#ifdef _WIN32
#define NOMINMAX
#endif

#include <XCEngine/Audio/WindowsAudioBackend.h>
#include <iostream>
#include <algorithm>

namespace XCEngine {
namespace Audio {
namespace WaveOut {

namespace {

std::string ConvertWaveOutDeviceName(const TCHAR* deviceName) {
    if (deviceName == nullptr) {
        return {};
    }

#if defined(UNICODE) || defined(_UNICODE)
    const int requiredBytes = WideCharToMultiByte(
        CP_UTF8,
        0,
        deviceName,
        -1,
        nullptr,
        0,
        nullptr,
        nullptr);
    if (requiredBytes <= 1) {
        return {};
    }

    std::string utf8Name(static_cast<std::size_t>(requiredBytes - 1), '\0');
    WideCharToMultiByte(
        CP_UTF8,
        0,
        deviceName,
        -1,
        utf8Name.data(),
        requiredBytes,
        nullptr,
        nullptr);
    return utf8Name;
#else
    return std::string(deviceName);
#endif
}

} // namespace

WaveOutBackend::WaveOutBackend()
    : m_audioBuffer1(BufferSize * 2)
    , m_audioBuffer2(BufferSize * 2)
{
}

WaveOutBackend::~WaveOutBackend() {
    Shutdown();
}

bool WaveOutBackend::Initialize(const AudioConfig& config) {
    m_config = config;
    const size_t bufferSampleCount = static_cast<size_t>(config.bufferSize) * config.channels;
    m_audioBuffer1.assign(bufferSampleCount, 0);
    m_audioBuffer2.assign(bufferSampleCount, 0);
    m_renderBuffer.assign(bufferSampleCount, 0.0f);
    m_buffer1Available = true;
    m_buffer2Available = true;

    m_waveFormat.wFormatTag = WAVE_FORMAT_PCM;
    m_waveFormat.nChannels = static_cast<WORD>(config.channels);
    m_waveFormat.nSamplesPerSec = config.sampleRate;
    m_waveFormat.nAvgBytesPerSec = config.sampleRate * config.channels * (config.bitsPerSample / 8);
    m_waveFormat.nBlockAlign = static_cast<WORD>(config.channels * (config.bitsPerSample / 8));
    m_waveFormat.wBitsPerSample = config.bitsPerSample;
    m_waveFormat.cbSize = 0;

    MMRESULT result = InitDevice();
    if (result != MMSYSERR_NOERROR) {
        return false;
    }

    result = InitBuffer();
    if (result != MMSYSERR_NOERROR) {
        waveOutClose(m_hWaveOut);
        return false;
    }

    return true;
}

void WaveOutBackend::Shutdown() {
    if (m_isRunning.load()) {
        Stop();
    }

    if (m_hWaveOut != nullptr) {
        waveOutUnprepareHeader(m_hWaveOut, &m_waveHeader1, sizeof(WAVEHDR));
        waveOutUnprepareHeader(m_hWaveOut, &m_waveHeader2, sizeof(WAVEHDR));
        waveOutClose(m_hWaveOut);
        m_hWaveOut = nullptr;
    }
}

std::string WaveOutBackend::GetDeviceName() const {
    return m_deviceName;
}

void WaveOutBackend::GetAvailableDevices(std::vector<std::string>& devices) {
    devices.clear();
    for (const auto& caps : m_waveOutCaps) {
        devices.push_back(ConvertWaveOutDeviceName(caps.szPname));
    }
}

bool WaveOutBackend::SetDevice(const std::string& deviceName) {
    const bool useDefaultDevice = deviceName.empty() || deviceName == "Default Device";
    const std::string requestedName = useDefaultDevice ? "Default Device" : deviceName;

    if (m_hWaveOut != nullptr || m_isRunning.load()) {
        return requestedName == m_deviceName;
    }

    if (useDefaultDevice) {
        m_requestedDeviceName.clear();
        m_deviceName = "Default Device";
        return true;
    }

    for (UINT i = 0; i < waveOutGetNumDevs(); ++i) {
        WAVEOUTCAPS caps;
        waveOutGetDevCaps(i, &caps, sizeof(WAVEOUTCAPS));
        if (deviceName == ConvertWaveOutDeviceName(caps.szPname)) {
            m_requestedDeviceName = deviceName;
            m_deviceName = deviceName;
            return true;
        }
    }
    return false;
}

