#include "rockmacros.h"
#include "defs.h"
#include "pcm.h"
#include "sound.h"
#include "cpu-gb.h"
#include "hw.h"
#include "regs.h"
#include "noise.h"


static const byte sqwave[4][8] =
    {
        {  0, 0,-1, 0, 0, 0, 0, 0 },
        {  0,-1,-1, 0, 0, 0, 0, 0 },
        {  0,-1,-1,-1,-1, 0, 0, 0 },
        { -1, 0, 0,-1,-1,-1,-1,-1 }
    };

static const int freqtab[8] =
    {
        (1<<18)*2,
        (1<<18),
        (1<<18)/2,
        (1<<18)/3,
        (1<<18)/4,
        (1<<18)/5,
        (1<<18)/6,
        (1<<18)/7
    };

struct snd snd IBSS_ATTR;

#define RATE (snd.rate)
#define WAVE (ram.hi+0x30)
#define S1 (snd.ch[0])
#define S2 (snd.ch[1])
#define S3 (snd.ch[2])
#define S4 (snd.ch[3])

static void s1_freq_d(int d)
{
    if (RATE > (d<<4)) S1.freq = 0;
    else S1.freq = (RATE << 17)/d;
}

static void s1_freq(void)
{
    s1_freq_d(2048 - (((R_NR14&7)<<8) + R_NR13));
}

static void s2_freq(void)
{
    int d = 2048 - (((R_NR24&7)<<8) + R_NR23);
    if (RATE > (d<<4)) S2.freq = 0;
    else S2.freq = (RATE << 17)/d;
}

static void s3_freq(void)
{
    int d = 2048 - (((R_NR34&7)<<8) + R_NR33);
    if (RATE > d) S3.freq = 0;
    else S3.freq = (RATE << 21)/d;
}

static void s4_freq(void)
{
    S4.freq = (freqtab[R_NR43&7] >> (R_NR43 >> 4)) * RATE;
}

void sound_dirty(void)
{
    S1.swlen = ((R_NR10>>4) & 7) << 14;
    S1.len = (64-(R_NR11&63)) << 13;
    S1.envol = R_NR12 >> 4;
    S1.endir = (R_NR12>>3) & 1;
    S1.endir |= S1.endir - 1;
    S1.enlen = (R_NR12 & 3) << 15;
    s1_freq();
    S2.len = (64-(R_NR21&63)) << 13;
    S2.envol = R_NR22 >> 4;
    S2.endir = (R_NR22>>3) & 1;
    S2.endir |= S2.endir - 1;
    S2.enlen = (R_NR22 & 3) << 15;
    s2_freq();
    S3.len = (256-R_NR31) << 20;
    s3_freq();
    S4.len = (64-(R_NR41&63)) << 13;
    S4.envol = R_NR42 >> 4;
    S4.endir = (R_NR42>>3) & 1;
    S4.endir |= S4.endir - 1;
    S4.enlen = (R_NR42 & 3) << 15;
    s4_freq();
}

void sound_reset(void)
{
    int i;
    memset(&snd, 0, sizeof snd);
    if (pcm.hz) snd.rate = (1<<21) / pcm.hz;
    else snd.rate = 0;
    R_NR10 = 0x80;
    R_NR11 = 0xBF;
    R_NR12 = 0xF3;
    R_NR14 = 0xBF;
    R_NR21 = 0x3F;
    R_NR22 = 0x00;
    R_NR24 = 0xBF;
    R_NR30 = 0x7F;
    R_NR31 = 0xFF;
    R_NR32 = 0x9F;
    R_NR34 = 0xBF;
    R_NR41 = 0xFF;
    R_NR42 = 0x00;
    R_NR43 = 0x00;
    R_NR44 = 0xBF;
    R_NR50 = 0x77;
    R_NR51 = 0xF3;
    R_NR52 = 0xF1;
    for (i = 0; i < 16; i++) WAVE[i] = -(i&1);
    sound_dirty();
}

void sound_mix(void)
{
    int s, l, r, f, n;

    if (!RATE || cpu.snd < RATE) return;

    for (; cpu.snd >= RATE; cpu.snd -= RATE)
    {
        l = r = 0;

