/*******************************************************************************
 * Copyright (c) 2005, 2006 IBM Corporation 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:
 *     IBM Corporation - initial API and implementation
 *     Ken Gilmer - adaptation from internal class.
 *******************************************************************************/
package org.openembedded.bc.ui.filesystem;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URI;
import java.util.List;

import org.eclipse.core.filesystem.EFS;
import org.eclipse.core.filesystem.IFileInfo;
import org.eclipse.core.filesystem.IFileStore;
import org.eclipse.core.filesystem.IFileSystem;
import org.eclipse.core.filesystem.URIUtil;
import org.eclipse.core.filesystem.provider.FileInfo;
import org.eclipse.core.filesystem.provider.FileStore;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.MultiStatus;
import org.eclipse.core.runtime.NullProgressMonitor;
import org.eclipse.core.runtime.Status;
import org.eclipse.osgi.util.NLS;

/**
 * File system implementation based on storage of files in the local
 * operating system's file system.
 */
public class OEFile extends FileStore {
	private static int attributes(File aFile) {
		if (!aFile.exists() || aFile.canWrite())
			return EFS.NONE;
		return EFS.ATTRIBUTE_READ_ONLY;
	}
	
	/**
	 * The java.io.File that this store represents.
	 */
	protected final File file;
	private List ignorePaths;

	/**
	 * The absolute file system path of the file represented by this store.
	 */
	protected final String filePath;

	private final String root;

	/**
	 * Creates a new local file.
	 * 
	 * @param file The file this local file represents
	 * @param root 
	 */
	public OEFile(File file, List ignorePaths, String root) {
		this.file = file;
		this.ignorePaths = ignorePaths;
		this.root = root;
		this.filePath = file.getAbsolutePath();
	}

	/**
	 * This method is called after a failure to modify a file or directory.
	 * Check to see if the parent is read-only and if so then
	 * throw an exception with a more specific message and error code.
	 * 
	 * @param target The file that we failed to modify
	 * @param exception The low level exception that occurred, or <code>null</code>
	 * @throws CoreException A more specific exception if the parent is read-only
	 */
	private void checkReadOnlyParent(File target, Throwable exception) throws CoreException {
		File parent = target.getParentFile();
		if (parent != null && (attributes(parent) & EFS.ATTRIBUTE_READ_ONLY) != 0) {
			String message = NLS.bind(Messages.readOnlyParent, target.getAbsolutePath());
			Policy.error(EFS.ERROR_PARENT_READ_ONLY, message, exception);
		}
	}

	@Override
	public String[] childNames(int options, IProgressMonitor monitor) {
		String[] names = file.list();
		return (names == null ? EMPTY_STRING_ARRAY : names);
	}

	@Override
	public IFileStore[] childStores(int options, IProgressMonitor monitor) throws CoreException {
		String[] children = childNames(options, monitor);
		IFileStore[] wrapped = new IFileStore[children.length];
		
		for (int i = 0; i < wrapped.length; i++) {
			String fullPath = file.toString() +File.separatorChar + children[i];
			
			if (ignorePaths.contains(fullPath)) {
				wrapped[i] = getDeadChild(children[i]);
			} else {
				wrapped[i] = getChild(children[i]);
			}			
		}
		
		return wrapped;
	}

	@Override
	public void copy(IFileStore destFile, int options, IProgressMonitor monitor) throws CoreException {
		if (destFile instanceof OEFile) {
			File source = file;
			File destination = ((OEFile) destFile).file;
			//handle case variants on a case-insensitive OS, or copying between
			//two equivalent files in an environment that supports symbolic links.
			//in these nothing needs to be copied (and doing so would likely lose data)
			try {
				if (source.getCanonicalFile().equals(destination.getCanonicalFile())) {
					//nothing to do
					return;
				}
			} catch (IOException e) {
				String message = NLS.bind(Messages.couldNotRead, source.getAbsolutePath());
				Policy.error(EFS.ERROR_READ, message, e);
			}
		}
		//fall through to super implementation
		super.copy(destFile, options, monitor);
	}

	@Override
	public void delete(int options, IProgressMonitor monitor) throws CoreException {
		if (monitor == null)
			monitor = new NullProgressMonitor();
		else
			monitor = new NullProgressMonitor();
		try {
			monitor.beginTask(NLS.bind(Messages.deleting, this), 200);
			String message = Messages.deleteProblem;
			MultiStatus result = new MultiStatus(Policy.PI_FILE_SYSTEM, EFS.ERROR_DELETE, message, null);
			
			//don't allow Eclipse to delete entire OE directory
			
			if (!isProject()) {
				internalDelete(file, filePath, result, monitor);
			}
			
			if (!result.isOK())
				throw new CoreException(result);
		} finally {
			monitor.done();
		}
	}

	@Override
	public boolean equals(Object obj) {
		if (!(obj instanceof OEFile))
			return false;

