#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 20, 4); // Address 0x27, 20 columns, 4 rows

int buttonUp = 6;     // Digital pin for up button
int buttonDown = 7;   // Digital pin for down button
int buttonSelect = 8; // Digital pin for select button
int buttonBack = 9;   // Digital pin for back button

int menuIndex = 0;
int maxMenuIndex = 3; // Total number of menu items - 1

bool inSubMenu = false;

void setup() {
  Wire.begin();
    pinMode(buttonUp, INPUT_PULLUP);
      pinMode(buttonDown, INPUT_PULLUP);
        pinMode(buttonSelect, INPUT_PULLUP);
          pinMode(buttonBack, INPUT_PULLUP);

            lcd.init();
              lcd.backlight();
                lcd.setCursor(0, 0);
                  lcd.print("Menu:");
                  }

                  void loop() {
                    if (!inSubMenu) {
                        for (int i = 0; i < 4; i++) {
                              lcd.setCursor(0, i);
                                    if (menuIndex == i) {
                                            lcd.print("~  ");
                                                  } else {
                                                          lcd.print("   ");
                                                                }
                                                                      switch (i) {
                                                                              case 0:
                                                                                        lcd.print("Solar Setting ");
                                                                                                  break;
                                                                                                          case 1:
                                                                                                                    lcd.print("Battery Setting ");
                                                                                                                              break;
                                                                                                                                      case 2:
                                                                                                                                                lcd.print("Output Setting ");
                                                                                                                                                          break;
                                                                                                                                                                  case 3:
                                                                                                                                                                            lcd.print("Freq Setting ");
                                                                                                                                                                                      break;
                                                                                                                                                                                            }
                                                                                                                                                                                                }
                                                                                                                                                                                                  } else {
                                                                                                                                                                                                      // Display voltage, current, and power readings for option 1 sub-menu
                                                                                                                                                                                                          float voltage = 12.3; // Replace with actual voltage reading
                                                                                                                                                                                                              float current = 1.5;  // Replace with actual current reading
                                                                                                                                                                                                                  float power = voltage * current;

                                                                                                                                                                                                                      lcd.clear();
                                                                                                                                                                                                                          lcd.setCursor(0, 0);
                                                                                                                                                                                                                              lcd.print("Voltage: ");
                                                                                                                                                                                                                                  lcd.print(voltage);
                                                                                                                                                                                                                                      lcd.print("V");

                                                                                                                                                                                                                                          lcd.setCursor(0, 1);
                                                                                                                                                                                                                                              lcd.print("Current: ");
                                                                                                                                                                                                                                                  lcd.print(current);
                                                                                                                                                                                                                                                      lcd.print("A");

                                                                                                                                                                                                                                                          lcd.setCursor(0, 2);
                                                                                                                                                                                                                                                              lcd.print("Power: ");
                                                                                                                                                                                                                                                                  lcd.print(power);
                                                                                                                                                                                                                                                                      lcd.print("W");

                                                                                                                                                                                                                                                                          lcd.setCursor(0, 3);
                                                                                                                                                                                                                                                                              lcd.print("Press SELECT to return");
                                                                                                                                                                                                                                                                                }

                                                                                                                                                                                                                                                                                  if (digitalRead(buttonUp) == LOW) {
                                                                                                                                                                                                                                                                                      menuIndex = (menuIndex - 1 + maxMenuIndex + 1) % (maxMenuIndex + 1);
                                                                                                                                                                                                                                                                                          delay(200); // Button debounce
                                                                                                                                                                                                                                                                                            }

                                                                                                                                                                                                                                                                                              if (digitalRead(buttonDown) == LOW) {
                                                                                                                                                                                                                                                                                                  menuIndex = (menuIndex + 1) % (maxMenuIndex + 1);
                                                                                                                                                                                                                                                                                                      delay(200); // Button debounce
                                                                                                                                                                                                                                                                                                        }

                                                                                                                                                                                                                                                                                                          if (digitalRead(buttonSelect) == LOW) {
                                                                                                                                                                                                                                                                                                              if (!inSubMenu && menuIndex == 0) {
                                                                                                                                                                                                                                                                                                                    // Enter option 1 sub-menu
                                                                                                                                                                                                                                                                                                                          inSubMenu = true;
                                                                                                                                                                                                                                                                                                                              } else if (inSubMenu) {
                                                                                                                                                                                                                                                                                                                                    // Exit option 1 sub-menu
                                                                                                                                                                                                                                                                                                                                          inSubMenu = false;
                                                                                                                                                                                                                                                                                                                                              } else {
                                                                                                                                                                                                                                                                                                                                                    // Perform action based on selected menu item
                                                                                                                                                                                                                                                                                                                                                          // For simplicity, just print the selected menu index
                                                                                                                                                                                                                                                                                                                                                                lcd.clear();
                                                                                                                                                                                                                                                                                                                                                                      lcd.print("Selected: ");
                                                                                                                                                                                                                                                                                                                                                                            lcd.print(menuIndex + 1);
                                                                                                                                                                                                                                                                                                                                                                                  delay(1000); // Display for 1 second
                                                                                                                                                                                                                                                                                                                                                                                        lcd.clear();
                                                                                                                                                                                                                                                                                                                                                                                            }
                                                                                                                                                                                                                                                                                                                                                                                                delay(200); // Button debounce
                                                                                                                                                                                                                                                                                                                                                                                                  }

                                                                                                                                                                                                                                                                                                                                                                                                    if (digitalRead(buttonBack) == LOW) {
                                                                                                                                                                                                                                                                                                                                                                                                        // Return to main menu
                                                                                                                                                                                                                                                                                                                                                                                                            menuIndex = 0;
                                                                                                                                                                                                                                                                                                                                                                                                                inSubMenu = false;
                                                                                                                                                                                                                                                                                                                                                                                                                    lcd.clear();
                                                                                                                                                                                                                                                                                                                                                                                                                        lcd.setCursor(0, 0);
                                                                                                                                                                                                                                                                                                                                                                                                                            lcd.print("Menu:");
                                                                                                                                                                                                                                                                                                                                                                                                                                delay(200); // Button debounce
                                                                                                                                                                                                                                                                                                                                                                                                                                  }
                                                                                                                                                                                                                                                                                                                                                                                                                                  }