/*
 * Autopsy Forensic Browser
 *
 * Copyright 2013 Basis Technology Corp.
 * Contact: carrier <at> sleuthkit <dot> org
 *
 * Licensed 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.sleuthkit.autopsy.sevenzip;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Level;
import javax.swing.JPanel;
import net.sf.sevenzipjbinding.ISequentialOutStream;
import net.sf.sevenzipjbinding.ISevenZipInArchive;
import org.sleuthkit.autopsy.coreutils.Logger;
import org.sleuthkit.autopsy.ingest.IngestModuleAbstractFile;
import org.sleuthkit.autopsy.ingest.IngestModuleInit;
import org.sleuthkit.autopsy.ingest.IngestServices;
import org.sleuthkit.datamodel.AbstractFile;
import org.sleuthkit.datamodel.SleuthkitCase;
import net.sf.sevenzipjbinding.SevenZip;
import net.sf.sevenzipjbinding.SevenZipException;
import net.sf.sevenzipjbinding.SevenZipNativeInitializationException;
import net.sf.sevenzipjbinding.simple.ISimpleInArchive;
import net.sf.sevenzipjbinding.simple.ISimpleInArchiveItem;
import org.sleuthkit.autopsy.casemodule.Case;
import org.sleuthkit.autopsy.casemodule.services.FileManager;
import org.sleuthkit.autopsy.coreutils.MessageNotifyUtil;
import org.sleuthkit.datamodel.DerivedFile;
import org.sleuthkit.datamodel.ReadContentInputStream;
import org.sleuthkit.datamodel.TskCoreException;

/**
 * 7Zip ingest module Extracts supported archives, adds extracted DerivedFiles,
 * reschedules extracted DerivedFiles for ingest.
 *
 * Updates datamodel / directory tree with new files.
 */
public final class SevenZipIngestModule implements IngestModuleAbstractFile {

    private static final Logger logger = Logger.getLogger(SevenZipIngestModule.class.getName());
    public static final String MODULE_NAME = "7Zip";
    public static final String MODULE_DESCRIPTION = "Extracts archive files, add new files, reschedules them to current ingest and populates directory tree with new files.";
    final public static String MODULE_VERSION = "1.0";
    private String args;
    private IngestServices services;
    private volatile int messageID = 0;
    private boolean processedFiles;
    private SleuthkitCase caseHandle = null;
    private boolean initialized = false;
    private static SevenZipIngestModule instance = null;
    //TODO use content type detection instead of extensions
    static final String[] SUPPORTED_EXTENSIONS = {"zip", "rar",};
    private String unpackDir; //relative to the case, to store in db
    private String unpackDirPath; //absolute, to extract to
    private FileManager fileManager;

    //private constructor to ensure singleton instance 
    private SevenZipIngestModule() {
    }

    /**
     * Returns singleton instance of the module, creates one if needed
     *
     * @return instance of the module
     */
    public static synchronized SevenZipIngestModule getDefault() {
        if (instance == null) {
            instance = new SevenZipIngestModule();
        }
        return instance;
    }

    @Override
    public void init(IngestModuleInit initContext) {
        logger.log(Level.INFO, "init()");
        services = IngestServices.getDefault();
        initialized = false;

        final Case currentCase = Case.getCurrentCase();

        unpackDir = currentCase.getModulesOutputDirectory() + File.separator + MODULE_NAME;
        unpackDirPath = currentCase.getModulesOutputDirectoryPath() + File.separator + MODULE_NAME;

        fileManager = currentCase.getServices().getFileManager();

