features.length; i++) {
            if (features[i].getFeatureId().equals(primaryFeatureId)) {
                setInitialSelections(new Object[] { features[i] });
                return;
            }
        }

        // set a safe default		
        setInitialSelections(new Object[0]);
    }

    /* (non-Javadoc)
     * Method declared on Window.
     */
    protected void configureShell(Shell newShell) {
        super.configureShell(newShell);
        PlatformUI.getWorkbench().getHelpSystem().setHelp(newShell,
				helpContextId);
    }

    /* (non-Javadoc)
     * Method declared on Dialog.
     */
    protected Control createDialogArea(Composite parent) {
        Composite composite = (Composite) super.createDialogArea(parent);

        // Create label
        createMessageArea(composite);
        // Create list viewer	
        listViewer = new ListViewer(composite, SWT.SINGLE | SWT.H_SCROLL
                | SWT.V_SCROLL | SWT.BORDER);
        GridData data = new GridData(GridData.FILL_BOTH);
        data.heightHint = convertHeightInCharsToPixels(LIST_HEIGHT);
        data.widthHint = convertWidthInCharsToPixels(LIST_WIDTH);
        listViewer.getList().setLayoutData(data);
        listViewer.getList().setFont(parent.getFont());
        // Set the label provider		
        listViewer.setLabelProvider(new LabelProvider() {
            public String getText(Object element) {
                // Return the features's label.
                return element == null ? "" : ((AboutInfo) element).getFeatureLabel(); //$NON-NLS-1$
            }
        });

        // Set the content provider
        SimpleListContentProvider cp = new SimpleListContentProvider();
        cp.setElements(features);
        listViewer.setContentProvider(cp);
        listViewer.setInput(new Object());
        // it is ignored but must be non-null

        // Set the initial selection
        listViewer.setSelection(new StructuredSelection(
                getInitialElementSelections()), true);

        // Add a selection change listener
        listViewer.addSelectionChangedListener(new ISelectionChangedListener() {
            public void selectionChanged(SelectionChangedEvent event) {
                // Update OK button enablement
                getOkButton().setEnabled(!event.getSelection().isEmpty());
            }
        });

        // Add double-click listener
        listViewer.addDoubleClickListener(new IDoubleClickListener() {
            public void doubleClick(DoubleClickEvent event) {
                okPressed();
            }
        });
        return composite;
    }

    /* (non-Javadoc)
     * Method declared on Dialog.
     */
    protected void okPressed() {
        IStructuredSelection selection = (IStructuredSelection) listViewer
                .getSelection();
        setResult(selection.toList());
        super.okPressed();
    }
}