package yarfraw.io;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import java.net.URI;

 import org.apache.commons.httpclient.HttpClient;

 import org.apache.commons.httpclient.HttpURL;

 import org.apache.commons.httpclient.methods.GetMethod;

 import org.apache.commons.httpclient.params.HttpClientParams;

 import yarfraw.core.datamodel.FeedFormat;

 import yarfraw.core.datamodel.YarfrawException;

 import yarfraw.utils.FeedFormatDetector;

 /**

  * Provides a set of function to facilitate parsing of a RSS feed.

  * @author jliang

  *

  */

 abstract class AbstractBaseFeedParser extends AbstractBaseIO{

   protected HttpURL _httpUrl = null;

   protected HttpClientParams _httpClientParams = null;

   protected GetMethod _getMethod = null;

   public AbstractBaseFeedParser(File file, FeedFormat format){

     super(file, format);

   }

   public AbstractBaseFeedParser(String pathName, FeedFormat format){

     super(new File(pathName), format);

   }

   public AbstractBaseFeedParser(URI uri, FeedFormat format){

     super(new File(uri), format);

   } 

   public AbstractBaseFeedParser(File file){

     super(file);

   }

   public AbstractBaseFeedParser(String pathName){

     this(new File(pathName));

   }

   public AbstractBaseFeedParser(URI uri){

     this(new File(uri));

   }

   public AbstractBaseFeedParser(HttpURL httpUrl) throws YarfrawException, IOException{

     this(httpUrl, null);

   }

   public AbstractBaseFeedParser(HttpURL httpUrl, HttpClientParams params) throws YarfrawException, IOException{

     _httpUrl = httpUrl;

     _httpClientParams = params;

     //detect format automatically

     _format = FeedFormatDetector.getFormat(getStream());

   }

   public AbstractBaseFeedParser(GetMethod getMethod) throws YarfrawException, IOException{

     _getMethod = getMethod;

     _format = FeedFormatDetector.getFormat(getStream());

   }

   public HttpClientParams getHttpClientParams() {

     return _httpClientParams;

   }

   public void setHttpClientParams(HttpClientParams httpClientParams) {

     _httpClientParams = httpClientParams;

   }

   /**

    * The {@link GetMethod} object to be used to remote from a remote source.

    * @return

    */

   public GetMethod getGetMethod() {

     return _getMethod;

   }

   /**

    * Is the reader reading the feed from a remote http link.

    * @return true if reading remotely<br/>

    * false if reading from local file

    */

   public boolean isRemoteRead(){

     return _httpUrl != null || _getMethod != null;

   }

   protected InputStream getStream() throws IOException{

     InputStream stream;

     if(isRemoteRead()){

       GetMethod get = getGetMethod();

       if(get == null){

         get = new GetMethod(_httpUrl.toString());

         get.setFollowRedirects(true);

       } 

       HttpClient client = new HttpClient();

       if(_httpClientParams != null){

         client.setParams(_httpClientParams);

       }

       client.executeMethod(get);

       stream = get.getResponseBodyAsStream();

     }else{

       return new FileInputStream(_file);

     }

     return stream; 

   }

 }