#include "global.h"
#include "RageSoundDriver_OSS.h"

#include "RageLog.h"
#include "RageSound.h"
#include "RageSoundManager.h"
#include "RageUtil.h"

#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/soundcard.h>
#include <sys/select.h>

/* samples */
const int channels = 2;
const int bytes_per_frame = channels*2;		/* 16-bit */
const int chunk_order = 12;
const int num_chunks = 4;
const int buffersize = num_chunks * (1 << (chunk_order-1)); /* in bytes */
const int buffersize_frames = buffersize/bytes_per_frame;	/* in frames */

int RageSound_OSS::MixerThread_start(void *p)
{
	((RageSound_OSS *) p)->MixerThread();
	return 0;
}

void RageSound_OSS::MixerThread()
{
	/* We want to set a higher priority, but Unix only lets root renice
	 * < 0, which is silly.  Give it a try, anyway. */
	nice( -10 );

	while( !shutdown )
	{
		while(GetData())
			;

		fd_set f;
		FD_ZERO(&f);
		FD_SET(fd, &f);

		usleep( 10000 );

		struct timeval tv = { 0, 10000 };
		select(fd+1, NULL, &f, NULL, &tv);
	}
}

void RageSound_OSS::SetupDecodingThread()
{
	nice( -5 );
}

bool RageSound_OSS::GetData()
{
	/* Look for a free buffer. */
	audio_buf_info ab;
	if( ioctl(fd, SNDCTL_DSP_GETOSPACE, &ab) == -1 )
		RageException::Throw("ioctl(SNDCTL_DSP_GETOSPACE): %s", strerror(errno) );

	if( !ab.fragments )
		return false;
		
	const int chunksize = ab.fragsize;
	
	static int16_t *buf = NULL;
	if(!buf)
		buf = new int16_t[chunksize / sizeof(int16_t)];

	this->Mix( buf, chunksize/bytes_per_frame, last_cursor_pos, GetPosition( NULL ) );

	int wrote = write( fd, buf, chunksize );
  	if( wrote != chunksize )
		RageException::Throw( "write didn't: %i (%s)", wrote, wrote == -1? strerror(errno): "" );

	/* Increment last_cursor_pos. */
	last_cursor_pos += chunksize / bytes_per_frame;

	return true;
}

/* XXX: There's a race on last_cursor_pos here: new data might be written after the
 * ioctl returns, incrementing last_cursor_pos. */
int64_t RageSound_OSS::GetPosition(const RageSoundBase *snd) const
{
	ASSERT( fd != -1 );
	
	int delay;
	if(ioctl(fd, SNDCTL_DSP_GETODELAY, &delay) == -1)
		RageException::Throw("RageSound_OSS: ioctl(SNDCTL_DSP_GETODELAY): %s", strerror(errno));

	return last_cursor_pos - (delay / bytes_per_frame);
}

RString RageSound_OSS::CheckOSSVersion( int fd )
{
	int version = 0;

#if defined(HAVE_OSS_GETVERSION)
	if( ioctl(fd, OSS_GETVERSION, &version) != 0 )
	{
		LOG->Warn( "OSS_GETVERSION failed: %s", strerror(errno) );
		version = 0;
	}
#endif

	/*
	 * Find out if /dev/dsp is really ALSA emulating it.  ALSA's OSS emulation has
	 * been buggy.  If we got here, we probably failed to init ALSA.  The only case
	 * I've seen of this so far was not having access to /dev/snd devices.
	 */
	/* Reliable but only too recently available:
	if (ioctl(fd, OSS_ALSAEMULVER, &ver) == 0 && ver ) */

