#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <pitches.h>   // install 'PlayRtttl' library 


//version 29-2-2020
//https://www.youtube.com/watch?v=B5O9bT54BzI
//original with seperate start button https://www.youtube.com/watch?v=rzxisoU9D6c

LiquidCrystal_I2C lcd(0x27,16,2);
//LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);  // Set the LCD I2C address
//LiquidCrystal_I2C lcd(0x3f, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE); // Set the LCD I2C address
//LiquidCrystal_I2C lcd(0x38);  // Set the LCD I2C address


#define Start 4               // start stop button D4
// possible without button
// use encoder longpress to start
#define BuzzerPin 11          // buzzer D11 
//#define BACKLIGHT_PIN 13

int relay = 12;
int beepCounts = 0;
int hours = 0;
int minutes = 0;
int seconds = 0;
int sethours = 0;
int setminutes = 0;
int setseconds = 0;
boolean timeState = false;
#define encoderPinA 2        // encoder  CLK right
#define encoderPinB 3        // encoder  DT  left
#define encoderButton 5      // encoder  SW  switch
int HMS = 1;
int encoderPos = 0;               // a counter for the dial
unsigned int lastReportedPos = 1; // change management
static boolean rotating = false;  // debounce management
boolean A_set = false;
boolean B_set = false;


void setup() {

  pinMode(relay, OUTPUT);
  digitalWrite(relay, LOW); 
  pinMode(Start, INPUT_PULLUP);
  pinMode(encoderPinA, INPUT_PULLUP); //enabling pullups
  pinMode(encoderPinB, INPUT_PULLUP);
  pinMode(encoderButton, INPUT_PULLUP);
  attachInterrupt(0, doEncoderA, CHANGE); //pin 2
  attachInterrupt(1, doEncoderB, CHANGE); //pin 3
  Serial.begin(9600); // output
  //lcd.begin(16, 2); // initialize the lcd for 16 chars 2 lines, turn on backlight
  lcd.init();                      // initialize the lcd 
  lcd.clear();
  lcd.backlight();
  delay((500));
  //lcd.print("UV EXPOSURE UNIT");
  //lcd.setCursor(0, 1);
  showSpalshScreen();
  playStartupMelody();
  delay(1100);
  tone(BuzzerPin, NOTE_C4, 700);
  delay(200);  // Add a slight delay after the note
  lcd.clear();
  noTone(BuzzerPin);          // Stop the tone
}

void loop() {

  if (digitalRead(encoderButton) == LOW)
  {
    HMS = HMS + 1;
    if (HMS == 4)
    {
      HMS = 1;
    }
    tone(BuzzerPin, 1000, 100);
    int t = 80;
    while (digitalRead(encoderButton) == LOW) {   
      delay(10); t = t - 1;

     // if (t == 60) {tone(BuzzerPin, 200, 50);}
        if (t == 40) {tone(BuzzerPin, 200, 50);}
          if (t == 20) {tone(BuzzerPin, 200, 50);}
      if (t <= 1) {
        t = 1; timeState = true;
            sethours = hours;
            setminutes=minutes;
            setseconds=seconds;
        lcd.setCursor(0, 0); lcd.print("Ready!          ");
        tone(BuzzerPin, 1000, 100);
      }
    }
  }
  //  lcd.setCursor(0, 0);
  //  lcd.print("COUNT DOWN TIMER");
  //  delay(500);
  if (HMS == 1) {
    lcd.setCursor(0, 0);
    lcd.print("set HRS         ");
    lcd.setCursor(6, 2);
 
  }
  if (HMS == 2) {
    lcd.setCursor(0, 0);
    lcd.print("set   MIN       ");
  }
  if (HMS == 3) {
    lcd.setCursor(0, 0);
    lcd.print("set      SEC    ");
  }
  //delay(500);

  rotating = true; // reset the debouncer
  encoderPos = constrain(encoderPos, -1, 1);
  if (lastReportedPos != encoderPos) {


    if (HMS == 1) {
      hours = hours + encoderPos;
      hours = constrain(hours, 0, 48);
     
    }
    else if (HMS == 2) {
      minutes = minutes + encoderPos;
      minutes = constrain(minutes, 0, 60);
     
    }
    else if (HMS == 3) {
      seconds = seconds + encoderPos;
      seconds = constrain(seconds, 0, 60);
      
    }


    lcd.setCursor(4, 1);
    if (hours <= 9)
    {
      lcd.print("0");
    }
    lcd.print(hours);
    lcd.print(":");
    if (minutes <= 9)
    {
      lcd.print("0");
    }
    lcd.print(minutes);
    lcd.print(":");
    if (seconds <= 9)
    {
      lcd.print("0");
    }
    lcd.print(seconds);
    encoderPos = 0;
    lastReportedPos = encoderPos;

  }

  if (digitalRead(Start) == LOW || timeState == true) { //start count down timer
    lcd.setCursor(0, 0); lcd.print(" UV LIGHT- ON  ");
    timeState = true;
    digitalWrite(relay, HIGH); 
    delay(500);

    while (timeState == true) {
       
    //delay(992);           //maintime delay
    int period = 1000;
    unsigned long time_now = 0;
    time_now = millis();
    while(millis() < time_now + period){ //wait approx. [period] ms}

