/**
 * BeebhackDownloader
 * Class for downloading iPhone video off BBC iPlayer
 * @author Iain Wallace http://strawp.net
 */
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.Random;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.apache.http.Header;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

public class Downloader {
	
	public String coreMediaUserAgent = "Apple iPhone v1.1.1 CoreMedia v1.0.0.3A110a";
	public String iPhoneMediaSelectorPrefix = "http://www.bbc.co.uk/mediaselector/3/auth/iplayer_streaming_http_mp4";
	public String versionMediaSelectorPrefix = "http://www.bbc.co.uk/mediaselector/4/mtis/stream/";
	public String safariUserAgent = "Mozilla/5.0 (iPhone; U; CPU like Mac OS X; en) AppleWebKit/420.1 (KHTML, like Gecko) Version/3.0 Mobile/3A110a Safari/419.3";
	public String[] versionNames = "default original signed audiodescribed opensubtitled shortened lengthened other".split(" ");
	public String playlistPrefix = "http://www.bbc.co.uk/iplayer/playlist/";
	public String metaDataPrefix = "http://www.bbc.co.uk/iplayer/metafiles/episode/";
	public Boolean debug = true;
	private HttpClient client;
	private String downloadDestination = "";
	private String filename;
	private long blocksize = 524288; // 4194304;

	
	Downloader(){
		this.client = new DefaultHttpClient();
		this.client.getParams().setBooleanParameter("http.protocol.handle-redirects", false);
	}
	
	/**
	 * Download to a specific folder
	 * @param pid
	 * @param dest
	 * @return
	 */
	public Boolean downloadByPid( String pid, String dest ){
		this.downloadDestination = dest;
		return this.downloadByPid(pid);
	}
	
	/**
	 * Pass a programme ID and download the file, working out the details automatically
	 * @param pid
	 * @return
	 */
	public Boolean downloadByPid( String pid ){
		// Get stream url
		String streamUrl = this.getIphoneStreamUrl(pid);
		if( streamUrl == null ){
			System.out.println("streamUrl is null");
			return false;
		}
		return this.downloadIphoneStream( streamUrl, this.filename );
	}
	
	/**
	 * Work out the stream URL of a programme from the programme ID (pid)
	 * http://download.iplayer.bbc.co.uk/iplayer_streaming_http_mp4/5291651394040737632.mp4?token=iVXcx557SN8malAhHh1%2BZ%2FVk4n35UKfH4qGsJzA1oF%2BhC2K%2Bq9ok8Ky3z%2BkeoBmwfs9pJvH3SUKU%0A8c7z%2BxIG5tNEF2xNIl6%2F%2Bdwl3brQkb6ctOKggoHosrDAVwp5ZPqGNBdQKg%3D%3D%0A
	 * @param pid
	 * @return
	 * @throws IOException 
	 * @throws ClientProtocolException 
	 */
	public String getIphoneStreamUrl( String pid ) {
		
		String url = this.getValidVersionUrl(pid);
		if( url == null ) return null;
		if(this.debug) System.out.println("Getting " + url );
		
		HttpGet request = new HttpGet(url);
		request.addHeader("User-Agent", this.coreMediaUserAgent );
		request.addHeader("Accept", "*/*");
		request.addHeader("Range", "bytes=0-1");
		
		HttpResponse response;
		try {
			response = this.client.execute(request);
		} catch (ClientProtocolException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			System.out.println("Error: " + e.getLocalizedMessage());
			return null;
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			System.out.println("Error: " + e.getLocalizedMessage());
			return null;
		} 
		if(this.debug) System.out.println("Request completed");
		
		Header [] headers = response.getAllHeaders();
		for( int i=0; i<headers.length; i++ ){
			Header hdr = headers[i];
			System.out.println( hdr.getName()+ ": " + hdr.getValue() );
		}
		
		Header[] header = response.getHeaders("Location");
		if( header.length == 0 ){
			if(this.debug) System.out.println("No Location headers found in response");
			return null;
		}
		this.closeClientConnection(response);
		return header[0].getValue();
	}

	/**
	 * From a pid of a show, get the first valid stream url available
	 * @param pid
	 * @return
	 */
	public String getValidVersionUrl(String pid){
		if( this.debug ) System.out.println("getValidVersionUrl( " + pid + " )");
		
		// Get version pids
		String[] aPids = this.getVersionPids(pid);
		if(aPids.length == 0) return null;
		Random rand = new Random();
		String streamUrl = null;
		for(int i=0; i<aPids.length; i++ ){
			if( aPids[i] != null ){
				streamUrl = this.iPhoneMediaSelectorPrefix + "/" + aPids[i] + "?" + rand.nextInt(1000000);
				break;
			}
		}
		return streamUrl;
	}
	
	/**
	 * Download an iPhone H.264 stream from a URL to a file
	 * @throws IOException 
	 * @throws ClientProtocolException 
	 */
	public Boolean downloadIphoneStream( String url, String filename ) {
		
		if(this.debug) System.out.println( "downloadIphoneStream( " + url + ", " + filename + " );" );
		
		HttpGet request = new HttpGet(url);
		request.addHeader("User-Agent", this.coreMediaUserAgent );
		request.addHeader("Accept", "*/*");
		request.addHeader("Range", "bytes=0-1");
		
