package at.gv.egiz.pdfas.utils;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import at.gv.egiz.pdfas.api.commons.Constants;
import at.gv.egiz.pdfas.api.exceptions.ConfigUtilsException;

/**
 * @author <a href="mailto:thomas.knall@egiz.gv.at">Thomas Knall</a>
 */
public final class ConfigUtils {
   
   private ConfigUtils() {
   }
   
   /**
    * The log.
    */
   private static final Log logger_ = LogFactory.getLog(ConfigUtils.class);
   
   /**
    * Deploys the default configuration with apache commons vfs.
    * 
    * @param destination The destination folder.
    * @param overwriteExisting If set <code>true</code> an already existing configuration is overwritten. If <code>false</code> nothing is being copied if the destination folder already exists.
    * @return <code>true</code> if the configuration has been deployed, <code>false</code> if not.
    * @throws ConfigUtilsException Thrown if there was an error during the deployment of the configuration.
    */
   /*
   private static boolean deployWithCommonsVFS(String destination, boolean overwriteExisting) throws ConfigUtilsException {
      try {
         FileSystemManager fsManager = VFS.getManager();
         FileObject defaultConfigurationFile = fsManager.resolveFile("res:DefaultConfiguration");
         FileObject destinationFile = fsManager.resolveFile(destination);

         if (destinationFile.exists() && !overwriteExisting) {
            return false;
         }
         
         destinationFile.copyFrom(defaultConfigurationFile, new AllFileSelector());
         return true;
      } catch (FileSystemException e) {
         throw new ConfigUtilsException(e);
      }
   }
   */

   
   /**
    * Deploys the default configuration from an included zip file.
    * 
    * @param destination The destination folder.
    * @param overwriteExisting If set <code>true</code> an already existing configuration is overwritten. If <code>false</code> nothing is being copied if the destination folder already exists.
    * @return <code>true</code> if the configuration has been deployed, <code>false</code> if not.
    * @throws ConfigUtilsException Thrown if there was an error during the deployment of the configuration.
    */
   private static boolean deployFromZIP(String destination, boolean overwriteExisting) throws ConfigUtilsException {
      try {
         File destinationFolder = new File(destination);
         if (destinationFolder.exists() && !overwriteExisting) {
            return false;
         }
         InputStream in = ConfigUtils.class.getClassLoader().getResourceAsStream(Constants.DEFAULT_CONFIGURATION_ZIP_RESOURCE);
         if (in == null) {
            throw new ConfigUtilsException("Unable to find default configuration resource \"" + Constants.DEFAULT_CONFIGURATION_ZIP_RESOURCE + "\".");
         }
         ZipInputStream zis = new ZipInputStream(in);
         ZipEntry ze;
         destinationFolder.mkdirs();
         logger_.debug("Extracting default configuration to folder \"" + destinationFolder.getCanonicalPath() + "\".");
         while ((ze = zis.getNextEntry()) != null) {
            if (ze.isDirectory()) {
               File newFolder = new File(destinationFolder, ze.getName());
               logger_.debug("Extracting folder \"" + newFolder.getPath() + "\".");
               newFolder.mkdirs();
            } else {
               File destFile = new File(destinationFolder, ze.getName());
               logger_.trace("Extracting file \"" + destFile.getName() + "\".");
               toFile(zis, destFile);
            }
            zis.closeEntry();
         }
         zis.close();
         return true;
      } catch (IOException e) {
         throw new ConfigUtilsException(e);
      }
   }
   
   /**
    * Deploys the default configuration to the given destination folder.
    * 
    * @param destination The destination folder.
    * @param overwriteExisting If set <code>true</code> an already existing configuration is overwritten. If <code>false</code> nothing is being copied if the destination folder already exists.
    * @return <code>true</code> if the configuration has been deployed, <code>false</code> if not.
    * @throws ConfigUtilsException Thrown if there was an error during the deployment of the configuration.
    */
   public static boolean deployDefaultConfiguration(String destination, boolean overwriteExisting) throws ConfigUtilsException {
      if (destination == null) {
         throw new NullPointerException("Destination must not be null.");
      }
      if (destination.length() == 0) {
         throw new IllegalArgumentException("Destination must not be empty.");
      }
      return deployFromZIP(destination, overwriteExisting);
   }
   
   /**
    * Deploys the default configuration to the user's home directory to the subdirectory specified by
    * <code>Constants.Constants.USERHOME_CONFIG_FOLDER</code>.
    * 
    * @param overwriteExisting If set <code>true</code> an already existing configuration is overwritten. If <code>false</code> nothing is being copied if the destination folder already exists.
    * @return <code>true</code> if the configuration has been deployed, <code>false</code> if not.
    * @throws ConfigUtilsException Thrown if there was an error during the deployment of the configuration.
    * @see Constants#USERHOME_CONFIG_FOLDER
    */
   public static boolean deployDefaultConfiguration(boolean overwriteExisting) throws ConfigUtilsException {
      String userHome = System.getProperty("user.home");
      if (userHome == null || userHome.length() == 0) {
         return false;
      }
      return deployDefaultConfiguration(userHome + File.separator + Constants.USERHOME_CONFIG_FOLDER, overwriteExisting);
   }

   /**
    * Deploys the default configuration to the user's home directory to the subdirectory specified by
    * <code>Constants.Constants.USERHOME_CONFIG_FOLDER</code>.
    * 
    * @return <code>true</code> if the configuration has been deployed, <code>false</code> if not.
    * @throws ConfigUtilsException Thrown if there was an error during the deployment of the configuration.
    * @see Constants#USERHOME_CONFIG_FOLDER
    */
   public static boolean deployDefaultConfiguration() throws ConfigUtilsException {
      return deployDefaultConfiguration(false);
   }

   public static boolean toFile(InputStream inputStream, File file) throws IOException {
      boolean result = false;
      BufferedOutputStream bufferedOutputStream = null;
      try {
         bufferedOutputStream = new BufferedOutputStream(new FileOutputStream(file));
         writeInputStreamToOutputStream(inputStream, bufferedOutputStream);
      } finally {
         if (bufferedOutputStream != null) {
            try {
               bufferedOutputStream.close();
               result = true;
            } catch (IOException e) {
               result = false;
            }
         }
      }
      return result;
   }
   
   public static void writeInputStreamToOutputStream(InputStream inputStream, OutputStream outputStream) throws IOException {
      final int bufferSize = 1024;
      byte[] buffer = new byte[bufferSize];
      int len = -1;
      while ((len = inputStream.read(buffer)) != -1) {
         outputStream.write(buffer, 0, len);
      }
      outputStream.flush();
   }
   
}