/*

 * 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; either version 2

 * of the License, or (at your option) any later version.

 *

 * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 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();

                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;

        }

    }

}