/*
 * $Id$
 *
 * Copyright (C) 2003-2015 JNode.org
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; If not, write to the Free Software Foundation, Inc., 
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
package org.jnode.fs.fat;

import java.io.IOException;
import java.util.HashMap;
import org.jnode.driver.Device;
import org.jnode.driver.block.BlockDeviceAPI;
import org.jnode.fs.FSDirectory;
import org.jnode.fs.FSEntry;
import org.jnode.fs.FSFile;
import org.jnode.fs.FileSystemException;
import org.jnode.fs.spi.AbstractFileSystem;

/**
 * @author epr
 */
public class FatFileSystem extends AbstractFileSystem<FatRootEntry> {
    private BootSector bs;
    private Fat fat;
    private final FatDirectory rootDir;
    private final FatRootEntry rootEntry;
    private final HashMap<FatDirEntry, FatFile> files = new HashMap<FatDirEntry, FatFile>();

    /**
     * Constructor for FatFileSystem in specified readOnly mode
     */
    public FatFileSystem(Device device, boolean readOnly, FatFileSystemType type) throws FileSystemException {
        super(device, readOnly, type); // false = read/write mode

        try {
            bs = new BootSector(512);
            bs.read(getApi());
//            if (!bs.isaValidBootSector()) throw new FileSystemException(
//                "Can't mount this partition: Invalid BootSector");

            // System.out.println(bs);

            Fat[] fats = new Fat[bs.getNrFats()];
            rootDir = new FatLfnDirectory(this, bs.getNrRootDirEntries());
            FatType bitSize;

            if (bs.getMediumDescriptor() == 0xf8) {
                bitSize = FatType.FAT16;
            } else {
                bitSize = FatType.FAT12;
            }

            for (int i = 0; i < fats.length; i++) {
                Fat fat = new Fat(bitSize, bs.getMediumDescriptor(), bs.getSectorsPerFat(), bs.getBytesPerSector());
                fats[i] = fat;
                fat.read(getApi(), FatUtils.getFatOffset(bs, i));
            }

            for (int i = 1; i < fats.length; i++) {
                if (!fats[0].equals(fats[i])) {
                    System.out.println("FAT " + i + " differs from FAT 0");
                }
            }
            fat = fats[0];
            rootDir.read(getApi(), FatUtils.getRootDirOffset(bs));
            rootEntry = new FatRootEntry(rootDir);
            // files = new FatFile[fat.getNrEntries()];
        } catch (IOException ex) {
            throw new FileSystemException(ex);
        } catch (Exception e) { // something bad happened in the FAT boot
            // sector... just ignore this FS
            throw new FileSystemException(e);
        }
    }

    /**
     * Flush all changed structures to the device.
     *
     * @throws IOException
     */
    public void flush() throws IOException {

        final BlockDeviceAPI api = getApi();

        if (bs.isDirty()) {
            bs.write(api);
        }

        for (FatFile f : files.values()) {
            f.flush();
        }

        if (fat.isDirty()) {
            for (int i = 0; i < bs.getNrFats(); i++) {
                fat.write(api, FatUtils.getFatOffset(bs, i));
            }
        }

        if (rootDir.isDirty()) {
            rootDir.flush();
        }

    }

    /**
     * Gets the root entry of this filesystem. This is usually a directory, but this is not required.
     */
    public FatRootEntry getRootEntry() {
        return rootEntry;
    }

    /**
     * Gets the file for the given entry.
     *
     * @param entry
     */
    public synchronized FatFile getFile(FatDirEntry entry) {

        FatFile file = files.get(entry);
        if (file == null) {
            file = new FatFile(this, entry, entry.getStartCluster(), entry.getLength(), entry.isDirectory());
            files.put(entry, file);
        }
        return file;
    }

    public int getClusterSize() {
        return bs.getBytesPerSector() * bs.getSectorsPerCluster();
    }

    /**
     * Returns the fat.
     *
     * @return Fat
     */
    public Fat getFat() {
        return fat;
    }

    /**
     * Returns the bootsector.
     *
     * @return BootSector
     */
    public BootSector getBootSector() {
        return bs;
    }

    /**
     * Returns the rootDir.
     *
     * @return RootDirectory
     */
    public FatDirectory getRootDir() {
        return rootDir;
    }

    /**
     *
     */
    protected FSFile createFile(FSEntry entry) throws IOException {

        // TODO Auto-generated method stub
        return null;
    }

    /**
     *
     */
    protected FSDirectory createDirectory(FSEntry entry) throws IOException {
        // TODO Auto-generated method stub
        return null;
    }

    /**
     *
     */
    protected FatRootEntry createRootEntry() throws IOException {
        // TODO Auto-generated method stub
        return null;
    }

    public long getFreeSpace() {
        // TODO implement me
        return -1;
    }

    public long getTotalSpace() {
        // TODO implement me
        return -1;
    }

    public long getUsableSpace() {
        // TODO implement me
        return -1;
    }

    @Override
    public String getVolumeName() throws IOException {
        return ""; // TODO implement me
    }
}