// Emacs style mode select   -*- C++ -*- 
//-----------------------------------------------------------------------------
//
// $Id:$
//
// Copyright (C) 1993-1996 by id Software, Inc.
//
// This source is available for distribution and/or modification
// only under the terms of the DOOM Source Code License as
// published by id Software. All rights reserved.
//
// The source is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// FITNESS FOR A PARTICULAR PURPOSE. See the DOOM Source Code License
// for more details.
//
// $Log:$
//
// DESCRIPTION:
//      System interface for sound.
//
//-----------------------------------------------------------------------------

static const char
rcsid[] = "$Id: i_unix.c,v 1.5 1997/02/03 22:45:10 b1 Exp $";

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>

#include <math.h>

#include <sys/types.h>

#include <fcntl.h>

// Timer stuff. Experimental.
#include <time.h>
#include <signal.h>

#include "z_zone.h"

#include "i_system.h"
#include "i_sound.h"
#include "m_argv.h"
#include "m_misc.h"
#include "w_wad.h"

#include "doomdef.h"

// The number of internal mixing channels,
//  the samples calculated for each mixing step,
//  the size of the 16bit, 2 hardware channel (stereo)
//  mixing buffer, and the samplerate of the raw data.


// Needed for calling the actual sound output.
#define SAMPLECOUNT             512
#define NUM_CHANNELS    16
// It is 2 for 16bit, and 2 for two channels.
#define BUFMUL                  4
#define MIXBUFFERSIZE           (SAMPLECOUNT*BUFMUL)

#define SAMPLERATE              11025   // Hz
#define SAMPLESIZE              2       // 16bit

// The actual lengths of all sound effects.
int             lengths[NUMSFX];

// The actual output device.
int     audio_fd;

// The global mixing buffer.
// Basically, samples from all active internal channels
//  are modifed and added, and stored in the buffer
//  that is submitted to the audio device.
signed short    mixbuffer[MIXBUFFERSIZE];


// The channel step amount...
unsigned int    channelstep[NUM_CHANNELS];
// ... and a 0.16 bit remainder of last step.
unsigned int    channelstepremainder[NUM_CHANNELS];


// The channel data pointers, start and end.
unsigned char*  channels[NUM_CHANNELS];
unsigned char*  channelsend[NUM_CHANNELS];


// Time/gametic that the channel started playing,
//  used to determine oldest, which automatically
//  has lowest priority.
// In case number of active sounds exceeds
//  available channels.
int             channelstart[NUM_CHANNELS];

// The sound in channel handles,
//  determined on registration,
//  might be used to unregister/stop/modify,
//  currently unused.
int             channelhandles[NUM_CHANNELS];

// SFX id of the playing sound effect.
// Used to catch duplicates (like chainsaw).
int             channelids[NUM_CHANNELS];                       

// Pitch to stepping lookup, unused.
int             steptable[256];

// Volume lookups.
int             vol_lookup[128*256];

// Hardware left and right channel volume lookup.
int*            channelleftvol_lookup[NUM_CHANNELS];
int*            channelrightvol_lookup[NUM_CHANNELS];


//
// This function loads the sound data from the WAD lump,
//  for single sound.
//
void* getsfx (char* sfxname, int* len)
{
  unsigned char*      sfx;
  unsigned char*      paddedsfx;
  int                 i;
  int                 size;
  int                 paddedsize;
  char                name[20];
  int                 sfxlump;

    
    // Get the sound data from the WAD, allocate lump
    //  in zone memory.
    sprintf(name, "ds%s", sfxname);

    // Now, there is a severe problem with the
    //  sound handling, in it is not (yet/anymore)
    //  gamemode aware. That means, sounds from
    //  DOOM II will be requested even with DOOM
    //  shareware.
    // The sound list is wired into sounds.c,
    //  which sets the external variable.
    // I do not do runtime patches to that
    //  variable. Instead, we will use a
    //  default sound for replacement.
    if ( W_CheckNumForName(name) == -1 )
      sfxlump = W_GetNumForName("dspistol");
    else
      sfxlump = W_GetNumForName(name);
    
    size = W_LumpLength( sfxlump );

    // Debug.
    // fprintf( stderr, "." );
    //fprintf( stderr, " -loading  %s (lump %d, %d bytes)\n",
    //       sfxname, sfxlump, size );
    //fflush( stderr );
    
    sfx = (unsigned char*)W_CacheLumpNum( sfxlump, PU_STATIC );

    // Pads the sound effect out to the mixing buffer size.
    // The original realloc would interfere with zone memory.
    paddedsize = ((size-8 + (SAMPLECOUNT-1)) / SAMPLECOUNT) * SAMPLECOUNT;

    // Allocate from zone memory.
    paddedsfx = (unsigned char*)Z_Malloc( paddedsize+8, PU_STATIC, 0 );
    // ddt: (unsigned char *) realloc(sfx, paddedsize+8);
    // This should interfere with zone memory handling,
    //  which does not kick in in the soundserver.

