/*******************************************************************************
 * 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.resource.*;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;

/**
 * An abstract cell editor that uses a dialog.
 * Dialog cell editors usually have a label control on the left and a button on
 * the right. Pressing the button opens a dialog window (for example, a color dialog
 * or a file dialog) to change the cell editor's value.
 * The cell editor's value is the value of the dialog.
 * <p>
 * Subclasses may override the following method:
 * <ul>
 *	<li><code>createButton</code>: creates the cell editor's button control</li>
 *	<li><code>openDialogBox</code>: opens the dialog box when the end user presses
 *      the button</li>
 *	<li><code>updateLabel</code>: updates the cell editor's label after its
 *		value has changed</li>
 * </ul>
 * </p>
 */
public abstract class DialogCellEditor extends CellEditor {

	/**
	 * Image registry key for three dot image (value <code>"cell_editor_dots_button_image"</code>).
	 */
	public static final String CELL_EDITOR_IMG_DOTS_BUTTON = "cell_editor_dots_button_image";//$NON-NLS-1$

	/**
	 * The editor control.
	 */
	private Composite editor;

	/**
	 * The current contents.
	 */
	private Control contents;

	/**
	 * The label that gets reused by <code>updateLabel</code>.
	 */
	private Label defaultLabel;

	/**
	 * The button.
	 */
	private Button button;

	/**
	 * The value of this cell editor; initially <code>null</code>.
	 */
	private Object value = null;
	
	static {
		ImageRegistry reg = JFaceResources.getImageRegistry();
		reg.put(CELL_EDITOR_IMG_DOTS_BUTTON, ImageDescriptor.createFromFile(DialogCellEditor.class, "images/dots_button.gif"));//$NON-NLS-1$
	}

	/**
	 * Internal class for laying out the dialog.
	 */
	private class DialogCellLayout extends Layout {
		public void layout(Composite editor, boolean force) {
			Rectangle bounds = editor.getClientArea();
			Point size = button.computeSize(SWT.DEFAULT, SWT.DEFAULT, force);
			if (contents != null)
				contents.setBounds(0, 0, bounds.width-size.x, bounds.height);
			button.setBounds(bounds.width-size.x, 0, size.x, bounds.height);
		}
		public Point computeSize(Composite editor, int wHint, int hHint, boolean force) {
			if (wHint != SWT.DEFAULT && hHint != SWT.DEFAULT)
				return new Point(wHint, hHint);
			Point contentsSize = contents.computeSize(SWT.DEFAULT, SWT.DEFAULT, force); 
			Point buttonSize =  button.computeSize(SWT.DEFAULT, SWT.DEFAULT, force);
			// Just return the button width to ensure the button is not clipped
			// if the label is long.
			// The label will just use whatever extra width there is
			Point result = new Point(buttonSize.x,
							        Math.max(contentsSize.y, buttonSize.y));
			return result;			
		}
	}
	
	/**
	 * Default DialogCellEditor style
	 */
	private static final int defaultStyle = SWT.NONE;
	
/**
 * Creates a new dialog cell editor with no control
 * @since 2.1
 */
public DialogCellEditor() {
	setStyle(defaultStyle);
}	
/**
 * Creates a new dialog cell editor parented under the given control.
 * The cell editor value is <code>null</code> initially, and has no 
 * validator.
 *
 * @param parent the parent control
 */
protected DialogCellEditor(Composite parent) {
	this(parent, defaultStyle);
}
/**
 * Creates a new dialog cell editor parented under the given control.
 * The cell editor value is <code>null</code> initially, and has no 
 * validator.
 *
 * @param parent the parent control
 * @param style the style bits
 * @since 2.1
 */
protected DialogCellEditor(Composite parent, int style) {
	super(parent, style);
}
/**
 * Creates the button for this cell editor under the given parent control.
 * <p>
 * The default implementation of this framework method creates the button 
 * display on the right hand side of the dialog cell editor. Subclasses
 * may extend or reimplement.
 * </p>
 *
 * @param parent the parent control
 * @return the new button control
 */
protected Button createButton(Composite parent) {
	Button result = new Button(parent, SWT.DOWN);
	result.setText("..."); //$NON-NLS-1$
	return result;
}
/**
 * Creates the controls used to show the value of this cell editor.
 * <p>
 * The default implementation of this framework method creates
 * a label widget, using the same font and background color as the parent control.
 * </p>
 * <p>
 * Subclasses may reimplement.  If you reimplement this method, you
 * should also reimplement <code>updateContents</code>.
 * </p>
 *
 * @param cell the control for this cell editor
 */
protected Control createContents(Composite cell) {
	defaultLabel = new Label(cell, SWT.LEFT);
	defaultLabel.setFont(cell.getFont());
	defaultLabel.setBackground(cell.getBackground());
	return defaultLabel;
}
/* (non-Javadoc)
 * Method declared on CellEditor.
 */
protected Control createControl(Composite parent) {

