#include <Wire.h>
#include <RTClib.h>
#include <LiquidCrystal_I2C.h>
#include <Adafruit_INA219.h>
#include <SPI.h>
#include <SD.h>

// LCD 20x4
LiquidCrystal_I2C lcd(0x27, 20, 4);

// RTC DS1307
RTC_DS1307 rtc;

// INA219
Adafruit_INA219 ina219;

// SD card
const int chipSelect = 10; // CS pin for SD card

// Simulated potentiometer analog pins
const int voltagePotPin = A0; // Simulate 0-20V
const int currentPotPin = A1; // Simulate 0-0.5A
const int powerPotPin   = A2; // Simulate 0-10W

void setup() {
  Serial.begin(9600);
  
  // LCD
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Initializing...");

  // RTC
  if (!rtc.begin()) {
    Serial.println("Couldn't find RTC");
    lcd.setCursor(0, 1);
    lcd.print("RTC Fail");
    while (1);
  }

  if (!rtc.isrunning()) {
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__))); // Set time to compile time
  }

  // INA219
  if (!ina219.begin()) {
    Serial.println("Failed to find INA219");
    lcd.setCursor(0, 2);
    lcd.print("INA219 Fail");
    while (1);
  }

  // SD Card
  if (!SD.begin(chipSelect)) {
    Serial.println("SD init failed!");
    lcd.setCursor(0, 3);
    lcd.print("SD Card Fail");
    while (1);
  }

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("System Ready");
  delay(2000);
}

void loop() {
  // Get time
  DateTime now = rtc.now();
  char timeBuf[20];
  sprintf(timeBuf, "%02d:%02d:%02d", now.hour(), now.minute(), now.second());

  // Get simulated values
  float simVoltage = analogRead(voltagePotPin) * (20.0 / 1023.0);
  float simCurrent = analogRead(currentPotPin) * (0.5 / 1023.0);
  float simPower   = analogRead(powerPotPin) * (10.0 / 1023.0);

  // Get INA219 readings
  float busVoltage = ina219.getBusVoltage_V();  // V
  float current_mA = ina219.getCurrent_mA();    // mA
  float power_mW   = ina219.getPower_mW();      // mW

  // Display on LCD
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(timeBuf);

  lcd.setCursor(0, 1);
  lcd.print("V:");
  lcd.print(busVoltage, 1);
  lcd.print("V I:");
  lcd.print(current_mA / 1000.0, 3);
  lcd.print("A");

  lcd.setCursor(0, 2);
  lcd.print("P:");
  lcd.print(power_mW / 1000.0, 2);
  lcd.print("W");

  lcd.setCursor(0, 3);
  lcd.print("SimV:");
  lcd.print(simVoltage, 1);
  lcd.print(" SimA:");
  lcd.print(simCurrent, 2);

  // Save to SD card
  File dataFile = SD.open("datalog.txt", FILE_WRITE);
  if (dataFile) {
    dataFile.print(now.timestamp());
    dataFile.print(", V=");
    dataFile.print(busVoltage, 2);
    dataFile.print("V, I=");
    dataFile.print(current_mA / 1000.0, 3);
    dataFile.print("A, P=");
    dataFile.print(power_mW / 1000.0, 2);
    dataFile.println("W");
    dataFile.close();
  } else {
    Serial.println("Failed to open file");
  }

  delay(2000);
}