/* Copyright 2006 Laszlo Systems 
 * Authors: David Nault and Benjamin Shine 
 */ 
import java.io.*;
import java.net.*;
import javax.imageio.*;
import java.util.Properties;
import org.apache.commons.io.*;

/* To compile: javac -cp commons-io-1.2.jar ImageServer.java  
   To run: java -cp commons-io-1.2.jar:. ImageServer image.png
   Once running, get to it at http://localhost:9999/
   Control initial delay with value of initialDelay in 
   imageserver.properties 
*/ 
public class ImageServer {

    static public void buildResponse(
        OutputStream os, byte[] imageBytes, int initialDelay) 
        throws IOException, InterruptedException 
    {      
        // For testing purposes, we support an initial delay, 
        // specified in milliseconds, before returning an image.
        if (initialDelay > 0) {
            System.out.println("Sleeping for " + initialDelay + "ms"); 
            Thread.currentThread().sleep(initialDelay);
            System.out.println("Back from sleep."); 
        }
        
        // Build HTTP headers
        os.write("HTTP/1.0 200 OK\r\n".getBytes());
        // TODO The next line is where you would put a date; probably
        // a good idea to use "now". See GregorianCalendar, arg.
        // os.write("Date: Sun Aug 27 17:31:59 PDT 2006\r\n".getBytes());
        
        // TODO: change the mime-type if you want to return something other 
        // than a png.
        os.write("Content-Type: image/png\r\n".getBytes());
        os.write(("Content-Length: " + imageBytes.length +"\r\n").getBytes()); 
        os.write("\r\n".getBytes());
        os.write(imageBytes); 
        os.close(); 
    }
    
    public static void main(String args[]) throws Exception {
        String imageFileName = "image.png";
        if (args.length < 1) {
            System.out.println("Usage: java ImageServer <imagefile.png>");
        } else {
            imageFileName = args[0];
        }
        
        File imageFile = new File(imageFileName);
        System.out.println("Serving file : " + imageFile);
        byte[] imageBytes = FileUtils.readFileToByteArray(imageFile);
        System.out.println("image size in bytes: " + imageBytes.length);

        // declare a server socket and a client socket for the server
        // declare an input and an output stream
        ServerSocket echoServer = null;  
        InputStream is = null;
        OutputStream os = null;
        Socket clientSocket = null;

        // Try to open a server socket on port 9999
        try {
           echoServer = new ServerSocket(9999);
        }
        catch (IOException e) {
           System.out.println(e);
        }  

        // Create a socket object from the ServerSocket to listen and accept
        // connections.
        
        while (true) {
            try {
                // Re-read the properties each time we serve up a response, so that
                // response properties can be changed without restarting the server.        
                Properties props = new Properties();
                props.load(new FileInputStream("imageserver.properties") );
                String initialDelayStr = props.getProperty( "initialDelay", "0");
                int initialDelay = Integer.parseInt(initialDelayStr); 
            
                clientSocket = echoServer.accept();           
                System.out.println("starting response");

                os = clientSocket.getOutputStream();
                buildResponse(os, imageBytes, initialDelay);

                System.out.println("response complete");
                System.out.println();
            } catch (Exception e) {
                System.out.println(e);
            } finally {
                IOUtils.closeQuietly(is);
                IOUtils.closeQuietly(os);
            }
        }
    }
}