#include <LiquidCrystal_I2C.h>
#include <Wire.h>
#include <Encoder.h>
#include <DallasTemperature.h>
#include <OneWire.h>

int pinA = 3; // Connected to CLK on KY-040
int pinB = 4; // Connected to DT on KY-040
int relayPin = 5; // Relay trigger pin
int buzzerPin = 6; // Buzzer pin
int DS18B20pin = 8; // Temp read pin
int setTimer = 15; // Initial timer value in minutes
int setTemp = 50; // Initial temperature value
int curTemp = 50; // Current temperature reading
bool encoderSW = false; // Encoder mode switch
bool mainSW = false; // Main mode switch
unsigned long timerStartMillis = 0; // Store the start time of the timer
bool timerRunning = false; // Timer running flag

/* Functions */
LiquidCrystal_I2C lcd(0x27, 16, 2); // LCD initialization
Encoder encoder(pinA, pinB); // Encoder initialization
OneWire oneWire(DS18B20pin);
DallasTemperature sensors(&oneWire); // DS18B20 setup

// Read encoder value and handle limits
int readEncoder(int value, int maxVal, int minVal);
// Update the LCD display
void updateDisp();
// Start and update the countdown timer
void countdownTimer(unsigned long timerDuration);
void regulateTemperature(int setTemp);
float getTemperatureF();

void setup() {
  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.setCursor(0, 0);

  pinMode(7, INPUT_PULLUP); // encoderSw
  pinMode(8, INPUT_PULLUP); // mainSW
  pinMode(relayPin, OUTPUT);
  digitalWrite(relayPin, LOW);

  sensors.begin(); // Initialize the DS18B20 sensor
}

void loop() {
  updateDisp();

  // Check if the encoder mode switch button is pressed
  if (digitalRead(7) == LOW) {
    encoderSW = !encoderSW;
    delay(50);
  }

  // Check if the main mode switch button is pressed
  if (digitalRead(9) == LOW) {
    mainSW = !mainSW;
    delay(50);
  }

  // Handle encoder input based on mode
  if (encoderSW) {
    if (!mainSW) {
      setTimer = readEncoder(setTimer, 60, 0);
    }
  } else {
    setTemp = readEncoder(setTemp, 75, 38);
  }

  curTemp = getTemperatureF();

  // Handle timer start and stop based on main mode switch
  if (mainSW) {
    regulateTemperature(setTemp, curTemp);
    setTemp = readEncoder(setTemp, 75, 38);
    if (!timerRunning) {
      timerStartMillis = millis() / 1000; // Store the start time in seconds
      timerRunning = true;
    }
  } else {
    timerRunning = false;
  }

  // Update the LCD display during timer operation
  if (timerRunning) {
    countdownTimer(setTimer * 60); // Convert setTimer to seconds
  }

  delay(100);
}

// Read encoder value and handle limits
int readEncoder(int value, int maxVal, int minVal) {
  int encoderValue = encoder.read();

  if (encoderValue > 0) {
    value++;
    if (value > maxVal)
      value = maxVal;
  } else if (encoderValue < 0) {
    value--;
    if (value < minVal)
      value = minVal;
  }

  encoder.write(0);
  return value;
}

// Update the LCD display
void updateDisp() {
  lcd.setCursor(0, 0);
  lcd.print("Set:");
  lcd.print(setTemp);
  lcd.print("F ");
  lcd.print("Temp:");
  lcd.print(curTemp);
  lcd.print("F ");
  lcd.setCursor(0, 1);
  if (!mainSW) {
    lcd.print("Time: ");
    lcd.setCursor(6, 1);
    lcd.print(setTimer);
    lcd.print(":00   ");
  }
}

// Start and update the countdown timer
void countdownTimer(unsigned long timerDuration) {
  unsigned long currentSeconds = millis() / 1000; // Current time in seconds
  if (currentSeconds - timerStartMillis >= timerDuration) {
    timerRunning = false;
    mainSW = false; // Set mainSW to false when the timer reaches 0:00
    tone(buzzerPin, 262, 3000); //Buzzer for 3 seconds (262 Hz)
    for(int i = 0; i < 15; i++){
      //buzzer command
      lcd.setCursor(6, 1);
      lcd.print("       "); 
      delay(100);
      lcd.setCursor(6, 1);
      lcd.print("0:00");
      delay(100);
   }
  } else {
    unsigned long remainingSeconds = timerDuration - (currentSeconds - timerStartMillis);
    unsigned long minutes = remainingSeconds / 60;
    unsigned long seconds = remainingSeconds % 60;

    lcd.setCursor(6, 1);
    if (seconds < 10) {
      lcd.print(String(minutes, DEC) + ":0" + String(seconds, DEC));
    } else {
      lcd.print(String(minutes, DEC) + ":" + String(seconds, DEC));
    }
  }
}

void regulateTemperature(int setTemp, float curTemp)
{
    if(curTemp > setTemp)
    {
      digitalWrite(relayPin, HIGH);
    }
    else
    {
      digitalWrite(relayPin, LOW);
    }
}

float getTemperatureF() {
  // Function to read the DS18B20 temperature in Fahrenheit
  sensors.requestTemperatures(); // Request temperature readings
  float tempC = sensors.getTempCByIndex(0); // Get the temperature in Celsius
  float tempF = (tempC * 9.0 / 5.0) + 32; // Convert to Fahrenheit
  return tempF;
}