/*******************************************************************************
 * Copyright (c) 2005-2008 Polarion Software.
 * 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:
 *    Igor Burilo - Initial API and implementation
 *******************************************************************************/

package org.eclipse.team.svn.core;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IResourceChangeEvent;
import org.eclipse.core.resources.IResourceChangeListener;
import org.eclipse.core.resources.IResourceDelta;
import org.eclipse.core.resources.IResourceDeltaVisitor;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.team.svn.core.connector.ISVNConnector;
import org.eclipse.team.svn.core.connector.ISVNConnector.Depth;
import org.eclipse.team.svn.core.connector.SVNEntryRevisionReference;
import org.eclipse.team.svn.core.connector.SVNRevision;
import org.eclipse.team.svn.core.operation.CompositeOperation;
import org.eclipse.team.svn.core.operation.LoggedOperation;
import org.eclipse.team.svn.core.operation.SVNProgressMonitor;
import org.eclipse.team.svn.core.operation.local.AbstractWorkingCopyOperation;
import org.eclipse.team.svn.core.operation.local.RefreshResourcesOperation;
import org.eclipse.team.svn.core.resource.ILocalResource;
import org.eclipse.team.svn.core.resource.IRepositoryLocation;
import org.eclipse.team.svn.core.svnstorage.SVNRemoteStorage;
import org.eclipse.team.svn.core.utility.FileUtility;
import org.eclipse.team.svn.core.utility.ProgressMonitorUtility;

/**
 * Handles the file deletion "Undo": there should be no change in the end.
 * If the files are different everything will be left as is. 
 * 
 * @author Igor Burilo
 */
public class FileReplaceListener implements IResourceChangeListener {

	public void resourceChanged(IResourceChangeEvent event) {
		try {
			final List<IFile> added = new ArrayList<IFile>();			
			event.getDelta().accept(new IResourceDeltaVisitor() {
				public boolean visit(IResourceDelta delta) throws CoreException {
					if (delta.getResource().getType() == IResource.FILE && delta.getKind() == IResourceDelta.ADDED) {
						added.add((IFile)delta.getResource());
					}					
					return true;
				}			
			});			
			if (!added.isEmpty()) {
				this.processResources(added.toArray(new IResource[0]));
			}
		} catch (CoreException e) {
			LoggedOperation.reportError(this.getClass().getName(), e);
		}
	}

	protected void processResources(IResource []resources) {
		AbstractWorkingCopyOperation mainOp = new AbstractWorkingCopyOperation("Operation_FileReplaceListener", SVNMessages.class, resources) { //$NON-NLS-1$
			protected void runImpl(IProgressMonitor monitor) throws Exception {																				
				for (IResource file : this.operableData()) {														
					if (monitor.isCanceled()) {
						return;
					}

					ILocalResource local = SVNRemoteStorage.instance().asLocalResource(file);
					if (!IStateFilter.SF_PREREPLACEDREPLACED.accept(local)) {
						continue;
					}
					IResource parent = file.getParent();
					ILocalResource localParent = SVNRemoteStorage.instance().asLocalResource(parent);
					if (IStateFilter.SF_DELETED.accept(localParent)) {
						continue;
					}
					
					File originalFile = new File(FileUtility.getWorkingCopyPath(file));
					File tmpFile = new File(originalFile + ".svntmp"); //$NON-NLS-1$
					try {
						IRepositoryLocation location = SVNRemoteStorage.instance().getRepositoryLocation(file);
						ISVNConnector proxy = location.acquireSVNProxy();
						FileOutputStream oStream = null;
						try {
							oStream = new FileOutputStream(tmpFile);
							proxy.streamFileContent(new SVNEntryRevisionReference(originalFile.getAbsolutePath(), null, SVNRevision.BASE), 8192, oStream, new SVNProgressMonitor(this, monitor, null));
							if (this.equals(originalFile, tmpFile)) {
								originalFile.delete();
								proxy.revert(originalFile.getAbsolutePath(), Depth.EMPTY, null, new SVNProgressMonitor(this, monitor, null));
							}
						}
						finally {
							if (oStream != null) {
								try {oStream.close();} catch (IOException ex) {}
							}
							location.releaseSVNProxy(proxy);
						}
					}
					finally {
						if (!originalFile.exists()) {
							tmpFile.renameTo(originalFile);
						}
						else {
							tmpFile.delete();
						}
					}
				}									
			}	
			
			protected boolean equals(File src1, File src2) throws IOException {
				long len = src1.length();
				if (len == src2.length()) {
					FileInputStream stream1 = null;
					FileInputStream stream2 = null;
					try {
						stream1 = new FileInputStream(src1);
						stream2 = new FileInputStream(src2);
						int bufSize = len < 8192 ? (int)len : 8192;
						byte []buffer1 = new byte[bufSize];
						byte []buffer2 = new byte[bufSize];
						int rem = (int)(len % bufSize);
						for (int off = 0; off < len; off += bufSize) {
							stream1.read(buffer1);							
							stream2.read(buffer2);
							if (!Arrays.equals(buffer1, buffer2)) {
								return false;
							}
						}
						if (rem != 0) {
							buffer1 = new byte[rem];
							buffer2 = new byte[rem];
							stream1.read(buffer1);
							stream2.read(buffer2);
							if (!Arrays.equals(buffer1, buffer2)) {
								return false;
							}
						}
						return true;
					}
					finally {
						if (stream1 != null) {
							try {stream1.close();} catch (IOException ex) {}
						}
						if (stream2 != null) {
							try {stream2.close();} catch (IOException ex) {}
						}
					}
				}
				return false;
			}
		};			
		
		CompositeOperation cmpOp = new CompositeOperation(mainOp.getId(), mainOp.getMessagesClass());
		cmpOp.add(mainOp);
		cmpOp.add(new RefreshResourcesOperation(resources));			
		ProgressMonitorUtility.doTaskScheduledDefault(cmpOp);
	}
}