        if (S1.on)
        {
            s = sqwave[R_NR11>>6][(S1.pos>>18)&7] & S1.envol;
            S1.pos += S1.freq;
            if ((R_NR14 & 64) && ((S1.cnt += RATE) >= S1.len))
                S1.on = 0;
            if (S1.enlen && (S1.encnt += RATE) >= S1.enlen)
            {
                S1.encnt -= S1.enlen;
                S1.envol += S1.endir;
                if (S1.envol < 0) S1.envol = 0;
                if (S1.envol > 15) S1.envol = 15;
            }
            if (S1.swlen && (S1.swcnt += RATE) >= S1.swlen)
            {
                f = ((R_NR14 & 7) << 8) + R_NR13;
                n = (R_NR10 & 7);
                if (R_NR10 & 8) f -= (f >> n);
                else f += (f >> n);
                if (f > 2047)
                    S1.on = 0;
                else
                {
                    R_NR13 = f;
                    R_NR14 = (R_NR14 & 0xF8) | (f>>8);
                    s1_freq_d(2048 - f);
                }
            }
            s <<= 2;
            if (R_NR51 & 1) l += s;
            if (R_NR51 & 16) r += s;
        }

        if (S2.on)
        {
            s = sqwave[R_NR21>>6][(S2.pos>>18)&7] & S2.envol;
            S2.pos += S2.freq;
            if ((R_NR24 & 64) && ((S2.cnt += RATE) >= S2.len))
                S2.on = 0;
            if (S2.enlen && (S2.encnt += RATE) >= S2.enlen)
            {
                S2.encnt -= S2.enlen;
                S2.envol += S2.endir;
                if (S2.envol < 0) S2.envol = 0;
                if (S2.envol > 15) S2.envol = 15;
            }
            s <<= 2;
            if (R_NR51 & 2) l += s;
            if (R_NR51 & 32) r += s;
        }

        if (S3.on)
        {
            s = WAVE[(S3.pos>>22) & 15];
            if (S3.pos & (1<<21)) s &= 15;
            else s >>= 4;
            s -= 8;
            S3.pos += S3.freq;
            if ((R_NR34 & 64) && ((S3.cnt += RATE) >= S3.len))
                S3.on = 0;
            if (R_NR32 & 96) s <<= (3 - ((R_NR32>>5)&3));
            else s = 0;
            if (R_NR51 & 4) l += s;
            if (R_NR51 & 64) r += s;
        }

        if (S4.on)
        {
            if (R_NR43 & 8) s = 1 & (noise7[
                                             (S4.pos>>24)&15] >> ((S4.pos>>21)&7));
            else s = 1 & (noise15[
                                  (S4.pos>>24)&4095] >> ((S4.pos>>21)&7));
            s = (-s) & S4.envol;
            S4.pos += S4.freq;
            if ((R_NR44 & 64) && ((S4.cnt += RATE) >= S4.len))
                S4.on = 0;
            if (S4.enlen && (S4.encnt += RATE) >= S4.enlen)
            {
                S4.encnt -= S4.enlen;
                S4.envol += S4.endir;
                if (S4.envol < 0) S4.envol = 0;
                if (S4.envol > 15) S4.envol = 15;
            }
            s <<= 2;
            if (R_NR51 & 8) l += s;
            if (R_NR51 & 128) r += s;
        }

        l *= (R_NR50 & 0x07);
        r *= ((R_NR50 & 0x70)>>4);
        l >>= 4;
        r >>= 4;

        if (l > 127) l = 127;
        else if (l < -128) l = -128;
        if (r > 127) r = 127;
        else if (r < -128) r = -128;

        if (pcm.buf)
        {
            if (pcm.pos >= pcm.len)
                pcm_submit();
            if (pcm.stereo)
            {
                pcm.buf[pcm.pos++] = l+128;
                pcm.buf[pcm.pos++] = r+128;
            }
            else pcm.buf[pcm.pos++] = ((l+r)>>1)+128;
        }
    }
    R_NR52 = (R_NR52&0xf0) | S1.on | (S2.on<<1) | (S3.on<<2) | (S4.on<<3);
}



byte sound_read(byte r)
{
    if(!options.sound) return 0;
    sound_mix();
    /* printf("read %02X: %02X\n", r, REG(r)); */
    return REG(r);
}

