#include <Adafruit_GFX.h>
#include <Adafruit_ILI9341.h>
#include <Encoder.h>

// TFT Pins
#define TFT_CS   5
#define TFT_DC   2
#define TFT_RST  4
Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC, TFT_RST);

// Rotary Encoder Pins
Encoder knob(32, 33);
#define BUTTON_PIN 25

// State & District Data
const char* states[] = {"Andhra Pradesh", "Karnataka", "Tamil Nadu"};
const char* districts[][5] = {
  {"Visakhapatnam", "Vijayawada", "Guntur", "Kurnool", "Tirupati"}, // AP
  {"Bengaluru", "Mysuru", "Mangaluru", "Hubli", "Belagavi"},         // Karnataka
  {"Chennai", "Coimbatore", "Madurai", "Salem", "Tirunelveli"}       // Tamil Nadu
};

int numStates = 3;
int numDistricts[3] = {5, 5, 5};

// Menu states
enum MenuStage { SELECT_STATE, SELECT_DISTRICT, SHOW_RESULT };
MenuStage stage = SELECT_STATE;

int selectedState = 0;
int selectedDistrict = 0;
long oldPos = -999;

void setup() {
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  tft.begin();
  tft.setRotation(1);
  tft.fillScreen(ILI9341_BLACK);
  drawMenu();
}

void loop() {
  long newPos = knob.read() / 4;
  
  if (newPos != oldPos) {
    oldPos = newPos;
    if (stage == SELECT_STATE) {
      selectedState = (newPos % numStates + numStates) % numStates;
    } else if (stage == SELECT_DISTRICT) {
      selectedDistrict = (newPos % numDistricts[selectedState] + numDistricts[selectedState]) % numDistricts[selectedState];
    }
    drawMenu();
  }
  
  if (digitalRead(BUTTON_PIN) == LOW) {
    delay(200); // debounce
    if (stage == SELECT_STATE) {
      stage = SELECT_DISTRICT;
      knob.write(0);
      oldPos = -999;
    } else if (stage == SELECT_DISTRICT) {
      stage = SHOW_RESULT;
    }
    drawMenu();
    while (digitalRead(BUTTON_PIN) == LOW); // wait for release
  }
}

void drawMenu() {
  tft.fillScreen(ILI9341_BLACK);
  tft.setTextSize(2);
  
  if (stage == SELECT_STATE) {
    tft.setCursor(10, 10);
    tft.setTextColor(ILI9341_YELLOW);
    tft.println("Select State:");
    for (int i = 0; i < numStates; i++) {
      tft.setCursor(20, 40 + i * 30);
      if (i == selectedState) tft.setTextColor(ILI9341_GREEN);
      else tft.setTextColor(ILI9341_WHITE);
      tft.println(states[i]);
    }
  } 
  else if (stage == SELECT_DISTRICT) {
    tft.setCursor(10, 10);
    tft.setTextColor(ILI9341_YELLOW);
    tft.println("Select District:");
    for (int i = 0; i < numDistricts[selectedState]; i++) {
      tft.setCursor(20, 40 + i * 30);
      if (i == selectedDistrict) tft.setTextColor(ILI9341_GREEN);
      else tft.setTextColor(ILI9341_WHITE);
      tft.println(districts[selectedState][i]);
    }
  } 
  else if (stage == SHOW_RESULT) {
    tft.setCursor(10, 50);
    tft.setTextColor(ILI9341_GREEN);
    tft.print("State: ");
    tft.println(states[selectedState]);
    tft.print("District: ");
    tft.println(districts[selectedState][selectedDistrict]);
  }
}