// DisplayLCD.java
// Author: Dan Burke
// copy "servlet-api.jar" from /common/lib/ in your jakarta installation
// to /webapps/ROOT/WEB-INF/classes/
// Place this source file "DisplayLCD.java: in your 
// /webapps/ROOT/WEB-INF/classes/ in your jakarta installation
// compile with javac -classpath "servlet-api.jar" DisplayLCD.java
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class DisplayLCD extends HttpServlet {
	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{

		response.setContentType("text/html");
		PrintWriter out = response.getWriter();
    
		String command = "display";

		Runtime runtime = Runtime.getRuntime();
		Process process = null;

		// Get the text input from the web page.
		String line1 = request.getParameter("line1");
		String line2 = request.getParameter("line2");
		String name = request.getParameter("yourname");
		
		String history[][] = new String[2][10];
				
		int x = 0;

 		if(line1 != null){
 
		try {

			// Open an output stream to a file to write the
			// text input from the webpage to a file
        		BufferedWriter outwriter = new BufferedWriter(new FileWriter("displayinput"));
			
			x = line1.length();
			
			// Pad the first line with space characters if
			// it's length is less than 16 characters.
			while(x < 16){
				line1 = line1 + " ";
				x = line1.length();
			}
			
			// Write the first line to the file.
			outwriter.write(line1);
		
			x = line2.length();
			if (x != 0){

				// Pad the second line with space
				// characters if it's length is less
				// than 16 characters.
				while (x < 16){
					line2 = line2 + " ";
					x = line2.length();
				}

				// Write the second line to the output
				// file.
				outwriter.write(line2);
        		}

			// Close the output stream to the file.
			outwriter.close();
			

			// Read the history file
			BufferedReader historyreader = new BufferedReader(new FileReader("messagehistory.txt"));
			for (int i = 0; i < 10; i++){
				history[0][i] = historyreader.readLine();
				history[1][i] = historyreader.readLine();
			}
			historyreader.close();
			BufferedWriter historywriter = new BufferedWriter(new FileWriter("messagehistory.txt"));
			
			x = name.length();

			// Write the name of the user to the history
			// file.
			if (x != 0){
				historywriter.write(name + "\n");
			} else {
				historywriter.write("Anonymous\n");
			}
			
			// Write line 1 to the history file
			if (line1.length() != 0){
				historywriter.write(line1);
			}
			else {
				historywriter.write("                ");
			}
			
			// Write line 2 to the history file
			if (line2.length() != 0){
				historywriter.write(line2);
			} else {
				historywriter.write("                ");
			}
			
			historywriter.write("\n");
			
			// Write the previous 9 history entries
			for (int i = 0; i < 9; i++){
				historywriter.write(history[0][i] + "\n");
				historywriter.write(history[1][i] + "\n");
			}
			historywriter.close();

    		} catch (IOException e) {
			System.out.println("Error");
    		}

    		} else {
      			out.println("No text entered.");
    		}

    		

		try{
			// Execute the shell program to write to the LCD
			// Display
			process = runtime.exec(command);

			// Busy work to wait for the text to be written.
			for (int y = 0; y < 60000; y++){
				System.out.println("Busy");
			}

			// Display the results web page.
			BufferedReader in = new BufferedReader(new FileReader("displayresult.htm"));
			String filetext = in.readLine();
			while (filetext != null){
				out.print(filetext);
				filetext = in.readLine();
			}
			in.close();
			out.close();
		} catch (Exception e){
			out.println("Couldn't exec utility");
		}
	}
}