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

//Constants
const int ldr_Pin = A0;
const int temp_Pin = A1;
const int speaker_Pin = A2;
const int button_Pin = 4;
#define TIMER 30


//Timer
unsigned long startTime = 0;
bool timerStarted = false;
const unsigned long timerDuration = 1800000; // 30 minutes in milliseconds

//Temperature
const float BETA = 3950;
float previousTemp = 0; // Initialize previousTemp variable to 0
const int high_Temp = 75; // in Celsius
const float room_Temp = 25; // in Celsius


// LDR Characteristics
const float GAMMA = 0.7;
const float RL10 = 50;
float previousLux = 0; // Initialize previousLux variable to 0
const int low_Light = 50; // in percentage

//Variables
LiquidCrystal_I2C lcd(0x27, 20, 4);
enum States {INIT, COUNT, END, ERR};
int state = INIT;
int Light;
float Heat;
int Timer = 0;
int Minute = 59;
int temperature = 0;
int Automate = INIT;
bool TemperatureOK = false;
bool LightOK = false;
bool point = true;

unsigned long previousMillis = 0;
const unsigned long interval = 1000;

void setup() {
  //Serial Monitor
  Serial.begin(9600);

  //LDR
  pinMode(ldr_Pin, INPUT);

  //LCD
  lcd.init();
  lcd.backlight();

  //Button and Speaker
  pinMode(button_Pin, INPUT_PULLUP);
  pinMode(speaker_Pin, OUTPUT);

  Automate = INIT;
}

void loop() {

  static int Point = 1;
  float measuredTemperature = getTemperature();
  temperature = measuredTemperature + 0;

  displayTemperature();
  displayLux();

  //Timer
  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis >= interval)
  {
    previousMillis = currentMillis;

    if (Automate == COUNT)
    {
      if (Point)
        Point = 0;
      else
        Point = 1;
      Minute--;
      if (Minute == 0)
      {
        Minute = 59;
        if (Timer)
          Timer--;
        lcd.setCursor(0,2);
        lcd.print("Count:");
        lcd.print(Timer);
      }
    }

    if (Automate == END)
      tone(3, 3000, 100);
    if (Automate == ERR)
      tone(3, 300, 200);
  }

  // Temperature and light level checks
  if (temperature >= high_Temp) {
    playTone(300, 300);
    lcd.setCursor(0, 2);
    lcd.print("Temp too high!");
  }
  if (temperature >= room_Temp) {
    TemperatureOK = true;
  } else {
    TemperatureOK = false;
  }

  int ldrValue = analogRead(ldr_Pin);
  float voltage = ldrValue / 1024.0 * 5.0;
  float resistance = 2000.0 * voltage / (1.0 - voltage / 5.0);
  float lux = pow(RL10 * 1000.0 * pow(10.0, GAMMA) / resistance, (1.0 / GAMMA));
  lux = round(lux * 100.0) / 100.0; // Round to nearest hundredth
  if (lux >= low_Light) {
    LightOK = true;
  } else {
    LightOK = false;
  }

  // State machine
  switch (Automate)
  {
    case INIT:
      Timer = 0;
      if ((!digitalRead(button_Pin)) && TemperatureOK)
      {
        Automate = COUNT;
        Timer = TIMER;
        tone(3, 3000, 500);
      }
      if ((!digitalRead(button_Pin)) && !TemperatureOK)
      {
        PrintLed("lowT");
        tone(3, 300, 200);
      }
      else
        PrintSensors("Init", Timer);
      break;

    case COUNT:
      if ((!digitalRead(button_Pin)) && !TemperatureOK)
      {
        Automate = ERR;
        tone(3, 300, 200);
      }
      if ((!digitalRead(button_Pin)) && LightOK)
      {
        Automate = END;
        tone(3, 3000, 100);
      }
      if (Timer == 0)
      {
        Automate = ERR;
        tone(3, 300, 200);
      }
      PrintSensors("Count", Timer);
      break;

    case END:
      if ((!digitalRead(button_Pin)) && !LightOK)
      {
        Automate = ERR;
        tone(3, 300, 200);
      }
      if (Timer == 0)
        Automate = INIT;
      PrintSensors("End", Timer);
      break;

    case ERR:
      if ((!digitalRead(button_Pin)) && (TemperatureOK || LightOK))
        Automate = INIT;
      PrintLed("Err");
      break;
  }
}

float measureSurTemp()
{
  // Surrounding temperature measurement logic
  // Implement your code here
  // Return the measured temperature value
  return 0;
}

float measureObjectTemp()
{
  // Object temperature measurement logic
  // Implement your code here
  // Return the measured temperature value
  return 0;
}

void PrintSensors(const char* state, int timer)
{
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("State: ");
  lcd.print(state);
  lcd.setCursor(0, 1);
  lcd.print("Timer: ");
  lcd.print(Timer);
  lcd.setCursor(0, 2);
  lcd.print("Heat: ");
  lcd.print(Heat);
  lcd.setCursor(0, 3);
  lcd.print("Light: ");
  lcd.print(Light);
}

void PrintLed(const char* state)
{
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("State: ");
  lcd.print(state);
}


// Function to get temperature from thermistor
float getTemperature() {
  int analogValue = analogRead(temp_Pin);
  float celsius = 1 / (log(1 / (1023. / analogValue - 1)) / BETA + 1.0 / 298.15) - 273.15;
  celsius = round(celsius * 100.0) / 100.0; // Round to nearest hundredth
  return celsius;
}

void playTone(long duration, int freq) {
  duration *= 3000;
  int period = (1.0 / freq) * 100000;
  long elapsed_time = 0;
  while (elapsed_time < duration) {
    digitalWrite(speaker_Pin, HIGH);
    delayMicroseconds(period / 2);
    digitalWrite(speaker_Pin, LOW);
    delayMicroseconds(period / 2);
    elapsed_time += (period);
  }
}

// Function to display temperature on LCD
void displayTemperature() {
  int analogValue = analogRead(temp_Pin);
  float celsius = 1 / (log(1 / (1023. / analogValue - 1)) / BETA + 1.0 / 298.15) - 273.15;
  celsius = round(celsius * 100.0) / 100.0; // Round to nearest hundredth
  // Only update screen if temperature value changes
  if (celsius != previousTemp) {
    lcd.clear(); // Clear the LCD screen

    lcd.setCursor(0, 0);
    lcd.print("Temp: ");
    lcd.print(celsius);
    lcd.print("C");

    previousTemp = celsius; // Update previousTemp variable to current temperature value
  }
}

void displayLux(){
  int analogValue = analogRead(A0);
  float voltage = analogValue / 1024.0 * 5.0;
  float resistance = 2000.0 * voltage / (1.0 - voltage / 5.0);
  float lux = pow(RL10 * 1000.0 * pow(10.0, GAMMA) / resistance, (1.0 / GAMMA));
  lux = round(lux * 100.0) / 100.0; // Round to nearest hundredth

  // Only update screen if Lux value changes
  if (lux != previousLux) {
    lcd.clear(); // Clear the LCD screen

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

    previousLux = lux; // Update previousLux variable to current Lux value
  }
}