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

public class Server {

    public static String newLine = "\n";
    public static HashMap<String, int[]> clientsHmap = new HashMap<String, int[]>(); //Stores client info

    private int port;
    private Socket socket = null;
    private BufferedReader in = null;
    private ServerSocket serverSocket = null;
    private PrintWriter out = null;
    private boolean listening = true;


    public Server(int port) {
        this.port = port;
    }

    public void run() throws IOException {
        try {
            serverSocket = new ServerSocket(this.port);
        } catch (IOException e) {
            System.err.println("Could not listen on port: " + this.port);
            System.exit(1);
        }
        System.out.println("Listening on port: " + this.port);

        while (listening) {
            try {

                socket = serverSocket.accept();

                out = new PrintWriter(socket.getOutputStream(), true); //Response
                in = new BufferedReader(
                    new InputStreamReader(socket.getInputStream())
                );

                String line;
                String request = "";
                String cookie = ""; // Cookie string


                while (in.ready()) {
                    line = in.readLine(); // Read input
                    //System.out.println(line); // Log
                    //out.println(line); // Echo
                    request += line + newLine;  // Structure request

                    if (line.contains("Cookie:")==true) {
                      cookie = line.replace("Cookie: JSESSIONID=", ""); // Store cookie
                    }

                    if (line.equals("")) {
                      handleRequest(request, cookie, in, out);
                      break;
                    }
                }
              }catch (IOException e){
                  e.printStackTrace();
              } finally {
                  out.close();
                  in.close();
                  socket.close();
              }
          }
          serverSocket.close();
      }

      // Handles incoming http request and generates appropriate response.
      // Generates a cookie for new clients through newGame() function and adds them to the clients Hashmap
      // calls sendResponse() function
      public void handleRequest(String request, String cookie, BufferedReader in, PrintWriter out) {
        int guess = 0;
        String guessStatus = "";

        if (request.contains("POST")) {
          char letter;
          StringBuilder postRequest = new StringBuilder();
          try {
            while (in.ready()) {
              letter = (char)in.read();
              postRequest.append(letter);
            }
          } catch (IOException e) {
            e.printStackTrace();
          }
          String guessString = postRequest.toString().replace("guess=", "");  // Extract client's guess

          //Check if guess is a number
          try{
            guess = Integer.parseInt(guessString);
          } catch (NumberFormatException e){
            // Invalid guess; not a number
            System.out.println("UNABLE TO CONVERT GUESS TO INT.");
            //sendResponse("invalidInt", cookie, in, out);
          }
        }

        // Generate Cookie if new client
        if ((request.contains("GET")) && (request.contains("Cookie:")==false)) {
          System.out.println("NEW CLIENT. GENERATE COOKIE.");
          newGame(in, out);
        } else {         // Update game
          int[] clientInfo = new int[4]; // 0: correct answer, 1: number of guesses, 2: min, 3: max
          clientInfo = clientsHmap.get(cookie); // Gives value for cookie-key

          // Reset client cookie if null
          if ((request.contains("GET")) && (clientInfo == null)) {
            System.out.println("CLIENT HAS NULLCOOKIE. GENERATING NEW COOKIE.");
            newGame(in, out);
          }

          // If client closes and reopens browser
          else if ((request.contains("GET")) && (request.contains("Cookie:")))  {
            System.out.println("CLIENT CLOSED AND REOPENED BROWSER");
            sendResponse("reopenedBrowser", cookie, in, out);
          }

          // Correct guess from client
          else if ((request.contains("POST")) && (guess==clientInfo[0])) {
            sendResponse("end", cookie, in, out);
            clientsHmap.remove(cookie);
          }

