DownloadFileTask.java

/*
 * Copyright (C) 2013 Alex Kuiper
 *
 * This file is part of PageTurner
 *
 * PageTurner 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 3 of the License, or
 * (at your option) any later version.
 *
 * PageTurner 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 PageTurner.  If not, see <http://www.gnu.org/licenses/>.*
 */
package net.nightwhistler.pageturner.catalog;

import android.content.Context;
import android.os.AsyncTask;
import com.google.inject.Inject;
import jedi.option.None;
import jedi.option.Option;
import net.nightwhistler.pageturner.Configuration;
import net.nightwhistler.pageturner.library.LibraryService;
import net.nightwhistler.pageturner.scheduling.QueueableAsyncTask;
import nl.siegmann.epublib.domain.Book;
import nl.siegmann.epublib.epub.EpubReader;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.nio.charset.Charset;

import static jedi.functional.FunctionalPrimitives.isEmpty;
import static jedi.option.Options.none;

public class DownloadFileTask extends QueueableAsyncTask<String, Long, Void> {

	private File destFile;
	
	private Exception failure;
		
	private DownloadFileCallback callBack;
	
	@Inject
	private Context context;
	
	@Inject
	private Configuration config;
	
	@Inject
	private LibraryService libraryService;
	
	@Inject
	private HttpClient httpClient;
	
	private static final Logger LOG = LoggerFactory.getLogger("DownloadFileTask");
	
	public interface DownloadFileCallback {
		
		void onDownloadStart();
		
		void downloadSuccess(File destinationFile);
		void downloadFailed();
		
		void progressUpdate( long progress, long total, int percentage );
	}
	
	DownloadFileTask(){}
	
	public void setCallBack(DownloadFileCallback callBack) {
		this.callBack = callBack;
	}
	
	@Override
	public void doOnPreExecute() {
		callBack.onDownloadStart();
	}
	
	@Override
	public Option<Void> doInBackground(String... params) {

		try {

			String url = params[0];
			LOG.debug("Downloading: " + url);

			String fileName = url.substring(url.lastIndexOf('/') + 1);
			fileName = fileName.replaceAll("\\?|&|=", "_");
			
			HttpGet get = new HttpGet(url);
            get.setHeader("User-Agent", config.getUserAgent() );
			HttpResponse response = httpClient.execute(get);

			if (response.getStatusLine().getStatusCode() == 200) {

				Option<File> destFolderOption = config.getDownloadsFolder();

				if ( isEmpty(destFolderOption) ) {
					throw new IllegalStateException("Could not get download folder!");
				}

				File destFolder = destFolderOption.unsafeGet();

				if (!destFolder.exists()) {
					destFolder.mkdirs();
				}
				
				/**
				 * Make sure we always store downloaded files as .epub, 
				 * so they show up in scans later on.
				 */
				if ( ! fileName.endsWith(".epub") ) {
					fileName = fileName + ".epub";
				}

                // Default Charset for android is UTF-8*
                String charsetName = Charset.defaultCharset().name();

                if (!Charset.isSupported(charsetName)) {
                    LOG.warn("{} is not a supported Charset. Will fall back to UTF-8", charsetName);
                    charsetName = "UTF-8";
                }

                try {
                    destFile = new File(destFolder, URLDecoder.decode(fileName,charsetName));
                } catch (UnsupportedEncodingException e) {
                    // Won't ever reach here
                    throw new AssertionError(e);
                }


				if (destFile.exists()) {
					destFile.delete();
				}

				// lenghtOfFile is used for calculating download progress
				long lenghtOfFile = response.getEntity().getContentLength();

				// this is where the file will be seen after the download
				FileOutputStream f = new FileOutputStream(destFile);
				
				try {
					// file input is from the url
					InputStream in = response.getEntity().getContent();

					// here's the download code
					byte[] buffer = new byte[1024];
					int len1 = 0;
					long total = 0;

					while ((len1 = in.read(buffer)) > 0 && ! isCancelled() ) {

						// Make sure the user can cancel the download.
						if (isCancelled()) {
							return new None();
						}

						total += len1;						
						publishProgress(total, lenghtOfFile, (long) ((total * 100) / lenghtOfFile));
						f.write(buffer, 0, len1);
					}
				} finally {
					f.close();
				}

                if ( ! isCancelled() ) {
				    //FIXME: This doesn't belong here really...
				    Book book = new EpubReader().readEpubLazy( destFile.getAbsolutePath(), "UTF-8" );
				    libraryService.storeBook(destFile.getAbsolutePath(), book, false, config.getCopyToLibraryOnScan() );
                }
				
			} else {
				this.failure = new RuntimeException(response
						.getStatusLine().getReasonPhrase());
				LOG.error("Download failed: "
						+ response.getStatusLine().getReasonPhrase());
			}

		} catch (Exception e) {
			LOG.error("Download failed.", e);
			this.failure = e;
		}

		return none();
	}

    @Override
    public void doOnProgressUpdate(Long... values) {
		callBack.progressUpdate(values[0], values[1], values[2].intValue() );
	}

	@Override
	public void doOnPostExecute(Option<Void> unused) {
		if (!isCancelled() && failure == null) {
			callBack.downloadSuccess(destFile);			
		} else if (failure != null) {
			callBack.downloadFailed();
		}
	}
}