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

final class HttpRequest implements Runnable
{
    final static String CRLF = "\r\n";
    Socket socket;
    
    // Constructor
    public HttpRequest(Socket socket) throws Exception
    {
        this.socket = socket;
    }
    
    // Implement the run() method of the Runnable interface.
    public void run()
    {
        try {
            processRequest();
        } catch (Exception e) {
            System.out.println(e);
        }
    }

    private void processRequest() throws Exception
    {
        // Set up output stream
        DataOutputStream os = new DataOutputStream(socket.getOutputStream());
        
        // Set up input stream filters.
        BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));

        // Get the request line of the HTTP request message.
        String requestLine = br.readLine();

        // Extract the filename from the request line.
        StringTokenizer tokens = new StringTokenizer(requestLine);
        tokens.nextToken();  // skip over the method, which should be "GET"
        String fileName = tokens.nextToken();
        
        // Prepend a "." so that file request is within the current directory.
        fileName = "." + fileName ;
        
        // Open the requested file.
        FileInputStream fis = null ;
        boolean fileExists = true ;
        try {
            fis = new FileInputStream(fileName);
        } catch (FileNotFoundException e) {
            fileExists = false ;
        }

        // Debug info for private use
        System.out.println("Incoming!!!");
        System.out.println(requestLine);
        String headerLine = null;
        while ((headerLine = br.readLine()).length() != 0) {
            System.out.println(headerLine);
        }
        
        // Construct the response message.
        String statusLine = null;
        String contentTypeLine = null;
        String entityBody = null;
        if (fileExists) {
            statusLine = "HTTP/1.0 200 OK" + CRLF;
            contentTypeLine = "Content-Type: " + 
                contentType(fileName) + CRLF;
        } else {
            statusLine = "HTTP/1.0 404 Not Found" + CRLF;
            contentTypeLine = "text/html" + CRLF;
            entityBody = "<HTML>" + 
                "<HEAD><TITLE>Not Found</TITLE></HEAD>" +
                "<BODY>Not Found</BODY></HTML>";
        }
        // Send the status line.
        os.writeBytes(statusLine);

        // Send the content type line.
        os.writeBytes(contentTypeLine);

        // Send a blank line to indicate the end of the header lines.
        os.writeBytes(CRLF);

        // Send the entity body.
        if (fileExists) {
            sendBytes(fis, os);
            fis.close();
        } else {
            os.writeBytes(entityBody) ;
        }

        // Close streams and socket.
        os.close();
        br.close();
        socket.close();
    }

    private static void sendBytes(FileInputStream fis, 
                                  OutputStream os) throws Exception
    {
        // Construct a 1K buffer to hold bytes on their way to the socket.
        byte[] buffer = new byte[1024];
        int bytes = 0;
        
        // Copy requested file into the socket's output stream.
        while ((bytes = fis.read(buffer)) != -1) {
              os.write(buffer, 0, bytes);
        }
    }

    private static String contentType(String fileName)
    {
        if(fileName.endsWith(".htm") || fileName.endsWith(".html")) {
            return "text/html";
        }

        if(fileName.endsWith(".gif")) {
            return "image/gif";
        }

        if (fileName.endsWith(".jpg") || fileName.endsWith(".jpeg"))
        {
            return "image/jpeg";
        }
        
        return "application/octet-stream" ;
    }
}