	Font font = parent.getFont();
	Color bg = parent.getBackground();

	editor = new Composite(parent, getStyle());
	editor.setFont(font);
	editor.setBackground(bg);
	editor.setLayout(new DialogCellLayout());

	contents = createContents(editor);
	updateContents(value);
	
	button = createButton(editor);
	button.setFont(font);

	button.addKeyListener(new KeyAdapter() {
		public void keyReleased(KeyEvent e) {
			if (e.character == '\u001b') { // Escape
				fireCancelEditor();
			}
		}
	});

	button.addSelectionListener(new SelectionAdapter() {
		public void widgetSelected(SelectionEvent event) {
			Object newValue = openDialogBox(editor);
			if (newValue != null) {
				boolean newValidState = isCorrect(newValue);
				if (newValidState) {
					markDirty();
					doSetValue(newValue);
				} else {
					// try to insert the current value into the error message.
					setErrorMessage(MessageFormat.format(getErrorMessage(), new Object[] { newValue.toString()}));
				}
				fireApplyEditorValue();
			}
		}
	});

	setValueValid(true);

	return editor;
}
/* (non-Javadoc)
 * Method declared on CellEditor.
 */
protected Object doGetValue() {
	return value;
}
/* (non-Javadoc)
 * Method declared on CellEditor.
 * The focus is set to the cell editor's button. 
 */
protected void doSetFocus() {
	button.setFocus();
}
/* (non-Javadoc)
 * Method declared on CellEditor.
 */
protected void doSetValue(Object value) {
	this.value = value;
	updateContents(value);
}
/**
 * Returns the default label widget created by <code>createContents</code>.
 *
 * @return the default label widget
 */
protected Label getDefaultLabel() {
	return defaultLabel;
}
/**
 * Opens a dialog box under the given parent control and returns the
 * dialog's value when it closes, or <code>null</code> if the dialog
 * was cancelled or no selection was made in the dialog.
 * <p>
 * This framework method must be implemented by concrete subclasses.
 * It is called when the user has pressed the button and the dialog
 * box must pop up.
 * </p>
 *
 * @param cellEditorWindow the parent control cell editor's window
 *   so that a subclass can adjust the dialog box accordingly
 * @return the selected value, or <code>null</code> if the dialog was 
 *   cancelled or no selection was made in the dialog
 */
protected abstract Object openDialogBox(Control cellEditorWindow);
/**
 * Updates the controls showing the value of this cell editor.
 * <p>
 * The default implementation of this framework method just converts
 * the passed object to a string using <code>toString</code> and
 * sets this as the text of the label widget.
 * </p>
 * <p>
 * Subclasses may reimplement.  If you reimplement this method, you
 * should also reimplement <code>createContents</code>.
 * </p>
 *
 * @param value the new value of this cell editor
 */
protected void updateContents(Object value) {
	if (defaultLabel == null)
		return;
		
	String text = "";//$NON-NLS-1$
	if (value != null)
		text = value.toString(); 
	defaultLabel.setText(text);
}
}