    }
       //seconds = seconds - 1;
        
      if (seconds > 0) {
         seconds--;
       } else {
         // If seconds reach zero, decrease one minute
         if (minutes > 0) {
           minutes--;
           seconds = 59;
         } else {
           // If minutes reach zero, decrease one hour
           if (hours > 0) {
             hours--;
             minutes = 59;
             seconds = 59;
           }
         }
       }
           
      if (minutes == 0 && hours == 0 && seconds == 0) { //count down alarm
         
        lcd.clear();
        beepCounts = 0;
        while (timeState == true) {
            //lcd.clear();
            digitalWrite(relay, LOW);
            lcd.setCursor(0, 0);
            lcd.print(" UV LIGHT- OFF  ");
            lcd.setCursor(5, 1);
            lcd.print("FINISH!");
            if (beepCounts < 5) {
              tone(BuzzerPin, NOTE_G4, 400);
              //tone(BuzzerPin, 1000);  // Play a tone of 1000 Hz on the buzzer
              delay(300); 
              noTone(BuzzerPin);      
              delay(300); 
              tone(BuzzerPin, NOTE_C5, 400);      // Keep the tone for 200 milliseconds
              //noTone(BuzzerPin);      // Turn off the buzzer
              delay(300); 
              noTone(BuzzerPin);    
              beepCounts++;           // Increment the beep coun
              delay(300);  // Wait for half a second between beeps
              }

          if (digitalRead(Start) == LOW) { // turn alarm off with switch
            timeState = false;
            seconds = 1;
            lcd.clear();
            lcd.setCursor(0, 0);
            lcd.print("COUNT DOWN TIMER");
            lcd.setCursor(4, 1);
            lcd.print("00:00:00");
                        
            hours = sethours;
            minutes=setminutes;
            seconds=setseconds;
            break;
          }

          if (digitalRead(encoderButton) == LOW) { // turn alarm off with rotary encoder switch
            timeState = false;
            //seconds = 1;
            lcd.clear();
            //lcd.setCursor(0, 0);
            //lcd.print("COUNT DOWN TIMER");
            //lcd.setCursor(4, 1);
            //lcd.print("Done!");
            while(digitalRead(encoderButton) == LOW){delay(300);}//wait for release switch
    
            tone(BuzzerPin, NOTE_C4, 700);
            delay(200);  // Add a slight delay after the note
            noTone(BuzzerPin);          // Stop the tone
            while(digitalRead(encoderButton) == LOW){delay(1000);}//wait for release switch
            
            hours = sethours;
            minutes=setminutes;
            seconds=setseconds;
            break;
          }


        }
      }

      lcd.setCursor(4, 1);
      if (hours <= 9)
      {
        lcd.print("0");
      }
      lcd.print(hours);
      lcd.print(":");
      if (minutes <= 9)
      {
        lcd.print("0");
      }
      lcd.print(minutes);
      lcd.print(":");
      if (seconds <= 9)
      {
        lcd.print("0");
      }
      lcd.print(seconds);


      if (digitalRead(Start) == LOW) {           // pauze countdown with start button
        delay(1000);
        digitalWrite(relay, LOW);
        timeState = false;
        
        break;
      }
      if (digitalRead(encoderButton) == LOW) {    // pauze countdown with encoder button
        delay(1000);
        tone(BuzzerPin, 500, 100);
        digitalWrite(relay, LOW);
        timeState = false;
        break;
      }
    }
  }
}


// Interrupt on A changing state
void doEncoderA() {
  // debounce
  if ( rotating ) delay (10); // wait a little until the bouncing is done
  // Test transition, did things really change?
  if ( digitalRead(encoderPinA) != A_set ) { // debounce once more
    A_set = !A_set;
    // adjust counter + if A leads B
    if ( A_set && !B_set )
      encoderPos = 1;
    rotating = false; // no more debouncing until loop() hits again
  }
}

// Interrupt on B changing state
void doEncoderB() {
  if ( rotating ) delay (10);
  if ( digitalRead(encoderPinB) != B_set ) {
    B_set = !B_set;
    // adjust counter – 1 if B leads A
    if ( B_set && !A_set )
      encoderPos = -1;
    rotating = false;
  }
}

void playStartupMelody() {
  // Define the notes and durations for the melody
  int melody[] = { NOTE_C4, NOTE_E4, NOTE_G4, NOTE_C5 };
  int durations[] = { 4, 4, 4, 4 }; // 4 denotes a quarter note

  // Play the melody
  for (int i = 0; i < sizeof(melody) / sizeof(melody[0]); i++) {
    int noteDuration = 750 / durations[i];
    tone(BuzzerPin, melody[i], noteDuration);
    
    delay(noteDuration * 1.1); // Add a slight delay between notes
    noTone(BuzzerPin); // Stop the tone
  }
}
void showSpalshScreen() {
  lcd.print("UV EXPOSURE UNIT");
  lcd.setCursor(0, 1);
  String message = "----------------";
  for (byte i = 0; i < message.length(); i++) {
    lcd.print(message[i]);
    delay(20);
  }

}