/*
 * This is an alternate backend for the sound effect system.
 * It uses SDL_mixer to provide a more reliable playback,
 * and allow processing of multiple audio formats.
 *
 * This file is based on the original D1X arch/sdl/digi.c
 *
 *  -- MD2211 (2006-10-12)
 */

#ifdef HAVE_CONFIG_H
#include <conf.h>
#endif

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

#include <SDL/SDL.h>
#include <SDL/SDL_audio.h>
#include <SDL/SDL_mixer.h>

#include "types.h"
#include "error.h"
#include "mono.h"
#include "fix.h"
#include "digi.h"
#include "sounds.h"
#include "mixmusic.h"

#define MIX_DIGI_DEBUG 0

#define MIX_OUTPUT_FREQUENCY	44100	// in 2006, we can afford it! 
#define MIX_OUTPUT_FORMAT	AUDIO_S16
#define MIX_OUTPUT_CHANNELS	2

int digi_sample_rate = 11025; //SAMPLE_RATE_11K;

//edited 05/17/99 Matt Mueller - added ifndef NO_ASM
//added on 980905 by adb to add inline fixmul for mixer on i386
#ifndef NO_ASM
#ifdef __i386__
#define do_fixmul(x,y)				\
({						\
	int _ax, _dx;				\
	asm("imull %2\n\tshrdl %3,%1,%0"	\
	    : "=a"(_ax), "=d"(_dx)		\
	    : "rm"(y), "i"(16), "0"(x));	\
	_ax;					\
})
extern inline fix fixmul(fix x, fix y) { return do_fixmul(x,y); }
#endif
#endif
//end edit by adb
//end edit -MM

#define MAX_SOUND_SLOTS 32
#define SOUND_BUFFER_SIZE 512
#define MIN_VOLUME 10

//added/changed on 980905 by adb to make sfx volume work, on 990221 by adb changed F1_0 to F1_0 / 2
#define SOUND_MAX_VOLUME (F1_0 / 2)
int digi_volume = SOUND_MAX_VOLUME;
//end edit by adb

static int digi_initialised = 0;
static int digi_max_channels = MAX_SOUND_SLOTS;
inline int fix2byte(fix f) { return (f / 256) % 256; }
Mix_Chunk SoundChunks[MAX_SOUNDS];


/* Initialise audio */
int digi_init() {
  if (MIX_DIGI_DEBUG) printf("digi_init %d (SDL_Mixer)\n", MAX_SOUNDS);
  if (SDL_InitSubSystem(SDL_INIT_AUDIO) < 0) Error("SDL audio initialisation failed: %s.", SDL_GetError());

  if (Mix_OpenAudio(MIX_OUTPUT_FREQUENCY, MIX_OUTPUT_FORMAT, MIX_OUTPUT_CHANNELS, SOUND_BUFFER_SIZE)) {
    //edited on 10/05/98 by Matt Mueller - should keep running, just with no sound.
    printf("\nError: Couldn't open audio: %s\n", SDL_GetError());
    return 1;
  }

  Mix_AllocateChannels(digi_max_channels);
  Mix_Pause(0);

  atexit(digi_close);
  digi_initialised = 1;
  return 0;
}

/* Shut down audio */
void digi_close() {
  if (!digi_initialised) return;
  digi_initialised = 0;
  Mix_CloseAudio();
}

/*
 * Play-time conversion. Performs output conversion only once per sound effect used.
 * Once the sound sample has been converted, it is cached in SoundChunks[]
 */
void mixdigi_convert_sound(int i) {

