#include <LiquidCrystal.h>  //Header file for LCD from https://www.arduino.cc/en/Reference/LiquidCrystal
#include <RotaryEncoder.h>

#define BTN     11
#define PIN_IN1 12
#define PIN_IN2 13

const int rs = 2, en = 3, d4 = 4, d5 = 5, d6 = 6, d7 = 7; //Pins to which LCD is connected
LiquidCrystal lcd(rs, en, d4, d5,  d6, d7);

// IN PROGRESS - Function to print on LCD to reduce clutter
// Can add a mode variable to choose what its printing (time, date, etc.)

// IN PROGRESS - Encoder
// Years get messed up when changing to a value less than the previous one
// Store previous values of encoder to provide easier access
// Flash current selection?
// When clicking button to lock in date, tracked as another button press and messes up other values - Made an extra state as a buffer, better way to do this?
// 


int day = 1;
int hours = 12;
int milHour = 0;
int min = 0;
int sec = 0;
bool aPm = true; // true if AM, false if PM
int currMonth = 0;
char* months[12] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
int year = 2024;

bool btn_pressed = false;
bool long_press = true;
int btn_num = 0;
uint32_t mdelay = 0;
uint32_t loopDelay = 0;

uint16_t duty = 0;
int newEncoderValue = 0, oldEncoderVlue = 0;

// Initialize rotary encoder
RotaryEncoder encoder(PIN_IN1, PIN_IN2, RotaryEncoder::LatchMode::FOUR3);

// Collect encoder value and return it - This may need to be edited to save the previous time values
int getEncoderChanges() {
  int retVal = 0;
  newEncoderValue = encoder.getPosition();
  if(newEncoderValue != oldEncoderVlue){
    if(oldEncoderVlue > newEncoderValue){
      retVal = 1;
    }else{
      retVal = -1;
    }
    oldEncoderVlue = newEncoderValue;
  }
  return retVal;
}

// Change date and time by counting button presses and using encoder
void changeDateTime(int btn_num) {
  // Use button presses to choose unit of time to change w/ encoder
  switch(btn_num) {
    case(0): // Change month
      currMonth += getEncoderChanges();
      if(currMonth > 11) {
        currMonth = 11;
      }
    break;
    case(1): // Change day
      day += getEncoderChanges();
        if(day < 1) {
          day = 1;
        }
        if(currMonth==3 || currMonth==5 || currMonth==8 || currMonth==10) {
          if(day > 30) {
            day = 30;
          }
        }
        else if(currMonth==1) {
          if(day > 28) {
            day = 28;
          }
        }
        else {
          if(day > 31) {
            day = 31;
          }
        }
    break;
    case(2): // Change year
      year += getEncoderChanges();
    break;
    case(3): // Change hours
      hours += getEncoderChanges();
      if(hours > 12) {
        hours = 12;
      }
      if(hours < 1) {
        hours = 1;
      }
    break;
    case(4): // Change minutes
      min += getEncoderChanges();
      if(min > 59) {
        min = 59;
      }
    break;
    case(5): // Change seconds
      sec += getEncoderChanges();
      if(sec > 59) {
        sec = 59;
      }
    break;
    case(6): // Change AM PM
      if(encoder.getPosition() % 2 == 0) {
        aPm = true;
        milHour = hours;
      }
      else {
        aPm = false;
        milHour = 12 + hours;
      }
    break;
    case(7): 
    // Buffer state - enter when done setting clock 
    break;
    
  } // switch

}

// Cursor to flash currently selected time unit
void cursor_flash(uint16_t duty) {
  if(duty == 10) {
    lcd.clear();
    duty = 0;
  }
}

// Check button return to see if it was pressed/held/released
int check_btn_status() {
  int bs = 0;
  // Tracking a button press or long press
  if(digitalRead(BTN) == LOW && !btn_pressed) {
    mdelay = millis(); // Important to set this here for long button press
    btn_pressed = true;
  }
  else if(digitalRead(BTN) == LOW && btn_pressed) {
    if(millis() - mdelay > 2000) {
        mdelay = millis();
        long_press = true;
        bs = 2;
    }
  }
  else if(digitalRead(BTN) == HIGH && btn_pressed) {
    btn_pressed = false;
    if(millis() - mdelay < 300 && millis() - mdelay > 100) {
      bs = 1;
    }
  }

