package com.java21days.bots;

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.text.NumberFormat;
import java.util.Date;
import java.util.Locale;

public class FreeSpaceBot {
    
    protected void start() {
        ServerSocket serverSocket = null;        
        System.out.println("Waiting for connection on port 8011 ...");
        while (true) {
            try {
                if (serverSocket == null) {
                    // attempt to create the server socket
                    serverSocket = new ServerSocket(8011);
                }
                // wait for an incoming connection
                Socket socket = serverSocket.accept();
                // make the connection
                InputStream stream = socket.getInputStream();
                BufferedReader reader = new BufferedReader(
                    new InputStreamReader(stream));

                // retrieve the request headers
                String header = null;
                while ((header = reader.readLine()).length() != 0) {
                    System.out.println(header);
                }

                // retrieve the request body
                StringBuilder body = new StringBuilder();
                while (reader.ready()) {
                    body.append((char) reader.read());
                }
                System.out.println("\n" + body.toString() + "\n");

                // create an output writer
                PrintWriter writer = new PrintWriter(new BufferedOutputStream(
                    socket.getOutputStream()), false);

                // send output headers
                writer.println(
                    "HTTP/1.0 200 OK\r\n" +
                    "Date: " + new Date() + "\r\n" +
                    "Server: WebServer2/1.0\r\n" +
                    "Content-Type: application/json\r\n" +
                    "\r\n"
                );

                // collect information on free disk space
                File[] root = File.listRoots();
                String free = formatNumber(root[0].getFreeSpace());
                String total = formatNumber(root[0].getTotalSpace());
                double percent = Math.floor(
                    (double) root[0].getFreeSpace() /
                    (double) root[0].getTotalSpace() * 100D);
                String message = "The server has " + free +
                    " bytes free out of " + total + " total (" + percent
                    + "%).";
                String sub = (percent < 10) ? "Running low!" : "Looking good!";

                // send the output body (as JSON)
                writer.println("{\"text\": \"" + message + "\"," +
                    "\"attachments\": [{\"text\":\"" + sub + "\"}]}");
                writer.flush();
                // close the stream to send the response
                stream.close();
            } catch (IOException ioe) {
                System.out.println("Error: " + ioe.getMessage());
            }
        }
    }
    
    // format a large number with commas
    private String formatNumber(long input) {
        return NumberFormat.getNumberInstance(Locale.US).format(input);
    }
    
    public static void main(String arguments[]) {
        FreeSpaceBot bot = new FreeSpaceBot();
        bot.start();
    }
}