/**
 * Reads a potentiometer on A5 and uses the value to control
 * LED brightness via PWM on GPIO 13.
 *
 * Demonstrates: analogRead (12-bit), map(), ledcWrite (8-bit PWM),
 * and preprocessor defines for portable code.
 *
 * See: https://makeabilitylab.github.io/physcomp/esp32/pot-fade
 */

// Preprocessor defines for cross-platform portability ---
#if defined(ESP32)
  const int MAX_ANALOG_VAL = 4095;  // ESP32 has a 12-bit ADC (0-4095)
#else
  const int MAX_ANALOG_VAL = 1023;  // AVR Arduinos have a 10-bit ADC (0-1023)
#endif

const int LED_OUTPUT_PIN = 1; 
const int POT_INPUT_PIN = 4;  

const int PWM_FREQ = 5000;     // 5 kHz PWM frequency
const int PWM_RESOLUTION = 8;  // 8-bit resolution: duty cycle 0-255
const int MAX_DUTY_CYCLE = (1 << PWM_RESOLUTION) - 1;  // 2^8 - 1 = 255

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

  // Attach PWM to the LED pin (v3.x API — channel assigned automatically)
  ledcAttach(LED_OUTPUT_PIN, PWM_FREQ, PWM_RESOLUTION);
}

void loop() {
  // Read the potentiometer (returns 0-4095 on the ESP32's 12-bit ADC)
  int potVal = analogRead(POT_INPUT_PIN);

  // Map the 12-bit input (0-4095) to the 8-bit PWM range (0-255)
  int dutyCycle = map(potVal, 0, MAX_ANALOG_VAL, 0, MAX_DUTY_CYCLE);

  // Set the LED brightness
  ledcWrite(LED_OUTPUT_PIN, dutyCycle);

  // Print both values for debugging (use Serial Plotter to visualize!)
  Serial.print("PotVal:");
  Serial.print(potVal);
  Serial.print(", DutyCycle:");
  Serial.println(dutyCycle);

  delay(10);  // Small delay for stable readings
}