          // Incorrect guess from client
          else if ((request.contains("POST")) && (guess != clientInfo[0])) {
            if ((guess < 1) || (guess > 100)) { // Check if guess is out of bounds, i.e not in [1,100]
              guessStatus = "outOfBounds";
            } else { // Guess is valid, in range -> accepted
              if (guess < clientInfo[0]) {
                if (guess >= clientInfo[2]) {
                  clientInfo[2] = guess;  // Update min
                  guessStatus = "minUpdated";
                } else {
                guessStatus = "minUpdated";
              }
              }
              if (guess > clientInfo[0]) {
                if (guess <= clientInfo[3]) {
                  clientInfo[3] = guess;  // Update max
                  guessStatus = "maxUpdated";
                } else {
                  guessStatus = "maxUpdated";
                }
              }
              clientInfo[1] += 1; // Increment number of guesses for client

            }
            clientsHmap.put(cookie, clientInfo); // Update clients log
            sendResponse(guessStatus, cookie, in, out);
          }
        }
        showActiveClients(); // Run after every request to track clients and gamestates
      }

    // Builds a HTML-response based on
    // guessStatus = "start", "end", "outOfBounds", "minUpdated", "maxUpdated"
    // and client's cookie
    public void sendResponse(String guessStatus, String cookie, BufferedReader in, PrintWriter out) {
      String[] htmlResponse = readHtmlFile();

      int[] clientInfo = new int[4];
      clientInfo = clientsHmap.get(cookie); // Get client info from clients hash map

      out.println("HTTP/1.1 200 OK"); // Initial line
      out.println("Content-Type: text/html"); // Specifies content in message

      if (guessStatus.equals("start")) {
        out.println(cookie);
      }

      out.println(newLine);
      out.println(htmlResponse[0]);
      out.println(htmlResponse[1]);
      out.println(htmlResponse[2]);
      out.println(htmlResponse[3]);
      out.println(htmlResponse[4]);
      out.println(htmlResponse[5]);
      out.println(htmlResponse[6]);
      out.println(htmlResponse[7]);

      String top_text;
      String middle_text;
      String bottom_text;

      if (guessStatus.equals("start")) {
        top_text = "Welcome to the Number Guess Game.";
        middle_text = "Guess a number between 1 and 100.";
        bottom_text = "";
        out.println(htmlResponse[8].replace("{top_text}", top_text));
        out.println(htmlResponse[9].replace("{middle_text}", middle_text));
        out.println(htmlResponse[10].replace("{bottom_text}", bottom_text));
      }
      if (guessStatus.equals("invalidInt")) {
        top_text = "Wops!!! You did not enter a number!";
        middle_text = "Guess a number between "+Integer.toString(clientInfo[2])+" and "+Integer.toString(clientInfo[3])+".";
        bottom_text = "You have guessed "+Integer.toString(clientInfo[1])+" times.";
        out.println(htmlResponse[8].replace("{top_text}", top_text));
        out.println(htmlResponse[9].replace("{middle_text}", middle_text));
        out.println(htmlResponse[10].replace("{bottom_text}", bottom_text));
      }
      if (guessStatus.equals("outOfBounds")) {
        top_text = "Wops!!! Guess was out of range!";
        middle_text = "Guess a number between "+Integer.toString(clientInfo[2])+" and "+Integer.toString(clientInfo[3])+".";
        bottom_text = "You have guessed "+Integer.toString(clientInfo[1])+" times.";
        out.println(htmlResponse[8].replace("{top_text}", top_text));
        out.println(htmlResponse[9].replace("{middle_text}", middle_text));
        out.println(htmlResponse[10].replace("{bottom_text}", bottom_text));
      }
      if (guessStatus.equals("minUpdated")) {
        top_text = "Guess was too low!";
        middle_text = "Guess a number between "+clientInfo[2]+" and "+clientInfo[3]+".";
        bottom_text = "You have guessed "+Integer.toString(clientInfo[1])+" times.";
        out.println(htmlResponse[8].replace("{top_text}", top_text));
        out.println(htmlResponse[9].replace("{middle_text}", middle_text));
        out.println(htmlResponse[10].replace("{bottom_text}", bottom_text));
      }
      if (guessStatus.equals("maxUpdated")) {
        top_text = "Guess was too high!";
        middle_text = "Guess a number between "+Integer.toString(clientInfo[2])+" and "+Integer.toString(clientInfo[3])+".";
        bottom_text = "You have guessed "+Integer.toString(clientInfo[1])+" times.";
        out.println(htmlResponse[8].replace("{top_text}", top_text));
        out.println(htmlResponse[9].replace("{middle_text}", middle_text));
        out.println(htmlResponse[10].replace("{bottom_text}", bottom_text));
      }
      if (guessStatus.equals("reopenedBrowser")) {
        top_text = "Welcome back!";
        middle_text = "Guess a number between "+Integer.toString(clientInfo[2])+" and "+Integer.toString(clientInfo[3])+".";
        bottom_text = "You have guessed "+Integer.toString(clientInfo[1])+" times.";
        out.println(htmlResponse[8].replace("{top_text}", top_text));
        out.println(htmlResponse[9].replace("{middle_text}", middle_text));
        out.println(htmlResponse[10].replace("{bottom_text}", bottom_text));
      }
      if (guessStatus.equals("end")) {
        top_text = "You made it! Nice job!";
        middle_text = "It took you "+Integer.toString(clientInfo[1])+" guesses to win.";
        bottom_text = "<P><a href='.'>'New Game'</a></P>";
        out.println(htmlResponse[8].replace("{top_text}", top_text));
        out.println(htmlResponse[9].replace("{middle_text}", middle_text));
        out.println(htmlResponse[10].replace("{bottom_text}", bottom_text));
      } else {
        out.println(htmlResponse[11]);
        out.println(htmlResponse[12]);
        out.println(htmlResponse[13]);
        out.println(htmlResponse[14]);
      }
      out.println(htmlResponse[15]);
      out.println(htmlResponse[16]);
    }

