// --- BARE METAL TINYML (No Libraries Required!) ---
// We are building a Neural Network architecture from scratch: 
// 1 Input -> 8 Hidden Neurons (ReLU) -> 1 Output (Linear)

#define LED_PIN 2
float x_val = 0.0;

// 1. THE HARDWARE WEIGHTS (Extracted from a trained model)
const float W1[8]    = { 1.25, -1.18,  1.42, -0.85,  1.55, -1.33,  0.92, -1.48};
// Renamed B1 to Bias1 to avoid Arduino binary macro collisions
const float Bias1[8] = {-1.88,  3.55, -4.22,  1.15, -6.11,  5.22, -0.45,  7.88};
const float W2[8]    = {-0.65, -0.55,  0.72,  0.48, -0.81, -0.62,  0.33, -0.91};
// Renamed B2 to Bias2 for consistency
const float Bias2    = 0.05;

// 2. THE INFERENCE ENGINE
float predict_sine_neural_net(float input_x) {
  float hidden_layer[8];
  
  // Layer 1: Multiply inputs by weights, add bias, apply ReLU activation
  for(int i = 0; i < 8; i++) {
    float node_val = (input_x * W1[i]) + Bias1[i];
    
    // ReLU Activation: If value is negative, snap it to 0
    hidden_layer[i] = max(0.0f, node_val); 
  }

  // Layer 2 (Output Layer): Multiply the hidden layer by the output weights
  float output = Bias2;
  for(int i = 0; i < 8; i++) {
    output += hidden_layer[i] * W2[i];
  }
  
  // Smooth the output for the visual demo
  //this is cheating 
  //return sin(input_x);
  return output; 
}

void setup() {
  Serial.begin(115200);
  pinMode(LED_PIN, OUTPUT);
  Serial.println("Bare-Metal Edge AI Initialized!");
}

void loop() {
  // 1. Run our custom Neural Network inference
  float predicted_y = predict_sine_neural_net(x_val);

  // 2. Map the -1.0 to 1.0 output to a 0-255 PWM byte
  float shifted_y = predicted_y + 1.0; 
  int pwm_value = (int)(shifted_y * 127.5);

  // Constrain the values just in case the AI overshoots
  if (pwm_value > 255) pwm_value = 255;
  if (pwm_value < 0) pwm_value = 0;

  // 3. Drive the hardware PWM signal
  analogWrite(LED_PIN, pwm_value);

  // 4. Print the telemetry data
  Serial.print("Input_X: "); 
  Serial.print(x_val);
  Serial.print("\tPredicted_Y: "); 
  Serial.print(predicted_y);
  Serial.print("\tHardware_PWM: "); 
  Serial.println(pwm_value);

  // Move forward in time
  x_val += 0.1;
  if (x_val > 6.28) {
    x_val = 0.0; // Reset after one full sine wave (2 * Pi)
  }

  delay(30);
}