package org.musicontroller.gui.edit;
   
   import java.io.File;
   import java.io.FileInputStream;
   import java.io.FileOutputStream;
   import java.io.IOException;
   import java.io.InputStream;
   import java.util.Collection;
   
  import org.apache.tapestry.IExternalPage;
  import org.apache.tapestry.IRequestCycle;
  import org.apache.tapestry.annotations.InjectObject;
  import org.apache.tapestry.engine.ExternalServiceParameter;
  import org.apache.tapestry.engine.IEngineService;
  import org.apache.tapestry.engine.ILink;
  import org.apache.tapestry.html.BasePage;
  import org.apache.tapestry.request.IUploadFile;
  import org.musicontroller.core.Playlist;
  import org.musicontroller.service.McService;
  import org.varienaja.util.coverart.CoverArtManager;
  import org.varienaja.util.coverart.CoverArtSearchResult;
  import org.varienaja.util.coverart.ImageScaler;
  
  /**
   * <p>Implements the MusiController cover art edit screen. The functions of this screen:
   * <ul>
   *   <li> Change the cover art of a playlist, by selecting the new cover art image from a list.
   *   <li> Upload a cover art image for a playlist. The uploaded image becomes the new cover art image.
   * </ul>
   * <p>In additon, this screen provides:
   * <ul>
   *   <li> A link to the playlist edit screen of the playlist.
   *   <li> A picture of the current cover art.
   * </ul>
   * <p>This page receives parameters as External page link parameters. These are:
   * <ol>
   * <li>The playlistid, this can be null in case of a non-persistent playlist. If not null,
   *     the search criteria for the cover art search are queried from this playlist.
   * <li>The name of the return page. This page will render the named page when a cover is
   *     selected.
   * <li>A band name, and -
   * <li>A playlist name. The band name and playlist name are used as search criteria if the playlist
   *     id is null.
   * </ol>
   * 
   * @author Hans Drexler
   * @version $Id: CoverArtEdit.java,v 1.1 2010/03/16 18:55:42 varienaja Exp $
   */
  public abstract class CoverArtEdit extends BasePage implements IExternalPage {
  	/**
  	 * The maximum width of displayed images.
  	 */
  	private final static int MAXDISPLAYWIDTH=600;
  
  	public abstract long getPlaylistId();
  	public abstract void setPlaylistId(long id);
  	public abstract void setPlaylistName(String playlistname);
  	public abstract String getPlaylistName();
  	public abstract void setBandName(String bandname);
  	public abstract String getBandName(); 
  	public abstract Playlist getPlaylist();
  	public abstract void setPlaylist(Playlist playlist);
  	public abstract String getReturnPage();
  	public abstract void setReturnPage(String returnPage);
  	public abstract IUploadFile getUploadFile();
  	public abstract McService getMcService();
  	public abstract void setCoverArtCandidate(CoverArtSearchResult index);
  	public abstract CoverArtSearchResult getCoverArtCandidate();
  
  	@InjectObject("engine-service:external")
  	public abstract IEngineService getExternalService();
  
  	/**
  	 * Interpret the parameters passed to this page. The page has 2 parameters:
  	 * <ul>
  	 * <li>playlistid - The Id of the playlist whose cover art is edited. This parameter
  	 *                  can be null, in whcih case the playlist is not persistent (yet).
  	 * <li>returnpage - This is the name of the tapestry page to use as return page.
  	 * </ul>
  	 */
  	public void activateExternalPage(Object[] args, IRequestCycle cycle) {
  		long playlistid = -1;
  		if(args[0]==null) {
  			// The playlist is not persistent (yet). Don't use the database!
  			Playlist transientPlaylist = new Playlist();
  			transientPlaylist.setId(playlistid);
  			setPlaylist(transientPlaylist);
  			// If the playlist id is null, then the third and fourth parameter can specify the search criteria.
  			if(args.length>2 && args[2]!=null) {
  				setBandName((String)args[2]);
  			}
  			if(args.length>3 && args[3]!=null) {
  				setPlaylistName((String)args[3]);
  				getPlaylist().setName(getPlaylistName());
  			}
  		} else {
  			playlistid = (Long) args[0];			
  			setPlaylist(getMcService().getPlaylistById(playlistid));
  		}
 		String returnPage = (String) args[1];
 		setPlaylistId(playlistid);
 		setReturnPage(returnPage);
 	}
 
