/**
@author  Scott Marshall
@author  University of Glasgow, MSc IT Project 2001
@author  Building an OnLine Course in Computing Fundamentals

Multiple Choice Questions

*/

package ukacgla_HTMLMulti;

import ukacgla_HTMLMulti.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
import java.util.*;
import java.net.*;

/**
TestItem holds ALL the the lines for a single question. 
TestItem is a single test, made of one question and a number of answers. 
Answers are built from reading a txt file located at the answerURL location.  
Each option to be displayed is a separate object, a TestLine object.
This class reads the txt file passed in as answerURL, and constructs TestLine objects. 
TestLine objects are then held in the Vector answerList. 
*/
public class TestItem { 

	/** Holds the TestLines that make this TestItem. */
	private Vector answerList;										

	/** URL of Question HTML file to be displayed. */
	private URL questionURL;	

	/** URL of each option to be displayed. */
	private URL answerURL;		

	/** URL of any images to be displayed. */
	private URL iconURL;		

	/** URL of any follow up HTML files to be displayed. */
	private URL followOnURL;	

	/** If the TestLine is specified as containing an image, it will be created as this icon. */
	private ImageIcon icon;	
	

	/**
	Reads input txt file.
	Constructs a TestLine object from information read from file.
	Places TestLine objects into a vector, then randomises the order of the vector	
	*/
	public TestItem(URL questionURL, URL answerURL)	{
		this.questionURL = questionURL;
		this.answerURL = answerURL;
		answerList = new Vector();		
		
		try	{
			//open a stream to read the answer file
			InputStream inStream = answerURL.openStream();
			BufferedReader dataStream = new BufferedReader(new InputStreamReader(inStream));
			String inLine = null;
			
			while ((inLine = dataStream.readLine())!=null){
	
				//use a StringTokenizer to read all the info held in inLine
				StringTokenizer t = new StringTokenizer(inLine,"$*");
				
				//use this to make URL of the follow up information
				while (t.hasMoreTokens()){

					//test if there is signal for an icon
					if (t.nextToken().equals("Icon")) {

						//Form the URL of any image icons
						try	{
							iconURL = new URL(answerURL,new String(t.nextToken()));
						}
						
						catch (MalformedURLException e)	{
							System.out.println("Invalid iconURL read from file : " + iconURL);
						}
						
						icon = new ImageIcon(iconURL);					
					}
					
					else {
						String chaff = t.nextToken();	//skips next token
						icon = null;					//records no icon with this file
					}						
						
					//get HTML fragment from inLine
					String HTMLtext = t.nextToken();

					//use this to make URL of the follow up information
					try	{
						followOnURL = new URL(answerURL,new String(t.nextToken()));
					}
					
					catch (MalformedURLException e)	{
						System.out.println("Invalid followOnURL read from file : " + followOnURL);
					}
					
					//then read if answer is correct or not
					int correct = Integer.parseInt(t.nextToken());
					TestLine temp = new TestLine(icon, HTMLtext, followOnURL, correct);
					answerList.add(temp);
					
				
				}//ends hasMoreTokens
			
			}//ends while


			TestRandomiser random = new TestRandomiser(answerList.size());
			answerList = random.randomise(answerList);

				
		}//ends try
		
		catch(IOException e){ }
	
	}//ends ctor


	/** Returns questionURL for this TestItem.	*/
	protected URL getQuestionURL(){
		return questionURL;
	}


	/** Returns number of TestLines in current TestItem	*/
	protected int getNumLines(){
		return answerList.size();
	}

	/** Returns a specific TestLine held in the answerList vector */
	protected TestLine getLine(int n){
		return (TestLine) answerList.get(n);
	}


	
}//ends class