/*
 * File    : DownloadManager.java
 * Created : 06-Jan-2004
 * By      : parg
 * 
 * Azureus - a Java Bittorrent client
 *
 * 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.
 *
 * 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 ( see the LICENSE file ).
 *
 * 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.gudy.azureus2.plugins.download;

import java.io.File;
import java.net.URL;

import org.gudy.azureus2.plugins.torrent.Torrent;

/**
 * The DownloadManager gives access to functions used to monitor and manage Azureus's downloads
 * @author parg
 */

public interface 
DownloadManager 
{
	/**
	 * Add a torrent from a file. This may prompt the user for a download location etc. if required.
	 * This is an async operation, so no Download is returned.
	 * 
	 * If you want to force a download to be added without prompting the user, you should create a
	 * Torrent object first, and then use an alternative addDownload method.
	 * 
	 * @see #addDownload(Torrent)
	 * @see #addDownload(Torrent, File, File)
	 * @see org.gudy.azureus2.plugins.torrent.TorrentManager#createFromBEncodedFile(File) TorrentManager.createFromBEncodedFile
	 * @param torrent_file
	 * @throws DownloadException
   *
   * @since 2.0.7.0
	 */
	public void 
	addDownload(
		File 	torrent_file )
	
		throws DownloadException;
	
	/**
	 * add a torrent from a URL. This will prompt the user for download location etc. if required
	 * This is an async operation so no Download returned
	 * @param url
	 * @throws DownloadException
   *
   * @since 2.0.7.0
	 */
	public void 
	addDownload(
		URL		url )
	
		throws DownloadException;
	
	/**
	 * Add a torrent from a URL with explicit auto-download option
	 * @param url
	 * @param auto_download
	 * @throws DownloadException
	 * @since 2403
	 */
	
	public void 
	addDownload(
		URL			url,
		boolean		auto_download )
	
		throws DownloadException;
	
	/**
	 * add a torrent from a URL. This will prompt the user for download location etc. if required
	 * This is an async operation so no Download returned
	 * @param url
	 * @param referer
	 * @throws DownloadException
	 *
	 * @since 2.1.0.6
	 */
	public void 
	addDownload(
		final URL	url,
		final URL 	referer);
	
	/**
	 * Add a torrent from a "Torrent" object. The default torrent file and data locations will be
	 * used if defined - a DownloadException will be thrown if they're not. You can explicitly set
	 * these values by using the {@link #addDownload(Torrent, File, File) addDownload(Torrent, File, File)} method. 
	 * @param torrent
	 * @see #addDownload(Torrent, File, File)
	 * @return
   *
   * @since 2.0.8.0
	 */
	public Download
	addDownload(
		Torrent		torrent )
	
		throws DownloadException;
	

	/**
	 * Add a torrent from a "Torrent" object and point it at the data location.
	 * 
	 * The torrent_location should be the location of where the torrent file is on disk.
	 * This will be the torrent file that Azureus will use internally. If null is passed,
	 * then a file to store the torrent data in will be automatically created by Azureus.
	 * 
	 * @param torrent The torrent object to create a download with.
	 * @param torrent_location The location of the file on disk - if  <code>null</code>,
	 *   a file to store the torrent data into will be created automatically. 
	 * @param data_location null -> user default data save location if defined
	 * @return
   * support for null params for torrent_location/data_location since 2.1.0.4
   * @since 2.0.7.0
	 */
	public Download
	addDownload(
		Torrent		torrent,
		File		torrent_location,
		File		data_location )
	
		throws DownloadException;
	
	/**
	 * Explicit way of adding a download in a stopped state
	 * @since 3013
	 * @param torrent
	 * @param torrent_location
	 * @param data_location
	 * @return
	 * @throws DownloadException
	 */
	
	public Download
	addDownloadStopped(
		Torrent		torrent,
		File		torrent_location,
		File		data_location )
	
		throws DownloadException;
	
	/**
	 * Add a non-persistent download. Such downloads are not persisted by Azureus and as such will
	 * not be remembered across an Azureus close and restart.
	 * @param torrent
	 * @param torrent_location
	 * @param data_location
	 * @return
	 * @throws DownloadException
   *
   * @since 2.0.7.0
	 */
	public Download
	addNonPersistentDownload(
		Torrent		torrent,
		File		torrent_location,
		File		data_location )
	
		throws DownloadException;
	
