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

// Pin configuration
#define DHTPIN 2
#define MQ2PIN A1 // Analog pin for MQ2 sensor
#define BUZZERPIN 3
#define BUTTON1PIN 4
#define BUTTON2PIN 5
#define BUTTON3PIN 6

// DHT setup
#define DHTTYPE DHT11
DHT dht(DHTPIN, DHTTYPE);

// LCD setup
#define I2C_ADDR    0x27
#define LCD_COLUMNS 20
#define LCD_LINES   4
LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLUMNS, LCD_LINES);

// Thresholds
const int temperatureThresholds[] = {80, 85, 95}; // Example thresholds, replace as needed
const int MQ2Threshold = 500;

// Variables
int currentPage = 1;
bool buzzerActive = false;
bool buzzerMQ2Active = false;
unsigned long buzzerStartTime = 0;
int currentThresholdIndex = 0;

// Function declarations
void updateDisplay(float temperature = NAN, float humidity = NAN, int mq2Value = -1);
void togglePage();
void manageBuzzer(float temperature, int mq2Value);
void scrollPresets();
bool detectSensor(int pin);
bool checkAndUpdate(float& cache, float newValue);
bool checkAndUpdate(int& cache, int newValue);

void setup() {
  // Initialize the LCD
  lcd.init();      // Initialize the LCD
  lcd.backlight(); // Turn on the backlight

  // Initialize the DHT sensor
  dht.begin();

  // Set pin modes
  pinMode(MQ2PIN, INPUT);
  pinMode(BUZZERPIN, OUTPUT);
  pinMode(BUTTON1PIN, INPUT_PULLUP);
  pinMode(BUTTON2PIN, INPUT_PULLUP);
  pinMode(BUTTON3PIN, INPUT_PULLUP);

  // Display initial page
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Welcome to your");
  lcd.setCursor(0, 1);
  lcd.print("Smart 3D Enclosure");
  lcd.setCursor(0, 2);
  lcd.print("v1.0.1");
  delay(3000); // Show welcome message for 3 seconds

  updateDisplay();
}

void loop() {
  // Read button states
  if (digitalRead(BUTTON1PIN) == LOW) {
    delay(200); // Debounce delay
    if (digitalRead(BUTTON1PIN) == LOW) {
      tone(BUZZERPIN, 500); // Sound buzzer for 0.5 seconds
      delay(500);
      noTone(BUZZERPIN);
      togglePage();
    }
  }

  if (digitalRead(BUTTON2PIN) == LOW) {
    delay(200); // Debounce delay
    if (digitalRead(BUTTON2PIN) == LOW) {
      tone(BUZZERPIN, 500); // Sound buzzer for 0.5 seconds
      delay(500);
      noTone(BUZZERPIN);
      lcd.clear(); // Clear the display
    }
  }

  if (digitalRead(BUTTON3PIN) == LOW) {
    delay(200); // Debounce delay
    if (digitalRead(BUTTON3PIN) == LOW) {
      tone(BUZZERPIN, 500); // Sound buzzer for 0.5 seconds
      delay(500);
      noTone(BUZZERPIN);
      scrollPresets(); // Scroll through presets
    }
  }

  // Read sensors
  float temperature = dht.readTemperature(true); // Temperature in Fahrenheit
  float humidity = dht.readHumidity();
  int mq2Value = analogRead(MQ2PIN);

  // Update display based on button interactions
  updateDisplay(temperature, humidity, mq2Value);