    // Now copy and pad.
    memcpy(  paddedsfx, sfx, size );
    for (i=size ; i<paddedsize+8 ; i++)
        paddedsfx[i] = 128;

    // Remove the cached lump.
    Z_Free( sfx );
    
    // Preserve padded length.
    *len = paddedsize;

    // Return allocated padded data.
    return (void *) (paddedsfx + 8);
}

//
// This function adds a sound to the
//  list of currently active sounds,
//  which is maintained as a given number
//  (eight, usually) of internal channels.
// Returns a handle.
//

static unsigned short   handlenums = 0;

int addsfx(int sfxid, int volume, int step, int seperation)
{

    int         i;
    int         rc = -1;
    
    int         oldest = gametic;
    int         oldestnum = 0;
    int         slot;

    int         rightvol;
    int         leftvol;

    // Chainsaw troubles.
    // Play these sound effects only one at a time.
    if ( sfxid == sfx_sawup
         || sfxid == sfx_sawidl
         || sfxid == sfx_sawful
         || sfxid == sfx_sawhit
         || sfxid == sfx_stnmov
         || sfxid == sfx_pistol  )
    {
        // Loop all channels, check.
        for (i=0 ; i<NUM_CHANNELS ; i++)
        {
            // Active, and using the same SFX?
            if ( (channels[i])
                 && (channelids[i] == sfxid) )
            {
                // Reset.
                channels[i] = 0;
                // We are sure that iff,
                //  there will only be one.
                break;
            }
        }
    }

    // Loop all channels to find oldest SFX.
    for (i=0; (i<NUM_CHANNELS) && (channels[i]); i++)
    {
        if (channelstart[i] < oldest)
        {
            oldestnum = i;
            oldest = channelstart[i];
        }
    }

    // Tales from the cryptic.
    // If we found a channel, fine.
    // If not, we simply overwrite the first one, 0.
    // Probably only happens at startup.
    if (i == NUM_CHANNELS)
        slot = oldestnum;
    else
        slot = i;

    // Okay, in the less recent channel,
    //  we will handle the new SFX.
    // Set pointer to raw data.
    channels[slot] = (unsigned char *) S_sfx[sfxid].data;
    // Set pointer to end of raw data.
    channelsend[slot] = channels[slot] + lengths[sfxid];

    // Reset current handle number, limited to 0..100.
    if (!handlenums)
        handlenums = 100;

    // Assign current handle number.
    // Preserved so sounds could be stopped (unused).
    channelhandles[slot] = rc = handlenums++;

    channelstep[slot] = step;
 
    channelstepremainder[slot] = 0;
    // Should be gametic, I presume.
    channelstart[slot] = gametic;

    // Separation, that is, orientation/stereo.
    //  range is: 1 - 256
    seperation += 1;
 
    volume *=7; 
    // Per left/right channel.
    //  x^2 seperation,
    //  adjust volume properly.
    leftvol =
        volume - ((volume*seperation*seperation) >> 16); ///(256*256);
    seperation = seperation - 257;
    rightvol =
        volume - ((volume*seperation*seperation) >> 16);        

    // Sanity check, clamp volume.
    if (rightvol < 0 || rightvol > 127)
        I_Error("rightvol out of bounds");
    
    if (leftvol < 0 || leftvol > 127)
        I_Error("leftvol out of bounds");
    
    // Get the proper lookup table piece
    //  for this volume level???
    channelleftvol_lookup[slot] = &vol_lookup[leftvol*256];
    channelrightvol_lookup[slot] = &vol_lookup[rightvol*256];

    // Preserve sound SFX id,
    //  e.g. for avoiding duplicates of chainsaw.
    channelids[slot] = sfxid;

