/*******************************************************************************
 * Copyright (c) 2000, 2010 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.gef.tools;

import java.lang.reflect.Constructor;

import org.eclipse.swt.events.ControlAdapter;
import org.eclipse.swt.events.ControlEvent;
import org.eclipse.swt.events.ControlListener;
import org.eclipse.swt.events.VerifyListener;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;

import org.eclipse.jface.viewers.CellEditor;
import org.eclipse.jface.viewers.ICellEditorListener;

import org.eclipse.draw2d.AbstractBorder;
import org.eclipse.draw2d.AncestorListener;
import org.eclipse.draw2d.Border;
import org.eclipse.draw2d.ColorConstants;
import org.eclipse.draw2d.Figure;
import org.eclipse.draw2d.Graphics;
import org.eclipse.draw2d.IFigure;
import org.eclipse.draw2d.geometry.Insets;
import org.eclipse.draw2d.geometry.Rectangle;

import org.eclipse.gef.EditPart;
import org.eclipse.gef.EditPartListener;
import org.eclipse.gef.GraphicalEditPart;
import org.eclipse.gef.LayerConstants;
import org.eclipse.gef.commands.Command;
import org.eclipse.gef.commands.CommandStack;
import org.eclipse.gef.editparts.LayerManager;
import org.eclipse.gef.requests.DirectEditRequest;

/**
 * Manages the direct edit operation by creating and maintaining the
 * {@link org.eclipse.jface.viewers.CellEditor} and executing the resulting
 * command if the cell editor value has changed.
 */
public abstract class DirectEditManager {

	private static final Color BLUE = ColorConstants.menuBackgroundSelected;
	private static final Border BORDER_FRAME = new DirectEditBorder();

	private AncestorListener ancestorListener;
	private EditPartListener editPartListener;
	private ControlListener controlListener;
	private IFigure cellEditorFrame;
	private ICellEditorListener cellEditorListener;
	private boolean showingFeedback;
	private boolean dirty;
	private DirectEditRequest request;
	private CellEditorLocator locator;
	private GraphicalEditPart source;
	private CellEditor ce;
	private Class editorType;
	private boolean committing = false;
	private Object feature;

	/**
	 * Constructs a new DirectEditManager for the given source edit part. The
	 * cell editor will be created by instantiating the type <i>editorType</i>.
	 * The cell editor will be placed using the given CellEditorLocator.
	 * 
	 * @param source
	 *            the source edit part
	 * @param editorType
	 *            the cell editor type
	 * @param locator
	 *            the locator
	 */
	public DirectEditManager(GraphicalEditPart source, Class editorType,
			CellEditorLocator locator) {
		this.source = source;
		this.locator = locator;
		this.editorType = editorType;
	}

	/**
	 * Constructs a new DirectEditManager for the given source edit part. The
	 * cell editor will be created by instantiating the type <i>editorType</i>.
	 * The cell editor will be placed using the given CellEditorLocator.
	 * 
	 * @param source
	 *            the source edit part
	 * @param editorType
	 *            the cell editor type
	 * @param locator
	 *            the locator
	 * @param feature
	 *            If the EditPart supports direct editing of multiple features,
	 *            this parameter can be used to discriminate among them.
	 * @since 3.2
	 */
	public DirectEditManager(GraphicalEditPart source, Class editorType,
			CellEditorLocator locator, Object feature) {
		this(source, editorType, locator);
		this.feature = feature;
	}

	/**
	 * Cleanup is done here. Any feedback is erased and listeners unhooked. If
	 * the cell editor is not <code>null</code>, it will be
	 * {@link CellEditor#deactivate() deativated}, {@link CellEditor#dispose()
	 * disposed}, and set to <code>null</code>.
	 */
	protected void bringDown() {
		eraseFeedback();
		unhookListeners();
		if (getCellEditor() != null) {
			getCellEditor().deactivate();
			getCellEditor().dispose();
			setCellEditor(null);
		}
		request = null;
		dirty = false;
	}

	/**
	 * Commits the current value of the cell editor by getting a {@link Command}
	 * from the source edit part and executing it via the {@link CommandStack}.
	 * Finally, {@link #bringDown()} is called to perform and necessary cleanup.
	 */
	protected void commit() {
		if (committing)
			return;
		committing = true;
		try {
			eraseFeedback();
			if (isDirty()) {
				CommandStack stack = getEditPart().getViewer().getEditDomain()
						.getCommandStack();
				stack.execute(getEditPart().getCommand(getDirectEditRequest()));
			}
		} finally {
			bringDown();
			committing = false;
		}
	}