 	/**
 	 * The user uploads a cover art image.
 	 *
 	 */
 	public void uploadCoverArt() {
 		if (getUploadFile() == null) {
 			return;
 		}
 
 		InputStream fis = getUploadFile().getStream();
 		FileOutputStream fos = null;
 
 		try {
 			fos = new FileOutputStream(new File(getUploadFile().getFileName()));
 			byte[] buffer = new byte[1024];
 			while (true) {
 				int length = fis.read(buffer);
 				if (length < 0) {
 					break;
 				}
 				fos.write(buffer, 0, length);
 			}
 			fis.close();
 			fos.close();
 			File uploaded = new File(getUploadFile().getFileName());
 			CoverArtManager.purge(getPlaylistId());
 			CoverArtManager.add(getPlaylistId(), new FileInputStream(uploaded));
 		} catch (IOException ioe) {
 			ioe.printStackTrace();
 		} finally {
 			if (fis != null) {
 				try {
 					fis.close();
 				} catch (IOException ioe) {
 				}
 			}
 			if (fos != null) {
 				try {
 					fos.close();
 				} catch (IOException ioe) {
 				}
 			}
 		}
 	}
 	
 	/**
 	 * Ask the Mc Service to return a list of possible cover art for this
 	 * playlist.
 	 * 
 	 * @return A list of cover art candidates for persistent playlists.
 	 */
 	public Collection<CoverArtSearchResult> getCoverArtList() {
 		if (isPersistentPlaylist()) {
 			return getMcService().getCoverArtList(getPlaylist());
 		} else {
 			String bandname = null;
 			if(isPersistentPlaylist()) {
 		    	try {
 		    		bandname = getPlaylist().getSongs().iterator().next().getSong().getBand().getName();
 		    	} catch (Exception e) {
 		    		bandname = "Various";
 		    	}
 			} else {
 				bandname = getBandName();
 			}
 			return getMcService().getCoverArtList(bandname, getPlaylist().getName());
 		}
 	}
 
 	/**
 	 * Set the selected image as the cover art image for the playlist if the playlist is persistent.  
 	 * <p>Returns to the page passed to coverArtedit by the <code>returnPage</code> property. Sets the <code>playlistId</code>
 	 * and the <code>coverArt</code> property on the return page before returning. 
 	 * 
 	 * @param cycle The Tapestry MVC cycle.
 	 * @param selected The selected cover art image.
 	 */
 	public ILink selectCoverArt(IRequestCycle cycle, CoverArtSearchResult selected) {
 		try {
 			if(isPersistentPlaylist()) {
 				getMcService().setPlaylistCoverArt(getPlaylist(),selected);
 			}
 			if(getReturnPage()!=null) {
 				IEngineService service = getExternalService();
 				ExternalServiceParameter parameter = new ExternalServiceParameter(getReturnPage(), new Object[]{getPlaylist().getId(),selected,getPlaylist().getName()});
 				ILink link = service.getLink(false, parameter);
 				return link;
 			}
 		} catch (IOException e) {
 			// TODO: Inform the user of the problem that has occured.
 		}
 		return null;
 	}
 	
 	/**
 	 * Tests if a persistent playlist is loaded in this page.
 	 * @return True if a persistent playlist is loaded, otherwise false.
 	 */
 	public boolean isPersistentPlaylist() {
 		return getPlaylistId()>=0;
 	}
 	
 	/**
 	 * @return The height for the currently displayed searchresult, taking into
 	 * account that the maximum width is 400px.
 	 */
 	public int getHeight() {
 		CoverArtSearchResult casr = getCoverArtCandidate();
 		if (casr.getWidth()>MAXDISPLAYWIDTH) {
 			return ImageScaler.calculateNewDimension(casr.getWidth(), casr.getHeight(), MAXDISPLAYWIDTH).height;
 		} else {
 			return casr.getHeight();
 		}
 	}
 
 	/**
 	 * @return The width for the currently displayed searchresult, taking into
 	 * account that the maximum width is 400px.
 	 */
 	public int getWidth() {
 		CoverArtSearchResult casr = getCoverArtCandidate();
 		if (casr.getWidth()>MAXDISPLAYWIDTH) {
 			return ImageScaler.calculateNewDimension(casr.getWidth(), casr.getHeight(), MAXDISPLAYWIDTH).width;
 		} else {
 			return casr.getWidth();
 		}
 	}
 
 }