void s1_init(void)
{
    S1.swcnt = 0;
    S1.envol = R_NR12 >> 4;
    S1.endir = (R_NR12>>3) & 1;
    S1.endir |= S1.endir - 1;
    S1.enlen = (R_NR12 & 7) << 15;
    S1.on = 1;
    S1.pos = 0;
    S1.cnt = 0;
    S1.encnt = 0;
}

void s2_init(void)
{
    S2.envol = R_NR22 >> 4;
    S2.endir = (R_NR22>>3) & 1;
    S2.endir |= S2.endir - 1;
    S2.enlen = (R_NR22 & 7) << 15;
    S2.on = 1;
    S2.pos = 0;
    S2.cnt = 0;
    S2.encnt = 0;
}

void s3_init(void)
{
    S3.pos = 0;
    S3.cnt = 0;
    S3.on = R_NR30 >> 7;
}

void s4_init(void)
{
    S4.envol = R_NR42 >> 4;
    S4.endir = (R_NR42>>3) & 1;
    S4.endir |= S4.endir - 1;
    S4.enlen = (R_NR42 & 7) << 15;
    S4.on = 1;
    S4.pos = 0;
    S4.cnt = 0;
    S4.encnt = 0;
}


void sound_write(byte r, byte b)
{
    if(!options.sound) return;

    if (!(R_NR52 & 128) && r != RI_NR52) return;
    if ((r & 0xF0) == 0x30)
    {
        if (S3.on) sound_mix();
        if (!S3.on) WAVE[r - 0x30] = b;
        return;
    }
    sound_mix();
    switch (r)
    {
    case RI_NR10:
        R_NR10 = b;
        break;
    case RI_NR11:
        R_NR11 = b;
        S1.len = (64-(R_NR11&63)) << 13;
        break;
    case RI_NR12:
        R_NR12 = b;
        S1.envol = R_NR12 >> 4;
        S1.endir = (R_NR12>>3) & 1;
        S1.endir |= S1.endir - 1;
        S1.enlen = (R_NR12 & 7) << 15;
        break;
    case RI_NR13:
        R_NR13 = b;
        s1_freq();
        break;
    case RI_NR14:
        R_NR14 = b;
        s1_freq();
        if (b & 128) s1_init();
        break;
    case RI_NR21:
        R_NR21 = b;
        S2.len = (64-(R_NR21&63)) << 13;
        break;
    case RI_NR22:
        R_NR22 = b;
        S2.envol = R_NR22 >> 4;
        S2.endir = (R_NR22>>3) & 1;
        S2.endir |= S2.endir - 1;
        S2.enlen = (R_NR22 & 7) << 15;
        break;
    case RI_NR23:
        R_NR23 = b;
        s2_freq();
        break;
    case RI_NR24:
        R_NR24 = b;
        s2_freq();
        if (b & 128) s2_init();
        break;
    case RI_NR30:
        R_NR30 = b;
        if (!(b & 128)) S3.on = 0;
        break;
    case RI_NR31:
        R_NR31 = b;
        S3.len = (256-R_NR31) << 20;
        break;
    case RI_NR32:
        R_NR32 = b;
        break;
    case RI_NR33:
        R_NR33 = b;
        s3_freq();
        break;
    case RI_NR34:
        R_NR34 = b;
        s3_freq();
        if (b & 128) s3_init();
        break;
    case RI_NR41:
        R_NR41 = b;
        S4.len = (64-(R_NR41&63)) << 13;
        break;
    case RI_NR42:
        R_NR42 = b;
        S4.envol = R_NR42 >> 4;
        S4.endir = (R_NR42>>3) & 1;
        S4.endir |= S4.endir - 1;
        S4.enlen = (R_NR42 & 7) << 15;
        break;
    case RI_NR43:
        R_NR43 = b;
        s4_freq();
        break;
    case RI_NR44:
        R_NR44 = b;
        if (b & 128) s4_init();
        break;
    case RI_NR50:
        R_NR50 = b;
        break;
    case RI_NR51:
        R_NR51 = b;
        break;
    case RI_NR52:
        R_NR52 = b;
        if (!(R_NR52 & 128))
            sound_reset();
        break;
    default:
        return;
    }
}