        File unpackDirPathFile = new File(unpackDirPath);
        if (!unpackDirPathFile.exists()) {
            try {
                unpackDirPathFile.mkdirs();
            } catch (SecurityException e) {
                logger.log(Level.SEVERE, "Error initializing output dir: " + unpackDirPath, e);
                MessageNotifyUtil.Notify.error("Error initializing " + MODULE_NAME, "Error initializing output dir: " + unpackDirPath + ": " + e.getMessage());
                return;
            }
        }

        try {
            SevenZip.initSevenZipFromPlatformJAR();
            String platform = SevenZip.getUsedPlatform();
            logger.log(Level.INFO, "7-Zip-JBinding library was initialized on supported platform: " + platform);
        } catch (SevenZipNativeInitializationException e) {
            logger.log(Level.SEVERE, "Error initializing 7-Zip-JBinding library", e);
            MessageNotifyUtil.Notify.error("Error initializing " + MODULE_NAME, "Could not initialize 7-ZIP library");
            return;
        }


        initialized = true;
    }

    @Override
    public ProcessResult process(AbstractFile abstractFile) {

        if (initialized == false) //error initializing indexing/Solr
        {
            logger.log(Level.WARNING, "Skipping processing, module not initialized, file: " + abstractFile.getName());
            return ProcessResult.OK;
        }

        if (abstractFile.isFile() == false || !isSupported(abstractFile)) {
            //do not process dirs and files that are not supported
            return ProcessResult.OK;
        }

        //check if already has derived files, skip
        try {
            if (abstractFile.hasChildren()) {
                logger.log(Level.INFO, "File already has been processed as it has children, skipping: " + abstractFile.getName());
                return ProcessResult.OK;
            }
        } catch (TskCoreException e) {
            logger.log(Level.INFO, "Error checking if file already has been processed, skipping: " + abstractFile.getName());
            return ProcessResult.OK;
        }


        logger.log(Level.INFO, "Processing with 7ZIP: " + abstractFile.getName());


        List<DerivedFile> unpacked = unpack(abstractFile);
        //TODO send event to dir tree
        
        //TODO reschedule unpacked file for ingest

        //process, return error if occurred

        return ProcessResult.OK;
    }

    /**
     * Unpack the file to local folder and return a list of derived files
     *
     * @param file file to unpack
     * @return list of unpacked derived files
     */
    private List<DerivedFile> unpack(AbstractFile file) {
        final List<DerivedFile> unpacked = new ArrayList<DerivedFile>();

        ISevenZipInArchive inArchive = null;
        SevenZipContentReadStream stream = null;
        try {
            stream = new SevenZipContentReadStream(new ReadContentInputStream(file));
            inArchive = SevenZip.openInArchive(null, // autodetect archive type
                    stream);

            logger.log(Level.INFO, "Count of items in archive: " + file.getName() + ": "
                    + inArchive.getNumberOfItems());

            final ISimpleInArchive simpleInArchive = inArchive.getSimpleInterface();
            AbstractFile currentParent = file;
            for (ISimpleInArchiveItem item : simpleInArchive.getArchiveItems()) {
                final boolean isDir = item.isFolder();
                
                final String extractedPath = item.getPath();
                
                final boolean isEncrypted = item.isEncrypted(); //TODO handle this
                if (isEncrypted) {
                    logger.log(Level.WARNING, "Skipping encrypted file in archive: " + extractedPath);
                    continue;
                }

                logger.log(Level.INFO, "Extracted item path: " + extractedPath);

                int lastSep = extractedPath.lastIndexOf("/\\");
                String fileName;
                if (lastSep != -1) {
                    fileName = extractedPath.substring(lastSep);
                } else {
                    fileName = extractedPath;
                }
                final String localFileRelPath = file.getId() + File.separator + extractedPath; //TODO check if ok using ID of parent file 
                final String localRelPath = unpackDir + File.separator + localFileRelPath;
                final String localAbsPath = unpackDirPath + File.separator + localFileRelPath;

                File f = new java.io.File(localAbsPath);
                if (!f.exists()) {
                    try {
                        if (isDir) {
                            f.mkdirs();
                        } else {
                            f.getParentFile().mkdirs();
                            try {
                                f.createNewFile();
                            } catch (IOException ex) {
                                logger.log(Level.SEVERE, "Error creating extracted file: " + f.getAbsolutePath(), ex);
                            }
                        }
                    } catch (SecurityException e) {
                        logger.log(Level.SEVERE, "Error setting up output path for unpacked file: " + extractedPath);
                        //TODO consider bail out / msg to the user
                    }
                }

                long size = item.getSize();
                try {
                    DerivedFile df = fileManager.addDerivedFile(fileName, localRelPath, size, !isDir, currentParent, "", "", "", "");
                    unpacked.add(df);
                    
                    if (isDir) {
                        //set the new parent for the next unzipped file
                        //assuming 7zip unzips top down TODO check
                        currentParent = df;
                    }


