/**
 * Code is taken from Computer Networking: A Top-Down Approach Featuring 
 * the Internet, second edition, copyright 1996-2002 J.F Kurose and K.W. Ross, 
 * All Rights Reserved.
 **/

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

class seqHTTPServer {

    public static int serverPort = 6789;    
    //public static String WWW_ROOT = "/home/httpd/html/zoo/classes/cs433/";
    public static String WWW_ROOT = "./";

    public static void main(String args[]) throws Exception  {
	
	// see if we do not use default server port
	if (args.length >= 1)
	    serverPort = Integer.parseInt(args[0]);

	// see if we want a different root
	if (args.length >= 2)
	    WWW_ROOT = args[1];

	// create server socket
	ServerSocket listenSocket = new ServerSocket(serverPort);
	System.out.println("server listening at: " + listenSocket);
	System.out.println("server www root: " + WWW_ROOT);

	while (true) {

	    try {
		// take a ready connection from the accepted queue
		Socket connectionSocket = listenSocket.accept();
		System.out.println("receive request from " + connectionSocket);
	
		// read the request from client
		BufferedReader inFromClient =
		    new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));

		String requestMessageLine;	
		requestMessageLine = inFromClient.readLine();
		System.out.println("request line: " + requestMessageLine);

		// process the request
		StringTokenizer tokenizedLine =
		    new StringTokenizer(requestMessageLine);

		if (tokenizedLine.nextToken().equals("GET")) {

		    String urlName;	    
		    // parse URL to retrieve file name
		    urlName = tokenizedLine.nextToken();
	    
		    if (urlName.startsWith("/") == true )
			urlName  = urlName.substring(1);
		    
		    processRequest(urlName, connectionSocket);

		} // end of if
		else 
		    System.out.println("Bad Request Message");
	    } catch (Exception e)
		{
		}
	} // end of while (true)
	
    } // end of main

    private static void processRequest(String urlName, Socket connectionSocket) throws Exception
    {

	// get output stream
	DataOutputStream outToClient =
	    new DataOutputStream(connectionSocket.getOutputStream());

	// map file name
	String fileLoc = WWW_ROOT + urlName;
	System.out.println ("Request: GET " + fileLoc);

	File file = new File( fileLoc );
	if (!file.isFile())
	{
	    // generate response header
	    outToClient.writeBytes("HTTP/1.0 404 Not Found\r\n");
	} else {

	    int numOfBytes = (int) file.length();
	    
	    FileInputStream inFile  = new FileInputStream (fileLoc);
	
	    byte[] fileInBytes = new byte[numOfBytes];
	    inFile.read(fileInBytes);

	    // generate response header
	    outToClient.writeBytes("HTTP/1.0 200 Document Follows\r\n");
	
	    if (urlName.endsWith(".jpg"))
		outToClient.writeBytes("Content-Type: image/jpeg\r\n");
	    if (urlName.endsWith(".gif"))
		outToClient.writeBytes("Content-Type: image/gif\r\n");
	
	    outToClient.writeBytes("Content-Length: " + numOfBytes + "\r\n");
	    outToClient.writeBytes("\r\n");
	
	    // send file content
	    outToClient.write(fileInBytes, 0, numOfBytes);
	}

	// close connectionSocket
	connectionSocket.close();
    } // end of processARequest
    
} // end of class WebServer