#include <LiquidCrystal_I2C.h>

// Define LCD
LiquidCrystal_I2C lcd(0x27, 16, 2);  // Change the address if needed

// Define button pins
const int menuButtonPin = 2;
const int upButtonPin = 3;
const int downButtonPin = 4;

// Define analog output pins
const int voltagePin = 9;
const int currentPin = 10;

// Define voltage and current limits
const float maxVoltage = 56.0;
const float maxCurrent = 35.0;

float setVoltage = 0.0;
float setCurrent = 0.0;

// Define menu states
enum MenuState {
  VOLTAGE,
  CURRENT
};

MenuState currentMenuState = VOLTAGE;

void setup() {
  // Initialize LCD
  lcd.begin(16, 2);

  // Initialize buttons
  pinMode(menuButtonPin, INPUT_PULLUP);
  pinMode(upButtonPin, INPUT_PULLUP);
  pinMode(downButtonPin, INPUT_PULLUP);

  // Set initial values
  analogWrite(voltagePin, 0);
  analogWrite(currentPin, 0);

  // Display initial values on LCD
  updateLCD();
}

void loop() {
  // Check buttons
  if (digitalRead(menuButtonPin) == LOW) {
    // Change menu state when the menu button is pressed
    if (currentMenuState == VOLTAGE) {
      currentMenuState = CURRENT;
    } else {
      currentMenuState = VOLTAGE;
    }
    delay(200);  // debounce
    updateLCD();
  }

  if (digitalRead(upButtonPin) == LOW) {
    // Increase voltage or current based on the menu state
    if (currentMenuState == VOLTAGE) {
      setVoltage = constrain(setVoltage + 1.0, 0.0, maxVoltage);
      analogWrite(voltagePin, map(setVoltage, 0, maxVoltage, 0, 255));
    } else {
      setCurrent = constrain(setCurrent + 1.0, 0.0, maxCurrent);
      analogWrite(currentPin, map(setCurrent, 0, maxCurrent, 0, 255));
    }
    delay(200);  // debounce
    updateLCD();
  }

  if (digitalRead(downButtonPin) == LOW) {
    // Decrease voltage or current based on the menu state
    if (currentMenuState == VOLTAGE) {
      setVoltage = constrain(setVoltage - 1.0, 0.0, maxVoltage);
      analogWrite(voltagePin, map(setVoltage, 0, maxVoltage, 0, 255));
    } else {
      setCurrent = constrain(setCurrent - 1.0, 0.0, maxCurrent);
      analogWrite(currentPin, map(setCurrent, 0, maxCurrent, 0, 255));
    }
    delay(200);  // debounce
    updateLCD();
  }
}

void updateLCD() {
  lcd.clear();
  lcd.setCursor(0, 0);

  if (currentMenuState == VOLTAGE) {
    lcd.print("Voltage: ");
    lcd.print(setVoltage);
    lcd.print(" V");
  } else {
    lcd.print("Current: ");
    lcd.print(setCurrent);
    lcd.print(" A");
  }

  lcd.setCursor(0, 1);
  lcd.print("Use Menu to switch");

  // Display voltage bar, battery icon, and status graph in row 3
  lcd.setCursor(0, 2);
  displayVoltageBar();
  lcd.print(" ");
  displayBatteryIcon();
  lcd.print(" ");
  displayStatusGraph();
}

void displayVoltageBar() {
  int barLength = map(setVoltage, 0, maxVoltage, 0, 16);
  for (int i = 0; i < barLength; ++i) {
    lcd.write(255);  // Display a block character to represent the voltage bar
  }
}

void displayBatteryIcon() {
  lcd.write(6);  // Display a custom character representing a battery icon
}

void displayStatusGraph() {
  // Display a simple status graph based on the current value
  int graphLength = map(setCurrent, 0, maxCurrent, 0, 16);
  for (int i = 0; i < graphLength; ++i) {
    lcd.write(7);  // Display a custom character representing a graph
  }
}