import java.io.*;
import javax.servlet.http.*;
import java.util.Collection;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.HashMap;

/**
 * Sets up the input map for the Processor and invokes it.  Prints out the
 * result to the resulting HTML page.
 */
public class Output extends HttpServlet
{
	private static final String PAGE_TITLE = "Output Page";
	private static final int SLEEP_TIME = 50;

	public void doGet(HttpServletRequest req, HttpServletResponse rsp)
	{
		PrintWriter out = null;

		try
		{
			rsp.setContentType("text/html");
			out = rsp.getWriter();

			HttpSession session = req.getSession(false);

			if(session == null)
			{
				HTMLUtils.printRedirectPage(out,
					"You must login to the system prior to viewing this page.",
					"Login");

				return;
			}

			TranscriptRequest transReq = (TranscriptRequest)
				session.getAttribute("transcript_request");

			if(transReq == null)
			{
				transReq = new TranscriptRequest();
				session.setAttribute("transcript_request", transReq);
			}

			if(!transReq.isStarted())
			{
				HTMLUtils.printRedirectPage(out, 
					"You must login to the system prior to viewing this page.",
					"Login");
			}
			else
			{
				HTMLUtils.printRedirectPage(out,
					"You must specify your preferences prior to viewing this page.",
					"Input");
			}
		}
		catch(Exception e)
		{
			try
			{
				HTMLUtils.printException(out, e);
			}
			catch(Exception e2) {}		
		}		
	}

	public void doPost(HttpServletRequest req, HttpServletResponse rsp)
	{
		PrintWriter out = null;

		try
		{
			rsp.setContentType("text/html");
			out = rsp.getWriter();

			if(req.getCookies() == null)
			{
				HTMLUtils.printRedirectPage(out,
					"You must enable cookies in your browser before using the advisement system.",
					"Login");

				return;
			}


			HttpSession session = req.getSession(false);

			if(session == null)
			{
				HTMLUtils.printRedirectPage(out,
					"You must login to the system prior to viewing this page.",
					"Login");

				return;
			}

			TranscriptRequest transReq = (TranscriptRequest)
				session.getAttribute("transcript_request");

			if(transReq == null)
			{
				transReq = new TranscriptRequest();
				session.setAttribute("transcript_request", transReq);
			}
			
			if(!transReq.isStarted())
			{
				HTMLUtils.printRedirectPage(out,
					"You must login to the system prior to viewing this page.",
					"Login");

				return;
			}

			while(!transReq.isDone())						
				Thread.sleep(SLEEP_TIME);

			Exception e = transReq.getException();

			if(e != null)
			{
				if(e instanceof TranscriptException)
				{
					int errorCode = ((TranscriptException) e).getErrorCode();

					if(errorCode == TranscriptException.ERROR_CONTINUE)
					{
						HTMLUtils.printRedirectPage(out,
							e.getMessage(),
							"Login");

						return;
					}
				}
				
				throw e;
			}

			HashMap map = new HashMap();
			String major, secondMajor, minor, coreNeeded;

			if((major = req.getParameter("major")) == null)
			{
				throw new FrontEndException(
					"Missing POST Data: major");
			}

			if((minor = req.getParameter("minor")) == null)
			{
				throw new FrontEndException(
					"Missing POST Data: minor");
			}

			if((secondMajor = req.getParameter("secondmajor")) == null)
			{
				throw new FrontEndException(
					"Missing POST Data: secondmajor");
			}

			if((coreNeeded = req.getParameter("coreneeded")) == null)
			{
				throw new FrontEndException(
					"Missing POST Data: coreneeded");
			}

			Collection courseList = transReq.getCourses();
			RetrieverUtils.translateCourseList(courseList);

			map.put("courses", courseList);
			map.put("major", major);
			map.put("secondmajor", secondMajor);
			map.put("minor", minor);
			map.put("coreneeded", coreNeeded);
			map.put("totalcredits", transReq.getTotalCreditCount());
			map.put("transfercredits", transReq.getTransferCreditCount());

			String errorStr;			
			if((errorStr=InputChecker.isInputMapOk(map)) != null)
			{			
				HTMLUtils.printRedirectPage(out, errorStr, "Input");
				return;
			}

			HTMLUtils.printHeader(out, PAGE_TITLE);

			Processor processor = new Processor(map);
			ArrayList arrList = processor.go();
			
			HTMLUtils.printTable(out, arrList);

			HTMLUtils.printFooter(out);
		}
		catch(Exception e)
		{
			try
			{
				HTMLUtils.printException(out, e);
			}
			catch(Exception e2) {}
		}		
	}
}