Copyright (c) 2006, 2017 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
/*******************************************************************************
 * Copyright (c) 2006, 2017 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.team.internal.core.history;

import java.net.URI;

import org.eclipse.core.filesystem.URIUtil;
import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IFileState;
import org.eclipse.core.resources.IStorage;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.osgi.util.NLS;
import org.eclipse.team.core.history.IFileRevision;
import org.eclipse.team.core.history.ITag;
import org.eclipse.team.core.history.provider.FileRevision;
import org.eclipse.team.internal.core.Messages;

A LocalFileRevision is used for wrapping local files in order to display
them in the History View. As such, this class can be used to wrap either
a local file's IFileState or an IFile.
/**
 * A LocalFileRevision is used for wrapping local files in order to display
 * them in the History View. As such, this class can be used to wrap either
 * a local file's IFileState or an IFile.
 */
public class LocalFileRevision extends FileRevision {
	/*
	 * Either one or the other of these fields is intended
	 * to be used.
	 */
	//Used for wrapping local file history items
	private IFileState state;

	//Used for displaying the "real" current file
	private IFile file;
	//Used for displaying which base revision
	private IFileRevision baseRevision;

	/*
	 * Used for wrapping an IFileState.
	 */
	public LocalFileRevision(IFileState state) {
		this.state = state;
		this.file = null;
		this.baseRevision = null;
	}

	/*
	 * Used for wrapping an IFile. This is generally used to represent the local
	 * current version of the file being displayed in the history. Make sure to
	 * also pass in the base revision associated with this current version.
	 *
	 * @see #setBaseRevision(IFileRevision)
	 */
	public LocalFileRevision(IFile file) {
		this.file = file;
		this.baseRevision = null;
		this.state = null;
	}

	@Override
	public String getContentIdentifier() {
		if (file != null)
			return baseRevision == null ?  NLS.bind(Messages.LocalFileRevision_currentVersion, "") : NLS.bind(Messages.LocalFileRevision_currentVersion, baseRevision.getContentIdentifier()); //$NON-NLS-1$
		return ""; //$NON-NLS-1$
	}

	@Override
	public String getAuthor() {
		return ""; //$NON-NLS-1$
	}

	@Override
	public String getComment() {
		if (file != null)
			return Messages.LocalFileRevision_currentVersionTag;
		return null;
	}

	@Override
	public ITag[] getTags() {
		return new ITag[0];
	}

	@Override
	public IStorage getStorage(IProgressMonitor monitor) throws CoreException {
		if (file != null) {
			return file;
		}
		return state;
	}

	@Override
	public String getName() {
		if (file != null) {
			return file.getName();
		}

		return state.getName();
	}

	@Override
	public long getTimestamp() {
		if (file != null) {
			return file.getLocalTimeStamp();
		}

		return state.getModificationTime();
	}

	/*
	 * A LocalFileRevision generally should exist, but if it doesn't, this method
	 * should tell the truth.
	 */
	@Override
	public boolean exists() {
		if (file != null) {
			return file.exists();
		}

		return state.exists();
	}

	/*
	 * Sets the base revision. Can be used to associate a base revision
	 * with an IFile.
	 */
	public void setBaseRevision(IFileRevision baseRevision) {
		this.baseRevision = baseRevision;
	}

	@Override
	public boolean isPropertyMissing() {
		return true;
	}


	@Override
	public IFileRevision withAllProperties(IProgressMonitor monitor) {
		return this;
	}

	public boolean isPredecessorOf(IFileRevision revision) {
		long compareRevisionTime = revision.getTimestamp();
		return (this.getTimestamp() < compareRevisionTime);
	}

	public boolean isDescendentOf(IFileRevision revision) {
		long compareRevisionTime = revision.getTimestamp();
		return (this.getTimestamp() > compareRevisionTime);
	}

	@Override
	public URI getURI() {
		if (file != null)
			return file.getLocationURI();

		return URIUtil.toURI(state.getFullPath());
	}

	public IFile getFile() {
		return file;
	}

	public IFileState getState() {
		return state;
	}

	public boolean isCurrentState() {
		return file != null;
	}

	@Override
	public boolean equals(Object obj) {
		if (obj == this)
			return true;
		if (obj instanceof LocalFileRevision) {
			LocalFileRevision other = (LocalFileRevision) obj;
			if (file != null && other.file != null)
				return file.equals(other.file);
			if (state != null && other.state != null)
				return statesEqual(state, other.state);
		}
		return false;
	}

	private boolean statesEqual(IFileState s1, IFileState s2) {
		return (s1.getFullPath().equals(s2.getFullPath()) && s1.getModificationTime() == s2.getModificationTime());
	}

	@Override
	public int hashCode() {
		if (file != null)
			return file.hashCode();
		if (state != null)
			return (int)state.getModificationTime();
		return super.hashCode();
	}
}