/*******************************************************************************
 * Copyright (c) 2006 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.tests.commands;

import org.eclipse.core.commands.AbstractHandlerWithState;
import org.eclipse.core.commands.Command;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.IStateListener;
import org.eclipse.core.commands.State;
import org.eclipse.core.commands.common.CommandException;
import org.eclipse.ui.commands.ICommandService;
import org.eclipse.ui.handlers.IHandlerActivation;
import org.eclipse.ui.handlers.IHandlerService;
import org.eclipse.ui.tests.harness.util.UITestCase;

/**
 * Tests various aspects of command state.
 * 
 * @since 3.2
 */
public class StateTest extends UITestCase {

	private static final class ObjectStateHandler extends
			AbstractHandlerWithState {

		Object currentValue;

		public final Object execute(final ExecutionEvent event) {
			getState(OBJECT_STATE_ID).setValue(OBJECT_CHANGED);
			return OBJECT_CHANGED;
		}

		public final void handleStateChange(final State state,
				final Object oldValue) {
			if (OBJECT_STATE_ID.equals(state.getId())) {
				currentValue = state.getValue();
			}
		}
	}

	private static final class StateListener implements IStateListener {
		Object currentValue;

		public final void handleStateChange(final State state,
				final Object oldValue) {

			if (OBJECT_STATE_ID.equals(state.getId())) {
				currentValue = state.getValue();
			}
		}
	}

	/**
	 * The identifier of the command with state that we wish to test.
	 */
	private static final String COMMAND_ID = "org.eclipse.ui.tests.commandWithState";

	/**
	 * The object to which the command is set as a test.
	 */
	private static final Object OBJECT_CHANGED = "CHANGED";

	/**
	 * The object to which the command is set before the test starts.
	 */
	private static final Object OBJECT_INITIAL = "INITIAL";

	/**
	 * The identifier of the state storing a simple object.
	 */
	private static final String OBJECT_STATE_ID = "OBJECT";

	/**
	 * The object state handler.
	 */
	private ObjectStateHandler handler;

	/**
	 * The handler activation for the object state handler.
	 */
	private IHandlerActivation handlerActivation;

	/**
	 * Constructor for <code>StateTest</code>.
	 * 
	 * @param name
	 *            The name of the test
	 */
	public StateTest(String name) {
		super(name);
	}

	protected final void doSetUp() {
		// Reset the object state to the initial object.
		final ICommandService commandService = (ICommandService) fWorkbench
				.getService(ICommandService.class);
		final Command command = commandService.getCommand(COMMAND_ID);
		command.getState(OBJECT_STATE_ID).setValue(OBJECT_INITIAL);

		// Register the object state handler.
		handler = new ObjectStateHandler();
		final IHandlerService handlerService = (IHandlerService) fWorkbench
				.getService(IHandlerService.class);
		handlerActivation = handlerService.activateHandler(COMMAND_ID, handler);
	}

	protected final void doTearDown() {
		// Unregister the object state handler.
		final IHandlerService handlerService = (IHandlerService) fWorkbench
				.getService(IHandlerService.class);
		handlerService.deactivateHandler(handlerActivation);
		handlerActivation = null;
		handler.dispose();
		handler = null;
	}

	/**
	 * Tests that if the handler changes the state, a listener to the state
	 * retrieved from the command is notified.
	 * 
	 * @throws CommandException
	 *             Never.
	 */
	public final void testCommandNotifiedOfStateChange()
			throws CommandException {
		// Attach a listener to the state on the command.
		final ICommandService commandService = (ICommandService) fWorkbench
				.getService(ICommandService.class);
		final Command command = commandService.getCommand(COMMAND_ID);
		final State state = command.getState(OBJECT_STATE_ID);
		final StateListener listener = new StateListener();
		listener.currentValue = state.getValue();
		state.addListener(listener);

		// Check the initial state.
		assertSame("The initial state was not correct", OBJECT_INITIAL,
				listener.currentValue);

		// Run the handler.
		final IHandlerService handlerService = (IHandlerService) fWorkbench
				.getService(IHandlerService.class);
		handlerService.executeCommand(COMMAND_ID, null);

		// Check the state.
		assertSame(
				"The state on the command after the handler changed was not correct",
				OBJECT_CHANGED, listener.currentValue);

		// Remove the listener.
		state.removeListener(listener);
	}

	/**
	 * Tests that if the handler changes the state, the command reflects these
	 * changes.
	 * 
	 * @throws CommandException
	 *             Never.
	 */
	public final void testStateChangeReflectedInCommand()
			throws CommandException {
		// Get the command.
		final ICommandService commandService = (ICommandService) fWorkbench
				.getService(ICommandService.class);
		final Command command = commandService.getCommand(COMMAND_ID);

		// Check the initial state.
		assertSame("The initial state was not correct", OBJECT_INITIAL, command
				.getState(OBJECT_STATE_ID).getValue());

		// Run the handler.
		final IHandlerService handlerService = (IHandlerService) fWorkbench
				.getService(IHandlerService.class);
		handlerService.executeCommand(COMMAND_ID, null);

		// Check the state.
		assertSame(
				"The state on the command after the handler changed was not correct",
				OBJECT_CHANGED, command.getState(OBJECT_STATE_ID).getValue());
	}

	/**
	 * Tests that if the command changes the state, the handler reflects these
	 * changes.
	 */
	public final void testStateChangeReflectedInHandler() {
		// Check the initial state.
		assertSame("The initial state was not correct", OBJECT_INITIAL,
				handler.currentValue);

		// Change the state on the command.
		final ICommandService commandService = (ICommandService) fWorkbench
				.getService(ICommandService.class);
		final Command command = commandService.getCommand(COMMAND_ID);
		command.getState(OBJECT_STATE_ID).setValue(OBJECT_CHANGED);

		// Check the state.
		assertSame(
				"The state on the command after the handler changed was not correct",
				OBJECT_CHANGED, handler.currentValue);
	}
}