/*
 * keypad.c
 *
 * Created: 2022-05-13 12:34:20
 * Author : ca4215be-s
 */ 



#define F_CPU 16000000UL 
#include <avr/io.h> 
#include <util/delay.h> 
#include <string.h> 
#include <avr/interrupt.h>



int fill_entered(); // Fills code entering array with -1
int fill_correct(); // Fills code checking array with -1
void enter_digit(int enter); // Enters digit into enter array
void enter_code(); // Checks state, either the checking code or entering code, uses functions such as checkCode and too_Short
int checkCode(); // Compares checking array with enter array, returns true if code i correct
int too_short(); // Checks if input into checking array is less than 4 elements, returns true if true
void clear(); // Clears the checking array or the enter code array and LCD 



void lcd_data(unsigned char data); // Writes data to LCD
void lcd_cmd(unsigned char command); // Sends a command code to LCD
void stringwrite(unsigned char s[]); // Builds string to be printed on LCD
void lcd_initialise(); // Initializes LCD



void beep(); // beep
void green(); // green
void red(); // red



int correct_code[16]; 					
int entered_code[16]; 



static int choose_or_enter = 0;  // States (0 = choose code), (1 = enter code)
static int counter = 0;			// Keeps track of next place in the code array where entered number is to be placed			



int main(void) {

	DDRB=0xFF; 
	DDRA|=(1<<0)|(1<<1)|(1<<3)|(1<<4)|(1<<2);

	lcd_initialise();

	sei(); // Initializes Interrupt function
	PCICR =  0b00001000; // chooses interrupt register bank (port D) 
	PCMSK3 = 0b00000111; 
		

	fill_correct(); // fills correct_code array with *s
	fill_entered(); // fills entered_code array with *s
	

while(1) {

}



}



ISR(PCINT3_vect) { // Interrupt-routine for button-push

	_delay_ms(30);

	if (PIND == 0b00001001) {
		stringwrite("1");
		beep();
		enter_digit(1);

	}

	else if (PIND == 0b00001010) {

		stringwrite("2");
		beep();
		enter_digit(2);

	}

	else if (PIND == 0b00001100) {

		stringwrite("3");
		beep();
		enter_digit(3);

	}

	else if (PIND == 0b00010001) {

		stringwrite("4");
		beep();
		enter_digit(4);

	}

	else if (PIND == 0b00010010) {

		stringwrite("5");
		beep();
		enter_digit(5);

	}

	else if (PIND == 0b00010100) {

		stringwrite("6");
		beep();
		enter_digit(6);

	}

	else if (PIND == 0b00100001) {

		stringwrite("7");
		beep();
		enter_digit(7);

	}

	else if (PIND == 0b00100010) {

		stringwrite("8");
		beep();
		enter_digit(8);

	}

	else if (PIND == 0b00100100) {

		stringwrite("9");
		beep();
		enter_digit(9);

	}

	else if (PIND == 0b01000010) {

		stringwrite("0");
		beep();
		enter_digit(0);

	}

	else if (PIND == 0b01000100) {

		enter_code();

	}

	else if (PIND == 0b01000001) {

		beep();
		clear();
		beep();

	}

	_delay_ms(40);

}



int fill_entered() { // 0 = correct_code, 1 = entered_code

	for (int k = 0; k<16; k++) {
		entered_code[k] = -1;

	}

}



int fill_correct() { // 0 = correct_code, 1 = entered_code

	for (int i = 0; i<16; i++) {
		correct_code[i] = -1;

	}

}



void enter_digit(int enter) {

	if (choose_or_enter == 0) {
		correct_code[counter] = enter;
		counter++;

	}

	else if (choose_or_enter == 1) {
		entered_code[counter] = enter;
		counter++;

	}

}



void enter_code() {

	lcd_cmd(0x01);

	if (choose_or_enter == 0) {  // when choosing code

		if (too_short()) {
			lcd_cmd(0x80);
			stringwrite("Code too short,");
			lcd_cmd(0xC0);
			stringwrite("enter code > 4");
			_delay_ms(1500);
			clear();

		}

		else {

			choose_or_enter = 1;
			lcd_cmd(0x80);
			stringwrite("Enter code:");
			lcd_cmd(0xC0);
			counter = 0;

		}

	}

	else if (choose_or_enter == 1) {  // when entering code

		if (checkCode()) {
			green();
			lcd_cmd(0x80);
			stringwrite("Access Granted!");
			lcd_cmd(0xC0);
			_delay_ms(1500);
			clear();

		}

		else {

			red();
			lcd_cmd(0x80);
			stringwrite("Access Denied!");
			lcd_cmd(0xC0);
			_delay_ms(1500);
			clear();

		}

		counter = 0;

	}

}



int checkCode() {
	if (entered_code[0] == -1){
		return 0;
	}
	for (int i = 0; i<16; i++) {
		if (entered_code[i] != -1 && entered_code[i] != correct_code[i]) {
			return 0;
		}
	}
	return 1;
}



int too_short() {

	int counter1 = 0;
	
	for (int y = 0; y<16; y++) {
		if (correct_code[y] == -1) {
			break;
		}
		counter1++;
	}

	if (counter1 < 4) {
		return 1;
	}

	else {
		return 0;
	}

}



void clear() {

	lcd_cmd(0x01);

	if (choose_or_enter == 0) {
		lcd_cmd(0x80);
		stringwrite("Choose code:");
		lcd_cmd(0xC0);
		fill_correct(); // fills correct_code array with -1
		counter = 0;

	}

	else if (choose_or_enter == 1) {
		lcd_cmd(0x80);
		stringwrite("Enter code:");
		lcd_cmd(0xC0);
		fill_entered(); // fills entered_code array with -1
		counter = 0;

	}

}



void lcd_data(unsigned char data) {
	PORTB=data;
	PORTA|=(1<<0);
	PORTA|=(1<<1);
	_delay_ms(10);
	PORTA&=(~(1<<1));
	_delay_ms(10);
}



void lcd_cmd(unsigned char command) {
	PORTB=command;
	PORTA &= ~(1<<0);
	PORTA |=(1<<1);
	
	_delay_ms(10);
	PORTA &=(~(1<<1));
	_delay_ms(10);

}



void stringwrite(unsigned char s[]) {

	int i;

	for (i=0;s[i]!=0;i++) {
		lcd_data(s[i]);
	}

}



void lcd_initialise() {

	lcd_cmd(0x38); // 16x2 8-bit
	lcd_cmd(0x0C); // display on, cursor off
	lcd_cmd(0x06); // Auto Increment cursor
	lcd_cmd(0x01); // clear display
	lcd_cmd(0x02); // cursor at home position
	stringwrite("Choose Code:");
	lcd_cmd(0xC0);

}



void beep() {

	PORTA|=(1<<3);
	_delay_ms(200);
	PORTA&=~(1<<3);

}



void red() {

	PORTA|=(1<<2);
	_delay_ms(200);
	PORTA&=~(1<<2);

}



void green() {

	PORTA|=(1<<4);
	_delay_ms(200);
	PORTA&=~(1<<4);

}