// This is part of Pico Library

// (c) Copyright 2004 Dave, All rights reserved.
// (c) Copyright 2006,2007 notaz, All rights reserved.
// Free for non-commercial use.

// For commercial use, separate licencing terms must be obtained.


#include <string.h>
#include "ym2612.h"
#include "sn76496.h"
#include "../pico_int.h"
#include "../cd/pcm.h"
#include "mix.h"

void (*PsndMix_32_to_16l)(short *dest, int *src, int count) = mix_32_to_16l_stereo;

// master int buffer to mix to
static int PsndBuffer[2*(44100+100)/50];

// dac
static unsigned short dac_info[312+4]; // pppppppp ppppllll, p - pos in buff, l - length to write for this sample

// cdda output buffer
short cdda_out_buffer[2*1152];

// for Pico
int PsndRate=0;
int PsndLen=0; // number of mono samples, multiply by 2 for stereo
int PsndLen_exc_add=0; // this is for non-integer sample counts per line, eg. 22050/60
int PsndLen_exc_cnt=0;
int PsndDacLine=0;
short *PsndOut=NULL; // PCM data buffer

// timers
int timer_a_next_oflow, timer_a_step; // in z80 cycles
int timer_b_next_oflow, timer_b_step;

// sn76496
extern int *sn76496_regs;


static void dac_recalculate(void)
{
  int i, dac_cnt, pos, len, lines = Pico.m.pal ? 312 : 262, mid = Pico.m.pal ? 68 : 93;

  if (PsndLen <= lines)
  {
    // shrinking algo
    dac_cnt = -PsndLen;
    len=1; pos=0;
    dac_info[225] = 1;

    for(i=226; i != 225; i++)
    {
      if (i >= lines) i = 0;
      len = 0;
      if(dac_cnt < 0) {
        len=1;
        pos++;
        dac_cnt += lines;
      }
      dac_cnt -= PsndLen;
      dac_info[i] = (pos<<4)|len;
    }
  }
  else
  {
    // stretching
    dac_cnt = PsndLen;
    pos=0;
    for(i = 225; i != 224; i++)
    {
      if (i >= lines) i = 0;
      len=0;
      while(dac_cnt >= 0) {
        dac_cnt -= lines;
        len++;
      }
      if (i == mid) // midpoint
        while(pos+len < PsndLen/2) {
          dac_cnt -= lines;
          len++;
        }
      dac_cnt += PsndLen;
      dac_info[i] = (pos<<4)|len;
      pos+=len;
    }
    // last sample
    for(len = 0, i = pos; i < PsndLen; i++) len++;
    if (PsndLen_exc_add) len++;
    dac_info[224] = (pos<<4)|len;
  }
  mid = (dac_info[lines-1] & 0xfff0) + ((dac_info[lines-1] & 0xf) << 4);
  for (i = lines; i < sizeof(dac_info) / sizeof(dac_info[0]); i++)
    dac_info[i] = mid;
  //for(i=len=0; i < lines; i++) {
  //  printf("%03i : %03i : %i\n", i, dac_info[i]>>4, dac_info[i]&0xf);
  //  len+=dac_info[i]&0xf;
  //}
  //printf("rate is %i, len %f\n", PsndRate, (double)PsndRate/(Pico.m.pal ? 50.0 : 60.0));
  //printf("len total: %i, last pos: %i\n", len, pos);
  //exit(8);
}


PICO_INTERNAL void PsndReset(void)
{
  void *ym2612_regs;

  // also clear the internal registers+addr line
  ym2612_regs = YM2612GetRegs();
  memset(ym2612_regs, 0, 0x200+4);
  timers_reset();

  PsndRerate(0);
}


// to be called after changing sound rate or chips
void PsndRerate(int preserve_state)
{
  void *state = NULL;
  int target_fps = Pico.m.pal ? 50 : 60;

  // not all rates are supported in MCD mode due to mp3 decoder limitations
  if (PicoAHW & PAHW_MCD) {
    if (!(11025-100 <= PsndRate && PsndRate <= 11025+100) &&
        !(22050-100 <= PsndRate && PsndRate <= 22050+100) &&
        !(44100-100 <= PsndRate && PsndRate <= 44100+100))
      PsndRate = 22050;
    PicoOpt |= POPT_EN_STEREO; // force stereo
  }

  if (preserve_state) {
    state = malloc(0x204);
    if (state == NULL) return;
    ym2612_pack_state();
    memcpy(state, YM2612GetRegs(), 0x204);
  }
  YM2612Init(Pico.m.pal ? OSC_PAL/7 : OSC_NTSC/7, PsndRate);
  if (preserve_state) {
    // feed it back it's own registers, just like after loading state
    memcpy(YM2612GetRegs(), state, 0x204);
    ym2612_unpack_state();
    if ((PicoAHW & PAHW_MCD) && !(Pico_mcd->s68k_regs[0x36] & 1) && (Pico_mcd->scd.Status_CDC & 1))
      cdda_start_play();
  }

  if (preserve_state) memcpy(state, sn76496_regs, 28*4); // remember old state
  SN76496_init(Pico.m.pal ? OSC_PAL/15 : OSC_NTSC/15, PsndRate);
  if (preserve_state) memcpy(sn76496_regs, state, 28*4); // restore old state

  if (state)
    free(state);