		OEFile otherFile = (OEFile) obj;

		return file.equals(otherFile.file);
	}

	@Override
	public IFileInfo fetchInfo(int options, IProgressMonitor monitor) {
		//in-lined non-native implementation
		FileInfo info = new FileInfo(file.getName());
		final long lastModified = file.lastModified();
		if (lastModified <= 0) {
			//if the file doesn't exist, all other attributes should be default values
			info.setExists(false);
			return info;
		}
		info.setLastModified(lastModified);
		info.setExists(true);
		info.setLength(file.length());
		info.setDirectory(file.isDirectory());
		info.setAttribute(EFS.ATTRIBUTE_READ_ONLY, file.exists() && !file.canWrite());
		info.setAttribute(EFS.ATTRIBUTE_HIDDEN, file.isHidden());
		return info;
	}
	
	@Override
	public IFileStore getChild(IPath path) {
		return new OEFile(new File(file, path.toOSString()), ignorePaths, root);
	}

	@Override
	public IFileStore getChild(String name) {
		return new OEFile(new File(file, name), ignorePaths, root);
	}

	private IFileStore getDeadChild(String name) {
		return new OEIgnoreFile(new File(file, name));
	}

	/*
	 * (non-Javadoc)
	 * @see org.eclipse.core.filesystem.IFileStore#getFileSystem()
	 */
	@Override
	public IFileSystem getFileSystem() {
		return OEFileSystem.getInstance();
	}

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

	@Override
	public IFileStore getParent() {
		File parent = file.getParentFile();
		return parent == null ? null : new OEFile(parent, ignorePaths, root);
	}

	@Override
	public int hashCode() {
		return file.hashCode();
	}

	/**
	 * Deletes the given file recursively, adding failure info to
	 * the provided status object.  The filePath is passed as a parameter
	 * to optimize java.io.File object creation.
	 */
	private boolean internalDelete(File target, String pathToDelete, MultiStatus status, IProgressMonitor monitor) {
		//first try to delete - this should succeed for files and symbolic links to directories
		if (target.delete() || !target.exists())
			return true;
		if (target.isDirectory()) {
			monitor.subTask(NLS.bind(Messages.deleting, target));
			String[] list = target.list();
			if (list == null)
				list = EMPTY_STRING_ARRAY;
			int parentLength = pathToDelete.length();
			boolean failedRecursive = false;
			for (int i = 0, imax = list.length; i < imax; i++) {
				//optimized creation of child path object
				StringBuffer childBuffer = new StringBuffer(parentLength + list[i].length() + 1);
				childBuffer.append(pathToDelete);
				childBuffer.append(File.separatorChar);
				childBuffer.append(list[i]);
				String childName = childBuffer.toString();
				// try best effort on all children so put logical OR at end
				failedRecursive = !internalDelete(new java.io.File(childName), childName, status, monitor) || failedRecursive;
				monitor.worked(1);
			}
			try {
				// don't try to delete the root if one of the children failed
				if (!failedRecursive && target.delete())
					return true;
			} catch (Exception e) {
				// we caught a runtime exception so log it
				String message = NLS.bind(Messages.couldnotDelete, target.getAbsolutePath());
				status.add(new Status(IStatus.ERROR, Policy.PI_FILE_SYSTEM, EFS.ERROR_DELETE, message, e));
				return false;
			}
		}
		//if we got this far, we failed
		String message = null;
		if (fetchInfo().getAttribute(EFS.ATTRIBUTE_READ_ONLY))
			message = NLS.bind(Messages.couldnotDeleteReadOnly, target.getAbsolutePath());
		else
			message = NLS.bind(Messages.couldnotDelete, target.getAbsolutePath());
		status.add(new Status(IStatus.ERROR, Policy.PI_FILE_SYSTEM, EFS.ERROR_DELETE, message, null));
		return false;
	}

	@Override
	public boolean isParentOf(IFileStore other) {
		if (!(other instanceof OEFile))
			return false;
		String thisPath = filePath;
		String thatPath = ((OEFile) other).filePath;
		int thisLength = thisPath.length();
		int thatLength = thatPath.length();
		//if equal then not a parent
		if (thisLength >= thatLength)
			return false;
		if (getFileSystem().isCaseSensitive()) {
			if (thatPath.indexOf(thisPath) != 0)
				return false;
		} else {
			if (thatPath.toLowerCase().indexOf(thisPath.toLowerCase()) != 0)
				return false;
		}
		//The common portion must end with a separator character for this to be a parent of that
		return thisPath.charAt(thisLength - 1) == File.separatorChar || thatPath.charAt(thisLength) == File.separatorChar;
	}

	/**
	 * @return
	 */
	private boolean isProject() {
		return this.file.toString().equals(root);
	}

	@Override
	public IFileStore mkdir(int options, IProgressMonitor monitor) throws CoreException {
		boolean shallow = (options & EFS.SHALLOW) != 0;
		//must be a directory
		if (shallow)
			file.mkdir();
		else
			file.mkdirs();
		if (!file.isDirectory()) {
			checkReadOnlyParent(file, null);
			String message = NLS.bind(Messages.failedCreateWrongType, filePath);
			Policy.error(EFS.ERROR_WRONG_TYPE, message);
		}
		return this;
	}