	/**
	 * Gets the download for a particular torrent, returns null if not found
	 * @param torrent
	 * @return
   *
   * @since 2.0.7.0
	 */
	public Download
	getDownload(
		Torrent		torrent );
	
	/**
	 * Gets a download given its hash
	 * @param hash
	 * @return
	 * @throws DownloadException
	 * @since 2.3.0.7
	 */

	public Download
	getDownload(
		byte[]		hash )
	
		throws DownloadException;
	
	/**
	 * Gets all the downloads. Returned in Download "index" order
	 * @return
   *
   * @since 2.0.7.0
	 */
	public Download[]
	getDownloads();
	
	/**
	 * Gets all the downloads. 
	 * @param bSorted true - Returned in Download "index" order.<BR>
	 *                false - Order not guaranteed.  Faster retrieval.
	 * @return array of Download object
   *
   * @since 2.0.8.0
	 */
	public Download[]
	getDownloads(boolean bSorted);

	/**
	 * pause all running downloads
	 * @since 2.1.0.5
	 *
	 */
	
	public void
	pauseDownloads();
	
	public boolean
	canPauseDownloads();
	
	/**
	 * resume previously paused downloads
	 * @since 2.1.0.5
	 */
	
	public void
	resumeDownloads();
	
	public boolean
	canResumeDownloads();
	
	/**
	 * starts all non-running downloads
	 * @since 2.1.0.5
	 */
	
	public void
	startAllDownloads();
	
	/**
	 * stops all running downloads
	 * @since 2.1.0.5
	 */
	
	public void
	stopAllDownloads();
	
	/**
	 * Get the download manager statistics
	 * @return
	 */
	
	public DownloadManagerStats
	getStats();
	
		/**
		 * indicates whether or not all active downloads are in a seeding (or effective) seeding state
		 * @since 2.3.0.5
		 * @return
		 */
	
	public boolean
	isSeedingOnly();
	
    /**
	 * Add a listener that will be informed when a download is added to and removed
	 * from Azureus.
	 * <p />
	 * Invoking this method is equivalent to <code>addListener(l, true)</code>.
	 * 
	 * @param l The listener to add.
	 * @since 2.0.7.0
	 * @see #addListener(DownloadManagerListener, boolean)
	 */
	public void addListener(DownloadManagerListener l);
	
	/**
	 * Add a listener that will be informed when a download is added to and removed
	 * from Azureus.
	 * @param l The listener to add.
	 * @param notify_of_current_downloads <tt>true</tt> - if you want the listener to
	 *   have its {@link DownloadManagerListener#downloadAdded(Download) downloadAdded}
	 *   method invoked immediately with all downloads currently managed by Azureus.
	 *   <tt>false</tt> - if you only want to be notified about new downloads added after
	 *   this method is called.
	 * @since 3.0.0.7
	 */
	public void addListener(DownloadManagerListener l, boolean notify_of_current_downloads);
	
	/**
	 * Removes a previously added listener.
     * @param l The listener to remove.
	 * @param notify_of_current_downloads <tt>true</tt> - if you want the listener to
	 *   have its {@link DownloadManagerListener#downloadRemoved(Download) downloadRemoved}
	 *   method invoked immediately with all downloads currently managed by Azureus,
	 *   <tt>false</tt> otherwise.
	 *  @since 3.0.0.7
	 */
	public void removeListener(DownloadManagerListener l, boolean notify_of_current_downloads);
	
    /**
     * Removes a previously added listener.
     * <p />
     * Invoking this method is equivalent to <code>removeListener(l, false)</code>.
     * @see #removeListener(DownloadManagerListener, boolean)
     * @param l The listener to remove.
     * @since 2.0.7.0
     */
	public void	removeListener(DownloadManagerListener l);
	
	public void
	addDownloadWillBeAddedListener(
		DownloadWillBeAddedListener		listener );
	
	public void
	removeDownloadWillBeAddedListener(
		DownloadWillBeAddedListener		listener );
	
	/**
	 * Return a {@link DownloadEventNotifier} object which can be used as
	 * an easy way to register listeners against all downloads handled by
	 * Azureus.
	 * 
	 * @since 3.0.1.5
	 */
	public DownloadEventNotifier getGlobalDownloadEventNotifier();
}