	/**
	 * Creates the cell editor on the given composite. The cell editor is
	 * created by instantiating the cell editor type passed into this
	 * DirectEditManager's constuctor.
	 * 
	 * @param composite
	 *            the composite to create the cell editor on
	 * @return the newly created cell editor
	 */
	protected CellEditor createCellEditorOn(Composite composite) {
		try {
			Constructor constructor = editorType
					.getConstructor(new Class[] { Composite.class });
			return (CellEditor) constructor
					.newInstance(new Object[] { composite });
		} catch (Exception e) {
			return null;
		}
	}

	/**
	 * Creates and returns the DirectEditRequest.
	 * 
	 * @return the direct edit request
	 */
	protected DirectEditRequest createDirectEditRequest() {
		DirectEditRequest req = new DirectEditRequest();
		req.setCellEditor(getCellEditor());
		req.setDirectEditFeature(getDirectEditFeature());
		return req;
	}

	/**
	 * Asks the source edit part to erase source feedback.
	 */
	protected void eraseFeedback() {
		if (showingFeedback) {
			LayerManager.Helper.find(getEditPart())
					.getLayer(LayerConstants.FEEDBACK_LAYER)
					.remove(getCellEditorFrame());
			cellEditorFrame = null;
			getEditPart().eraseSourceFeedback(getDirectEditRequest());
			showingFeedback = false;
		}
	}

	/**
	 * Returns the cell editor.
	 * 
	 * @return the cell editor
	 */
	protected CellEditor getCellEditor() {
		return ce;
	}

	private IFigure getCellEditorFrame() {
		if (cellEditorFrame != null)
			return cellEditorFrame;
		cellEditorFrame = new Figure();
		cellEditorFrame.setBorder(BORDER_FRAME);
		return cellEditorFrame;
	}

	private Control getControl() {
		return ce.getControl();
	}

	/**
	 * @return <code>Object</code> that can be used if the EditPart supports
	 *         direct editing of multiple features, this parameter can be used
	 *         to discriminate among them.
	 * @since 3.2
	 */
	protected Object getDirectEditFeature() {
		return feature;
	}

	/**
	 * Returns the direct edit request, creating it if needed.
	 * 
	 * @return the direct edit request
	 */
	protected DirectEditRequest getDirectEditRequest() {
		if (request == null)
			request = createDirectEditRequest();
		return request;
	}

	/**
	 * Returns the source edit part.
	 * 
	 * @return the source edit part
	 */
	protected GraphicalEditPart getEditPart() {
		return source;
	}

	protected CellEditorLocator getLocator() {
		return locator;
	}

	protected void handleValueChanged() {
		setDirty(true);
		showFeedback();
		placeCellEditor();
	}

	protected void hookListeners() {
		ancestorListener = new AncestorListener.Stub() {
			public void ancestorMoved(IFigure ancestor) {
				placeCellEditor();
			}
		};
		getEditPart().getFigure().addAncestorListener(ancestorListener);

		Control control = getControl();

		controlListener = new ControlAdapter() {
			public void controlMoved(ControlEvent e) {
				// This must be handled async because during scrolling, the
				// CellEditor moves
				// first, but then afterwards the viewport Scrolls, which would
				// cause the
				// shadow to move twice
				Display.getCurrent().asyncExec(new Runnable() {
					public void run() {
						placeBorder();
					}
				});
			}

			public void controlResized(ControlEvent e) {
				placeBorder();
			}
		};
		control.addControlListener(controlListener);

		cellEditorListener = new ICellEditorListener() {
			public void applyEditorValue() {
				commit();
			}

			public void cancelEditor() {
				bringDown();
			}

			public void editorValueChanged(boolean old, boolean newState) {
				handleValueChanged();
			}
		};
		getCellEditor().addListener(cellEditorListener);

		editPartListener = new EditPartListener.Stub() {
			public void partDeactivated(EditPart editpart) {
				bringDown();
			}
		};
		getEditPart().addEditPartListener(editPartListener);
	}

