/*******************************************************************************
 * Copyright (c) 2014, 2015 Google, Inc 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:
 * 	   Sergey Prigogin (Google) - initial API and implementation
 *******************************************************************************/
package org.eclipse.cdt.internal.ui.refactoring.rename;

import java.util.HashMap;
import java.util.Map;

import org.eclipse.core.resources.IContainer;
import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IResourceProxy;
import org.eclipse.core.resources.IResourceProxyVisitor;
import org.eclipse.core.resources.IWorkspaceRoot;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.OperationCanceledException;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.Status;
import org.eclipse.ltk.core.refactoring.Change;
import org.eclipse.ltk.core.refactoring.RefactoringStatus;
import org.eclipse.ltk.core.refactoring.participants.CheckConditionsContext;
import org.eclipse.ltk.core.refactoring.participants.ISharableParticipant;
import org.eclipse.ltk.core.refactoring.participants.RefactoringArguments;
import org.eclipse.ltk.core.refactoring.participants.RenameArguments;
import org.eclipse.ltk.core.refactoring.participants.RenameParticipant;

/**
 * Updates include statements and include guards in response to a file or a folder rename.
 */
public class HeaderFileRenameParticipant extends RenameParticipant implements ISharableParticipant {
	private Map<IResource, RenameArguments> renamedResources;
	private Change change;

	public HeaderFileRenameParticipant() {
	}

	@Override
	protected boolean initialize(Object element) {
		addElement(element, getArguments());
		return renamedResources != null;
	}

	@Override
	public void addElement(Object element, RefactoringArguments arguments) {
		if (element instanceof IResource && arguments instanceof RenameArguments) {
			if (renamedResources == null)
				renamedResources = new HashMap<>();
			renamedResources.put((IResource) element, (RenameArguments) arguments);
		}
	}

	@Override
	public RefactoringStatus checkConditions(IProgressMonitor pm, CheckConditionsContext context)
			throws OperationCanceledException {
		try {
			if (renamedResources == null)
				return RefactoringStatus.create(Status.OK_STATUS);

			// Maps the affected files to new, not yet existing, files.
			final Map<IFile, IFile> movedFiles = new HashMap<>();
			final Map<IContainer, IContainer> renamedContainers = new HashMap<>();

			for (Map.Entry<IResource, RenameArguments> entry : renamedResources.entrySet()) {
				IResource renamedResource = entry.getKey();
				RenameArguments args = entry.getValue();
				if (!args.getUpdateReferences())
					continue;
				if (renamedResource.isLinked())
					continue;
				String newName = args.getNewName();
		
				if (renamedResource instanceof IContainer) {
					IContainer container = (IContainer) renamedResource;
					final IPath oldPath = container.getFullPath();
					final IPath newPath = oldPath.removeLastSegments(1).append(newName);
					final IWorkspaceRoot workspaceRoot = container.getWorkspace().getRoot();
					IContainer newContainer = container.getType() == IResource.FOLDER ?
							workspaceRoot.getFolder(newPath) : workspaceRoot.getProject(newName);
					renamedContainers.put(container, newContainer);
					container.accept(new IResourceProxyVisitor() {
						@Override
						public boolean visit(IResourceProxy proxy) throws CoreException {
							if (proxy.isLinked())
								return false;
							if (proxy.getType() == IResource.FILE) {
								IFile file = (IFile) proxy.requestResource();
								IPath path = replacePrefix(file.getFullPath(), oldPath.segmentCount(), newPath);
								movedFiles.put(file, workspaceRoot.getFile(path));
								return false;
							}
							return true;
						}
					}, IResource.NONE);
				} else if (renamedResource instanceof IFile) {
					IFile file = (IFile) renamedResource;
					movedFiles.put(file, file.getParent().getFile(new Path(newName)));
				}
			}
			HeaderFileReferenceAdjuster includeAdjuster =
					new HeaderFileReferenceAdjuster(movedFiles, renamedContainers, getProcessor());
			change = includeAdjuster.createChange(context, pm);
		} catch (CoreException e) {
			return RefactoringStatus.create(e.getStatus());
		} finally {
			pm.done();
		}
		return RefactoringStatus.create(Status.OK_STATUS);
	}

	@Override
	public Change createPreChange(IProgressMonitor pm) throws CoreException, OperationCanceledException {
		change = RenameParticipantHelper.postprocessParticipantChange(change, this);
		pm.done();
		return change;
	}

	@Override
	public Change createChange(IProgressMonitor pm) throws CoreException, OperationCanceledException {
		pm.done();
		return null;
	}

	@Override
	public String getName() {
		return RenameMessages.HeaderFileRenameParticipant_name;
	}

	/**
	 * Replaces first few segments of the given path with the contents of another path.
	 *
	 * @param path the original path
	 * @param prefixLength the number of segments of {@code path} to replace
	 * @param newPrefix the replacement path
	 * @return the modified path
	 */
	private static IPath replacePrefix(IPath path, int prefixLength, IPath newPrefix) {
		return newPrefix.append(path.removeFirstSegments(prefixLength));
	}
}