/*****************************************************************************\
     Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.
                This file is licensed under the Snes9x License.
   For further information, consult the LICENSE file in the root directory.
\*****************************************************************************/

#include <math.h>
#include "../snes9x.h"
#include "apu.h"
#include "../msu1.h"
#include "../snapshot.h"
#include "../display.h"
#include "hermite_resampler.h"

#include "bapu/snes/snes.hpp"

#define APU_DEFAULT_INPUT_RATE		31950 // ~ 59.94Hz
#define APU_MINIMUM_SAMPLE_COUNT	512
#define APU_MINIMUM_SAMPLE_BLOCK	128
#define APU_NUMERATOR_NTSC			15664
#define APU_DENOMINATOR_NTSC		328125
#define APU_NUMERATOR_PAL			34176
#define APU_DENOMINATOR_PAL			709379

namespace SNES
{
#include "bapu/dsp/blargg_endian.h"

	CPU	cpu;
}

namespace spc
{
	static apu_callback	sa_callback     = NULL;
	static void			*extra_data     = NULL;

	static bool8		sound_in_sync   = TRUE;
	static bool8		sound_enabled   = FALSE;

	static int			buffer_size;
	static int			lag_master      = 0;
	static int			lag             = 0;

	static uint8		*landing_buffer = NULL;
	static uint8		*shrink_buffer  = NULL;

	static Resampler	*resampler      = NULL;

	static int32		reference_time;
	static uint32		remainder;

	static const int	timing_hack_numerator   = 256;
	static int			timing_hack_denominator = 256;
	/* Set these to NTSC for now. Will change to PAL in S9xAPUTimingSetSpeedup
	   if necessary on game load. */
	static uint32		ratio_numerator = APU_NUMERATOR_NTSC;
	static uint32		ratio_denominator = APU_DENOMINATOR_NTSC;

	static double		dynamic_rate_multiplier = 1.0;
}

namespace msu
{
	static int			buffer_size;
	static uint8		*landing_buffer = NULL;
	static Resampler	*resampler		= NULL;
	static int			resample_buffer_size	= -1;
	static uint8		*resample_buffer		= NULL;
}

static void EightBitize (uint8 *, int);
static void DeStereo (uint8 *, int);
static void ReverseStereo (uint8 *, int);
static void UpdatePlaybackRate (void);
static void SPCSnapshotCallback (void);
static inline int S9xAPUGetClock (int32);
static inline int S9xAPUGetClockRemainder (int32);


static void EightBitize (uint8 *buffer, int sample_count)
{
	uint8	*buf8  = (uint8 *) buffer;
	int16	*buf16 = (int16 *) buffer;

	for (int i = 0; i < sample_count; i++)
		buf8[i] = (uint8) ((buf16[i] / 256) + 128);
}

static void DeStereo (uint8 *buffer, int sample_count)
{
	int16	*buf = (int16 *) buffer;
	int32	s1, s2;

	for (int i = 0; i < (sample_count >> 1); i++)
	{
		s1 = (int32) buf[2 * i];
		s2 = (int32) buf[2 * i + 1];
		buf[i] = (int16) ((s1 + s2) >> 1);
	}
}

static void ReverseStereo (uint8 *src_buffer, int sample_count)
{
	int16	*buffer = (int16 *) src_buffer;

	for (int i = 0; i < sample_count; i += 2)
	{
		buffer[i + 1] ^= buffer[i];
		buffer[i] ^= buffer[i + 1];
		buffer[i + 1] ^= buffer[i];
	}
}

bool8 S9xMixSamples (uint8 *buffer, int sample_count)
{
	static int	shrink_buffer_size = -1;
	uint8		*dest;

	if (!Settings.SixteenBitSound || !Settings.Stereo)
	{
		/* We still need both stereo samples for generating the mono sample */
		if (!Settings.Stereo)
			sample_count <<= 1;

