#include"AudioEngine.h"


AudioEngine::AudioEngine()
{
  
}

AudioEngine::~AudioEngine()
{
    ExitAudioEngine();
    delete[] m_audioBuffer1;
    delete[] m_audioBuffer2;
}

void AudioEngine::InitAudioEngine()
{
    InitWavFormat();
    InitDevice();
    InitWavHeader();
    InitAudioThread();
}

void AudioEngine::ExitAudioEngine()
{
    m_isRunning = false;
    m_audioThread.join();
    waveOutUnprepareHeader(m_hWaveOut, &m_waveHeader1, sizeof(WAVEHDR));
    waveOutUnprepareHeader(m_hWaveOut, &m_waveHeader2, sizeof(WAVEHDR));
    waveOutClose(m_hWaveOut);
}

void AudioEngine::SubmitSource(AudioSource* p_audioSource)
{
    if (p_audioSource)
    {
        m_audioSource = p_audioSource;
    }
}

void AudioEngine::Update(double p_deltaTime)
{

}

MMRESULT AudioEngine::PlayFrontData()
{
    WAVEHDR* m_frontHeader = m_isBuffer1Front ? &m_waveHeader1 : &m_waveHeader2;
    MMRESULT result = waveOutWrite(m_hWaveOut, m_frontHeader, sizeof(WAVEHDR));
    if (result != MMSYSERR_NOERROR)
    {
        std::cout << "Failed to write audio data1" << std::endl;
        return result;
    }
    return MMSYSERR_NOERROR;
}

void AudioEngine::PrepareBackData()
{
    if (!m_audioSource || !m_audioSource->IsActive()) { return; }
    m_audioSource->PrepareBufferData();
    short* backBuffer = (m_isBuffer1Front ? m_audioBuffer2 : m_audioBuffer1);
    memcpy(backBuffer, m_audioSource->GetBufferData(), sizeof(m_audioBuffer1));
}

void AudioEngine::SwapBuffer()
{
    m_isBuffer1Front = !m_isBuffer1Front;
}

MMRESULT AudioEngine::InitAudioThread()
{
    MMRESULT result = MMSYSERR_NOERROR;
    m_isRunning = true;
    m_audioThread = std::thread([&]() {
        PlayFrontData();
        SwapBuffer();
        PlayFrontData();
        });

    if (!m_audioThread.joinable()) {
        std::cout << "Failed to create audio thread" << std::endl;
        result = MMSYSERR_ERROR; 
    }
    return result;
}

void AudioEngine::InitWavFormat()
{
    m_waveFormat.wFormatTag = WAVE_FORMAT_PCM;
    m_waveFormat.nChannels = 2;
    m_waveFormat.nSamplesPerSec = 44100;
    m_waveFormat.nAvgBytesPerSec = 176400;
    m_waveFormat.nBlockAlign = 4;
    m_waveFormat.wBitsPerSample = 16;
    m_waveFormat.cbSize = 0;
}

MMRESULT AudioEngine::InitDevice()
{
    MMRESULT result;
    /*音频设备枚举*/
    WAVEOUTCAPS waveOutCaps;
    for (UINT i = 0; i < waveOutGetNumDevs(); ++i)
    {
        waveOutGetDevCaps(i, &waveOutCaps, sizeof(WAVEOUTCAPS));
        m_waveOutCaps.push_back(waveOutCaps);
        std::cout << "Device #" << i << ": " << waveOutCaps.szPname << std::endl;
    }
    /*打开默认音频设备*/
    //同时设置该设备的回调
    result = waveOutOpen(&m_hWaveOut, WAVE_MAPPER, &m_waveFormat, (DWORD_PTR)&AudioEngine::StaticAudioCallback, reinterpret_cast<DWORD_PTR>(this), CALLBACK_FUNCTION);
    if (result != MMSYSERR_NOERROR)
    {
        std::cout << "Failed to open audio device" << std::endl;
        return result;
    }
    return MMSYSERR_NOERROR;
}

void AudioEngine::OnAudioCallback(HWAVEOUT hwo, UINT uMsg, DWORD_PTR dwInstance, DWORD_PTR dwParam1, DWORD_PTR dwParam2)
{
    // 在这里处理音频事件
    if (uMsg == WOM_DONE) {
        PrepareBackData();
        SwapBuffer();
        PlayFrontData();
    }
}

void CALLBACK AudioEngine::StaticAudioCallback(HWAVEOUT hwo, UINT uMsg, DWORD_PTR dwInstance, DWORD_PTR dwParam1, DWORD_PTR dwParam2)
{
    // 通过 dwInstance 恢复到实际的 AudioEngine 实例
    AudioEngine* audioEngine = reinterpret_cast<AudioEngine*>(dwInstance);
    if (audioEngine != nullptr) {
        audioEngine->OnAudioCallback(hwo, uMsg, dwInstance, dwParam1, dwParam2);
    }
}

MMRESULT AudioEngine::InitWavHeader()
{
    MMRESULT result;
    /*header1-initialize*/
    m_waveHeader1.lpData = (LPSTR)m_audioBuffer1;
    m_waveHeader1.dwBufferLength = sizeof(m_audioBuffer1);
    m_waveHeader1.dwFlags = 0;
    result = waveOutPrepareHeader(m_hWaveOut, &m_waveHeader1, sizeof(WAVEHDR));
    if (result != MMSYSERR_NOERROR)
    {
        std::cout << "Failed to prepare audio header1" << std::endl;
        return result;
    }
    /*header2-initialize*/
    m_waveHeader2.lpData = (LPSTR)m_audioBuffer2;
    m_waveHeader2.dwBufferLength = sizeof(m_audioBuffer2);
    m_waveHeader2.dwFlags = 0;
    result = waveOutPrepareHeader(m_hWaveOut, &m_waveHeader2, sizeof(WAVEHDR));
    if (result != MMSYSERR_NOERROR)
    {
        std::cout << "Failed to prepare audio header2" << std::endl;
        return result;
    }
    return MMSYSERR_NOERROR;
}