  // calculate PsndLen
  PsndLen=PsndRate / target_fps;
  PsndLen_exc_add=((PsndRate - PsndLen*target_fps)<<16) / target_fps;
  PsndLen_exc_cnt=0;

  // recalculate dac info
  dac_recalculate();

  if (PicoAHW & PAHW_MCD)
    pcm_set_rate(PsndRate);

  // clear all buffers
  memset32(PsndBuffer, 0, sizeof(PsndBuffer)/4);
  memset(cdda_out_buffer, 0, sizeof(cdda_out_buffer));
  if (PsndOut)
    PsndClear();

  // set mixer
  PsndMix_32_to_16l = (PicoOpt & POPT_EN_STEREO) ? mix_32_to_16l_stereo : mix_32_to_16_mono;

  if (PicoAHW & PAHW_PICO)
    PicoReratePico();
}


PICO_INTERNAL void PsndDoDAC(int line_to)
{
  int pos, pos1, len;
  int dout = ym2612.dacout;
  int line_from = PsndDacLine;

  PsndDacLine = line_to + 1;

  pos =dac_info[line_from]>>4;
  pos1=dac_info[line_to];
  len = ((pos1>>4)-pos) + (pos1&0xf);
  if (!len) return;

  if (PicoOpt & POPT_EN_STEREO) {
    short *d = PsndOut + pos*2;
    for (; len > 0; len--, d+=2) *d = dout;
  } else {
    short *d = PsndOut + pos;
    for (; len > 0; len--, d++)  *d = dout;
  }

#if 0
  if (do_pcm) {
    int *d = PsndBuffer;
    d += (PicoOpt&8) ? pos*2 : pos;
    pcm_update(d, len, 1);
  }
#endif
}

// cdda
static pm_file *cdda_stream = NULL;

static void cdda_raw_update(int *buffer, int length)
{
  int ret, cdda_bytes, mult = 1;
  if (cdda_stream == NULL)
    return;

  cdda_bytes = length*4;
  if (PsndRate <= 22050 + 100) mult = 2;
  if (PsndRate <  22050 - 100) mult = 4;
  cdda_bytes *= mult;

  ret = pm_read(cdda_out_buffer, cdda_bytes, cdda_stream);
  if (ret < cdda_bytes) {
    memset((char *)cdda_out_buffer + ret, 0, cdda_bytes - ret);
    cdda_stream = NULL;
    return;
  }

  // now mix
  switch (mult) {
    case 1: mix_16h_to_32(buffer, cdda_out_buffer, length*2); break;
    case 2: mix_16h_to_32_s1(buffer, cdda_out_buffer, length*2); break;
    case 4: mix_16h_to_32_s2(buffer, cdda_out_buffer, length*2); break;
  }
}

PICO_INTERNAL void cdda_start_play(void)
{
  int lba_offset, index, lba_length, i;

  elprintf(EL_STATUS, "cdda play track #%i", Pico_mcd->scd.Cur_Track);

  index = Pico_mcd->scd.Cur_Track - 1;

  lba_offset = Pico_mcd->scd.Cur_LBA - Track_to_LBA(index + 1);
  if (lba_offset < 0) lba_offset = 0;
  lba_offset += Pico_mcd->TOC.Tracks[index].Offset;

  // find the actual file for this track
  for (i = index; i >= 0; i--)
    if (Pico_mcd->TOC.Tracks[i].F != NULL) break;

  if (Pico_mcd->TOC.Tracks[i].F == NULL) {
    elprintf(EL_STATUS|EL_ANOMALY, "no track?!");
    return;
  }

  if (Pico_mcd->TOC.Tracks[i].ftype == TYPE_MP3)
  {
    int pos1024 = 0;

    lba_length = Pico_mcd->TOC.Tracks[i].Length;
    for (i++; i < Pico_mcd->TOC.Last_Track; i++) {
      if (Pico_mcd->TOC.Tracks[i].F != NULL) break;
      lba_length += Pico_mcd->TOC.Tracks[i].Length;
    }

    if (lba_offset)
      pos1024 = lba_offset * 1024 / lba_length;

    mp3_start_play(Pico_mcd->TOC.Tracks[index].F, pos1024);
    return;
  }

  cdda_stream = Pico_mcd->TOC.Tracks[i].F;
  PicoCDBufferFlush(); // buffering relies on fp not being touched
  pm_seek(cdda_stream, lba_offset * 2352, SEEK_SET);
  if (Pico_mcd->TOC.Tracks[i].ftype == TYPE_WAV)
  {
    // skip headers, assume it's 44kHz stereo uncompressed
    pm_seek(cdda_stream, 44, SEEK_CUR);
  }
}