		/* We still have to generate 16-bit samples for bit-dropping, too */
		if (shrink_buffer_size < (sample_count << 1))
		{
			delete[] spc::shrink_buffer;
			spc::shrink_buffer = new uint8[sample_count << 1];
			shrink_buffer_size = sample_count << 1;
		}

		dest = spc::shrink_buffer;
	}
	else
		dest = buffer;

	if (Settings.MSU1 && msu::resample_buffer_size < (sample_count << 1))
	{
		delete[] msu::resample_buffer;
		msu::resample_buffer = new uint8[sample_count << 1];
		msu::resample_buffer_size = sample_count << 1;
	}

	if (Settings.Mute)
	{
		memset(dest, 0, sample_count << 1);
		spc::resampler->clear();

		if(Settings.MSU1)
			msu::resampler->clear();

		return (FALSE);
	}
	else
	{
		if (spc::resampler->avail() >= (sample_count + spc::lag))
		{
			spc::resampler->read((short *) dest, sample_count);
			if (spc::lag == spc::lag_master)
				spc::lag = 0;

			if (Settings.MSU1)
			{
				if (msu::resampler->avail() >= sample_count)
				{
					msu::resampler->read((short *)msu::resample_buffer, sample_count);
					for (int i = 0; i < sample_count; ++i)
						*((int16*)(dest+(i * 2))) += *((int16*)(msu::resample_buffer +(i * 2)));
				}
				else // should never occur
					assert(0);
			}
		}
		else
		{
			memset(buffer, (Settings.SixteenBitSound ? 0 : 128), (sample_count << (Settings.SixteenBitSound ? 1 : 0)) >> (Settings.Stereo ? 0 : 1));
			if (spc::lag == 0)
				spc::lag = spc::lag_master;

			return (FALSE);
		}
	}

	if (Settings.ReverseStereo && Settings.Stereo)
		ReverseStereo(dest, sample_count);

	if (!Settings.Stereo || !Settings.SixteenBitSound)
	{
		if (!Settings.Stereo)
		{
			DeStereo(dest, sample_count);
			sample_count >>= 1;
		}

		if (!Settings.SixteenBitSound)
			EightBitize(dest, sample_count);

		memcpy(buffer, dest, (sample_count << (Settings.SixteenBitSound ? 1 : 0)));
	}

	return (TRUE);
}

int S9xGetSampleCount (void)
{
	return (spc::resampler->avail() >> (Settings.Stereo ? 0 : 1));
}

/* TODO: Attach */
void S9xFinalizeSamples (void)
{
	bool drop_current_msu1_samples = true;

	if (!Settings.Mute)
	{
		drop_current_msu1_samples = false;

		if (!spc::resampler->push((short *)spc::landing_buffer, SNES::dsp.spc_dsp.sample_count()))
		{
			/* We weren't able to process the entire buffer. Potential overrun. */
			spc::sound_in_sync = FALSE;

			if (Settings.SoundSync && !Settings.TurboMode)
				return;

			// since we drop the current dsp samples we also want to drop generated msu1 samples
			drop_current_msu1_samples = true;
		}
	}

	// only generate msu1 if we really consumed the dsp samples (sample_count() resets at end of function),
	// otherwise we will generate multiple times for the same samples - so this needs to be after all early
	// function returns
	if (Settings.MSU1)
	{
		// generate the same number of msu1 samples as dsp samples were generated
		S9xMSU1SetOutput((int16 *)msu::landing_buffer, msu::buffer_size);
		S9xMSU1Generate(SNES::dsp.spc_dsp.sample_count());
		if (!drop_current_msu1_samples && !msu::resampler->push((short *)msu::landing_buffer, S9xMSU1Samples()))
		{
			// should not occur, msu buffer is larger and we drop msu samples if spc buffer overruns
			assert(0);
		}
	}


	if (!Settings.SoundSync || Settings.TurboMode || Settings.Mute)
		spc::sound_in_sync = TRUE;
	else
	if (spc::resampler->space_empty() >= spc::resampler->space_filled())
		spc::sound_in_sync = TRUE;
	else
		spc::sound_in_sync = FALSE;