	@Override
	public void move(IFileStore destFile, int options, IProgressMonitor monitor) throws CoreException {
		if (!(destFile instanceof OEFile)) {
			super.move(destFile, options, monitor);
			return;
		}
		File source = file;
		File destination = ((OEFile) destFile).file;
		boolean overwrite = (options & EFS.OVERWRITE) != 0;
		monitor = Policy.monitorFor(monitor);
		try {
			monitor.beginTask(NLS.bind(Messages.moving, source.getAbsolutePath()), 10);
			//this flag captures case renaming on a case-insensitive OS, or moving
			//two equivalent files in an environment that supports symbolic links.
			//in these cases we NEVER want to delete anything
			boolean sourceEqualsDest = false;
			try {
				sourceEqualsDest = source.getCanonicalFile().equals(destination.getCanonicalFile());
			} catch (IOException e) {
				String message = NLS.bind(Messages.couldNotMove, source.getAbsolutePath());
				Policy.error(EFS.ERROR_WRITE, message, e);
			}
			if (!sourceEqualsDest && !overwrite && destination.exists()) {
				String message = NLS.bind(Messages.fileExists, destination.getAbsolutePath());
				Policy.error(EFS.ERROR_EXISTS, message);
			}
			if (source.renameTo(destination)) {
				// double-check to ensure we really did move
				// since java.io.File#renameTo sometimes lies
				if (!sourceEqualsDest && source.exists()) {
					// XXX: document when this occurs
					if (destination.exists()) {
						// couldn't delete the source so remove the destination and throw an error
						// XXX: if we fail deleting the destination, the destination (root) may still exist
						new OEFile(destination, ignorePaths, root).delete(EFS.NONE, null);
						String message = NLS.bind(Messages.couldnotDelete, source.getAbsolutePath());
						Policy.error(EFS.ERROR_DELETE, message);
					}
					// source exists but destination doesn't so try to copy below
				} else {
					if (!destination.exists()) {
						// neither the source nor the destination exist. this is REALLY bad
						String message = NLS.bind(Messages.failedMove, source.getAbsolutePath(), destination.getAbsolutePath());
						Policy.error(EFS.ERROR_WRITE, message);
					}
					//the move was successful
					monitor.worked(10);
					return;
				}
			}
			// for some reason renameTo didn't work
			if (sourceEqualsDest) {
				String message = NLS.bind(Messages.couldNotMove, source.getAbsolutePath());
				Policy.error(EFS.ERROR_WRITE, message, null);
			}
			// fall back to default implementation
			super.move(destFile, options, Policy.subMonitorFor(monitor, 10));
		} finally {
			monitor.done();
		}
	}

	@Override
	public InputStream openInputStream(int options, IProgressMonitor monitor) throws CoreException {
		monitor = Policy.monitorFor(monitor);
		try {
			monitor.beginTask("", 1); //$NON-NLS-1$
			return new FileInputStream(file);
		} catch (FileNotFoundException e) {
			String message;
			if (!file.exists())
				message = NLS.bind(Messages.fileNotFound, filePath);
			else if (file.isDirectory())
				message = NLS.bind(Messages.notAFile, filePath);
			else
				message = NLS.bind(Messages.couldNotRead, filePath);
			Policy.error(EFS.ERROR_READ, message, e);
			return null;
		} finally {
			monitor.done();
		}
	}

	@Override
	public OutputStream openOutputStream(int options, IProgressMonitor monitor) throws CoreException {
		monitor = Policy.monitorFor(monitor);
		try {
			monitor.beginTask("", 1); //$NON-NLS-1$
			return new FileOutputStream(file, (options & EFS.APPEND) != 0);
		} catch (FileNotFoundException e) {
			checkReadOnlyParent(file, e);
			String message;
			String path = filePath;
			if (file.isDirectory())
				message = NLS.bind(Messages.notAFile, path);
			else
				message = NLS.bind(Messages.couldNotWrite, path);
			Policy.error(EFS.ERROR_WRITE, message, e);
			return null;
		} finally {
			monitor.done();
		}
	}

	@Override
	public void putInfo(IFileInfo info, int options, IProgressMonitor monitor) throws CoreException {
		boolean success = true;

		//native does not currently set last modified
		if ((options & EFS.SET_LAST_MODIFIED) != 0)
			success &= file.setLastModified(info.getLastModified());
		if (!success && !file.exists())
			Policy.error(EFS.ERROR_NOT_EXISTS, NLS.bind(Messages.fileNotFound, filePath));
	}

	/* (non-Javadoc)
	 * @see org.eclipse.core.filesystem.provider.FileStore#toLocalFile(int, org.eclipse.core.runtime.IProgressMonitor)
	 */
	@Override
	public File toLocalFile(int options, IProgressMonitor monitor) throws CoreException {
		if (options == EFS.CACHE)
			return super.toLocalFile(options, monitor);
		return file;
	}

	/* (non-Javadoc)
	 * @see org.eclipse.core.filesystem.IFileStore#toString()
	 */
	@Override
	public String toString() {
		return file.toString();
	}

	/* (non-Javadoc)
	 * @see org.eclipse.core.filesystem.IFileStore#toURI()
	 */
	@Override
	public URI toURI() {
		return URIUtil.toURI(filePath);
	}
}