#include <inttypes.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#define __DELAY_BACKWARD_COMPATIBLE__
#include <util/delay.h>
#include <stdlib.h>
#include <avr/pgmspace.h>
#include "freq_table.h"
#include <lib/bughal.h> 



static uint16_t	osc0     ;
static uint16_t	osc1     ;
static uint16_t	sample   ;
static uint8_t	row      ;
static uint16_t	speedtime;


void synth_init(void){
	cli();
	osc0 = osc1 = sample = row = 0;
	speedtime = 3000;

	/* set timer0 to CTC & prescaler 64 → 125kHz increment */
	TCCR0A = (1 << WGM01);
	TCCR0B = (1 << CS00) | (1 << CS01);

	OCR0A = 4;  /* TOP */
	TCNT0 = 0;

	/*enable interrupt */
	TIMSK0 |= (1 << OCIE0A);

	sei();
	return;
}


void synth_deinit(void) {
	cli();
	TIMSK0 = 0;
	sei();
	return;
}

enum {
	SONG_LENGTH = 128,
	xxx = 0,
	c_0 = 0, cs0 = 1, d_0 = 2, ds0 = 3, e_0 = 4, f_0 = 5,
	fs0 = 6, g_0 = 7, gs0 = 8, a_0 = 9, as0 = 10, b_0 = 11,
	c_1 = 12, cs1 = 13, d_1 = 14, ds1 = 15, e_1 = 16, f_1 = 17,
	fs1 = 18, g_1 = 19, gs1 = 20, a_1 = 21, as1 = 22, b_1 = 23,
	c_2 = 24, cs2 = 25, d_2 = 26, ds2 = 27, e_2 = 28, f_2 = 29,
	fs2 = 30, g_2 = 31, gs2 = 32, a_2 = 33, as2 = 34, b_2 = 35,
	c_3 = 36, cs3 = 37, d_3 = 38, ds3 = 39, e_3 = 40, f_3 = 41,
	fs3 = 42, g_3 = 43, gs3 = 44, a_3 = 45, as3 = 46, b_3 = 47,
};

const char music_data[2][SONG_LENGTH] PROGMEM = {
	{
		e_1, xxx, e_2, xxx, e_1, xxx, e_2, xxx,
		e_1, xxx, e_2, xxx, e_1, xxx, e_2, xxx,
		a_0, xxx, a_1, xxx, a_0, xxx, a_1, xxx,
		a_0, xxx, a_1, xxx, a_0, xxx, a_1, xxx,
		gs0, xxx, gs1, xxx, gs0, xxx, gs1, xxx,
		gs0, xxx, gs1, xxx, gs0, xxx, gs1, xxx,
		a_0, xxx, a_1, xxx, a_0, xxx, a_1, xxx,
		a_0, xxx, a_0, xxx, b_0, xxx, c_1, xxx,
		d_1, xxx, d_2, xxx, d_1, xxx, d_2, xxx,
		d_1, xxx, d_2, xxx, d_1, xxx, d_2, xxx,
		c_1, xxx, c_2, xxx, c_1, xxx, c_2, xxx,
		c_1, xxx, c_2, xxx, c_1, xxx, c_2, xxx,
		b_0, xxx, b_1, xxx, b_0, xxx, b_1, xxx,
		b_0, xxx, b_1, xxx, b_0, xxx, b_1, xxx,
		a_0, xxx, a_1, xxx, a_0, xxx, a_1, xxx,
		a_0, xxx, xxx, xxx, xxx, xxx, xxx, xxx,
	}, {
		e_3, e_3, e_3, e_3, b_2, b_2, c_3, c_3,
		d_3, d_3, e_3, d_3, c_3, c_3, b_2, b_2,
		a_2, a_2, a_2, a_2, a_2, a_2, c_3, c_3,
		e_3, e_3, e_3, e_3, d_3, d_3, c_3, c_3,
		b_2, b_2, b_2, b_2, b_2, b_2, c_3, c_3,
		d_3, d_3, d_3, d_3, e_3, e_3, e_3, e_3,
		c_3, c_3, c_3, c_3, a_2, a_2, a_2, a_2,
		a_2, a_2, a_2, a_2, a_2, a_2, a_2, a_2,
		xxx, xxx, d_3, d_3, d_3, d_3, f_3, f_3,
		a_3, a_3, a_3, a_3, g_3, g_3, f_3, f_3,
		e_3, e_3, e_3, e_3, e_3, e_3, c_3, c_3,
		e_3, e_3, e_3, e_3, d_3, d_3, c_3, c_3,
		b_2, b_2, b_2, b_2, b_2, b_2, c_3, c_3,
		d_3, d_3, d_3, d_3, e_3, e_3, e_3, e_3,
		c_3, c_3, c_3, c_3, a_2, a_2, a_2, a_2,
		a_2, a_2, a_2, a_2, xxx, xxx, xxx, xxx,
	}
};




ISR(TIMER0_COMPA_vect,ISR_NOBLOCK)
{
	osc0 += pgm_read_word(&freq_table[ pgm_read_byte(&music_data[0][row])]);
	osc1 += pgm_read_word(&freq_table[ pgm_read_byte(&music_data[1][row])]);
	if (++sample == speedtime ) {
		sample = 0;

		if (speedtime > 600) speedtime -= 4;
		if (++row == SONG_LENGTH) {
			row = 0;
			if (speedtime <= 600) speedtime = 3000;
		}
		if (row&4){
			led_on(LED_R);
			led_off(LED_L);
		}else{
			led_on(LED_L);
			led_off(LED_R);
		}	}

	if (osc0 >= 0x8000) PORTB |= (1 << PORTB2);
	else PORTB &= ~(1<< PORTB2);
	if (osc1 >= 0xc000) PORTC |= (1 << PORTC5);
	else PORTC &= ~(1<< PORTC5);
}