	SNES::dsp.spc_dsp.set_output((SNES::SPC_DSP::sample_t *) spc::landing_buffer, spc::buffer_size);
}

void S9xLandSamples (void)
{
	if (spc::sa_callback != NULL)
		spc::sa_callback(spc::extra_data);
	else
		S9xFinalizeSamples();
}

void S9xClearSamples (void)
{
	spc::resampler->clear();
	if (Settings.MSU1)
		msu::resampler->clear();
	spc::lag = spc::lag_master;
}

bool8 S9xSyncSound (void)
{
	if (!Settings.SoundSync || spc::sound_in_sync)
		return (TRUE);

	S9xLandSamples();

	return (spc::sound_in_sync);
}

void S9xSetSamplesAvailableCallback (apu_callback callback, void *data)
{
	spc::sa_callback = callback;
	spc::extra_data  = data;
}

void S9xUpdateDynamicRate (int avail, int buffer_size)
{
	spc::dynamic_rate_multiplier = 1.0 + (Settings.DynamicRateLimit * (buffer_size - 2 * avail)) /
					(double)(1000 * buffer_size);

	UpdatePlaybackRate();
}

static void UpdatePlaybackRate (void)
{
	if (Settings.SoundInputRate == 0)
		Settings.SoundInputRate = APU_DEFAULT_INPUT_RATE;

	double time_ratio = (double) Settings.SoundInputRate * spc::timing_hack_numerator / (Settings.SoundPlaybackRate * spc::timing_hack_denominator);

	if (Settings.DynamicRateControl)
	{
		time_ratio *= spc::dynamic_rate_multiplier;
	}

	spc::resampler->time_ratio(time_ratio);

	if (Settings.MSU1)
	{
		time_ratio = (44100.0 / Settings.SoundPlaybackRate) * (Settings.SoundInputRate / 32040.0);
		msu::resampler->time_ratio(time_ratio);
	}
}

bool8 S9xInitSound (int buffer_ms, int lag_ms)
{
	// buffer_ms : buffer size given in millisecond
	// lag_ms    : allowable time-lag given in millisecond

	int	sample_count     = buffer_ms * 32040 / 1000;
	int	lag_sample_count = lag_ms    * 32040 / 1000;

	spc::lag_master = lag_sample_count;
	if (Settings.Stereo)
		spc::lag_master <<= 1;
	spc::lag = spc::lag_master;

	if (sample_count < APU_MINIMUM_SAMPLE_COUNT)
		sample_count = APU_MINIMUM_SAMPLE_COUNT;

	spc::buffer_size = sample_count << 2;
	msu::buffer_size = (int)((sample_count << 2) * 1.5); // Always 16-bit, Stereo; 1.5 to never overflow before dsp buffer

	printf("Sound buffer size: %d (%d samples)\n", spc::buffer_size, sample_count);

	if (spc::landing_buffer)
		delete[] spc::landing_buffer;
	spc::landing_buffer = new uint8[spc::buffer_size * 2];
	if (!spc::landing_buffer)
		return (FALSE);
	if (msu::landing_buffer)
		delete[] msu::landing_buffer;
	msu::landing_buffer = new uint8[msu::buffer_size * 2];
	if (!msu::landing_buffer)
		return (FALSE);

	/* The resampler and spc unit use samples (16-bit short) as
	   arguments. Use 2x in the resampler for buffer leveling with SoundSync */
	if (!spc::resampler)
	{
		spc::resampler = new HermiteResampler(spc::buffer_size >> (Settings.SoundSync ? 0 : 1));
		if (!spc::resampler)
		{
			delete[] spc::landing_buffer;
			return (FALSE);
		}
	}
	else
		spc::resampler->resize(spc::buffer_size >> (Settings.SoundSync ? 0 : 1));


	if (!msu::resampler)
	{
		msu::resampler = new HermiteResampler(msu::buffer_size);
		if (!msu::resampler)
		{
			delete[] msu::landing_buffer;
			return (FALSE);
		}
	}
	else
		msu::resampler->resize(msu::buffer_size);