	/*
	 * Ack.  We can't just check for /proc/asound, since a few systems have ALSA
	 * loaded but actually use OSS.  ALSA returns a specific version; check that,
	 * too.  It looks like that version is potentially a valid OSS version, so
	 * check both.
	 */
#ifndef FORCE_OSS
#define ALSA_SNDRV_OSS_VERSION         ((3<<16)|(8<<8)|(1<<4)|(0))
	if( version == ALSA_SNDRV_OSS_VERSION && IsADirectory("/rootfs/proc/asound") )
		return "RageSound_OSS: ALSA detected.  ALSA OSS emulation is buggy; use ALSA natively.";
#endif
	if( version )
	{
		int major, minor, rev;
		if( version < 361 )
		{
			major = (version/100)%10;
			minor = (version/10) %10;
			rev =   (version/1)  %10;
		} else {
			major = (version/0x10000) % 0x100;
			minor = (version/0x00100) % 0x100;
			rev =   (version/0x00001) % 0x100;
		}

		LOG->Info("OSS: %i.%i.%i", major, minor, rev );
	}

	return "";
}

RageSound_OSS::RageSound_OSS()
{
	fd = -1;
	shutdown = false;
	last_cursor_pos = 0;
}

RString RageSound_OSS::Init()
{
	fd = open("/dev/dsp", O_WRONLY|O_NONBLOCK);
	if( fd == -1 )
		return ssprintf( "RageSound_OSS: Couldn't open /dev/dsp: %s", strerror(errno) );

	RString sError = CheckOSSVersion( fd );
	if( sError != "" )
		return sError;

	int i = AFMT_S16_LE;
	if(ioctl(fd, SNDCTL_DSP_SETFMT, &i) == -1)
		return ssprintf( "RageSound_OSS: ioctl(SNDCTL_DSP_SETFMT, %i): %s", i, strerror(errno) );
	if(i != AFMT_S16_LE)
		return ssprintf( "RageSound_OSS: Wanted format %i, got %i instead", AFMT_S16_LE, i );

	i = channels;
	if(ioctl(fd, SNDCTL_DSP_CHANNELS, &i) == -1)
		return ssprintf( "RageSound_OSS: ioctl(SNDCTL_DSP_CHANNELS, %i): %s", i, strerror(errno) );
	if(i != channels)
		return ssprintf( "RageSound_OSS: Wanted %i channels, got %i instead", channels, i );
		
	i = 44100;
	if(ioctl(fd, SOUND_PCM_WRITE_RATE, &i) == -1 )
		return ssprintf( "RageSound_OSS: ioctl(SOUND_PCM_WRITE_RATE, %i): %s", i, strerror(errno) );
	samplerate = i;
	LOG->Trace("RageSound_OSS: sample rate %i", samplerate);
	i = (num_chunks << 16) + chunk_order;
	if(ioctl(fd, SNDCTL_DSP_SETFRAGMENT, &i) == -1)
		return ssprintf( "RageSound_OSS: ioctl(SNDCTL_DSP_SETFRAGMENT, %i): %s", i, strerror(errno) );
	StartDecodeThread();
	
	MixingThread.SetName( "RageSound_OSS" );
	MixingThread.Create( MixerThread_start, this );

	return "";
}

RageSound_OSS::~RageSound_OSS()
{
	if( MixingThread.IsCreated() )
	{
		/* Signal the mixing thread to quit. */
		shutdown = true;
		LOG->Trace("Shutting down mixer thread ...");
		MixingThread.Wait();
		LOG->Trace("Mixer thread shut down.");
	}

	if( fd != -1 )
		close( fd );
}

float RageSound_OSS::GetPlayLatency() const
{
	return 0; // (1.0f / samplerate) * (buffersize_frames - chunksize_frames);
}

/*
 * (c) 2002-2004 Glenn Maynard
 * All rights reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, and/or sell copies of the Software, and to permit persons to
 * whom the Software is furnished to do so, provided that the above
 * copyright notice(s) and this permission notice appear in all copies of
 * the Software and that both the above copyright notice(s) and this
 * permission notice appear in supporting documentation.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF
 * THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS
 * INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT
 * OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
 * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */
