#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_ILI9341.h>
#include <Adafruit_FT6206.h>

// TFT Pins
#define TFT_CS   5
#define TFT_DC   2
#define TFT_RST  4

// I2C Touch
#define I2C_SDA 21
#define I2C_SCL 22

Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC, TFT_RST);
Adafruit_FT6206 ctp = Adafruit_FT6206();

String inputValue = "";

// Keypad layout
const char* keys[4][3] = {
  {"1","2","3"},
  {"4","5","6"},
  {"7","8","9"},
  {"C","0","OK"}
};

int keyWidth = 80;
int keyHeight = 60;
int startX = 40;
int startY = 80;

void drawKeypad() {
  tft.fillScreen(ILI9341_BLACK);

  // Display input field
  tft.drawRect(20, 20, 280, 40, ILI9341_WHITE);
  tft.setTextSize(2);
  tft.setCursor(30, 30);
  tft.print(inputValue);

  // Draw buttons
  for(int row=0; row<4; row++){
    for(int col=0; col<3; col++){
      int x = startX + col * (keyWidth + 10);
      int y = startY + row * (keyHeight + 10);

      tft.fillRect(x, y, keyWidth, keyHeight, ILI9341_BLUE);
      tft.drawRect(x, y, keyWidth, keyHeight, ILI9341_WHITE);

      tft.setTextColor(ILI9341_WHITE);
      tft.setTextSize(2);
      tft.setCursor(x + keyWidth/2 - 10, y + keyHeight/2 - 10);
      tft.print(keys[row][col]);
    }
  }
}

void setup() {
  Serial.begin(115200);

  Wire.begin(I2C_SDA, I2C_SCL);

  tft.begin();
  tft.setRotation(0);   // Portrait

  if (!ctp.begin(40)) {  
    Serial.println("Couldn't start FT6206 touchscreen controller");
    while (1);
  }

  drawKeypad();
}

void loop() {
  if (!ctp.touched()) return;

  TS_Point p = ctp.getPoint();

  // Map touch coordinates (may need adjustment)
  int x = map(p.y, 0, 240, 0, 320);
  int y = map(p.x, 0, 320, 0, 240);

  for(int row=0; row<4; row++){
    for(int col=0; col<3; col++){
      int btnX = startX + col * (keyWidth + 10);
      int btnY = startY + row * (keyHeight + 10);

      if(x > btnX && x < (btnX + keyWidth) &&
         y > btnY && y < (btnY + keyHeight)) {

        String key = keys[row][col];

        if(key == "C"){
          inputValue = "";
        }
        else if(key == "OK"){
          Serial.println("Entered: " + inputValue);
        }
        else{
          inputValue += key;
        }

        drawKeypad();
        delay(300); // debounce
      }
    }
  }
}