	SNES::dsp.spc_dsp.set_output ((SNES::SPC_DSP::sample_t *) spc::landing_buffer, spc::buffer_size);

	UpdatePlaybackRate();

	spc::sound_enabled = S9xOpenSoundDevice();

	return (spc::sound_enabled);
}

void S9xSetSoundControl (uint8 voice_switch)
{
	SNES::dsp.spc_dsp.set_stereo_switch (voice_switch << 8 | voice_switch);
}

void S9xSetSoundMute (bool8 mute)
{
	Settings.Mute = mute;
	if (!spc::sound_enabled)
		Settings.Mute = TRUE;
}

void S9xDumpSPCSnapshot (void)
{
	SNES::dsp.spc_dsp.dump_spc_snapshot();

}

static void SPCSnapshotCallback (void)
{
	S9xSPCDump(S9xGetFilenameInc((".spc"), SPC_DIR));
	printf("Dumped key-on triggered spc snapshot.\n");
}

bool8 S9xInitAPU (void)
{
	spc::landing_buffer = NULL;
	spc::shrink_buffer  = NULL;
	spc::resampler      = NULL;
	msu::resampler		= NULL;

	return (TRUE);
}

void S9xDeinitAPU (void)
{
	if (spc::resampler)
	{
		delete spc::resampler;
		spc::resampler = NULL;
	}

	if (spc::landing_buffer)
	{
		delete[] spc::landing_buffer;
		spc::landing_buffer = NULL;
	}

	if (spc::shrink_buffer)
	{
		delete[] spc::shrink_buffer;
		spc::shrink_buffer = NULL;
	}

	if (msu::resampler)
	{
		delete msu::resampler;
		msu::resampler = NULL;
	}

	if (msu::landing_buffer)
	{
		delete[] msu::landing_buffer;
		msu::landing_buffer = NULL;
	}

	if (msu::resample_buffer)
	{
		delete[] msu::resample_buffer;
		msu::resample_buffer = NULL;
	}

	S9xMSU1DeInit();
}

static inline int S9xAPUGetClock (int32 cpucycles)
{
	return (spc::ratio_numerator * (cpucycles - spc::reference_time) + spc::remainder) /
			spc::ratio_denominator;
}

static inline int S9xAPUGetClockRemainder (int32 cpucycles)
{
	return (spc::ratio_numerator * (cpucycles - spc::reference_time) + spc::remainder) %
			spc::ratio_denominator;
}

uint8 S9xAPUReadPort (int port)
{
	S9xAPUExecute ();
	return ((uint8) SNES::smp.port_read (port & 3));
}

void S9xAPUWritePort (int port, uint8 byte)
{
	S9xAPUExecute ();
	SNES::cpu.port_write (port & 3, byte);
}

void S9xAPUSetReferenceTime (int32 cpucycles)
{
	spc::reference_time = cpucycles;
}

void S9xAPUExecute (void)
{
	SNES::smp.clock -= S9xAPUGetClock (CPU.Cycles);
	SNES::smp.enter ();

	spc::remainder = S9xAPUGetClockRemainder(CPU.Cycles);

	S9xAPUSetReferenceTime(CPU.Cycles);
}

void S9xAPUEndScanline (void)
{
	S9xAPUExecute();
	SNES::dsp.synchronize();

	if (SNES::dsp.spc_dsp.sample_count() >= APU_MINIMUM_SAMPLE_BLOCK || !spc::sound_in_sync)
		S9xLandSamples();
}

void S9xAPUTimingSetSpeedup (int ticks)
{
	if (ticks != 0)
		printf("APU speedup hack: %d\n", ticks);

	spc::timing_hack_denominator = 256 - ticks;

	spc::ratio_numerator = Settings.PAL ? APU_NUMERATOR_PAL : APU_NUMERATOR_NTSC;
	spc::ratio_denominator = Settings.PAL ? APU_DENOMINATOR_PAL : APU_DENOMINATOR_NTSC;
	spc::ratio_denominator = spc::ratio_denominator * spc::timing_hack_denominator / spc::timing_hack_numerator;