	/**
	 * Initializes the cell editor. Subclasses should implement this to set the
	 * initial text and add things such as {@link VerifyListener
	 * VerifyListeners}, if needed.
	 */
	protected abstract void initCellEditor();

	/**
	 * Returns <code>true</code> if the cell editor's value has been changed.
	 * 
	 * @return <code>true</code> if the cell editor is dirty
	 */
	protected boolean isDirty() {
		return dirty;
	}

	private void placeBorder() {
		if (showingFeedback) {
			IFigure shadow = getCellEditorFrame();
			Rectangle rect = new Rectangle(getCellEditor().getControl()
					.getBounds());
			rect.expand(shadow.getInsets());
			shadow.translateToRelative(rect);
			shadow.setBounds(rect);
		}
	}

	private void placeCellEditor() {
		getLocator().relocate(getCellEditor());
	}

	/**
	 * Sets the cell editor to the given editor.
	 * 
	 * @param editor
	 *            the cell editor
	 */
	protected void setCellEditor(CellEditor editor) {
		ce = editor;
		if (ce == null)
			return;
		hookListeners();
	}

	/**
	 * Sets the dirty property.
	 * 
	 * @param value
	 *            the dirty property
	 */
	protected void setDirty(boolean value) {
		dirty = value;
	}

	/**
	 * Sets the source edit part.
	 * 
	 * @param source
	 *            the source edit part
	 */
	protected void setEditPart(GraphicalEditPart source) {
		this.source = source;
		// source.addEditPartListener();
	}

	/**
	 * Sets the CellEditorLocator used to place the cell editor in the correct
	 * location.
	 * 
	 * @param locator
	 *            the locator
	 */
	public void setLocator(CellEditorLocator locator) {
		this.locator = locator;
	}

	/**
	 * Shows the cell editor when direct edit is started. Calls
	 * {@link #initCellEditor()}, {@link CellEditor#activate()}, and
	 * {@link #showFeedback()}.
	 */
	public void show() {
		if (getCellEditor() != null)
			return;
		Composite composite = (Composite) source.getViewer().getControl();
		setCellEditor(createCellEditorOn(composite));
		if (getCellEditor() == null)
			return;
		initCellEditor();
		getCellEditor().activate();
		placeCellEditor();
		getControl().setVisible(true);
		getCellEditor().setFocus();
		showFeedback();
	}

	private void showCellEditorFrame() {
		LayerManager.Helper.find(getEditPart())
				.getLayer(LayerConstants.FEEDBACK_LAYER)
				.add(getCellEditorFrame());
		placeBorder();
	}

	/**
	 * Asks the source edit part to show source feedback.
	 */
	public void showFeedback() {
		if (!showingFeedback)
			showCellEditorFrame();
		showingFeedback = true;
		showCellEditorFrame();
		getEditPart().showSourceFeedback(getDirectEditRequest());
	}

	/**
	 * Unhooks listeners. Called from {@link #bringDown()}.
	 */
	protected void unhookListeners() {
		getEditPart().getFigure().removeAncestorListener(ancestorListener);
		getEditPart().removeEditPartListener(editPartListener);
		ancestorListener = null;
		editPartListener = null;

		if (getCellEditor() == null)
			return;
		getCellEditor().removeListener(cellEditorListener);
		cellEditorListener = null;

		Control control = getCellEditor().getControl();
		if (control == null || control.isDisposed())
			return;
		control.removeControlListener(controlListener);
		controlListener = null;
	}

	private static class DirectEditBorder extends AbstractBorder {
		private static final Insets insets = new Insets(1, 2, 2, 2);

		public Insets getInsets(IFigure figure) {
			return insets;
		}

		public void paint(IFigure figure, Graphics graphics, Insets insets) {
			Rectangle rect = getPaintRectangle(figure, insets);
			graphics.setForegroundColor(ColorConstants.white);
			graphics.drawLine(rect.x, rect.y, rect.x, rect.bottom());
			rect.x++;
			rect.width--;
			rect.resize(-1, -1);
			graphics.setForegroundColor(ColorConstants.black);
			graphics.drawLine(rect.x + 2, rect.bottom(), rect.right(),
					rect.bottom());
			graphics.drawLine(rect.right(), rect.bottom(), rect.right(),
					rect.y + 2);

			rect.resize(-1, -1);
			graphics.setForegroundColor(BLUE);
			graphics.drawRectangle(rect);
		}
	}

}