  return bs;
}


void setup() {
  Serial.begin(115200);
  lcd.begin(16, 2); //We are using a 16*2 LCD  display
  pinMode(BTN, INPUT_PULLUP); // Intialize button
}

void loop() {
	if(long_press) {
	  // Start encoder
	  encoder.tick();

	  int bs = check_btn_status();
    Serial.print("Button Staus>> ");
    Serial.println(bs);
	  if(bs == 1) {
		btn_num++;
		// Wrap back to setting month if btn_num > 7
		if(btn_num == 7) {
			btn_num = 0;
		}
	}else if(bs == 2) {
		long_press = false;
	  }
	  
	  // Change date and time using encoder and number of button presses to determine what 
	  // unit of time being changed
	  changeDateTime(btn_num);
	  
	  // Print Date
	  lcd.setCursor(0, 0);
	  lcd.print(months[currMonth]);
	  lcd.print(" ");
	  lcd.print(day);
	  lcd.print(", ");
	  lcd.print(year);

	  // Print time
	  lcd.setCursor(0,1);
	  if(hours < 10){
		lcd.print(0);
		lcd.print(hours);
	  }
	  else{
		lcd.print(hours);
	  }
	  lcd.print(":");
	  // Set minutes
	  if(min < 10) {
		lcd.print(0);
		lcd.print(min);
	  }
	  else{
		lcd.print(min);
	  }
	  lcd.print(":");
	  // Set seconds
	  if(sec < 10) {
		lcd.print(0);
		lcd.print(sec);
	  }
	  else{
		lcd.print(sec);
	  }
	  // Print AM or PM
	  if(aPm == true){
		lcd.print(" AM");
	  }
	  else{
		lcd.print(" PM");
	  }

	  // Call flash cursor function
	  cursor_flash(duty);

	  duty++;

	} // if long press false
	else 
	{
	  if(check_btn_status() == 2){
      long_press = true;
      btn_num = 0;
	  }

	  if(millis() - loopDelay >= 1000) {
		loopDelay = millis();
		// Normal clock functionality
		// Reset second and minute count
		if(sec >= 60) {
		  min++;
		  sec = 0;
		}
		if(min >= 60) {
		  hours++;
		  milHour++;
		  min = 0;
		}
		// Flipping AM and PM, resetting 12 hour count
		if(hours == 12 && sec == 0 && min == 0){
		  aPm = !aPm;
		}
		if(hours > 12) {
		  hours = 1;
		}
		// Incrementing day, resetting 24 hour count
		if(milHour == 24 && sec == 0 && min == 0) {
		  day++;
		}
		if(milHour > 24){
		  milHour = 0;
		}
		// Make correct number of days for current month, reset when new month
		if(currMonth==3 || currMonth==5 || currMonth==8 || currMonth==10) {
		  if(day > 30) {
			day = 0;
			currMonth++;
		  }
		}
		else if(currMonth==1) {
		  if(day > 28) {
			day = 0;
			currMonth++;
		  }
		}
		else {
		  if(day > 31) {
			day = 0;
			currMonth++;
		  }
		}
		// Reset month count
		if(currMonth > 12) {
		  currMonth = 0;
		  year++;
		}

		// Print Date
		lcd.setCursor(0, 0);
		lcd.print(months[currMonth]);
		lcd.print(" ");
		lcd.print(day);
		lcd.print(", ");
		lcd.print(year);

		// Print time on line below, insert placeholder 0 when values < 10
		lcd.setCursor(0,1);
		if(hours < 10){
		  lcd.print(0);
		  lcd.print(hours);
		}
		else{
		  lcd.print(hours);
		}

		lcd.print(":");

		// Set minutes
		if(min < 10) {
		  lcd.print(0);
		  lcd.print(min);
		}
		else{
		  lcd.print(min);
		}

		// Set seconds
		lcd.print(":");
		if(sec < 10) {
		  lcd.print(0);
		  lcd.print(sec);
		}
		else{
		  lcd.print(sec);
		}

		// Print AM or PM
		if(aPm == true){
		  lcd.print(" AM");
		}
		else{
		  lcd.print(" PM");
		}
		// Increment seconds after every loop
		sec++;
	  } // if(millis() - loopDelay >= 1000)
	} // else long press is true

}