		HttpResponse response;
		try {
			response = this.client.execute(request);
		} catch (ClientProtocolException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			System.out.println("Error: " + e.getLocalizedMessage());
			return false;
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			System.out.println("Error: " + e.getLocalizedMessage());
			return false;
		}
		
		Header[] header = response.getHeaders("Content-Range");
		if( header.length == 0 ) return false;
		String contentRange = header[0].getValue();
		Long downloadLength = Long.parseLong(contentRange.split("/")[1]);
		// Integer downloadLength = Integer.parseInt(contentRange.split("/")[1]);
		System.out.println("Download length: " + downloadLength.toString());
		this.closeClientConnection(response);
		
		long filesize = 0;
		File dest = new File( this.downloadDestination + this.filename ); 
		if( dest.exists() && dest.isFile() ){
			filesize = dest.length();
		}
		long end = 0;
		
		while( filesize < downloadLength ){
			end = this.downloadBlock(url, this.downloadDestination + this.filename, downloadLength );
			filesize += this.blocksize;
			System.out.println( end + "/" + downloadLength );
		}
		return true;
	}
	
	/**
	 * Download a chunk of iPhone video data, return the position in the file of the last byte downloaded
	 * Creates HTTP request using "Range" header
	 */
	private long downloadBlock( String url, String filename, Long downloadLength ){
		if(this.debug) System.out.println("downloadBlock( "+ url + ", " + filename + ", " + downloadLength + " );" );
		
		File dest = new File(filename);
		long start = dest.length();
		Long end = Math.min( start + this.blocksize - 1, downloadLength );
		FileOutputStream fos;
		DataOutputStream ds;
		
		HttpGet request = new HttpGet(url);
		request.addHeader("User-Agent", this.coreMediaUserAgent );
		request.addHeader("Accept", "*/*");
		request.addHeader("Range", "bytes=" + start + "-" + end );
		
		try {
			fos = new FileOutputStream(filename,true);
			// Wrap the FileOutputStream with a
			// DataOutputStream to obtain its writeInt()
			// method.
		    ds = new DataOutputStream( fos );
		} catch (IOException ioe) {
			System.out.println( "IO error: " + ioe );
			return 0;
		} 
		
		HttpResponse response;
		try {
			response = this.client.execute(request);
			byte[] data = EntityUtils.toByteArray(response.getEntity());
			ds.write(data);
		} catch (ClientProtocolException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			System.out.println("Error: " + e.getLocalizedMessage());
			return 0;
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			System.out.println("Error: " + e.getLocalizedMessage());
			return 0;
		}
		this.closeClientConnection(response);
		return end;
	}
	
	private void closeClientConnection(HttpResponse response){
		try {
			response.getEntity().consumeContent();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	
	/**
	 * Get the various pids of an episode of a programme, e.g. subtitled, audiodescribed etc
	 * @param pid
	 * @return
	 * @throws ParserConfigurationException
	 * @throws SAXException
	 * @throws MalformedURLException
	 */
	public String[] getVersionPids( String pid ) {
		if( this.debug ) System.out.println("getVersionPids( " + pid + " )");
		Document doc = getDocument(this.playlistPrefix+pid);
		if( doc == null ) return null;
		
		// Get episode name, use for filename, destination
		NodeList title = doc.getElementsByTagName("title");
		if( title.getLength() > 0 ){
			String strTitle = title.item(0).getTextContent();
			strTitle = strTitle.replaceAll(":", " -" );
			strTitle = strTitle.replaceAll("/[^-a-zA-Z0-9]/", "");
			this.filename = strTitle.trim() + ".mov";
		}
	
		NodeList nodes = doc.getElementsByTagName("item");
		int versionCount = nodes.getLength();
		if( versionCount == 0 ) return null;
		String[] aPids = new String[versionCount];
		for(int i=0; i<versionCount; i++){
			Node identifier = nodes.item(i).getAttributes().getNamedItem("identifier");
			if( identifier != null ){ 
				System.out.println(identifier.getNodeValue());
				aPids[i] = identifier.getNodeValue();
			}
		}
		return aPids;
	}
	
	/**
	 * Get an XML Document from a string
	 * @param url
	 * @return
	 */
	public Document getDocument( String url ){
		DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
		DocumentBuilder db;
		try {
			db = dbf.newDocumentBuilder();
			Document doc = getDocument( db, url );
			return doc;
		} catch (ParserConfigurationException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return null;
	}
	
   /**
    * This method gets an XML document from the given URL.
    */
	public Document getDocument( DocumentBuilder db, String urlString ) {
	   if( this.debug ) System.out.println("Attempting to make DOM doc from " + urlString );
      try {
         URL url = new URL( urlString );
         try {
            URLConnection URLconnection = url.openConnection();
            HttpURLConnection httpConnection = (HttpURLConnection) URLconnection;
            int responseCode = httpConnection.getResponseCode();
            if ( responseCode == HttpURLConnection.HTTP_OK) {
               InputStream in = httpConnection.getInputStream();
               try {
                  Document doc = db.parse( in );
                  return doc;
               } catch( org.xml.sax.SAXException e ) {
                  e.printStackTrace();
               }
            } else
               System.out.println( "HTTP connection response != HTTP_OK" );
         } catch ( IOException e ) {
            e.printStackTrace();
         } // catch
      } catch ( MalformedURLException e ) {
         e.printStackTrace();
      } // catch
      return null;
   } // getDocument
}