PICO_INTERNAL void PsndClear(void)
{
  int len = PsndLen;
  if (PsndLen_exc_add) len++;
  if (PicoOpt & POPT_EN_STEREO)
    memset32((int *) PsndOut, 0, len); // assume PsndOut to be aligned
  else {
    short *out = PsndOut;
    if ((int)out & 2) { *out++ = 0; len--; }
    memset32((int *) out, 0, len/2);
    if (len & 1) out[len-1] = 0;
  }
}


static int PsndRender(int offset, int length)
{
  int  buf32_updated = 0;
  int *buf32 = PsndBuffer+offset;
  int stereo = (PicoOpt & 8) >> 3;
  // emulating CD && PCM option enabled && PCM chip on && have enabled channels
  int do_pcm = (PicoAHW & PAHW_MCD) && (PicoOpt&POPT_EN_MCD_PCM) &&
		(Pico_mcd->pcm.control & 0x80) && Pico_mcd->pcm.enabled;
  offset <<= stereo;

#if !SIMPLE_WRITE_SOUND
  if (offset == 0) { // should happen once per frame
    // compensate for float part of PsndLen
    PsndLen_exc_cnt += PsndLen_exc_add;
    if (PsndLen_exc_cnt >= 0x10000) {
      PsndLen_exc_cnt -= 0x10000;
      length++;
    }
  }
#endif

  // PSG
  if (PicoOpt & POPT_EN_PSG)
    SN76496Update(PsndOut+offset, length, stereo);

  if (PicoAHW & PAHW_PICO) {
    PicoPicoPCMUpdate(PsndOut+offset, length, stereo);
    return length;
  }

  // Add in the stereo FM buffer
  if (PicoOpt & POPT_EN_FM) {
    buf32_updated = YM2612UpdateOne(buf32, length, stereo, 1);
  } else
    memset32(buf32, 0, length<<stereo);

//printf("active_chs: %02x\n", buf32_updated);

  // CD: PCM sound
  if (do_pcm) {
    pcm_update(buf32, length, stereo);
    //buf32_updated = 1;
  }

  // CD: CDDA audio
  // CD mode, cdda enabled, not data track, CDC is reading
  if ((PicoAHW & PAHW_MCD) && (PicoOpt & POPT_EN_MCD_CDDA) &&
		!(Pico_mcd->s68k_regs[0x36] & 1) && (Pico_mcd->scd.Status_CDC & 1))
  {
    // note: only 44, 22 and 11 kHz supported, with forced stereo
    int index = Pico_mcd->scd.Cur_Track - 1;

    if (Pico_mcd->TOC.Tracks[index].ftype == TYPE_MP3)
      mp3_update(buf32, length, stereo);
    else
      cdda_raw_update(buf32, length);
  }

  // convert + limit to normal 16bit output
  PsndMix_32_to_16l(PsndOut+offset, buf32, length);

  return length;
}

// to be called on 224 or line_sample scanlines only
PICO_INTERNAL void PsndGetSamples(int y)
{
#if SIMPLE_WRITE_SOUND
  if (y != 224) return;
  PsndRender(0, PsndLen);
  if (PicoWriteSound) PicoWriteSound(PsndLen);
  PsndClear();
#else
  static int curr_pos = 0;

  if (y == 224)
  {
    if (emustatus & 2)
         curr_pos += PsndRender(curr_pos, PsndLen-PsndLen/2);
    else curr_pos  = PsndRender(0, PsndLen);
    if (emustatus&1) emustatus|=2; else emustatus&=~2;
    if (PicoWriteSound) PicoWriteSound(curr_pos);
    // clear sound buffer
    PsndClear();
  }
  else if (emustatus & 3) {
    emustatus|= 2;
    emustatus&=~1;
    curr_pos = PsndRender(0, PsndLen/2);
  }
#endif
}

PICO_INTERNAL void PsndGetSamplesMS(void)
{
  int *buf32 = PsndBuffer;
  int stereo = (PicoOpt & 8) >> 3;
  int length = PsndLen;

#if !SIMPLE_WRITE_SOUND
  // compensate for float part of PsndLen
  PsndLen_exc_cnt += PsndLen_exc_add;
  if (PsndLen_exc_cnt >= 0x10000) {
    PsndLen_exc_cnt -= 0x10000;
    length++;
  }
#endif

  // PSG
  if (PicoOpt & POPT_EN_PSG)
    SN76496Update(PsndOut, length, stereo);

  // convert + limit to normal 16bit output
  PsndMix_32_to_16l(PsndOut, buf32, length);

  if (PicoWriteSound != NULL)
    PicoWriteSound(length);
  PsndClear();
}