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

#define DHTPIN 2
#define DHTTYPE DHT22

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

//=======================
// PIN
//=======================
const int ldrPin = A0;
const int pirPin = 3;
const int buttonPin = 4;

const int lampPin = 5;      // LED Putih
const int fanPin = 6;       // LED Biru
const int alarmLed = 7;     // LED Merah
const int buzzerPin = 8;

//=======================
// Variabel
//=======================
bool manualMode = false;
bool manualLamp = false;

unsigned long lastLCD = 0;
byte lcdPage = 0;

const int ldrThreshold = 500;

//=======================

void setup() {

  pinMode(ldrPin, INPUT);
  pinMode(pirPin, INPUT);
  pinMode(buttonPin, INPUT_PULLUP);

  pinMode(lampPin, OUTPUT);
  pinMode(fanPin, OUTPUT);
  pinMode(alarmLed, OUTPUT);
  pinMode(buzzerPin, OUTPUT);

  dht.begin();

  lcd.init();
  lcd.backlight();

  lcd.setCursor(0,0);
  lcd.print("SMART CLASSROOM");
  lcd.setCursor(0,1);
  lcd.print("Initializing...");
  delay(2000);
  lcd.clear();
}

//=======================

void loop() {

  //=======================
  // BACA SENSOR
  //=======================

  float suhu = dht.readTemperature();
  float hum = dht.readHumidity();

  int ldrValue = analogRead(ldrPin);

  bool adaOrang = digitalRead(pirPin);

  //=======================
  // BUTTON MANUAL
  //=======================

  static bool lastButton = HIGH;
  bool button = digitalRead(buttonPin);

  if (lastButton == HIGH && button == LOW) {

    manualMode = !manualMode;

    if (manualMode)
      manualLamp = !manualLamp;

    delay(200);
  }

  lastButton = button;

  //=======================
  // LAMPU
  //=======================

  bool lampStatus;

  if (manualMode) {

    lampStatus = manualLamp;

  } else {

    lampStatus = (ldrValue < ldrThreshold && adaOrang);

  }

  digitalWrite(lampPin, lampStatus);

  //=======================
  // KIPAS
  //=======================

  bool fanStatus = false;

  if (!isnan(suhu)) {

    if (suhu > 30)
      fanStatus = true;

  }

  digitalWrite(fanPin, fanStatus);

  //=======================
  // ALARM
  //=======================

  bool alarmStatus = false;

  if (!isnan(suhu)) {

    if (suhu > 35)
      alarmStatus = true;

  }

  digitalWrite(alarmLed, alarmStatus);

  if (alarmStatus) {

    tone(buzzerPin, 1000);

  } else {

    noTone(buzzerPin);

  }

  //=======================
  // LCD BERGANTI TIAP 3 DETIK
  //=======================

  if (millis() - lastLCD >= 3000) {

    lastLCD = millis();

    lcd.clear();

    switch (lcdPage) {

      case 0:

        lcd.setCursor(0,0);
        lcd.print("Suhu:");
        lcd.print(suhu,1);
        lcd.print((char)223);
        lcd.print("C");

        lcd.setCursor(0,1);
        lcd.print("Hum :");
        lcd.print(hum,0);
        lcd.print("%");

        break;

      case 1:

        lcd.setCursor(0,0);
        lcd.print("Lampu : ");

        if (lampStatus)
          lcd.print("ON");
        else
          lcd.print("OFF");

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

        if (fanStatus)
          lcd.print("ON");
        else
          lcd.print("OFF");

        break;

      case 2:

        lcd.setCursor(0,0);

        if (adaOrang)
          lcd.print("Ada Orang");
        else
          lcd.print("Kosong");

        lcd.setCursor(0,1);

        if (manualMode)
          lcd.print("Mode: Manual");
        else
          lcd.print("Mode: Auto");

        break;

      case 3:

        lcd.setCursor(0,0);
        lcd.print("LDR:");
        lcd.print(ldrValue);

        lcd.setCursor(0,1);

        if (ldrValue < ldrThreshold)
          lcd.print("Gelap");
        else
          lcd.print("Terang");

        break;
    }

    lcdPage++;

    if (lcdPage > 3)
      lcdPage = 0;
  }

}