#include <Keypad.h>
#include "SPI.h"
#include "Adafruit_GFX.h"
#include "Adafruit_ILI9341.h"

#define TFT_DC 9
#define TFT_CS 10
Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC);

struct coord {
  int x, y;
};

const uint8_t ROWS = 4;
const uint8_t COLS = 4;
char keys[ROWS][COLS] = {
  { '1', '2', '3', 'A' },
  { '4', '5', '6', 'B' },
  { '7', '8', '9', 'C' },
  { '*', '0', '#', 'D' }
};

uint8_t colPins[COLS] = { 4, 3, 2, 1 }; // Pins connected to C1, C2, C3, C4
uint8_t rowPins[ROWS] = { 8, 7, 6, 5 }; // Pins connected to R1, R2, R3, R4

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);
boolean gameStarted = false;

const coord pos[] = {
  {60, 90},
  {120, 90},
  {180, 90},
  {60, 150},
  {120, 150},
  {180, 150},
  {60, 210},
  {120, 210},
  {180, 210}
};

int board[] = {0, 0, 0, 0, 0, 0, 0, 0, 0}; // holds position data 0 is blank, 1 human, 2 is computer
int moves = 0, winner = 0;

void setup() {
  Serial.begin(9600);
  tft.begin();


  tft.setCursor(20, 20);
  tft.setTextColor(ILI9341_RED);
  tft.setTextSize(3);
  tft.println("Welcome to X|O");

  tft.setCursor(20, 160);
  tft.setTextColor(ILI9341_GREEN);
  tft.setTextSize(2);
  tft.println("Press '*' to play");
}

void loop() {
  char key = keypad.getKey();

  if (key == '*' && !gameStarted) {
    disp_game();
    gameStarted = true;
  }
}

void disp_game() {
  disp_reset();

  do {
    // (moves & 1)?cpuMove():playerMove();
    if(moves & 1)cpuMove();
    else playerMove();
    checkWinner();
    moves++;
  }while (winner == 0 && moves < 9);

  if (winner == 1)
    dispGameOverMsg("Human wins!");
  else if (winner == 2)
    dispGameOverMsg("CPU WINS");
  else
    dispGameOverMsg("DRAW");

}

void cpuMove() {
  int b = 0;
  int counter = 0;
  int movesPlayed = 0;

  int firstMoves[] = {0, 2, 6, 8}; // will use these positions first

  for (counter = 0; counter < 4; counter++) {
    if (board[firstMoves[counter]] != 0) movesPlayed++;
  }
  do {
    if (moves <= 2){
      int randomMove = random(4);
      int c = firstMoves[randomMove];

      if (board[c] == 0){
        delay(1000);
        board[c] = 2;
        drawO(firstMoves[randomMove]);
        b = 1;
      }

    } 
    else{
      int nextMove = checkOpponent();
      if (nextMove == 100){
        if (movesPlayed == 4) //All first moves are played{
          int randomMove = random(9);
          if (board[randomMove] == 0){
            delay(1000);
            board[randomMove] = 2;
            drawO(randomMove);
            b = 1;
          }
        } 
        else{
          int randomMove = random(4);
          int c = firstMoves[randomMove];

          if (board[c] == 0){
            delay(1000);
            board[c] = 2;
            drawO(firstMoves[randomMove]);
            b = 1;
          }
        }
      } 
      else{
        delay(1000);
        board[nextMove] = 2;
        drawO(nextMove);
        b = 1;
      }
    }
  }
  while (b < 1);
}

void playerMove() {
  while (1) {
    char key = keypad.getKey();
    if (key != NO_KEY && key >= '1' && key <= '9' && board[key - '1'] == 0) {
      drawX(key);
      board[key - '1'] = 1;
      break;
    }
  }
}

void drawO(int key) {
  tft.drawCircle(pos[key].x, pos[key].y, 18, ILI9341_GREEN);
}

void drawX(int key) {
  tft.drawLine(pos[key - '1'].x - 18, pos[key - '1'].y - 18, pos[key - '1'].x + 18, pos[key - '1'].y + 18, ILI9341_YELLOW);
  tft.drawLine(pos[key - '1'].x - 18, pos[key - '1'].y + 18, pos[key - '1'].x + 18, pos[key - '1'].y - 18, ILI9341_YELLOW);
}