    public static String[] readHtmlFile() {
      String[] html = new String[17];
      String guessFile = "guess.html";
      String line;
      try {
        FileReader fr = new FileReader(guessFile);
        BufferedReader br = new BufferedReader(fr);

        int row = 0;
        while ((line = br.readLine()) != null) {
          html[row] = line;
          row += 1;
        }
        br.close();
      } catch (FileNotFoundException e) {
        // Could not find file
        System.out.println("Could not find file: '"+guessFile+"'.");
      } catch (IOException e) {
        // Could not read file
        e.printStackTrace();
      }

      return html;
    }

    // Generates new cookie for client
    public void newGame(BufferedReader in, PrintWriter out) {
      int[] clientInfo = new int[4];  // 0: correct answer, 1: number of guesses, 2: min, 3: max

      long currentTimeLong = System.currentTimeMillis(); // Using current time (milliseconds) as cookie
      String currentTime = Long.toString(currentTimeLong);
      String cookie = "Set-Cookie: JSESSIONID="+currentTime;
      int correctAnswer = (int)(Math.random() * 100 + 1); // Generating correct answer

      clientInfo[0] = correctAnswer;
      clientInfo[1] = 0;
      clientInfo[2] = 1;
      clientInfo[3] = 100;

      clientsHmap.put(currentTime, clientInfo);
      sendResponse("start", cookie, in, out);
    }

    // Displays all active clients and their info
    public void showActiveClients() {
      //System.out.println("-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/");
      int[] clientInfo = new int[4];
      Set<String> keys = clientsHmap.keySet();
      for(String key: keys) {
        System.out.println("Client: " + key);
        clientInfo = clientsHmap.get(key);
        for (int i=0; i<4; i++) {
          System.out.println(clientInfo[i]);
        }
      }
      System.out.println("-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/");
    }

    public static void main(String[] args) throws IOException {
        Server s = new Server(8989);
        s.run();
    }
}