/**

  * Distribution License:

  * JSword is free software; you can redistribute it and/or modify it under

  * the terms of the GNU Lesser General Public License, version 2.1 or later

  * as published by the Free Software Foundation. This program 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.

  *

  * The License is available on the internet at:

  *      http://www.gnu.org/copyleft/lgpl.html

  * or by writing to:

  *      Free Software Foundation, Inc.

  *      59 Temple Place - Suite 330

  *      Boston, MA 02111-1307, USA

  *

  * © CrossWire Bible Society, 2005 - 2016

  *

  */

 package org.crosswire.jsword.book.sword;

 import java.io.File;

 import java.io.IOException;

 import java.io.RandomAccessFile;

 import java.net.URI;

 import org.crosswire.common.activate.Activatable;

 import org.crosswire.common.activate.Activator;

 import org.crosswire.common.activate.Lock;

 import org.crosswire.common.util.FileUtil;

 import org.crosswire.common.util.NetUtil;

 import org.crosswire.common.util.Reporter;

 import org.crosswire.jsword.JSMsg;

 import org.crosswire.jsword.JSOtherMsg;

 import org.crosswire.jsword.book.BookException;

 import org.crosswire.jsword.passage.DefaultKeyList;

 import org.crosswire.jsword.passage.Key;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 /**

  * TreeKeyIndex reads Sword index files that are path based. Paths are of the

  * form /a/b/c, and can be of any depth. The ultimate output of a TreeKeyIndex

  * is the offset and length of a chunk of data in another file that can be read.

  * 

  * @see gnu.lgpl.License The GNU Lesser General Public License for details.

  * @author DM Smith

  */

 public class TreeKeyIndex implements Activatable {

     /**

      * Simple ctor

      * 

      * @param sbmd 

      */

     public TreeKeyIndex(SwordBookMetaData sbmd) {

         bmd = sbmd;

     }

     /**

      * @return the root TreeNode for the module.

      * @throws IOException

      */

     public TreeNode getRoot() throws IOException {

         return getTreeNode(getOffset(0));

     }

     /**

      * Get the parent of the TreeNode.

      * 

      * @param node

      *            the node being worked upon

      * @return the parent node

      * @throws IOException

      */

     public TreeNode getParent(TreeNode node) throws IOException {

         return getTreeNode(getOffset(node.getParent()));

     }

     /**

      * Get the first child of the TreeNode.

      * 

      * @param node

      *            the node being worked upon

      * @return the first child node

      * @throws IOException

      */

     public TreeNode getFirstChild(TreeNode node) throws IOException {

         return getTreeNode(getOffset(node.getFirstChild()));

     }

     /**

      * Get the next sibling of the TreeNode.

      * 

      * @param node

      *            the node being worked upon

      * @return the next sibling node

      * @throws IOException

      */

     public TreeNode getNextSibling(TreeNode node) throws IOException {

         return getTreeNode(getOffset(node.getNextSibling()));

     }

     /**

      * The idx file contains offsets into the dat file.

      * 

      * @param index

      *            the record id

      * @return an offset into the dat file

      * @throws IOException

      */

     private int getOffset(int index) throws IOException {

         if (index == -1) {

             return -1;

         }

         checkActive();

         byte[] buffer = SwordUtil.readRAF(idxRaf, index, 4);

         return SwordUtil.decodeLittleEndian32(buffer, 0);

     }

     /**

      * Given an offset get the TreeNode from the dat file.

      * 

      * @param offset

      *            start of a TreeNode record in the dat file.