  SDL_AudioCVT cvt;
  Uint8 *data = GameSounds[i].data;
  Uint32 dlen = GameSounds[i].length;
  int freq = GameSounds[i].freq;
  //int bits = GameSounds[i].bits;

  if (SoundChunks[i].abuf) return; //proceed only if not converted yet

  if (data) {
    if (MIX_DIGI_DEBUG) printf("converting %d (%d)\n", i, dlen);
    SDL_BuildAudioCVT(&cvt, AUDIO_U8, 1, freq, MIX_OUTPUT_FORMAT, MIX_OUTPUT_CHANNELS, MIX_OUTPUT_FREQUENCY);

    cvt.buf = malloc(dlen * cvt.len_mult);
    cvt.len = dlen;
    memcpy(cvt.buf, data, dlen);
    if (SDL_ConvertAudio(&cvt)) printf("conversion of %d failed\n", i);

    SoundChunks[i].abuf = cvt.buf;
    SoundChunks[i].alen = dlen * cvt.len_mult;
    SoundChunks[i].allocated = 1;
    SoundChunks[i].volume = 128; // Max volume = 128
  }
}

// Volume 0-F1_0
int digi_start_sound(short soundnum, fix volume, int pan, int looping, int loop_start, int loop_end, int soundobj)
{
  if (!digi_initialised) return -1;
  Assert(GameSounds[soundnum].data != (void *)-1);

  mixdigi_convert_sound(soundnum);

  int mix_vol = fix2byte(fixmul(digi_volume, volume));
  int mix_pan = fix2byte(pan);
  int mix_loop = looping * -1;

  if (MIX_DIGI_DEBUG) printf("digi_start_sound %d, volume %d, pan %d (start=%d, end=%d)\n", soundnum, mix_vol, mix_pan, loop_start, loop_end);

  int channel = Mix_PlayChannel(-1, &(SoundChunks[soundnum]), mix_loop);
  Mix_SetPanning(channel, 255-mix_pan, mix_pan);
  Mix_SetDistance(channel, 255-mix_vol);

  return channel;
}

void digi_set_channel_volume(int channel, int volume) {
  int mix_vol = fix2byte(volume);
  Mix_SetDistance(channel, 255-mix_vol);
}

void digi_set_channel_pan(int channel, int pan) {
  int mix_pan = fix2byte(pan);
  Mix_SetPanning(channel, 255-mix_pan, mix_pan);
}

void digi_stop_sound(int channel) {
  if (MIX_DIGI_DEBUG) printf("digi_stop_sound %d\n", channel);
  Mix_HaltChannel(channel);
}

void digi_end_sound(int channel) {
  digi_stop_sound(channel);
}

//added on 980905 by adb from original source to make sfx volume work
void digi_set_digi_volume( int dvolume )
{
	dvolume = fixmuldiv( dvolume, SOUND_MAX_VOLUME, 0x7fff);
	if ( dvolume > SOUND_MAX_VOLUME )
		digi_volume = SOUND_MAX_VOLUME;
	else if ( dvolume < 0 )
		digi_volume = 0;
	else
		digi_volume = dvolume;

	if ( !digi_initialised ) return;

	digi_sync_sounds();
}
//end edit by adb

void digi_set_volume( int dvolume, int mvolume ) {
  digi_set_digi_volume(dvolume);
  digi_set_midi_volume(mvolume);
}


int digi_find_channel(int soundno) { return 0; }
int digi_is_sound_playing(int soundno) { return 0; }
int digi_is_channel_playing(int channel) { return 0; }

void digi_reset() {}
void digi_stop_all_channels() {}

extern void digi_end_soundobj(int channel);	
int verify_sound_channel_free(int channel);

 //added on 980905 by adb to make sound channel setting work
void digi_set_max_channels(int n) { }
int digi_get_max_channels() { return digi_max_channels; }
// end edit by adb


// MIDI stuff follows.

#ifndef _WIN32
void digi_set_midi_volume( int mvolume ) { 
  mix_set_music_volume(mvolume);
}
void digi_play_midi_song( char * filename, char * melodic_bank, char * drum_bank, int loop ) {
  mix_play_music(filename, loop);
}
void digi_stop_current_song() {
  mix_stop_music();
}
#endif

void digi_pause_midi() {}
void digi_resume_midi() {}

#ifndef NDEBUG
void digi_debug() {}
#endif