  // Check thresholds and manage buzzer
  manageBuzzer(temperature, mq2Value);

  delay(500); // Update every 0.5 seconds
}

void togglePage() {
  currentPage = (currentPage == 1) ? 2 : (currentPage == 2) ? 3 : 1;
  lcd.clear(); // Clear the display to avoid overlapping content
  updateDisplay(); // Update display based on the new page
}

void manageBuzzer(float temperature, int mq2Value) {
  unsigned long currentTime = millis();

  if (temperature > temperatureThresholds[currentThresholdIndex]) {
    if (!buzzerActive) {
      buzzerActive = true;
      buzzerStartTime = currentTime;
    }
    
    if (buzzerActive && (currentTime - buzzerStartTime >= 1000)) {
      tone(BUZZERPIN, 1000); // 1 kHz frequency
      delay(1000); // Buzzer on for 1 second
      noTone(BUZZERPIN);
      delay(4000); // Wait for 4 seconds
      buzzerStartTime = millis(); // Reset buzzer start time
    }
  } else {
    noTone(BUZZERPIN);
    buzzerActive = false;
  }

  if (mq2Value > MQ2Threshold) {
    if (!buzzerMQ2Active) {
      buzzerMQ2Active = true;
      buzzerStartTime = currentTime;
    }
    
    if (buzzerMQ2Active && (currentTime - buzzerStartTime >= 1500)) {
      tone(BUZZERPIN, 1000); // 1 kHz frequency
      delay(1500); // Buzzer on for 1.5 seconds
      noTone(BUZZERPIN);
      delay(3500); // Wait for 3.5 seconds
      buzzerStartTime = millis(); // Reset buzzer start time
    }
  } else {
    noTone(BUZZERPIN);
    buzzerMQ2Active = false;
  }
}

void updateDisplay(float temperature, float humidity, int mq2Value) {
  if (currentPage == 1) {
    lcd.setCursor(0, 0);
    lcd.print("Temp: ");
    if (isnan(temperature)) {
      lcd.print("NA");
    } else {
      lcd.print(temperature);
      lcd.print(" F");
    }

    lcd.setCursor(0, 1);
    lcd.print("Hum: ");
    if (isnan(humidity)) {
      lcd.print("NA");
    } else {
      lcd.print(humidity);
      lcd.print(" %");
    }

    lcd.setCursor(0, 2);
    lcd.print("MQ2 Value: ");
    if (mq2Value == -1) {
      lcd.print("NA");
    } else {
      lcd.print(mq2Value);
      lcd.print("   ");
    }

    lcd.setCursor(0, 3);
    lcd.print("Page 1");
  } else if (currentPage == 2) {
    lcd.setCursor(0, 0);
    lcd.print("Page 2");

    lcd.setCursor(0, 1);
    lcd.print("Preset Temp: ");
    lcd.print(temperatureThresholds[currentThresholdIndex]);

    lcd.setCursor(0, 2);
    lcd.print(" Temp: ");
    if (isnan(temperature)) {
      lcd.print("NA");
    } else {
      lcd.print(temperature);
      lcd.print(" F   ");
    }
  } else if (currentPage == 3) {
    lcd.setCursor(0, 0);
    lcd.print("Uptime: ");
    long uptime = millis() / 1000;
    long hours = uptime / 3600;
    long minutes = (uptime % 3600) / 60;
    long seconds = uptime % 60;
    lcd.print(hours);
    lcd.print("h ");
    lcd.print(minutes);
    lcd.print("m ");
    lcd.print(seconds);
    lcd.print("s");

    lcd.setCursor(0, 1);
    lcd.print("Version: 1.2.1");

    lcd.setCursor(0, 3);
    lcd.print("Page 3");
  }
}

void scrollPresets() {
  currentThresholdIndex = (currentThresholdIndex + 1) % (sizeof(temperatureThresholds) / sizeof(temperatureThresholds[0]));
  updateDisplay();
}

bool detectSensor(int pin) {
  return digitalRead(pin) != LOW; // Adjust according to your sensor's logic
}

bool checkAndUpdate(float& cache, float newValue) {
  if (cache != newValue) {
    cache = newValue;
    return true;
  }
  return false;
}

bool checkAndUpdate(int& cache, int newValue) {
  if (cache != newValue) {
    cache = newValue;
    return true;
  }
  return false;
}