/*******************************************************************************
 * 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.ui.texteditor;


import java.util.ResourceBundle;

import org.eclipse.swt.custom.BusyIndicator;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

import org.eclipse.jface.text.ITextOperationTarget;

import org.eclipse.ui.IWorkbenchPartSite;


/**
 * An action which gets a text operation target from its text editor.
 * <p>
 * The action is initially associated with a text editor via the constructor,
 * but can subsequently be changed using <code>setEditor</code>.</p>
 * <p>
 * If this class is used as is, it works by asking the text editor for its
 * text operation target adapter (using <code>getAdapter(ITextOperationTarget.class)</code>. 
 * The action runs this operation with the pre-configured opcode.</p>
 */
public final class TextOperationAction extends TextEditorAction {
	
	/** The text operation code */
	private int fOperationCode= -1;
	/** The text operation target */
	private ITextOperationTarget fOperationTarget;
	/** 
	 * Indicates whether this action can be executed on read only editors
	 * @since 2.0
	 */
	private boolean fRunsOnReadOnly= false;
	
	/**
	 * Creates and initializes the action for the given text editor and operation 
	 * code. The action configures its visual representation from the given resource
	 * bundle. The action works by asking the text editor at the time for its 
	 * text operation target adapter (using
	 * <code>getAdapter(ITextOperationTarget.class)</code>. The action runs that
	 * operation with the given opcode.
	 *
	 * @param bundle the resource bundle
	 * @param prefix a prefix to be prepended to the various resource keys
	 *   (described in <code>ResourceAction</code> constructor), or 
	 *   <code>null</code> if none
	 * @param editor the text editor
	 * @param operationCode the operation code
	 * @see ResourceAction#ResourceAction
	 */
	public TextOperationAction(ResourceBundle bundle, String prefix, ITextEditor editor, int operationCode) {
		super(bundle, prefix, editor);
		fOperationCode= operationCode;
		update();
	}
	
	/**
	 * Creates and initializes the action for the given text editor and operation 
	 * code. The action configures its visual representation from the given resource
	 * bundle. The action works by asking the text editor at the time for its 
	 * text operation target adapter (using
	 * <code>getAdapter(ITextOperationTarget.class)</code>. The action runs that
	 * operation with the given opcode.
	 *
	 * @param bundle the resource bundle
	 * @param prefix a prefix to be prepended to the various resource keys
	 *   (described in <code>ResourceAction</code> constructor), or 
	 *   <code>null</code> if none
	 * @param editor the text editor
	 * @param operationCode the operation code
	 * @param runsOnReadOnly <code>true</code> if action can be executed on read-only files
	 * 
	 * @see ResourceAction#ResourceAction
	 * @since 2.0
	 */
	public TextOperationAction(ResourceBundle bundle, String prefix, ITextEditor editor, int operationCode, boolean runsOnReadOnly) {
		super(bundle, prefix, editor);
		fOperationCode= operationCode;
		fRunsOnReadOnly= runsOnReadOnly;
		update();
	}
	
	/**
	 * The <code>TextOperationAction</code> implementation of this 
	 * <code>IAction</code> method runs the operation with the current
	 * operation code.
	 */
	public void run() {
		if (fOperationCode == -1 || fOperationTarget == null)
			return;
			
		ITextEditor editor= getTextEditor();
		if (editor == null)
			return;

		if (!fRunsOnReadOnly) {
			if (editor instanceof ITextEditorExtension2) {
				ITextEditorExtension2 extension= (ITextEditorExtension2) editor;
				if (!extension.validateEditorInputState())
					return;
			}
		}
			
		Display display= null;
		
		IWorkbenchPartSite site= editor.getSite();
		Shell shell= site.getShell();
		if (shell != null && !shell.isDisposed()) 
			display= shell.getDisplay();
	
		BusyIndicator.showWhile(display, new Runnable() {
			public void run() {
				fOperationTarget.doOperation(fOperationCode);
			}
		});
	}
	
	/**
	 * The <code>TextOperationAction</code> implementation of this 
	 * <code>IUpdate</code> method discovers the operation through the current
	 * editor's <code>ITextOperationTarget</code> adapter, and sets the
	 * enabled state accordingly.
	 */
	public void update() {
		
		ITextEditor editor= getTextEditor();
		if (editor instanceof ITextEditorExtension2) {
			ITextEditorExtension2 extension= (ITextEditorExtension2) editor;
			if (!extension.isEditorInputModifiable() && !fRunsOnReadOnly) {
				setEnabled(false);
				return;
			}
		}
		
		if (fOperationTarget == null && editor!= null && fOperationCode != -1)
			fOperationTarget= (ITextOperationTarget) editor.getAdapter(ITextOperationTarget.class);
			
		boolean isEnabled= (fOperationTarget != null && fOperationTarget.canDoOperation(fOperationCode));
		setEnabled(isEnabled);
	}
	
	/*
	 * @see TextEditorAction#setEditor(ITextEditor)
	 */
	public void setEditor(ITextEditor editor) {
		super.setEditor(editor);
		fOperationTarget= null;
	}
}