/*******************************************************************************
 * Copyright (c) 2000, 2010 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ltk.internal.ui.refactoring;

import java.util.List;

import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IAdaptable;

import org.eclipse.core.resources.IResource;

import org.eclipse.jface.resource.ImageDescriptor;

import org.eclipse.ltk.core.refactoring.Change;
import org.eclipse.ltk.core.refactoring.CompositeChange;
import org.eclipse.ltk.core.refactoring.GroupCategory;
import org.eclipse.ltk.core.refactoring.TextEditBasedChange;
import org.eclipse.ltk.ui.refactoring.ChangePreviewViewerInput;
import org.eclipse.ltk.ui.refactoring.IChangePreviewViewer;
import org.eclipse.ltk.ui.refactoring.TextEditChangeNode;

public abstract class AbstractChangeNode extends PreviewNode {

	private final Change fChange;
	private PreviewNode[] fChildren;

	public static PreviewNode createNode(PreviewNode parent, RefactoringPreviewChangeFilter filter, Change change) {
		if (change instanceof CompositeChange) {
			return new CompositeChangeNode(parent, filter, (CompositeChange)change);
		} else if (change instanceof TextEditBasedChange) {
			InternalTextEditChangeNode result= change.getAdapter(TextEditChangeNode.class);
			if (result == null) {
				result= new TextEditChangeNode((TextEditBasedChange)change);
			}
			result.initialize(parent);
			return result;
		}
		return new DefaultChangeNode(parent, change);
	}

	public static PreviewNode createNode(PreviewNode parent, Change change) {
		return createNode(parent, null, change);
	}

	/**
	 * Creates a new <code>AbstractChangeNode</code> for the given
	 * change.
	 *
	 * @param parent the change nodes's parent or <code>null
	 * 	</code> if the change node doesn't have a parent
	 * @param change the actual change. Argument must not be
	 * 	<code>null</code>
	 */
	AbstractChangeNode(PreviewNode parent, Change change) {
		super(parent);
		Assert.isNotNull(change);
		fChange= change;
	}

	/**
	 * Returns the underlying <code>Change</code> object.
	 *
	 * @return the underlying change
	 */
	Change getChange() {
		return fChange;
	}

	@Override
	PreviewNode[] getChildren() {
		if (fChildren == null) {
			fChildren= doCreateChildren();
		}
		return fChildren;
	}

	abstract PreviewNode[] doCreateChildren();

	@Override
	public String getText() {
		return fChange.getName();
	}

	@Override
	public ImageDescriptor getImageDescriptor() {
		return RefactoringPluginImages.DESC_OBJS_DEFAULT_CHANGE;
	}

	@Override
	ChangePreviewViewerDescriptor getChangePreviewViewerDescriptor() throws CoreException {
		return ChangePreviewViewerDescriptor.get(fChange);
	}

	@Override
	void feedInput(IChangePreviewViewer viewer, List<GroupCategory> categories) throws CoreException {
		viewer.setInput(new ChangePreviewViewerInput(fChange));
	}

	@Override
	void setEnabled(boolean enabled) {
		fChange.setEnabled(enabled);
	}

	@Override
	void setEnabledShallow(boolean enabled) {
		fChange.setEnabledShallow(enabled);
	}

	@Override
	boolean hasOneGroupCategory(List<GroupCategory> categories) {
		for (PreviewNode child : getChildren()) {
			if (child.hasOneGroupCategory(categories)) {
				return true;
			}
		}
		return false;
	}

	@Override
	boolean hasDerived() {
		if (hasDerivedResourceChange(fChange))
			return true;
		for (PreviewNode child : getChildren()) {
			if (child.hasDerived()) {
				return true;
			}
		}
		return false;
	}

	int getDefaultChangeActive() {
		int result= fChange.isEnabled() ? ACTIVE : INACTIVE;
		if (fChildren != null) {
			for (PreviewNode child : fChildren) {
				result= ACTIVATION_TABLE[child.getActive()][result];
				if (result == PARTLY_ACTIVE)
					break;
			}
		}
		return result;
	}

	int getCompositeChangeActive() {
		if (fChildren != null && fChildren.length > 0) {
			int result= fChildren[0].getActive();
			for (int i= 1; i < fChildren.length; i++) {
				result= ACTIVATION_TABLE[fChildren[i].getActive()][result];
				if (result == PARTLY_ACTIVE)
					break;
			}
			return result;
		} else {
			return fChange.isEnabled() ? ACTIVE : INACTIVE;
		}
	}

	/**
	 * Returns <code>true</code> iff the change node contains a derived
	 * resource.
	 *
	 * @param change the change
	 * @return whether the change contains a derived resource
	 */
	static boolean hasDerivedResourceChange(Change change) {
		Object modifiedElement= change.getModifiedElement();
		if (modifiedElement instanceof IResource) {
			return ((IResource) modifiedElement).isDerived(IResource.CHECK_ANCESTORS);
		} else if (modifiedElement instanceof IAdaptable) {
			IAdaptable adaptable= (IAdaptable) modifiedElement;
			IResource resource= adaptable.getAdapter(IResource.class);
			if (resource != null) {
				return resource.isDerived(IResource.CHECK_ANCESTORS);
			}
		}
		return false;
	}
}