      * @return the TreeNode

      * @throws IOException

      */

     private TreeNode getTreeNode(int offset) throws IOException {

         TreeNode node = new TreeNode(offset);

         if (offset == -1) {

             return node;

         }

         checkActive();

         byte[] buffer = SwordUtil.readRAF(datRaf, offset, 12);

         node.setParent(SwordUtil.decodeLittleEndian32(buffer, 0));

         node.setNextSibling(SwordUtil.decodeLittleEndian32(buffer, 4));

         node.setFirstChild(SwordUtil.decodeLittleEndian32(buffer, 8));

         buffer = SwordUtil.readUntilRAF(datRaf, (byte) 0);

         int size = buffer.length;

         if (buffer[size - 1] == 0) {

             size--;

         }

         Key key = new DefaultKeyList(null, bmd.getName());

         // Some of the keys have extraneous whitespace, so remove it.

         node.setName(SwordUtil.decode(key.getName(), buffer, size, bmd.getBookCharset()).trim());

         buffer = SwordUtil.readNextRAF(datRaf, 2);

         int userDataSize = SwordUtil.decodeLittleEndian16(buffer, 0);

         if (userDataSize > 0) {

             node.setUserData(SwordUtil.readNextRAF(datRaf, userDataSize));

         }

         return node;

     }

     /* (non-Javadoc)

      * @see org.crosswire.common.activate.Activatable#activate(org.crosswire.common.activate.Lock)

      */

     public final void activate(Lock lock) {

         String path = null;

         try {

             path = getExpandedDataPath();

         } catch (BookException e) {

             Reporter.informUser(this, e);

             return;

         }

         idxFile = new File(path + EXTENSION_INDEX);

         datFile = new File(path + EXTENSION_DATA);

         if (!idxFile.canRead()) {

             // TRANSLATOR: Common error condition: The file could not be read. There can be many reasons.

             // {0} is a placeholder for the file.

             Reporter.informUser(this, new BookException(JSMsg.gettext("Error reading {0}", idxFile.getAbsolutePath())));

             return;

         }

         if (!datFile.canRead()) {

             // TRANSLATOR: Common error condition: The file could not be read. There can be many reasons.

             // {0} is a placeholder for the file.

             Reporter.informUser(this, new BookException(JSMsg.gettext("Error reading {0}", datFile.getAbsolutePath())));

             return;

         }

         try {

             idxRaf = new RandomAccessFile(idxFile, FileUtil.MODE_READ);

             datRaf = new RandomAccessFile(datFile, FileUtil.MODE_READ);

         } catch (IOException ex) {

             log.error("failed to open files", ex);

             idxRaf = null;

             datRaf = null;

         }

         active = true;

     }

     /* (non-Javadoc)

      * @see org.crosswire.common.activate.Activatable#deactivate(org.crosswire.common.activate.Lock)

      */

     public final void deactivate(Lock lock) {

         try {

             if (idxRaf != null) {

                 idxRaf.close();

             }

             if (datRaf != null) {

                 datRaf.close();

             }

         } catch (IOException ex) {

             log.error("failed to close nt files", ex);

         } finally {

             idxRaf = null;

             datRaf = null;

         }

         active = false;

     }

     /**

      * Helper method so we can quickly activate ourselves on access

      */

     protected final void checkActive() {

         if (!active) {

             Activator.activate(this);

         }

     }

     private String getExpandedDataPath() throws BookException {

         URI loc = NetUtil.lengthenURI(bmd.getLibrary(), bmd.getProperty(SwordBookMetaData.KEY_DATA_PATH));

         if (loc == null) {

             // FIXME(DMS): missing parameter

             throw new BookException(JSOtherMsg.lookupText("Missing data files for old and new testaments in {0}."));

         }

         return new File(loc.getPath()).getAbsolutePath();

     }

     private static final String EXTENSION_INDEX = ".idx";

     private static final String EXTENSION_DATA = ".dat";

     private SwordBookMetaData bmd;

     private File idxFile;

     private File datFile;

     private RandomAccessFile idxRaf;

     private RandomAccessFile datRaf;

     private boolean active;

     /**

      * The log stream

      */

     private static final Logger log = LoggerFactory.getLogger(TreeKeyIndex.class);

 }