/*

* Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

*

*/

package com.nokia.carbide.internal.cpp.epoc.engine.model;

import com.nokia.carbide.cpp.epoc.engine.EpocEnginePlugin;

import com.nokia.carbide.cpp.epoc.engine.model.IModelFactory;

import com.nokia.carbide.internal.cpp.epoc.engine.Messages;

import com.nokia.cpp.internal.api.utils.core.*;

import com.nokia.cpp.internal.api.utils.core.MultiResourceChangeListenerDispatcher.IResourceChangeHandler;

import com.nokia.sdt.utils.WorkspaceFileTracker;

import org.eclipse.core.resources.*;

import org.eclipse.core.runtime.*;

import java.io.File;

import java.io.IOException;

import java.util.Arrays;

import java.util.HashMap;

import java.util.Map;

/**

 * This is the model provider implementation that understands workspace

 * semantics.  All paths are workspace-relative.

 *

 */

public class WorkspaceModelProvider<Model, SharedModel> extends ModelProviderBase implements IResourceChangeHandler {

	private WorkspaceFileTracker fileHandler;

	private Map<IPath, Long> externalFileModDateMap;

	public WorkspaceModelProvider(IModelFactory modelFactory) {

		super(modelFactory);

		Check.checkState(Platform.isRunning());

		this.fileHandler = new WorkspaceFileTracker();

		this.externalFileModDateMap = new HashMap<IPath, Long>();

	}

	/**

	 * @param path

	 * @return

	 */

	private File getAbsoluteFileForPath(IPath path) {

		if (path.segmentCount() <= 1)

			return null;

		IResource resource = ResourcesPlugin.getWorkspace().getRoot().getFile(path);

		if (resource == null || resource.getLocation() == null)

			return null;

		// get the real file if a linked resource

		File file;

		IPath rawLocation = resource.getRawLocation();

		if (rawLocation != null)

			file = rawLocation.toFile();

		else

			file = resource.getLocation().toFile();

		return file;

	}

	/* (non-Javadoc)

	 * @see com.nokia.carbide.internal.cpp.epoc.engine.model.ModelProviderBase#getCanonicalPath(org.eclipse.core.runtime.IPath)

	 */

	@Override

	protected IPath getFullPath(IPath path) {

		File file;

		// oops, clients aren't following the "workspace-relative path" rule all the

		// time; this seems like a good way to tell the difference.

		if (path.getDevice() != null) {

			file = new File(path.toOSString());

		} else {

			file = getAbsoluteFileForPath(path);

			if (file == null)

				return path;

		}

		try {

		} catch (IOException e) {

			EpocEnginePlugin.log(e);

			return new Path(file.getAbsolutePath());

		}

	}

	/* (non-Javadoc)

	 * @see com.nokia.carbide.internal.cpp.epoc.engine.model.ModelProviderBase#loadDocument(org.eclipse.core.runtime.IPath)

	 */

	@Override

	protected String loadStorage(IPath fullPath) throws CoreException {

		File file = fullPath.toFile();

		if (file != null && file.exists()) {

			externalFileModDateMap.put(fullPath, file.lastModified());

			char[] text = fileHandler.loadFileText(file);

			return new String(text);

		} else {

			externalFileModDateMap.remove(fullPath);

			return null;

		}

	}

	/* (non-Javadoc)

	 * @see com.nokia.carbide.internal.cpp.epoc.engine.model.ModelProviderBase#saveDocument(org.eclipse.core.runtime.IPath, org.eclipse.jface.text.IDocument)

	 */

	@Override

	protected void saveStorage(IPath fullPath, final String text)

			throws CoreException {

		final File file = fullPath.toFile();

		if (file != null) {

			// get current contents and ignore save if nothing changed

			try {

				char[] currentChars = fileHandler.loadFileText(file);

				if (Arrays.equals(currentChars, text.toCharArray())) {

					return;

				}

			} catch (CoreException e) {

				// ignore

			}

			final char[] chars = text.toCharArray();

        	// back up file if outside workspace

			IPath wsPath = FileUtils.convertToWorkspacePath(fullPath, false);

			if (wsPath == null) {

	        	File backup = new Path(file.getAbsolutePath()).removeFileExtension().addFileExtension("bak").toFile(); //$NON-NLS-1$

	        	backup.delete();

