/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.jface.viewers;

import java.text.MessageFormat;

import org.eclipse.jface.util.Assert;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.CCombo;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;

/**
 * A cell editor that presents a list of items in a combo box.
 * The cell editor's value is the zero-based index of the selected
 * item.
 * <p>
 * This class may be instantiated; it is not intended to be subclassed.
 * </p>
 */
public class ComboBoxCellEditor extends CellEditor {

	/**
	 * The list of items to present in the combo box.
	 */
	private String[] items;

	/**
	 * The zero-based index of the selected item.
	 */
	int selection;

	/**
	 * The custom combo box control.
	 */
	CCombo comboBox;

	/**
	 * Default ComboBoxCellEditor style
	 */
	private static final int defaultStyle = SWT.NONE;

/**
 * Creates a new cell editor with no control and no  st of choices. Initially,
 * the cell editor has no cell validator.
 * 
 * @since 2.1
 * @see #setStyle
 * @see #create
 * @see #setItems
 * @see #dispose
 */
public ComboBoxCellEditor() {
	setStyle(defaultStyle);
}

/**
 * Creates a new cell editor with a combo containing the given 
 * list of choices and parented under the given control. The cell
 * editor value is the zero-based index of the selected item.
 * Initially, the cell editor has no cell validator and
 * the first item in the list is selected. 
 *
 * @param parent the parent control
 * @param items the list of strings for the combo box
 */
public ComboBoxCellEditor(Composite parent, String[] items) {
	this(parent, items, defaultStyle);
}

/**
 * Creates a new cell editor with a combo containing the given 
 * list of choices and parented under the given control. The cell
 * editor value is the zero-based index of the selected item.
 * Initially, the cell editor has no cell validator and
 * the first item in the list is selected. 
 *
 * @param parent the parent control
 * @param items the list of strings for the combo box
 * @param style the style bits
 * @since 2.1
 */
public ComboBoxCellEditor(Composite parent, String[] items, int style) {
	super(parent, style);
	setItems(items);
}

/**
 * Returns the list of choices for the combo box
 *
 * @return the list of choices for the combo box
 */
public String[] getItems() {
	return this.items;
}

/**
 * Sets the list of choices for the combo box
 *
 * @param items the list of choices for the combo box
 */
public void setItems(String[] items) {
	Assert.isNotNull(items);
	this.items = items;
	populateComboBoxItems();
}

/* (non-Javadoc)
 * Method declared on CellEditor.
 */
protected Control createControl(Composite parent) {
	
	comboBox = new CCombo(parent, getStyle());
	comboBox.setFont(parent.getFont());

	comboBox.addKeyListener(new KeyAdapter() {
		// hook key pressed - see PR 14201  
		public void keyPressed(KeyEvent e) {
			keyReleaseOccured(e);
		}
	});

	comboBox.addSelectionListener(new SelectionAdapter() {
		public void widgetDefaultSelected(SelectionEvent event) {
			applyEditorValueAndDeactivate();
		}
		
		public void widgetSelected(SelectionEvent event) {
			selection = comboBox.getSelectionIndex();
		}
	});

	comboBox.addTraverseListener(new TraverseListener() {
		public void keyTraversed(TraverseEvent e) {
			if (e.detail == SWT.TRAVERSE_ESCAPE || e.detail == SWT.TRAVERSE_RETURN) {
				e.doit = false;
			}
		}
	});

	comboBox.addFocusListener(new FocusAdapter() {
		public void focusLost(FocusEvent e) {
			ComboBoxCellEditor.this.focusLost();
		}
	});
	return comboBox;
}

/**
 * The <code>ComboBoxCellEditor</code> implementation of
 * this <code>CellEditor</code> framework method returns
 * the zero-based index of the current selection.
 *
 * @return the zero-based index of the current selection wrapped
 *  as an <code>Integer</code>
 */
protected Object doGetValue() {
	return new Integer(selection);
}

/* (non-Javadoc)
 * Method declared on CellEditor.
 */
protected void doSetFocus() {
	comboBox.setFocus();
}

/**
 * The <code>ComboBoxCellEditor</code> implementation of
 * this <code>CellEditor</code> framework method sets the 
 * minimum width of the cell.  The minimum width is 10 characters
 * if <code>comboBox</code> is not <code>null</code> or <code>disposed</code>
 * eles it is 60 pixels to make sure the arrow button and some text is visible.
 * The list of CCombo will be wide enough to show its longest item.
 */
public LayoutData getLayoutData() {
	LayoutData layoutData = super.getLayoutData();
	if ((comboBox == null) || comboBox.isDisposed())
		layoutData.minimumWidth = 60;
	else {
		// make the comboBox 10 characters wide
		GC gc = new GC(comboBox);
		layoutData.minimumWidth = (gc.getFontMetrics().getAverageCharWidth() * 10) + 10;
		gc.dispose();
	}
	return layoutData;
}

/**
 * The <code>ComboBoxCellEditor</code> implementation of
 * this <code>CellEditor</code> framework method
 * accepts a zero-based index of a selection.
 *
 * @param value the zero-based index of the selection wrapped
 *   as an <code>Integer</code>
 */
protected void doSetValue(Object value) {
	Assert.isTrue(comboBox != null && (value instanceof Integer));
	selection = ((Integer) value).intValue();
	comboBox.select(selection);
}

/**
 * Updates the list of choices for the combo box for the current control.
 */
private void populateComboBoxItems() {
	if (comboBox != null && items != null) {
		comboBox.removeAll();
		for (int i = 0; i < items.length; i++)
			comboBox.add(items[i], i);

		setValueValid(true);
		selection = 0;
	}
}
/**
 * Applies the currently selected value and deactiavates the cell editor
 */
void applyEditorValueAndDeactivate() {
	//	must set the selection before getting value
	selection = comboBox.getSelectionIndex();
	Object newValue = doGetValue();
	markDirty();
	boolean isValid = isCorrect(newValue);
	setValueValid(isValid);
	if (!isValid) {
		// try to insert the current value into the error message.
		setErrorMessage(
			MessageFormat.format(getErrorMessage(), new Object[] {items[selection]})); 
	}
	fireApplyEditorValue();
	deactivate();
}

/*
 *  (non-Javadoc)
 * @see org.eclipse.jface.viewers.CellEditor#focusLost()
 */
protected void focusLost() {
	if (isActivated()) {
		applyEditorValueAndDeactivate();
	}
}

/*
 *  (non-Javadoc)
 * @see org.eclipse.jface.viewers.CellEditor#keyReleaseOccured(org.eclipse.swt.events.KeyEvent)
 */
protected void keyReleaseOccured(KeyEvent keyEvent) {
	if (keyEvent.character == '\u001b') { // Escape character
		fireCancelEditor();
	} else if (keyEvent.character == '\t') { // tab key
		applyEditorValueAndDeactivate();
	}
}
}