	UpdatePlaybackRate();
}

void S9xResetAPU (void)
{
	spc::reference_time = 0;
	spc::remainder = 0;

	SNES::cpu.reset ();
	SNES::cpu.frequency = Settings.PAL ? PAL_MASTER_CLOCK : NTSC_MASTER_CLOCK;
	SNES::smp.power ();
	SNES::dsp.power ();
	SNES::dsp.spc_dsp.set_output ((SNES::SPC_DSP::sample_t *) spc::landing_buffer, spc::buffer_size >> 1);
	SNES::dsp.spc_dsp.set_spc_snapshot_callback(SPCSnapshotCallback);

	spc::resampler->clear();

	if (Settings.MSU1)
		msu::resampler->clear();
}

void S9xSoftResetAPU (void)
{
	spc::reference_time = 0;
	spc::remainder = 0;
	SNES::cpu.reset ();
	SNES::smp.reset ();
	SNES::dsp.reset ();
	SNES::dsp.spc_dsp.set_output ((SNES::SPC_DSP::sample_t *) spc::landing_buffer, spc::buffer_size >> 1);

	spc::resampler->clear();

	if (Settings.MSU1)
		msu::resampler->clear();
}

void S9xAPUSaveState (uint8 *block)
{
	uint8	*ptr = block;

	SNES::smp.save_state (&ptr);
	SNES::dsp.save_state (&ptr);

	SNES::set_le32(ptr, spc::reference_time);
	ptr += sizeof(int32);
	SNES::set_le32(ptr, spc::remainder);
	ptr += sizeof(int32);
	SNES::set_le32(ptr, SNES::dsp.clock);
	ptr += sizeof(int32);
	memcpy (ptr, SNES::cpu.registers, 4);
	ptr += sizeof(int32);

	memset (ptr, 0, SPC_SAVE_STATE_BLOCK_SIZE-(ptr-block));
}

void S9xAPULoadState (uint8 *block)
{
	uint8	*ptr = block;

	SNES::smp.load_state (&ptr);
	SNES::dsp.load_state (&ptr);

	spc::reference_time = SNES::get_le32(ptr);
	ptr += sizeof(int32);
	spc::remainder = SNES::get_le32(ptr);
	ptr += sizeof(int32);
	SNES::dsp.clock = SNES::get_le32(ptr);
	ptr += sizeof(int32);
	memcpy (SNES::cpu.registers, ptr, 4);
}

static void to_var_from_buf (uint8 **buf, void *var, size_t size)
{
  memcpy(var, *buf, size);
  *buf += size;
}

#undef IF_0_THEN_256
#define IF_0_THEN_256( n ) ((uint8) ((n) - 1) + 1)
void S9xAPULoadBlarggState(uint8 *oldblock)
{
    uint8	*ptr = oldblock;

    SNES::SPC_State_Copier copier(&ptr,to_var_from_buf);

    copier.copy(SNES::smp.apuram,0x10000); // RAM

    uint8 regs_in [0x10];
    uint8 regs [0x10];
    uint16 pc, spc_time, dsp_time;
    uint8 a,x,y,psw,sp;

    copier.copy(regs,0x10); // REGS
    copier.copy(regs_in,0x10); // REGS_IN

    // CPU Regs
    pc = copier.copy_int( 0, sizeof(uint16) );
    a = copier.copy_int( 0, sizeof(uint8) );
    x = copier.copy_int( 0, sizeof(uint8) );
    y = copier.copy_int( 0, sizeof(uint8) );
    psw = copier.copy_int( 0, sizeof(uint8) );
    sp = copier.copy_int( 0, sizeof(uint8) );
    copier.extra();

    // times
    spc_time = copier.copy_int( 0, sizeof(uint16) );
    dsp_time = copier.copy_int( 0, sizeof(uint16) );

    int cur_time = S9xAPUGetClock(CPU.Cycles);

