#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <DHT.h>
#include "loadingAnimation.h"

#define DHTPIN 4               // DHT sensor pin
#define DHTTYPE DHT11
#define ENCODER_CLK 3          // Rotary encoder CLK pin
#define ENCODER_DT 5           // Rotary encoder DT pin
#define BUTTON_PIN 2           // Rotary encoder button pin
#define DEBOUNCE_DELAY 50      // Short delay for debounce

LiquidCrystal_I2C lcd(0x27, 16, 2);
DHT dht(DHTPIN, DHTTYPE);

enum MenuState { MENU, SUBMENU };
MenuState currentState = MENU;

const char* menuItems[] = {"Temperature", "Humidity", "Option 1", "Message"};
const int totalMenuItems = sizeof(menuItems) / sizeof(menuItems[0]);
int selectedItem = 0;
int topItem = 0; // Tracks the top visible item
int lastEncoderCLK = HIGH; // To track the previous state of the CLK pin

void setup() {
  lcd.begin(16, 2);
  lcd.backlight();
  Serial.begin(9600);
  dht.begin();

  pinMode(ENCODER_CLK, INPUT_PULLUP);
  pinMode(ENCODER_DT, INPUT_PULLUP);
  pinMode(BUTTON_PIN, INPUT_PULLUP);

  loadingAnimation(lcd);
  lcd.clear();
  displayMenu();
}

void loop() {
  handleRotaryEncoder();
  handleButton();
  delay(DEBOUNCE_DELAY); // Short delay for debounce
}

void handleRotaryEncoder() {
  int currentEncoderCLK = digitalRead(ENCODER_CLK);

  if (currentEncoderCLK != lastEncoderCLK && currentEncoderCLK == LOW) { // Detect falling edge
    if (currentState == MENU) {
      // Only allow scrolling in the main menu
      if (digitalRead(ENCODER_DT) != currentEncoderCLK) {
        // Clockwise rotation
        selectedItem = (selectedItem + 1) % totalMenuItems;
      } else {
        // Counterclockwise rotation
        selectedItem = (selectedItem - 1 + totalMenuItems) % totalMenuItems;
      }

      // Adjust the top item for scrolling if needed
      if (selectedItem < topItem) {
        topItem = selectedItem;
      } else if (selectedItem >= topItem + 2) {
        topItem = selectedItem - 1;
      }

      displayMenu();
    }
  }
  lastEncoderCLK = currentEncoderCLK;
}

void handleButton() {
  static int lastButtonState = HIGH;
  int buttonState = digitalRead(BUTTON_PIN);

  if (buttonState == LOW && lastButtonState == HIGH) {
    // Button pressed
    if (currentState == MENU) {
      // Enter submenu
      currentState = SUBMENU;
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("< Main Menu");
      showSubmenu();
    } else if (currentState == SUBMENU) {
      // Return to the main menu
      currentState = MENU;
      displayMenu();
    }
  }
  lastButtonState = buttonState;
}

void displayMenu() {
  lcd.clear();
  for (int i = 0; i < 2; i++) { // Display up to 2 items at a time
    int index = topItem + i;
    if (index < totalMenuItems) {
      lcd.setCursor(0, i);
      lcd.print((index == selectedItem) ? "> " : "  ");
      lcd.print(menuItems[index]);
    }
  }
}

void showSubmenu() {
  switch (selectedItem) {
    case 0:
      displayTemperature();
      break;
    case 1:
      displayHumidity();
      break;
    case 2:
      lcd.print("Option 1");
      break;
    case 3:
      readMessage();
      break;
  }
}

void displayTemperature() {
  lcd.setCursor(0, 1);
  float temperature = dht.readTemperature();
  if (isnan(temperature)) {
    lcd.print("Sensor error!");
  } else {
    lcd.print("Temp: ");
    lcd.print(temperature);
    lcd.print("\xDF""C");
  }
}

void displayHumidity() {
  lcd.setCursor(0, 1);
  float humidity = dht.readHumidity();
  if (isnan(humidity)) {
    lcd.print("Sensor error!");
  } else {
    lcd.print("Hum: ");
    lcd.print(humidity);
    lcd.print("%");
  }
}

void readMessage() {
  lcd.setCursor(0, 1);
  lcd.print("Awaiting input...");
  if (Serial.available() > 0) {
    lcd.setCursor(0, 1);
    lcd.print("                "); // Clear the previous message
    String input = Serial.readStringUntil('\n'); // Read input from serial
    lcd.setCursor(0, 1);
    lcd.print(input);
  }
}