    // You tell me.
    return rc;
}

//
// SFX API
// Note: this was called by S_Init.
// However, whatever they did in the
// old DPMS based DOS version, this
// were simply dummies in the Linux
// version.
// See soundserver initdata().
//
void I_SetChannels()
{
  // Init internal lookups (raw data, mixing buffer, channels).
  // This function sets up internal lookups used during
  //  the mixing process. 
  int           i;
  int           j;
    
  int*  steptablemid = steptable + 128;
  
  // Okay, reset internal mixing channels to zero.
  for (i=0; i<NUM_CHANNELS; i++)
  {
    channels[i] = 0;
  }

//  for (i=-128 ; i<128 ; i++)
//    steptablemid[i] = (int)(pow(2.0, (i/64.0))*65536.0);
  
  // Generates volume lookup tables
  //  which also turn the unsigned samples
  //  into signed samples.
  for (i=0 ; i<128 ; i++)
    for (j=0 ; j<256 ; j++)
      vol_lookup[i*256+j] = (i*(j-128)*256)/127;
}       

 
void I_SetSfxVolume(int volume)
{
  // Identical to DOS.
  // Basically, this should propagate
  //  the menu/config file setting
  //  to the state variable used in
  //  the mixing.
  snd_SfxVolume = volume;
}

// MUSIC API - dummy. Some code from DOS version.
void I_SetMusicVolume(int volume)
{
  // Internal state variable.
  snd_MusicVolume = volume;
}


//
// Retrieve the raw data lump index
//  for a given SFX name.
//
int I_GetSfxLumpNum(sfxinfo_t* sfx)
{
    char namebuf[9];
    sprintf(namebuf, "ds%s", sfx->name);
    return W_GetNumForName(namebuf);
}

//
// Starting a sound means adding it
//  to the current list of active sounds
//  in the internal channels.
// As the SFX info struct contains
//  e.g. a pointer to the raw data,
//  it is ignored.
// As our sound handling does not handle
//  priority, it is ignored.
// Pitching (that is, increased speed of playback)
//
int I_StartSound(int id, int vol, int sep,
                 int pitch, int priority )
{
    // Returns a handle (not used).
    id = addsfx( id, vol, steptable[pitch], sep );
    return id;
}

void I_StopSound (int handle)
{
  // You need the handle returned by StartSound.
  // Would be looping all channels,
  //  tracking down the handle,
  //  an setting the channel to zero.
  
  // UNUSED.
  handle = 0;
}


int I_SoundIsPlaying(int handle)
{
    // Ouch.
    return gametic < handle;
}

//
// This function loops all active (internal) sound
//  channels, retrieves a given number of samples
//  from the raw sound data, modifies it according
//  to the current (internal) channel parameters,
//  mixes the per channel samples into the global
//  mixbuffer, clamping it to the allowed range,
//  and sets up everything for transferring the
//  contents of the mixbuffer to the (two)
//  hardware channels (left and right, that is).
//
// This function currently supports only 16bit.
//
void I_UpdateSound( void )
{
  
  // Mix current sound data.
  // Data, from raw sound, for right and left.
  register unsigned int sample;
  register int          dl;
  register int          dr;
  
  // Pointers in global mixbuffer, left, right, end.
  signed short*         leftout;
  signed short*         rightout;
  signed short*         leftend;
  // Step in mixbuffer, left and right, thus two.
  int                           step;

  // Mixing channel index.
  int                           chan;
    
    // Left and right channel
    //  are in global mixbuffer, alternating.
    leftout = mixbuffer;
    rightout = mixbuffer+1;
    step = 2;

    // Determine end, for left channel only
    //  (right channel is implicit).
    leftend = mixbuffer + SAMPLECOUNT*step;

    // Mix sounds into the mixing buffer.
    // Loop over step*SAMPLECOUNT,
    //  that is 512 values for two channels.
    while (leftout != leftend)
    {
        // Reset left/right value. 
        dl = 0;
        dr = 0;

        // Love thy L2 chache - made this a loop.
        // Now more channels could be set at compile time
        //  as well. Thus loop those  channels.
        for ( chan = 0; chan < NUM_CHANNELS; chan++ )
        {
            // Check channel, if active.
            if (channels[ chan ])
            {
                // Get the raw data from the channel. 
                sample = *channels[ chan ];
                // Add left and right part
                //  for this channel (sound)
                //  to the current data.
                // Adjust volume accordingly.
                dl += channelleftvol_lookup[ chan ][sample];
                dr += channelrightvol_lookup[ chan ][sample];
        
                channelstepremainder[ chan ] += channelstep[ chan ];
        
                channels[ chan ] += channelstepremainder[ chan ] >> 16;
        
                channelstepremainder[ chan ] &= 65536-1;