    // spc_time is absolute, dsp_time is relative
    // smp.clock is relative, dsp.clock relative but counting upwards
    SNES::smp.clock = spc_time - cur_time;
    SNES::dsp.clock = -1 * dsp_time;

    // DSP
    SNES::dsp.load_state(&ptr);

    // Timers
    uint16 next_time[3];
    uint8 divider[3], counter[3];
    for ( int i = 0; i < 3; i++ )
    {
        next_time[i] = copier.copy_int( 0, sizeof(uint16) );
        divider[i] = copier.copy_int( 0, sizeof(uint8) );
        counter[i] = copier.copy_int( 0, sizeof(uint8) );
        copier.extra();
    }
    // construct timers out of available parts from blargg smp
    SNES::smp.timer0.enable = regs[1] >> 0 & 1;                 // regs[1] = CONTROL
    SNES::smp.timer0.target = IF_0_THEN_256(regs[10]);          // regs[10+i] = TiTARGET
    // blargg counts time, get ticks through timer frequency
    // (assume tempo = 256)
    SNES::smp.timer0.stage1_ticks = 128 - (next_time[0] - cur_time) / 128;
    SNES::smp.timer0.stage2_ticks = divider[0];
    SNES::smp.timer0.stage3_ticks = counter[0];

    SNES::smp.timer1.enable = regs[1] >> 1 & 1;
    SNES::smp.timer1.target = IF_0_THEN_256(regs[11]);
    SNES::smp.timer1.stage1_ticks = 128 - (next_time[1] - cur_time) / 128;
    SNES::smp.timer1.stage2_ticks = divider[0];
    SNES::smp.timer1.stage3_ticks = counter[0];

    SNES::smp.timer2.enable = regs[1] >> 2 & 1;
    SNES::smp.timer2.target = IF_0_THEN_256(regs[12]);
    SNES::smp.timer2.stage1_ticks = 16 - (next_time[2] - cur_time) / 16;
    SNES::smp.timer2.stage2_ticks = divider[0];
    SNES::smp.timer2.stage3_ticks = counter[0];

    copier.extra();

    SNES::smp.opcode_number = 0;
    SNES::smp.opcode_cycle = 0;

    SNES::smp.regs.pc = pc;
    SNES::smp.regs.sp = sp;
    SNES::smp.regs.B.a = a;
    SNES::smp.regs.x = x;
    SNES::smp.regs.B.y = y;

    // blargg's psw has same layout as byuu's flags
    SNES::smp.regs.p = psw;

    // blargg doesn't explicitly store iplrom_enable
    SNES::smp.status.iplrom_enable = regs[1] & 0x80;

    SNES::smp.status.dsp_addr = regs[2];

    SNES::smp.status.ram00f8 = regs_in[8];
    SNES::smp.status.ram00f9 = regs_in[9];

    // default to 0 - we are on an opcode boundary, shouldn't matter
    SNES::smp.rd=SNES::smp.wr=SNES::smp.dp=SNES::smp.sp=SNES::smp.ya=SNES::smp.bit=0;

    spc::reference_time = SNES::get_le32(ptr);
    ptr += sizeof(int32);
    spc::remainder = SNES::get_le32(ptr);

    // blargg stores CPUIx in regs_in
    memcpy (SNES::cpu.registers, regs_in + 4, 4);
}

bool8 S9xSPCDump (const char *filename)
{
	FILE	*fs;
	uint8	buf[SPC_FILE_SIZE];
	size_t	ignore;

	fs = fopen(filename, "wb");
	if (!fs)
		return (FALSE);

	S9xSetSoundMute(TRUE);

	SNES::smp.save_spc (buf);

	ignore = fwrite (buf, SPC_FILE_SIZE, 1, fs);

	if (ignore == 0)
	{
		fprintf (stderr, "Couldn't write file %s.\n", filename);
	}

	fclose(fs);

	S9xSetSoundMute(FALSE);

	return (TRUE);
}