/* ====================================================================
   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.poi.poifs.filesystem;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.apache.poi.util.Internal;

@Internal
public class EntryUtils
{

    /**
     * Copies an Entry into a target POIFS directory, recursively
     */
    @Internal
    public static void copyNodeRecursively( Entry entry, DirectoryEntry target )
            throws IOException
    {
        // System.err.println("copyNodeRecursively called with "+entry.getName()+
        // ","+target.getName());
        DirectoryEntry newTarget = null;
        if ( entry.isDirectoryEntry() )
        {
            newTarget = target.createDirectory( entry.getName() );
            Iterator<Entry> entries = ( (DirectoryEntry) entry ).getEntries();

            while ( entries.hasNext() )
            {
                copyNodeRecursively( entries.next(), newTarget );
            }
        }
        else
        {
            DocumentEntry dentry = (DocumentEntry) entry;
            DocumentInputStream dstream = new DocumentInputStream( dentry );
            target.createDocument( dentry.getName(), dstream );
            dstream.close();
        }
    }

    /**
     * Copies nodes from one POIFS to the other minus the excepts
     * 
     * @param source
     *            is the source POIFS to copy from
     * @param target
     *            is the target POIFS to copy to
     * @param excepts
     *            is a list of Strings specifying what nodes NOT to copy
     */
    public static void copyNodes( DirectoryEntry sourceRoot,
            DirectoryEntry targetRoot, List<String> excepts )
            throws IOException
    {
        Iterator<Entry> entries = sourceRoot.getEntries();
        while ( entries.hasNext() )
        {
            Entry entry = entries.next();
            if ( !excepts.contains( entry.getName() ) )
            {
                copyNodeRecursively( entry, targetRoot );
            }
        }
    }

    /**
     * Copies nodes from one POIFS to the other minus the excepts
     * 
     * @param source
     *            is the source POIFS to copy from
     * @param target
     *            is the target POIFS to copy to
     * @param excepts
     *            is a list of Strings specifying what nodes NOT to copy
     */
    public static void copyNodes( POIFSFileSystem source,
            POIFSFileSystem target, List<String> excepts ) throws IOException
    {
        // System.err.println("CopyNodes called");
        copyNodes( source.getRoot(), target.getRoot(), excepts );
    }
    
    /**
     * Checks to see if the two Directories hold the same contents.
     * For this to be true, they must have entries with the same names,
     *  no entries in one but not the other, and the size+contents
     *  of each entry must match.
     * TODO Some sort of excepts support
     */
    public static boolean areDirectoriesIdentical(DirectoryNode dirA, DirectoryNode dirB) {
       // First up, check they have the same number of children
       if (dirA.getEntryCount() != dirB.getEntryCount()) {
          return false;
       }
       
       // Next, check entries and their types/sizes
       Map<String,Integer> aSizes = new HashMap<String, Integer>();
       final int isDirectory = -12345; 
       for (Entry a : dirA) {
          String aName = a.getName();
          if (a.isDirectoryEntry()) {
             aSizes.put(aName, isDirectory);
          } else {
             aSizes.put(aName, ((DocumentNode)a).getSize());
          }
       }
       for (Entry b : dirB) {
          String bName = b.getName();
          if (! aSizes.containsKey(bName)) {
             // In B but not A
             return false;
          }
          
          int size;
          if (b.isDirectoryEntry()) {
             size = isDirectory;
          } else {
             size = ((DocumentNode)b).getSize();
          }
          if (size != aSizes.get(bName)) {
             // Either the wrong type, or they're different sizes
             return false;
          }
          
          // Track it as checked
          aSizes.remove(bName);
       }
       if (!aSizes.isEmpty()) {
          // Nodes were in A but not B
          return false;
       }
       
       // If that passed, check entry contents
       for (Entry a : dirA) {
          try {
             Entry b = dirB.getEntry(a.getName());
             boolean match;
             if (a.isDirectoryEntry()) {
                match = areDirectoriesIdentical(
                      (DirectoryNode)a, (DirectoryNode)b);
             } else {
                match = areDocumentsIdentical(
                      (DocumentNode)a, (DocumentNode)b);
             }
             if (!match) return false;
          } catch(FileNotFoundException e) {
             // Shouldn't really happen...
             return false;
          } catch(IOException e) {
             // Something's messed up with one document, not a match
             return false;
          }
       }
       
       // If we get here, they match!
       return true;
    }
    
    /**
     * Checks to see if two Documents have the same name
     *  and the same contents. (Their parent directories are
     *  not checked)
     */
    public static boolean areDocumentsIdentical(DocumentNode docA, DocumentNode docB) throws IOException {
       if (! docA.getName().equals(docB.getName())) {
          // Names don't match, not the same
          return false;
       }
       if (docA.getSize() != docB.getSize()) {
          // Wrong sizes, can't have the same contents
          return false;
       }

       boolean matches = true;
       DocumentInputStream inpA = null, inpB = null;
       try {
          inpA = new DocumentInputStream(docA);
          inpB = new DocumentInputStream(docB);
          
          int readA, readB;
          do {
             readA = inpA.read();
             readB = inpB.read();
             if (readA != readB) {
                matches = false;
                break;
             }
          } while(readA != -1 && readB != -1);
       } finally {
          if (inpA != null) inpA.close();
          if (inpB != null) inpB.close();
       }
       
       return matches;
    }
}