import java.util.Vector;
import java.net.*;
import java.io.*;

/** An <CODE>AdditionalResultsFacade</CODE> defines an internal search engine
* that unmarshalls <CODE>SearchResult</CODE> from the Server.
*   
* @version 1.0
* @author Deric Bertrand - November 1999
*/ 
public class AdditionalResultsFacade extends SearchEngineFacade
{
	/** The ASP Session ID */
	private String m_SessionID = null;
	/** The number or Search Results returned */
	private int m_ResultCount;
	/** The State of the <CODE>SearchResultsCollector</CODE> on the Server */ 
	private int m_RemoteCollectorState; 
		
	/** 
	* Sets the value of the ASP Session ID
	* @param asSessionID  The ASP Session ID (cookie)
	*/
	public void setSessionId(String asSessionID)
	{
		m_SessionID = asSessionID;
	}

	/** 
	* Submits a query request to the <CODE>AdditionalResults.ASP</CODE> and unmarshalls the 
	* searialized results into a <CODE>SearchResult</CODE> collection
	* @param urlName  The URL of the <CODE>AdditionalResults.ASP</CODE>
	* @param listingIndex  Starting index of the query
	* @param theCollection  The <CODE>Vector</CODE> of <CODE>SearchResult</CODE>
	* @return  The number of results obtained from the current search request
	*/
	public int SubmitQuery(String urlName, int listingIndex, Vector theCollection)
		throws java.net.MalformedURLException, java.io.IOException, java.text.ParseException, Exception
	{
		HttpURLConnection theConnection;
		BufferedReader in = null;
		SearchResult searchResult;
		URL theURL;
		String resultLine;
		int resultCount;
	
		// Must have a sessionID to proceed
		if ( m_SessionID == null)
			throw new Exception("Session ID must be set before connecting to ASP.");
		
		// Append the search index to the url
		if ( listingIndex > +0)
			urlName += ("?listingIndex=" + listingIndex);
		
		theURL = new URL( urlName);

		// Handle the scenario of the AdditionalResults.asp finding an empty collection, 
		// but the collector is still searching
		do
		{
			theConnection = (HttpURLConnection) theURL.openConnection();
			theConnection.setRequestProperty("Cookie", m_SessionID);
			// added exception handling - 11/11/99 - Deric Bertrand
			if (( theConnection.getResponseCode() == -1) ||(theConnection.getResponseCode() != HttpURLConnection.HTTP_OK))
				throw new IOException("Bad response from URLconnect");
				
			// Get the header fields
			for (int i=1; theConnection.getHeaderFieldKey(i) != null; i++)
			{
				if (theConnection.getHeaderFieldKey(i).equals("result-count"))
					m_ResultCount = Integer.parseInt(theConnection.getHeaderField(i));
				else if (theConnection.getHeaderFieldKey(i).equals("collector-state"))
					m_RemoteCollectorState = Integer.parseInt(theConnection.getHeaderField(i));
			}

			in = new BufferedReader(new InputStreamReader(theConnection.getInputStream()));
			if (m_ResultCount <= 0 && m_RemoteCollectorState < SearchResultsCollector.S_Done)
				in.close();

		} while ( m_ResultCount <= 0 && m_RemoteCollectorState < SearchResultsCollector.S_Done);


		// Marshall the Search Results 
		for ( resultCount=0; resultCount < m_ResultCount; resultCount++)
		{  
			resultLine = in.readLine();
			searchResult = new SearchResult(resultLine);
			if ( searchResult.getRank() < listingIndex)
				throw new Exception(
					"Invalid Search Result retrieved for listingIndex"
				);
			theCollection.addElement( searchResult);
		}
		
		in.close();
		return resultCount;
	}
}