// -------------------------------------------------------------
//  AMPERÍMETRO + VOLTÍMETRO + WATTÍMETRO
//  Shunt: 0.300Ω
//  OLED SSD1306 128x32
// -------------------------------------------------------------

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

// ---------------- OLED -----------------
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 32
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// --------------- PINOS ------------------
const int pinCurrent = A0;  // Shunt
const int pinVoltage = A2;  // Divisor da bateria

// --------------- CONSTANTES --------------
const float Rshunt = 0.300;      // ohms
const float voltageMultiplier = 6.0; // R1=100k / R2=20k
const int samples = 30;

// ================= SETUP =================
void setup() {
  Serial.begin(9600);

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    while (true); // trava se o OLED não inicializar
  }

  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.println("Medidor Iniciado");
  display.display();
  delay(800);
}

// ================= LOOP ==================
void loop() {

  // ----------- Leitura Corrente -----------
  float sumA0 = 0;
  for (int i = 0; i < samples; i++)
    sumA0 += analogRead(pinCurrent);

  float vShunt = ((sumA0 / samples) * 5.0) / 1023.0;
  float current = vShunt / Rshunt;  // A


  // ----------- Leitura Tensao -------------
  float sumA2 = 0;
  for (int i = 0; i < samples; i++)
    sumA2 += analogRead(pinVoltage);

  float vA2 = ((sumA2 / samples) * 5.0) / 1023.0;
  float batteryVoltage = vA2 * voltageMultiplier;


  // ----------- Calculo Potencia -----------
  float power = batteryVoltage * current;  // W


  // ------------- OLED DISPLAY -------------
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0, 0);

  display.print("V: ");
  display.print(batteryVoltage, 2);
  display.println(" V");

  display.print("I: ");
  display.print(current, 2);
  display.println(" A");

  display.print("P: ");
  display.print(power, 2);
  display.println(" W");

  display.display();


  // ---------- Debug Serial (opcional) -----
  Serial.print("V = ");
  Serial.print(batteryVoltage, 2);
  Serial.print(" V   |   I = ");
  Serial.print(current, 2);
  Serial.print(" A   |   P = ");
  Serial.print(power, 2);
  Serial.println(" W");

  delay(150);
}