                // Check whether we are done.
                if (channels[ chan ] >= channelsend[ chan ])
                    channels[ chan ] = 0;
            }
        }
        
        // Clamp to range. Left hardware channel.
        // Has been char instead of short.
        // if (dl > 127) *leftout = 127;
        // else if (dl < -128) *leftout = -128;
        // else *leftout = dl;

        if (dl > 0x7fff)
            *leftout = 0x7fff;
        else if (dl < -0x8000)
            *leftout = -0x8000;
        else
            *leftout = dl;

        // Same for right hardware channel.
        if (dr > 0x7fff)
            *rightout = 0x7fff;
        else if (dr < -0x8000)
            *rightout = -0x8000;
        else
            *rightout = dr;

        // Increment current pointers in mixbuffer.
        leftout += step;
        rightout += step;
    }
 //   I_SubmitSound(mixbuffer);
}


// 
// This would be used to write out the mixbuffer
//  during each game loop update.
// Updates sound buffer and audio device at runtime. 
// It is called during Timer interrupt with SNDINTR.
// Mixing now done synchronous, and
//  only output be done asynchronous?
//
//void I_SubmitSound(void)
//{
  // Write it to DSP device.
//  write(audio_fd, mixbuffer, SAMPLECOUNT*BUFMUL);
//}


void I_UpdateSoundParams(int handle, int vol, int sep, int pitch)
{
  // I fail too see that this is used.
  // Would be using the handle to identify
  //  on which channel the sound might be active,
  //  and resetting the channel parameters.

  // UNUSED.
  handle = vol = sep = pitch = 0;
}

void I_ShutdownSound(void)
{    
  // Wait till all pending sounds are finished.
  int done = 0;
  int i;
  
  // FIXME (below).
  printf( "I_ShutdownSound: NOT finishing pending sounds\n");
  
  while ( !done )
  {
    for( i=0 ; i<8 && !channels[i] ; i++);
    
    // FIXME. No proper channel output.
    //if (i==8)
    done=1;
  }
  return;
}

void I_InitSound()
{ int i;

  printf("I_InitSound: ");
  
  for (i=1 ; i<NUMSFX ; i++)
  { 
    // Alias? Example is the chaingun sound linked to pistol.
    if (!S_sfx[i].link)
    {
      // Load data from WAD file.
      S_sfx[i].data = getsfx( S_sfx[i].name, &lengths[i] );
    }   
    else
    {
      // Previously loaded already?
      S_sfx[i].data = S_sfx[i].link->data;
      lengths[i] = lengths[(S_sfx[i].link - S_sfx)/sizeof(sfxinfo_t)];
    }
  }

  printf( " pre-cached all sound data\n");
  
  // Now initialize mixbuffer with zero.
  for ( i = 0; i< MIXBUFFERSIZE; i++ )
    mixbuffer[i] = 0;
  
  // Finished initialization.
  printf("I_InitSound: sound module ready\n");
    
}


//
// MUSIC API.
// Still no music done.
// Remains. Dummies.
//
void I_InitMusic(void)          { }
void I_ShutdownMusic(void)      { }

static int      looping=0;
static int      musicdies=-1;

void I_PlaySong(int handle, int looping)
{
  // UNUSED.
  handle = looping = 0;
  musicdies = gametic + TICRATE*30;
}

void I_PauseSong (int handle)
{
  // UNUSED.
  handle = 0;
}

void I_ResumeSong (int handle)
{
  // UNUSED.
  handle = 0;
}

void I_StopSong(int handle)
{
  // UNUSED.
  handle = 0;
  
  looping = 0;
  musicdies = 0;
}

void I_UnRegisterSong(int handle)
{
  // UNUSED.
  handle = 0;
}

int I_RegisterSong(void* data)
{
  // UNUSED.
  data = NULL;
  
  return 1;
}

// Is the song playing?
int I_QrySongPlaying(int handle)
{
  // UNUSED.
  handle = 0;
  return looping || musicdies > gametic;
}


// Interrupt handler.
void I_HandleSoundTimer( int ignore )
{
   
  // UNUSED, but required.
  ignore = 0;
  return;
}