#include <EEPROM.h>
#include <Keypad.h>
#include <DS3231.h>
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

DS3231 rtc(SDA, SCL);

Time t;

#define buz 7
#define OLED_MOSI 11
#define OLED_CLK 13
#define OLED_DC 9
#define OLED_CS 10
#define OLED_RESET 8

Adafruit_SSD1306 display(OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS);
int Hor, Min, Sec, tim, dat, h, m, s;
int ASCII = 48;
char key = 0;
char buffer[2];
const byte numRows= 4;
const byte numCols= 4;
char keymap[numRows][numCols]=

{
{'1', '2', '3', 'A'},
{'4', '5', '6', 'B'},
{'7', '8', '9', 'C'},
{'*', '0', '#', 'D'}
};

byte rowPins[numRows] = {A0, A1, A2, A3};
byte colPins[numCols]= {6, 5, 4, 3};
Keypad myKeypad= Keypad(makeKeymap(keymap), rowPins, colPins, numRows, numCols);

void setup() {

Wire.begin();
rtc.begin();
pinMode(buz, OUTPUT);
display.begin(SSD1306_SWITCHCAPVCC);
display.clearDisplay();
display.setTextColor(WHITE);
display.setTextSize(1);
welcome();

//uncomment these lines to set the date and time
//rtc.setDOW(SATURDAY); // Set Day-of-Week to SUNDAY
//rtc.setTime(10, 54, 0); // Set the time to 12:00:00 (24hr format)
//rtc.setDate(7, 1, 2017); // Day, Month, Year
}

void loop() {

t = rtc.getTime();
Hor = t.hour;
Min = t.min;
Sec = t.sec;
tim = rtc.getTimeStr();
dat = rtc.getDateStr();
char key = myKeypad.getKey();
if (key == 'C'){
digitalWrite(buz, LOW);
EEPROM.write(2, ASCII+6);
EEPROM.write(3, ASCII);
}

if(key == '#'){
display.clearDisplay();
display.setCursor(0,0);
display.print("Enter New Time");
display.setCursor(0,10);
display.display();
int j =0;
int i=0;
while( j<6)

{
if(i==2 || i == 5){
display.print(":");
display.display();
i++;
}

key=myKeypad.getKey();
if(key)
{
display.print(key);
display.display();
EEPROM.write(j,key);
j++;
i++;
}
}
}
changealarm();
checkalarm();
timedate();
}
void checkalarm(){
if( Hor == h && Min == m)
{
delay(200);
display.clearDisplay();
display.setCursor(0,10);
display.print("Hold C to stop Alarm");
display.display();
digitalWrite(buz, HIGH);
delay(200);
}
}

void changealarm(){

buffer[0]=EEPROM.read(0);
buffer[1]=EEPROM.read(1);
h = atoi(buffer);
buffer[0]=EEPROM.read(2);
buffer[1]=EEPROM.read(3);
m = atoi(buffer);
buffer[0]=EEPROM.read(4);
buffer[1]=EEPROM.read(5);
s = atoi(buffer);
}

void timedate(){

display.clearDisplay();
display.setTextColor(WHITE);
display.setTextSize(1);
display.setCursor(0,0);
display.print("Time: ");
display.print(rtc.getTimeStr());
display.setCursor(0,10);
display.print("Date: ");
display.print(rtc.getDateStr());
display.setCursor(0,20);
display.print("Alarm: ");
display.print(h);
display.print(".");
display.print(m);
display.print(".");
display.print(s);
display.display();
}

void welcome(){

display.setCursor(0,0);
display.print(" Welcome ");
display.display();
display.setCursor(0,10);
display.print(" To ");
display.display();
display.setCursor(0,20);
display.print("ElectronicsHobbyists ");
display.display();
delay(5000);
}