void checkWinner() {
  // X win
  for(int i=0;i<9;i+=3){
    if(board[i]!=winner &&(board[i]==board[i+1]==board[i+2])){ //horizontal win
      winner=board[i];
      return;
    }
  }
  for(int i=0;i<3;i++){
    if(board[i]!=winner &&(board[i]==board[i+3]==board[i+6])){ //vertical win
      winner=board[i];
      return;
    }
  }
  if(board[4]!=winner && (board[0]==board[4]==board[8])) winner = board[4];
  if(board[4]!=winner && (board[2]==board[4]==board[6])) winner = board[4];
  return;
  // noughts win?
  // if (board[0] == 1 && board[1] == 1 && board[2] == 1) {
  //   winner = 1;
  // }
  // if (board[3] == 1 && board[4] == 1 && board[5] == 1) {
  //   winner = 1;
  // }
  // if (board[6] == 1 && board[7] == 1 && board[8] == 1) {
  //   winner = 1;
  // }
  // if (board[0] == 1 && board[3] == 1 && board[6] == 1) {
  //   winner = 1;
  // }
  // if (board[1] == 1 && board[4] == 1 && board[7] == 1) {
  //   winner = 1;
  // }
  // if (board[2] == 1 && board[5] == 1 && board[8] == 1) {
  //   winner = 1;
  // }
  // if (board[0] == 1 && board[4] == 1 && board[8] == 1) {
  //   winner = 1;
  // }
  // if (board[2] == 1 && board[4] == 1 && board[6] == 1) {
  //   winner = 1;
  // }
  // // crosses win?
  // if (board[0] == 2 && board[1] == 2 && board[2] == 2) {
  //   winner = 2;
  // }
  // if (board[3] == 2 && board[4] == 2 && board[5] == 2) {
  //   winner = 2;
  // }
  // if (board[6] == 2 && board[7] == 2 && board[8] == 2) {
  //   winner = 2;
  // }
  // if (board[0] == 2 && board[3] == 2 && board[6] == 2) {
  //   winner = 2;
  // }
  // if (board[1] == 2 && board[4] == 2 && board[7] == 2) {
  //   winner = 2;
  // }
  // if (board[2] == 2 && board[5] == 2 && board[8] == 2) {
  //   winner = 2;
  // }
  // if (board[0] == 2 && board[4] == 2 && board[8] == 2) {
  //   winner = 2;
  // }
  // if (board[2] == 2 && board[4] == 2 && board[6] == 2) {
  //   winner = 2;
  // }

}

int checkOpponent()
{
  if (board[0] == 1 && board[1] == 1 && board[2] == 0)
    return 2;
  else if (board[0] == 1 && board[1] == 0 && board[2] == 1)
    return 1;
  else if (board[1] == 1 && board [2] == 1 && board[0] == 0)
    return 0;
  else if (board[3] == 1 && board[4] == 1 && board[5] == 0)
    return 5;
  else if (board[4] == 1 && board[5] == 1 && board[3] == 0)
    return 3;
  else if (board[3] == 1 && board[4] == 0 && board[5] == 1)
    return 4;
  else if (board[1] == 0 && board[4] == 1 && board[7] == 1)
    return 1;
  else
    return 100;
}

void disp_reset(){
  // Clear screen
  tft.fillScreen(ILI9341_BLACK);

  tft.setCursor(20, 20);
  tft.setTextColor(ILI9341_RED);
  tft.setTextSize(3);
  tft.println("TIC-TAC-TOE");
  winner = 0, moves = 0;
  for (int i = 0; i < 9; i++) board[i] = 0;


  // grid
  tft.drawRect(30, 60, 180, 180, ILI9341_WHITE);
  tft.drawFastVLine(90, 60, 180, ILI9341_WHITE);
  tft.drawFastVLine(150, 60, 180, ILI9341_WHITE);
  tft.drawFastHLine(30, 120, 180, ILI9341_WHITE);
  tft.drawFastHLine(30, 180, 180, ILI9341_WHITE);
}

void dispGameOverMsg(String msg){
  tft.fillScreen(ILI9341_BLACK);
  tft.setCursor(20, 20);
  tft.setTextColor(ILI9341_RED);
  tft.setTextSize(3);
  tft.println(msg);

  gameStarted = false;  

  tft.setCursor(20, 160);
  tft.setTextColor(ILI9341_GREEN);
  tft.setTextSize(2);
  tft.println("Press '*' to play again");
  while(1){
    char key = keypad.getKey();
    if (key == '*') {
      disp_game();
      gameStarted = true;
    }
  }
}