#include "samples.c"

#define SAMPLE_FREQUENCY 44100
#define NOTE_PERIOD (SAMPLE_FREQUENCY * 0x4000 / 11025)
#define ADSR_STEP (SAMPLE_FREQUENCY / 0xf)

typedef struct AudioChannel {
    u8 *samples;
    u16 n_samples;
	u16 position;
    u16 sampling_freq;
    u8 pitch;
    bool loop;
    // TODO: u16 adsr; // attack, decay, sustain, release
    // TODO: u8 pitch;  // Bit 8 is the "loop" bit
    // TODO: u8 volume; // VOL_LEFT | (VOL_RIGHT << 4)
	// u8 *addr;
	// u32 count, advance, period, age, a, d, s, r;
	// s8 volume[2];
	// u8 pitch, repeat;
} AudioChannel;

typedef struct APU {
    AudioChannel chan_0;
    // u32 *samples_1;
    // u32 *samples_2;
    // u32 *samples_3;
} APU;

static APU apu;


static u16 pitch_table[] = {
    12173,
    11490,
    10845,
    10237,
    9662,
    9120,
    8608,
    8125,
    7669,
    7238,
    6832,
    6448,
    6086,
    5745,
    5422,
    5118,
    4831,
    4560,
    4304,
    4062,
    3834,
    3619,
    3416,
    3224,
    3043,
    2872,
    2711,
    2559,
    2415,
    2280,
    2152,
    2031,
    1917,
    1809,
    1708,
    1612,
    1521,
    1436,
    1355,
    1279,
    1207,
    1140,
    1076,
    1015,
    958,
    904,
    854,
    806,
    760,
    718,
    677,
    639,
    603,
    570,
    538,
    507,
    479,
    452,
    427,
    403,
    380,
    359,
    338,
    319,
    301,
    285,
    269,
    253,
    239,
    226,
    213,
    201,
    190,
    179,
    169,
    159,
    150,
    142,
    134,
    126,
    119,
    113,
    106,
    100,
    95,
    89,
    84,
    79,
    75,
    71,
    67,
    63,
    59,
    56,
    53,
    50,
    47,
    44,
    42,
    39,
    37,
    35,
    33,
    31,
    29,
    28,
    26,
    25,
    23,
    22,
    21,
    19,
    18,
    17,
    16,
    15,
    14,
    14,
    13,
    12,
    0,
};

void
reset_sound(AudioChannel *chan) {
    TIMER_CTRL_0 = 0;
    TIMER_CTRL_1 = 0;
    DMA_CTRL(1) = 0;
    if (chan->pitch >= 108 || chan->n_samples == 0) {
        return;
    }

    // Set max volume, left-right sound, fifo reset and use timer 0 for
    // DirectSound A.
    SOUND_DSOUND_MASTER = SOUND_DSOUND_RATIO_A
        | SOUND_DSOUND_LEFT_A
        | SOUND_DSOUND_RIGHT_A
        | SOUND_DSOUND_RESET_A;

    // Prepare DMA copy.
    dma_transfer_copy(SOUND_FIFO_A, chan->samples, 1, 1,
            DMA_DST_FIXED | DMA_CHUNK_32 | DMA_REFRESH | DMA_REPEAT | DMA_ENABLE);

    // Timer 1 used to stop playing samples.
    u32 sample_duration = chan->n_samples;
    TIMER_DATA_1 = 0xFFFF - sample_duration;
    TIMER_CTRL_1 = TIMER_CTRL_IRQ
        | TIMER_CTRL_ENABLE
        | TIMER_CTRL_CASCADE;

    // Timer 0 used to stop sample playing.
    // TIMER_DATA_0 = 0xFFFF - sound_freq[chan->pitch];
    // TIMER_DATA_0 = 0xFFFF - CPU_FREQUENCY / chan->sampling_freq / chan->pitch;
    TIMER_DATA_0 = 0xFFFF - pitch_table[chan->pitch];
    TIMER_CTRL_0 = TIMER_CTRL_ENABLE;
}

u8 square_wave[] =  {
    0x00 + 0x80, 0xFF + 0x80
};
#include "text.h"


void
init_sound(AudioChannel *chan) {
    // chan->samples = &square_wave;
    // chan->n_samples = 2;
    // chan->samples = &samples;
    // chan->n_samples = LEN(samples);
    // chan->pitch++;
    // chan->pitch = chan->pitch == LEN(pitch_table) - 1 ? 0 : chan->pitch + 1;
    // chan->loop = true;
    // chan->sampling_freq = pitch_table[chan->pitch];
    // txt_printf("RATE: %lu", pitch_table[chan->pitch])
}

void
irs_stop_sample(void) {
    if (apu.chan_0.loop) {
        reset_sound(&apu.chan_0);
    } else {
        TIMER_CTRL_0 = 0;
        DMA_CTRL(1) = 0;
    }
}

// void
// apu_start(Apu *c, u16 adsr, u8 pitch) {
// 	// if(pitch < 108 && c->len)
// 	// 	c->advance = advances[pitch % 12] >> (8 - pitch / 12);
// 	// else {
// 	// 	c->advance = 0;
// 	// 	return;
// 	// }
// 	// c->a = ADSR_STEP * (adsr >> 12);
// 	// c->d = ADSR_STEP * (adsr >> 8 & 0xf) + c->a;
// 	// c->s = ADSR_STEP * (adsr >> 4 & 0xf) + c->d;
// 	// c->r = ADSR_STEP * (adsr >> 0 & 0xf) + c->s;
// 	// c->age = 0;
// 	// c->i = 0;
// 	// if(c->len <= 0x100) /* single cycle mode */
// 	// 	c->period = NOTE_PERIOD * 337 / 2 / c->len;
// 	// else /* sample repeat mode */
// 	// 	c->period = NOTE_PERIOD;
// }