/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.vfs2.impl;

import org.apache.commons.vfs2.FileName;
import org.apache.commons.vfs2.FileObject;
import org.apache.commons.vfs2.FileSystem;
import org.apache.commons.vfs2.FileSystemException;
import org.apache.commons.vfs2.FileType;
import org.apache.commons.vfs2.provider.AbstractFileName;
import org.apache.commons.vfs2.provider.AbstractFileSystem;
import org.apache.commons.vfs2.provider.AbstractVfsContainer;

/**
 * A virtual file system provider.
 */
public class VirtualFileProvider extends AbstractVfsContainer {

    /**
     * Creates a virtual file system, with the supplied file as its root.
     *
     * @param rootFile The root of the file system.
     * @return A FileObject in the FileSystem.
     * @throws FileSystemException if an error occurs.
     */
    public FileObject createFileSystem(final FileObject rootFile) throws FileSystemException {
        final AbstractFileName rootName = (AbstractFileName) getContext().getFileSystemManager()
                .resolveName(rootFile.getName(), FileName.ROOT_PATH);
        final VirtualFileSystem fs = new VirtualFileSystem(rootName, rootFile.getFileSystem().getFileSystemOptions());
        addComponent(fs);
        fs.addJunction(FileName.ROOT_PATH, rootFile);
        return fs.getRoot();
    }

    /**
     * Creates an empty virtual file system.
     *
     * @param rootUri The root of the file system.
     * @return A FileObject in the FileSystem.
     * @throws FileSystemException if an error occurs.
     */
    public FileObject createFileSystem(final String rootUri) throws FileSystemException {
        final AbstractFileName rootName = new VirtualFileName(rootUri, FileName.ROOT_PATH, FileType.FOLDER);
        final VirtualFileSystem fs = new VirtualFileSystem(rootName, null);
        addComponent(fs);
        return fs.getRoot();
    }

    /**
     * Close a VirtualFileSystem by removing it from the {@code #components} list of this provider.
     * <p>
     * This gets called from DefaultFileManager#_closeFileSystem.
     * </p>
     *
     * @param fileSystem the file system remembered by this provider.
     */
    void closeFileSystem(final FileSystem fileSystem) {
        final AbstractFileSystem fs = (AbstractFileSystem) fileSystem;

        removeComponent(fs);
        fs.close();
    }
}
