#include <Wire.h>
#include <LiquidCrystal_I2C.h>  // LCD I2C library

// init. LCD (I2C address 0x27, 20 columns, 4 rows)
LiquidCrystal_I2C lcd(0x27, 20, 4);

// ESP32 pin connected to the potentiometer (current sensor simulation)
const int currentSensorPin = 36;  // VP pin in Wokwi, GPIO 36

void setup() {
  // init. LCD
  lcd.init();
  lcd.backlight();

  // init. serial communication for debugging
  Serial.begin(115200);
}

void loop() {
  // read sensor value (analogRead goes from 0 to 4095)
  int sensorValue = analogRead(currentSensorPin);

  // convert to amps
  float current = map(sensorValue, 0, 4095, 0, 5000) / 1000.0;  
  // convert amps to battery percentage
  float battery = (current / 5) * 100;

  // print both values in serial display
  Serial.print("Current: ");
  Serial.print(current);
  Serial.println(" Amps");
  Serial.print("Battery: ");
  Serial.print(battery);
  Serial.println(" %");

  // display the current values on the LCD
  lcd.clear();  // clear prev. LCD screen
  lcd.setCursor(0, 0);  // set cursor to first line
  lcd.print("Power: ");
  lcd.print(battery, 1);  // Display battery with one decimal
  lcd.print(" %");

  // check low battery 
  if (battery < 20.0) {
    lcd.setCursor(0, 1);  
    lcd.print("Battery Low!     ");  // warning
  } else {
    lcd.setCursor(0, 1);  
    lcd.print("                ");  // clear second line
  }

  // wait 1 s before updating display
  delay(1000);
}