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

#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

RTC_DS1307 rtc;
LiquidCrystal_I2C lcd(0x27, 16, 2);
Adafruit_SSD1306 display = Adafruit_SSD1306(128, 64, &Wire);

// Alarmtime
int alarmHours = 0;
int alarmMinutes = 0;
bool alarmChosen = false;
char str[3];    // utilizzata per l'ora 
 

void setup(){

  // setting the pins
  pinMode(2, INPUT_PULLUP);

  // only needed when testing, start serial connection
  Serial.begin(9600);

  // starts the LCD 
  lcd.init();
  lcd.clear();
  lcd.backlight();

  display.setTextColor(WHITE, BLACK);
  display.setTextSize(2);
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.display();
  display.clearDisplay();

  // starts the RTC if it is found
  if (! rtc.begin()){
    lcd.print("RTC not found");
    while(1);
  }

  // Resets RTC time when needed
  if (! rtc.isrunning()){
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }

  // Selects the alarm time while setting up.
  while (! alarmChosen) {
    lcd.setCursor(0,0);
    lcd.print("To Start, Please");
    lcd.setCursor(0,1);
    lcd.print("Select An Alarm.");
    if (digitalRead(2) == LOW){
      alarmChangeTime();
      alarmChosen = true;
    }
  }
}
 
 
void loop(){
  DateTime current = rtc.now();
  screenDefault(current);
  if (digitalRead(2) == LOW){
    alarmChangeTime();
  }
}

// The default setting, prints the current time and date onto the screen
void screenDefault(DateTime current) {

  // Printing time onto the LCD
  lcd.setCursor(0,1);
  lcd.print("TIME");
  lcd.print(' ');
  lcd.print(current.hour());
  lcd.print(':');
  lcd.print(current.minute());
  lcd.print(':');
  lcd.print(current.second());
  lcd.print("  ");
  
  // Printing Date onto the LCD
  lcd.setCursor(0,0);
  lcd.print("DATE");
  lcd.print(" ");
  lcd.print(current.day());
  lcd.print("/");
  lcd.print(current.month());
  lcd.print("/");
  lcd.print(current.year());
  lcd.print("  ");

  display.setCursor(5,1);
  display.print(current.day());
  display.print("/");
  display.print(current.month());
  display.print("/");
  display.print(current.year());
  display.print("  ");

  display.setCursor(15,30);
  sprintf(str, "%02d", current.hour());
  display.print(str);
  display.print(':');
  sprintf(str, "%02d", current.minute());
  display.print(str);
  display.print(':');
  sprintf(str, "%02d", current.second());
  display.print(str);

  display.display();

}

void alarmActive() {

}

void alarmChangeTime() {
  int buttonPressed = millis();
  while (digitalRead(2) == LOW){}
  int buttonReleased = millis();
  
  int buttonHeld = buttonReleased - buttonPressed;

  // If the button was held more than 1.5 seconds 15 minutes is subtracted from the alarm time.
  // If the button was held less than 1.5 seconds 15 minutes is added the alarm time.
  
  if (buttonHeld < 1500){
    alarmMinutes += 15;
  }
  else{
    alarmMinutes -= 15;
  }

  // Since the millis() command gives a 32-bit value it has to be reset every fortynine days.
  // If the button were to be held while the reset happens the value of buttonHeld would be negative.

  // Adjusting the minutes.

  if (alarmMinutes >= 60){
    alarmMinutes = 0;
    alarmHours += 1; 
  }

  if (alarmMinutes < 0){
    alarmMinutes = 45;
    alarmHours -= 1;
  }

  // Adjusting the hours.

  if (alarmHours >= 24 && alarmMinutes != 0){
    alarmHours = 0;
    alarmMinutes = 15;
    }

  if (alarmHours < 0){
    alarmHours = 23;
    }

  lcd.clear();

  // Prints the current alarm time onto the screen

  lcd.setCursor(0,0);
  lcd.print("Alarm time:");
  lcd.setCursor(0,1);
  if (alarmHours == 0) {
    lcd.print("00");
  }
  else{
  lcd.print(alarmHours);
  }
  lcd.print(':');
  if (alarmMinutes == 0){
  lcd.print("00");
  }
  else{
  lcd.print(alarmMinutes);
  }
  lcd.print(':');
  lcd.print("00");

  delay(1500);

  lcd.clear();

}