	        	// copy it rather than rename it, so the original is always there.  otherwise saveFileText will fail since the original

	        	// resource would be missing

	        	if (file.exists()) {

		        	try {

						FileUtils.copyFile(file, backup);

					} catch (IOException e) {

						EpocEnginePlugin.log(e);

					}

	        	}

				fileHandler.saveFileText(file, null, chars);

				externalFileModDateMap.put(fullPath, file.lastModified());

			} else {

				// we can't be sure we have rights to modify the workspace

				// (e.g. might be triggered through a resource listener), so do this in a job

				//

				// also, due to boog 4636, a resource which exists in multiple

				// projects may be saved under a different scheduling rule;

				// we need to trap this and try again in a job if necessary.

				boolean retryInJob = false;

				if (ResourcesPlugin.getWorkspace().isTreeLocked()) {

					retryInJob = true;

				} else {

					try {

						fileHandler.saveFileText(file, null, chars);

					} catch (IllegalArgumentException e) {

						// too bad there is not a more specific error :(

						retryInJob = true;

					}

				}

				if (retryInJob) {

					WorkspaceJob job = new WorkspaceJob(Messages.getString("WorkspaceModelProvider.SavingModelFile.TaskLabel")) { //$NON-NLS-1$

						@Override

						public IStatus runInWorkspace(IProgressMonitor monitor)

								throws CoreException {

							fileHandler.saveFileText(file, null, chars);

							return Status.OK_STATUS;

						}

					};

					// note: because character sets might be changed, the rule is really the project

					job.setRule(ResourcesPlugin.getWorkspace().getRoot().getProject(wsPath.segment(0)));

					job.setPriority(WorkspaceJob.INTERACTIVE);

					job.schedule();

				}

			}

		}

	}

	/* (non-Javadoc)

	 * @see com.nokia.carbide.internal.cpp.epoc.engine.model.ModelProviderBase#startTrackingStorage(org.eclipse.core.runtime.IPath)

	 */

	protected void startTrackingStorage(IPath fullPath) {

		// the path is canonical already

		IPath wsPath = FileUtils.convertToWorkspacePath(fullPath, false);

		if (wsPath == null) {

			externalFileModDateMap.put(fullPath, fullPath.toFile().lastModified());

		} else {

			externalFileModDateMap.remove(fullPath);

			EpocEnginePlugin.getMultiResourceChangeListenerDispatcher().addResource(wsPath, this);

		}

	}

	/* (non-Javadoc)

	 * @see com.nokia.carbide.internal.cpp.epoc.engine.model.ModelProviderBase#stopTrackingStorage(org.eclipse.core.runtime.IPath)

	 */

	protected void stopTrackingStorage(IPath fullPath) {

		// remove stragglers if they were originally external and now workspace files

		externalFileModDateMap.remove(fullPath);

		IPath wsPath = FileUtils.convertToWorkspacePath(fullPath, false);

		if (wsPath != null) {

			EpocEnginePlugin.getMultiResourceChangeListenerDispatcher().removeResource(wsPath, this);

		}

	}

	@Override

	protected boolean hasTrackedStorageChanged(IPath fullPath) {

		Long prevTime = externalFileModDateMap.get(fullPath);

		if (prevTime == null) {

			IFile wsFile = FileUtils.convertFileToIFile(fullPath.toFile());

			// boog 4045: Eclipse may still give us a "workspace file" for something no

			// longer visible in the workspace (e.g. due to its project being deleted)! 

			// But we can tell if the IFile doesn't "exist".

			if (wsFile == null || !wsFile.exists()) {

				// we don't even know about it: e.g., cleanly registered file

				return true;

			}

			// if a workspace file, we're already tracking it

			return false;

		} else {

			// originally an external file (tho it may possibly now be a workspace file)

			if (prevTime.longValue() != fullPath.toFile().lastModified()) {

				return true;

			}

			return false;

		}

	}

	/* (non-Javadoc)

	 * @see com.nokia.cpp.internal.api.utils.core.*

	 */

	public void resourceChanged(IPath workspacePath) {

		fireStorageChanged(getFullPath(workspacePath));

	}

}