/*****************************************************************************\
     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 "CWaveOut.h"
#include "../snes9x.h"
#include "../apu/apu.h"
#include "wsnes9x.h"

CWaveOut::CWaveOut(void)
{
    hWaveOut = NULL;
    initDone = false;
}

CWaveOut::~CWaveOut(void)
{
    DeInitSoundOutput();
}

void CALLBACK WaveCallback(HWAVEOUT hWave, UINT uMsg, DWORD_PTR dwUser, DWORD_PTR dw1, DWORD_PTR dw2)
{
    if (uMsg == WOM_DONE)
    {
        InterlockedDecrement(((volatile LONG *)dwUser));
        SetEvent(GUI.SoundSyncEvent);
    }
}

bool CWaveOut::SetupSound()
{
    WAVEFORMATEX wfx;
    wfx.wFormatTag = WAVE_FORMAT_PCM;
    wfx.nChannels = 2;
    wfx.nSamplesPerSec = Settings.SoundPlaybackRate;
    wfx.nBlockAlign = 2 * 2;
    wfx.wBitsPerSample = 16;
    wfx.nAvgBytesPerSec = wfx.nSamplesPerSec * wfx.nBlockAlign;
    wfx.cbSize = 0;

    waveOutOpen(&hWaveOut, WAVE_MAPPER, &wfx, (DWORD_PTR)WaveCallback, (DWORD_PTR)&bufferCount, CALLBACK_FUNCTION);

    UINT32 blockTime = GUI.SoundBufferSize / blockCount;
    singleBufferSamples = (Settings.SoundPlaybackRate * blockTime) / 1000;
    singleBufferSamples *= 2;
    singleBufferBytes = singleBufferSamples * 2;
    sumBufferSize = singleBufferBytes * blockCount;
    writeOffset = 0;
    partialOffset = 0;

    waveHeaders.resize(blockCount);
    for (auto &w : waveHeaders)
    {
        w.lpData = (LPSTR)LocalAlloc(LMEM_FIXED, singleBufferBytes);
        w.dwBufferLength = singleBufferBytes;
        w.dwBytesRecorded = 0;
        w.dwUser = 0;
        w.dwFlags = 0;
        w.dwLoops = 0;
        w.lpNext = 0;
        w.reserved = 0;
        waveOutPrepareHeader(hWaveOut, &w, sizeof(WAVEHDR));
    }
    initDone = true;

    return true;
}

void CWaveOut::SetVolume(double volume)
{
    waveOutSetVolume(hWaveOut, 0xffffffff);
}

void CWaveOut::BeginPlayback()
{
    waveOutRestart(hWaveOut);
}

bool CWaveOut::InitSoundOutput()
{
    return true;
}

void CWaveOut::DeInitSoundOutput()
{
    if (!initDone)
        return;

    waveOutReset(hWaveOut);

    if (!waveHeaders.empty())
    {
        for (auto &w : waveHeaders)
        {
            waveOutUnprepareHeader(hWaveOut, &w, sizeof(WAVEHDR));
            LocalFree(w.lpData);
        }
    }
    waveHeaders.clear();

    waveOutClose(hWaveOut);

    initDone = false;
}

void CWaveOut::StopPlayback()
{
    waveOutPause(hWaveOut);
}

void CWaveOut::ProcessSound()
{
    int freeBytes = ((blockCount - bufferCount) * singleBufferBytes) - partialOffset;

    if (Settings.DynamicRateControl)
    {
        S9xUpdateDynamicRate(freeBytes, sumBufferSize);
    }

    UINT32 availableSamples;

    availableSamples = S9xGetSampleCount();

    if (Settings.DynamicRateControl && !Settings.SoundSync)
    {
        // Using rate control, we should always keep the emulator's sound buffers empty to
        // maintain an accurate measurement.
        if (availableSamples > (freeBytes >> 1))
        {
            S9xClearSamples();
            return;
        }
    }

    if (!initDone)
        return;

    if (partialOffset != 0) {
        UINT32 samplesleftinblock = (singleBufferBytes - partialOffset) >> 1;
        BYTE *offsetBuffer = (BYTE *)waveHeaders[writeOffset].lpData + partialOffset;

        if (availableSamples <= samplesleftinblock)
        {
            S9xMixSamples(offsetBuffer, availableSamples);
            partialOffset += availableSamples << 1;
            availableSamples = 0;
        }
        else
        {
            S9xMixSamples(offsetBuffer, samplesleftinblock);
            partialOffset = 0;
            availableSamples -= samplesleftinblock;
            waveOutWrite(hWaveOut, &waveHeaders[writeOffset], sizeof(WAVEHDR));
            InterlockedIncrement(&bufferCount);
            writeOffset++;
            writeOffset %= blockCount;
        }
    }

    while (availableSamples >= singleBufferSamples && bufferCount < blockCount) {
        BYTE *curBuffer = (BYTE *)waveHeaders[writeOffset].lpData;
        S9xMixSamples(curBuffer, singleBufferSamples);
        waveOutWrite(hWaveOut, &waveHeaders[writeOffset], sizeof(WAVEHDR));
        InterlockedIncrement(&bufferCount);
        writeOffset++;
        writeOffset %= blockCount;
        availableSamples -= singleBufferSamples;
    }

    if (availableSamples > 0 && bufferCount < blockCount) {
        S9xMixSamples((BYTE *)waveHeaders[writeOffset].lpData, availableSamples);
        partialOffset = availableSamples << 1;
    }
}