/*******************************************************************************
 * Copyright (c) 2000, 2008 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.mylyn.internal.tasks.ui;

import org.eclipse.jface.dialogs.Dialog;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;

/**
 * General purpose dialog for selecting an item from a combo box.
 * 
 * @author This was (essentially) copied from Eclipse's internal implementation by Wesley Coelho
 */
public class ComboSelectionDialog extends Dialog {

	private String fSelection = null;

	private final String fShellTitle;

	private final String fLabelText;

	private final String[] fAllowedStrings;

	private final int fInitialSelectionIndex;

	private int fSelectedIndex = -1;

	public ComboSelectionDialog(Shell parentShell, String shellTitle, String labelText, String[] comboStrings,
			int initialSelectionIndex) {
		super(parentShell);
		fShellTitle = shellTitle;
		fLabelText = labelText;
		fAllowedStrings = comboStrings;
		fInitialSelectionIndex = initialSelectionIndex;
	}

	public String getSelectedString() {
		return fSelection;
	}

	/*
	 * @see org.eclipse.jface.dialogs.Dialog#createDialogArea(org.eclipse.swt.widgets.Composite)
	 */
	@Override
	protected Control createDialogArea(Composite parent) {
		getShell().setText(fShellTitle);

		Composite composite = (Composite) super.createDialogArea(parent);
		Composite innerComposite = new Composite(composite, SWT.NONE);
		innerComposite.setLayoutData(new GridData());
		GridLayout gl = new GridLayout();
		gl.numColumns = 2;
		innerComposite.setLayout(gl);

		Label label = new Label(innerComposite, SWT.NONE);
		label.setText(fLabelText);
		label.setLayoutData(new GridData());

		final Combo combo = new Combo(innerComposite, SWT.READ_ONLY);
		for (String allowedString : fAllowedStrings) {
			combo.add(allowedString);
		}
		combo.select(fInitialSelectionIndex);
		fSelection = combo.getItem(combo.getSelectionIndex());
		GridData gd = new GridData();
		gd.widthHint = convertWidthInCharsToPixels(getMaxStringLength());
		combo.setLayoutData(gd);
		combo.addSelectionListener(new SelectionAdapter() {
			@Override
			public void widgetSelected(SelectionEvent e) {
				fSelection = combo.getItem(combo.getSelectionIndex());
				fSelectedIndex = combo.getSelectionIndex();
			}
		});
		applyDialogFont(composite);
		return composite;
	}

	/**
	 * Returns the array index of the selected string or -1 if no string was selected.
	 */
	public int getSelectedIndex() {
		return fSelectedIndex;
	}

	private int getMaxStringLength() {
		int max = 0;
		for (String allowedString : fAllowedStrings) {
			max = Math.max(max, allowedString.length());
		}
		return max;
	}
}