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

class ServiceThread extends Thread
{
    Socket conn = null;

    public ServiceThread(Socket c) { conn = c; }

    public void run()
    {
    try
    {
        Scanner scanin = new Scanner(conn.getInputStream());
        String line = null ;
        int nlines = 0;
        String inputLines[] = new String[32];

        while(true)
        {
            line = scanin.nextLine();
            if(line.length() == 0) break;
            inputLines[nlines] = line;
            nlines++;
        }

        // create scanner to extract command and resource location
        Scanner extract = new Scanner(inputLines[0]);
        String command = extract.next();
        String resource = extract.next();
        String protocol = extract.next();
        OutputStream outs = conn.getOutputStream();
        boolean isPointOne = false;
        boolean hostFound = false;
        boolean badRequest = false;
        Date now = new Date();
        SimpleDateFormat df = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz");
        String dateString = df.format(now);

        if(protocol.compareTo("HTTP/1.1") == 0)
        {
        String checkLine = "";
        int i = 0;

        while(i < 32)
        {
            checkLine = inputLines[i];
            System.out.println(checkLine);
            if(checkLine == null) break;
            if(checkLine.contains("Host:")) { hostFound = true; break;}
            i++;
        }

        isPointOne = true;

        }

        if(isPointOne == true && hostFound == false) { badRequest = true; }

        // check for "/"
        if(!resource.startsWith("/") || badRequest == true)
        {
        String reply = "HTTP/1.0 400 Bad Request\r\n" +
            "Connection: close\r\n" +
            "Date: " + dateString + "\r\n" +
            "Content-Type: text/html\r\n" +
            "\r\n" +
            "<b>Error 400:</b> Bad request\r\n";

        outs.write(reply.getBytes());
        }
        else // good request
        {
        // check correct command
        if(command.compareTo("GET") == 0 || command.compareTo("HEAD") == 0)
        {
            String fileName = "www"+resource;

            // check to see if file exist, if not send error 404
            File requestedFile = new File(fileName);

            if (!requestedFile.exists())
            {
            String reply = "HTTP/1.0 404 Not Found\r\n" +
                "Connection: close\r\n" +
                "Date: " + dateString + "\r\n" +
                "Content-Type: text/html\r\n" +
                "\r\n" +
                "<b>Error 404:</b> File not found\r\n";

            outs.write(reply.getBytes());
            }
            else
            { // file does exist

            if(requestedFile.isDirectory())
            {
                String checkFileName = "www"+resource+"/"+"index.html";
                File indexFile = new File(indexFile);

                if(!indexFile.exists())
                {
                String reply = "HTTP/1.0 404 Not Found\r\n" +
                    "Connection: close\r\n" +
                    "Date: " + dateString + "\r\n" +
                    "Content-Type: text/html\r\n" +
                    "\r\n" +
                    "<b>Error 404:</b> File not found\r\n";

                outs.write(reply.getBytes());
                }
                else
                {
                File requestedFile = new File(indexFile);
                }
            }

            InputStream inFile = new FileInputStream(requestedFile);
                byte buffer[] = new byte[1024];
            long lastModified = requestedFile.lastModified();
            Date lastModifiedDate = new Date(lastModified);
            SimpleDateFormat lmdf = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz");
            String lastModifiedDf = lmdf.format(lastModifiedDate);

            String fileLength = Long.toString(requestedFile.length()); // get file length
            String header = "HTTP/1.0 200 OK\r\n"+
                "Connection: close\r\n"+
                "Date: " + dateString + "\r\n" +
                "Last-Modified: " + lastModifiedDf + "\r\n" +
                "Content-Length: " + fileLength + "\r\n"+
                "Content-Type: text/html\r\n"+
                "\r\n";

                // send header
            outs.write(header.getBytes());

            if(command.compareTo("GET") == 0)
            {
                while(true)
                {
                int rc = inFile.read(buffer,0,1024);
                if(rc <= 0) break;
                outs.write(buffer,0,rc);
                }
            }
            }
        }
        else // incorrect command
        {
            String reply = "HTTP/1.0 501 Not Implemented\r\n" +
            "Connection: close\r\n" +
            "Date: " + dateString + "\r\n" +
            "Content-Type: text/html\r\n" +
            "\r\n" +
            "<b>Error 501:</b> Not implemented<br>\r\n";

            outs.write(reply.getBytes());
        }
        }
        // close the connection
        conn.close();
    }

    catch (IOException e)
    {
        System.err.println("HTTPServer: error reading socket");
        System.exit(1);
    }
    }
}





public class HTTPServer2
{
    public static void main(String args[])
    {
    try
    {
        if(args.length != 1)
        {
            System.out.println("Usage: HTTPServer <port>");
            System.exit(1);
        }

        int port = Integer.parseInt(args[0]);
        ServerSocket serverSock = new ServerSocket(port);

        while(true)
        {
            Socket connSock = serverSock.accept();
            ServiceThread serve = new ServiceThread(connSock);
            serve.start();
        }
    }
    catch (IOException e)
        {
        System.err.println("HTTPServer error on socket");
        System.exit(1);
    }
    }
}