                } catch (TskCoreException ex) {
                    logger.log(Level.SEVERE, "Error adding a derived file to db", ex);
                    break;
                }

                //unpack
                UnpackStream unpackStream = new UnpackStream(localAbsPath);
                item.extractSlow(unpackStream);
                unpackStream.close();


                //TODO handle directories / hierarchy in unzipped file



            }

        } catch (SevenZipException ex) {
            logger.log(Level.SEVERE, "Error unpacking file: " + file, ex);
        } finally {
            if (inArchive != null) {
                try {
                    inArchive.close();
                } catch (SevenZipException e) {
                    logger.log(Level.SEVERE, "Error closing archive: " + file, e);
                }
            }

            if (stream != null) {
                try {
                    stream.close();
                } catch (IOException ex) {
                    logger.log(Level.SEVERE, "Error closing stream after unpacking archive: " + file, ex);
                }
            }
        }


        return unpacked;
    }

    @Override
    public void complete() {
        logger.log(Level.INFO, "complete()");
        if (initialized == false) {
            return;
        }



    }

    @Override
    public void stop() {
        logger.log(Level.INFO, "stop()");


    }

    @Override
    public String getName() {
        return MODULE_NAME;
    }

    @Override
    public String getDescription() {
        return MODULE_DESCRIPTION;
    }

    @Override
    public String getVersion() {
        return MODULE_VERSION;
    }

    @Override
    public String getArguments() {
        return args;
    }

    @Override
    public void setArguments(String args) {
        this.args = args;
    }

    @Override
    public ModuleType getType() {
        return ModuleType.AbstractFile;
    }

    @Override
    public boolean hasBackgroundJobsRunning() {
        return false;
    }

    @Override
    public boolean hasSimpleConfiguration() {
        return false;
    }

    @Override
    public boolean hasAdvancedConfiguration() {
        return false;
    }

    @Override
    public void saveSimpleConfiguration() {
    }

    @Override
    public void saveAdvancedConfiguration() {
    }

    @Override
    public JPanel getSimpleConfiguration() {
        return null;
    }

    @Override
    public JPanel getAdvancedConfiguration() {
        return null;
    }

    public boolean isSupported(AbstractFile file) {
        String fileNameLower = file.getName().toLowerCase();
        int dotI = fileNameLower.lastIndexOf(".");
        if (dotI == -1 || dotI == fileNameLower.length() - 1) {
            return false; //no extension
        }
        final String extension = fileNameLower.substring(dotI + 1);
        for (int i = 0; i < SUPPORTED_EXTENSIONS.length; ++i) {
            if (extension.equals(SUPPORTED_EXTENSIONS[i])) {
                return true;
            }
        }
        return false;
    }

    /**
     * Stream used to unpack the archive to local file
     */
    private static class UnpackStream implements ISequentialOutStream {

        private OutputStream output;
        private String localAbsPath;

        UnpackStream(String localAbsPath) {
            try {
                output = new BufferedOutputStream(new FileOutputStream(localAbsPath));
            } catch (FileNotFoundException ex) {
                logger.log(Level.SEVERE, "Error writing extracted file: " + localAbsPath, ex);
            }

        }

        @Override
        public int write(byte[] bytes) throws SevenZipException {
            try {
                output.write(bytes);
            } catch (IOException ex) {
                throw new SevenZipException("Error writing unpacked file to: " + localAbsPath, ex);
            }
            return bytes.length;
        }

        public void close() {
            if (output != null) {
                try {
                    output.flush();
                    output.close();
                } catch (IOException e) {
                    logger.log(Level.SEVERE, "Error closing unpack stream for file: " + localAbsPath);
                }
            }
        }
    }
}