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

int iceil = 1;
int count = 0;

int seccount = 0;
int secceil = 120;

int newn = 0;
int newl = 30;

int ebr_upscale = 0;
int ebr_sharp = 0;

int newf = 34;

int notepointer = 0;

void set7seg(unsigned char num) {
	PORTD = (num&0xFC);
	PORTC = (num&0x03);
}

unsigned char get7seg(unsigned char num) {
	if(num==0) return 0b10111111;
	else if(num==1) return 0b11000110;
	else if(num==2) return 0b10100001;
	else if(num==3) return 0b10000110;
	else if(num==4) return 0b10001110;
	else if(num==5) return 0b10010000;
	else if(num==6) return 0b10001000;
	else if(num==7) return 0b10000011;
	else if(num==8) return 0b01000110;
	else if(num==9) return 0b00100001;
	else if(num==10) return 0b00000110;
	else if(num==11) return 0b00001110;
	else if(num==15) return 0b10011011;
	return 0;
}

int get_frequency(int note,int sharp) {
	if(sharp==0) {
		switch(note) {
			case 0: return 0;
			case 1: return 57;
			case 2: return 51;
			case 3: return 45;
			case 4: return 43;
			case 5: return 38;
			case 6: return 34;
			case 7: return 30;
			case 8: return 28;
			case 9: return 25;
			case 10: return 22;
			case 11: return 21;
			case 15: return 255;
		}
	} else {
		switch(note) {
			case 0: return 0;
			case 1: return 54;
			case 2: return 48;
			case 3: return 43;
			case 4: return 40;
			case 5: return 36;
			case 6: return 32;
			case 7: return 28;
			case 8: return 26;
			case 9: return 24;
			case 10: return 22;
			case 11: return 20;
			case 15: return 255;
		}
	}
	return 34;
}

void change_note() {
	newf = get_frequency(newn,ebr_sharp);

	if(ebr_upscale==1) newf/=2;

	secceil = newl;
	iceil = newf;
	if(iceil==0) TIMSK2 = 0;
	else if(iceil==255) {
		TIMSK2 = 0;
		TIMSK0 = 0;
	} else TIMSK2 = 1;
	set7seg(get7seg(newn));
}

void read_note() {
	if(!eeprom_is_ready())
		eeprom_busy_wait() ;
	uint8_t value = eeprom_read_byte((unsigned int) notepointer++);

	newn = value&0x0F;
	if((value&0x30)==0) newl = 30;
	else if((value&0x30)==0x10) newl = 60;
	else if((value&0x30)==0x20) newl = 15;
	else newl=120;

	// ebr code
	ebr_upscale = (value&0x40)>>6;
	ebr_sharp = (value&0x80);

	if(newn==14) {
		// reset
		notepointer = 0;
		read_note();
	}

}


ISR(TIMER2_OVF_vect) {
	count++;
	if(count==iceil) {
		count=0;
		PORTB^=2;
		PORTB^=16;
	}
	return;
}



ISR(TIMER0_OVF_vect) {
	seccount++;
	if(seccount==secceil) {
		seccount=0;
		//do
		change_note();
		read_note();
		iceil = newf;
		count = 0;
		// load new note
		PORTB ^= 4;
	}
	return;
}

int main(void) {
	DDRB |= 30;
	DDRC |= 3;
	DDRD |= 0xFC;

	PORTD = 0;
	PORTC = 0;
	PORTB |= 8;

	TCNT2 = 0;
	TIMSK2 = 1;
	TCCR2B = 1;

	TCNT0 = 0;
	TIMSK0 = 1;
	TCCR0B = 5;

	sei();

	while(1);
	return 0;
}