/*

 * Hedgewars for Android. An Android port of Hedgewars, a free turn based strategy game

 * Copyright (c) 2011-2012 Richard Deurwaarder <xeli@xelification.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; version 2 of the License

 *

 * 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA

 */

package org.hedgewars.hedgeroid.Downloader;

import java.io.BufferedInputStream;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.net.HttpURLConnection;

import java.net.URL;

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

import java.util.zip.ZipEntry;

import java.util.zip.ZipInputStream;

import org.hedgewars.hedgeroid.Downloader.DownloadService.DownloadTask;

import android.os.AsyncTask;

/**

 * This is an AsyncTask which will download a zip from an URL and unzip it to a specified path

 * 

 *  a typical call to start the task would be new DownloadAsyncTask().execute(getExternalStorage(), "www.hedgewars.org/data.zip");

 * @author Xeli

 *

 */

public class DownloadAsyncTask extends AsyncTask<DownloadPackage, Object, Integer> {

	//private final static String URL_WITHOUT_SUFFIX = "http://www.xelification.com/tmp/firebutton.";

	private final static String URL_ZIP_SUFFIX = ".zip";

	private final static String URL_HASH_SUFFIX = ".hash";

	public static final int EXIT_SUCCESS = 0;

	public static final int EXIT_URLFAIL = 1;

	public static final int EXIT_CONNERROR = 2;

	public static final int EXIT_FNF = 3;

	public static final int EXIT_MD5 = 4;

	public static final int EXIT_CANCELLED = 5;

	private DownloadTask task;

	private long lastUpdateMillis = 0;

	public DownloadAsyncTask(DownloadTask _task){

		task = _task;

	}

	/**

	 * 

	 * @param params - A {@link}DownloadTask which gives information about where to download from and store the files to 

	 */

	protected Integer doInBackground(DownloadPackage...packages) {

		DownloadPackage pack = packages[0];//just use one task per execute call for now

		HttpURLConnection conn = null;

		MessageDigest digester = null;

		String rootZipDest = pack.getPathToStore();

		File rootDest = new File(rootZipDest);//TODO check for nullpointer, it hints to the absence of an sdcard

		rootDest.mkdirs();

		try {

			URL url = new URL(pack.getURL() + URL_ZIP_SUFFIX);

			conn = (HttpURLConnection)url.openConnection();

		} catch (IOException e) {

			e.printStackTrace();

			return EXIT_URLFAIL;

		}

		String contentType = conn.getContentType();

		if(contentType == null || contentType.contains("zip")){ //Seeing as we provide the url if the contentType is unknown lets assume zips

			int bytesDecompressed = 0;

			ZipEntry entry = null;

			ZipInputStream input = null;

			FileOutputStream output = null;

			int kbytesToProcess = conn.getContentLength()/1024;

			byte[] buffer = new byte[1024];

			task.start(kbytesToProcess);

			try {

				digester = MessageDigest.getInstance("MD5");

			} catch (NoSuchAlgorithmException e1) {

				e1.printStackTrace();

			}

			try{

				input = new ZipInputStream(conn.getInputStream());

				entry = input.getNextEntry();	

			}catch(IOException e){

				e.printStackTrace();

				if(conn != null) conn.disconnect();

				return EXIT_CONNERROR;

			}

			while(entry != null){

				if(isCancelled()) break;

				try {

					String fileName = entry.getName();

					File f = new File(rootZipDest + fileName);

					bytesDecompressed += entry.getCompressedSize();

					if(entry.isDirectory()){

						f.mkdir();

					}else{

						if(f.exists()){

							f.delete();

						}

						f.createNewFile();

						output = new FileOutputStream(f);

						int count = 0;

						while((count = input.read(buffer)) != -1){

							output.write(buffer, 0, count);

							digester.update(buffer, 0, count);

							if(System.currentTimeMillis() - lastUpdateMillis > 1000){

								lastUpdateMillis = System.currentTimeMillis();

								publishProgress(bytesDecompressed, kbytesToProcess, fileName);

							}

						}

						output.flush();

						input.closeEntry();

					}//if isDir 

					entry = input.getNextEntry();

				} catch (FileNotFoundException e) {

					e.printStackTrace();

					if(conn != null) conn.disconnect();

					return EXIT_FNF;

				} catch (IOException e) {

					e.printStackTrace();

					if(conn != null) conn.disconnect();

					return EXIT_CONNERROR;

				}finally{

					try {

						if( output != null) output.close();

					} catch (IOException e) {}

				}

			}//end while(entry != null)

			if( input != null)

				try {

					input.close();

				} catch (IOException e) {}

		}else{//end if contentType == "zip"

			return EXIT_URLFAIL;

		}

		if(conn != null) conn.disconnect();

		if(checkMD5(digester, pack))return EXIT_SUCCESS;

		else return EXIT_MD5;

	}

	//TODO proper result handling

	protected void onPostExecute(Integer result){

		task.done(result);

	}

	protected void onProgressUpdate(Object...objects){

		task.update((Integer)objects[0], (Integer)objects[1], (String)objects[2]);

	}

	protected void onCancelled(){

		onPostExecute(EXIT_CANCELLED);

	}

	private boolean checkMD5(MessageDigest digester, DownloadPackage task){

		if(digester != null) {

			byte[] messageDigest = digester.digest();

			try {

				URL url = new URL(task.getURL() + URL_HASH_SUFFIX);

				HttpURLConnection conn = (HttpURLConnection)url.openConnection();

				byte[] buffer = new byte[1024];//size is large enough to hold the entire hash

				BufferedInputStream bis = new BufferedInputStream(conn.getInputStream());

				int bytesRead = bis.read(buffer);

				String hash = null;

				if(bytesRead > -1){

					hash = new String(buffer, 0, bytesRead);

				}

				StringBuffer sb = new StringBuffer();

				Integer tmp = 0;

				for(int i = 0; i < messageDigest.length; i++){

					tmp = 0xFF & messageDigest[i];

					if(tmp < 0xF) sb.append('0');

					sb.append(Integer.toHexString(tmp));

				}

				sb.append('\n');//add newline to become identical with the hash file

				return hash.equals(sb.toString());

			} catch (IOException e) {

				e.printStackTrace();

				return true;

			}

		}else{

			return true;	

		}

	}

}