#include <LiquidCrystal_I2C.h>
#include <SD.h>

// Pin Definitions
#define VOLTAGE_PIN A0    // Voltage simulated by potentiometer
#define CURRENT_PIN A1    // Current simulated by potentiometer
#define SD_CS 10          // Chip Select pin for SD Card Module

// Constants
const float REF_VOLTAGE = 5.0;   // Reference voltage for ADC
const int ADC_RESOLUTION = 1024; // ADC resolution
const float VOLTAGE_DIVIDER_RATIO = 5.0; // Voltage divider ratio
const float CURRENT_SENSOR_SENSITIVITY = 0.185; // Sensitivity for current sensor (A/V)

// Objects
LiquidCrystal_I2C lcd(0x27, 16, 2); // LCD with I2C address 0x27

// Global Variables
float voltage = 0.0;
float current = 0.0;
float power = 0.0;

void setup() {
  // Initialize Serial Monitor
  Serial.begin(9600);

  // Initialize LCD
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Initializing...");

  // Initialize SD card
  if (!SD.begin(SD_CS)) {
    Serial.println("SD Card failed or not present!");
    lcd.setCursor(0, 1);
    lcd.print("SD Failed!");
    while (true); // Halt the program if SD initialization fails
  } else {
    Serial.println("SD Card initialized.");
    lcd.setCursor(0, 1);
    lcd.print("SD Ready!");
  }

  delay(2000);
  lcd.clear();
}

void loop() {
  // Read voltage and current
  voltage = analogRead(VOLTAGE_PIN) * (REF_VOLTAGE / ADC_RESOLUTION) * VOLTAGE_DIVIDER_RATIO;
  current = (analogRead(CURRENT_PIN) * (REF_VOLTAGE / ADC_RESOLUTION) - 2.5) / CURRENT_SENSOR_SENSITIVITY;
  power = voltage * current;

  // Display data on LCD
  lcd.setCursor(0, 0);
  lcd.print("V: ");
  lcd.print(voltage, 2);
  lcd.print(" V");

  lcd.setCursor(0, 1);
  lcd.print("I: ");
  lcd.print(current, 2);
  lcd.print("A ");
  lcd.print("P: ");
  lcd.print(power, 2);

  // Log data to SD card
  File logFile = SD.open("energy_log.txt", FILE_WRITE);
  if (logFile) {
    logFile.print("Voltage: ");
    logFile.print(voltage, 2);
    logFile.print(" V, Current: ");
    logFile.print(current, 2);
    logFile.print(" A, Power: ");
    logFile.print(power, 2);
    logFile.println(" W");
    logFile.close();
    Serial.println("Data logged to SD card.");
  } else {
    Serial.println("Error opening file!");
  }

  delay(1000); // Update every second
}