const int PIN_JX = 26;    // X-axis: ADC0 (GP26)
const int PIN_JY = 27;    // Y-axis: ADC1 (GP27)
const int PIN_BTN = 22;   // Button: Digital GPIO

// === LED Definition - Cross-board Compatible ===
#ifndef LED_BUILTIN
  #define LED_BUILTIN 25  // Fallback for original Pico/Pico 2
#endif

// === ADC Configuration ===
const int ADC_BITS = 12;      // RP2040 supports 12-bit ADC
const int ADC_MAX = 4095;           // Max value for 12-bit
const int ADC_CENTER = ADC_MAX / 2; // ~2048
const int CENTER_THRESHOLD = 200;   // Deadzone around center

void setup() {
  // Initialize Serial1 for debugging
  Serial1.begin(115200);
  while (!Serial1); // Wait for native USB Serial1 connection
  
  // ⚠️ CRITICAL: Set ADC resolution to 12-bit for full range
  analogReadResolution(ADC_BITS);
  
  // Configure button with internal pull-up resistor
  pinMode(PIN_BTN, INPUT_PULLUP);
  
  // Configure onboard LED (compatible with all Pico variants)
  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(LED_BUILTIN, LOW); // Start with LED OFF
  
  Serial1.println("🎮 Joystick Initialized - Raspberry Pi Pico (Arduino)");
  Serial1.printf("ADC Resolution: %d-bit (Range: 0-%d)\n", ADC_BITS, ADC_MAX);
  Serial1.println("Move joystick or press button to see values...");
}

void loop() {
  // Read analog axes (12-bit: 0-4095 after analogReadResolution(12))
  int xVal = analogRead(PIN_JX);
  int yVal = analogRead(PIN_JY);
  
  // Read button state (LOW = pressed, due to INPUT_PULLUP)
  bool btnPressed = (digitalRead(PIN_BTN) == LOW);
  
  // Calculate direction with deadzone filtering
  String xDir = getDirection(xVal, "X");
  String yDir = getDirection(yVal, "Y");
  
  // Output to Serial1 Monitor
  Serial1.print("X: "); Serial1.print(xVal); Serial1.print(" ("); Serial1.print(xDir); Serial1.print(") | ");
  Serial1.print("Y: "); Serial1.print(yVal); Serial1.print(" ("); Serial1.print(yDir); Serial1.print(") | ");
  Serial1.print("Button: "); Serial1.println(btnPressed ? "PRESSED" : "Released");
  
  // Visual feedback: Toggle onboard LED on button press
  digitalWrite(LED_BUILTIN, btnPressed ? HIGH : LOW);
  
  delay(100); // Polling interval
}

// Helper: Determine direction with deadzone to ignore drift
String getDirection(int value, String axis) {
  if (abs(value - ADC_CENTER) < CENTER_THRESHOLD) {
    return "CENTER";
  } else if (value < ADC_CENTER) {
    return (axis == "X") ? "LEFT" : "DOWN";
  } else {
    return (axis == "X") ? "RIGHT" : "UP";
  }
}