void WaveOutBackend::Start() {
    if (m_isRunning.load()) {
        return;
    }

    m_isRunning = true;
    m_audioThread = std::thread(&WaveOutBackend::AudioThreadProc, this);
}

void WaveOutBackend::Stop() {
    m_isRunning = false;
    m_bufferReadyCond.notify_all();

    if (m_hWaveOut != nullptr) {
        waveOutReset(m_hWaveOut);
    }

    if (m_audioThread.joinable()) {
        m_audioThread.join();
    }
}

void WaveOutBackend::Suspend() {
    if (m_hWaveOut != nullptr) {
        waveOutReset(m_hWaveOut);
    }
}

void WaveOutBackend::Resume() {
    if (m_hWaveOut != nullptr) {
        MMRESULT result = waveOutRestart(m_hWaveOut);
        if (result != MMSYSERR_NOERROR) {
            std::cout << "Failed to resume audio playback" << std::endl;
        }
    }
}

void WaveOutBackend::ProcessAudio(float* buffer, uint32 frameCount,
                                uint32 channels, uint32 sampleRate) {
    (void)buffer;
    (void)frameCount;
    (void)channels;
    (void)sampleRate;
}

void WaveOutBackend::SetRenderCallback(RenderCallback callback) {
    std::lock_guard<std::mutex> lock(m_bufferMutex);
    m_renderCallback = std::move(callback);
}

MMRESULT WaveOutBackend::InitDevice() {
    m_waveOutCaps.clear();
    WAVEOUTCAPS waveOutCapsTemp;
    for (UINT i = 0; i < waveOutGetNumDevs(); ++i) {
        waveOutGetDevCaps(i, &waveOutCapsTemp, sizeof(WAVEOUTCAPS));
        m_waveOutCaps.push_back(waveOutCapsTemp);
    }

    UINT deviceId = WAVE_MAPPER;
    if (!m_requestedDeviceName.empty()) {
        bool foundRequestedDevice = false;
        for (UINT i = 0; i < m_waveOutCaps.size(); ++i) {
            if (m_requestedDeviceName == ConvertWaveOutDeviceName(m_waveOutCaps[i].szPname)) {
                deviceId = i;
                foundRequestedDevice = true;
                break;
            }
        }

        if (!foundRequestedDevice) {
            std::cout << "Requested audio device is no longer available" << std::endl;
            return MMSYSERR_BADDEVICEID;
        }
    }

    MMRESULT result = waveOutOpen(&m_hWaveOut, deviceId, &m_waveFormat,
                                  (DWORD_PTR)&WaveOutBackend::StaticAudioCallback,
                                  reinterpret_cast<DWORD_PTR>(this), CALLBACK_FUNCTION);
    if (result != MMSYSERR_NOERROR) {
        std::cout << "Failed to open audio device" << std::endl;
        return result;
    }

    m_deviceName = m_requestedDeviceName.empty() ? "Default Device" : m_requestedDeviceName;
    return MMSYSERR_NOERROR;
}

MMRESULT WaveOutBackend::InitBuffer() {
    m_waveHeader1.lpData = (LPSTR)m_audioBuffer1.data();
    m_waveHeader1.dwBufferLength = static_cast<DWORD>(m_audioBuffer1.size() * sizeof(int16_t));
    m_waveHeader1.dwFlags = 0;

    MMRESULT result = waveOutPrepareHeader(m_hWaveOut, &m_waveHeader1, sizeof(WAVEHDR));
    if (result != MMSYSERR_NOERROR) {
        std::cout << "Failed to prepare audio header1" << std::endl;
        return result;
    }

    m_waveHeader2.lpData = (LPSTR)m_audioBuffer2.data();
    m_waveHeader2.dwBufferLength = static_cast<DWORD>(m_audioBuffer2.size() * sizeof(int16_t));
    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;
        waveOutUnprepareHeader(m_hWaveOut, &m_waveHeader1, sizeof(WAVEHDR));
        return result;
    }

    return MMSYSERR_NOERROR;
}

DWORD WINAPI WaveOutBackend::AudioThreadProc(LPVOID lpParameter) {
    WaveOutBackend* backend = static_cast<WaveOutBackend*>(lpParameter);
    if (backend) {
        backend->AudioThread();
    }
    return 0;
}

void WaveOutBackend::AudioThread() {
    while (m_isRunning.load()) {
        std::unique_lock<std::mutex> lock(m_bufferMutex);
        m_bufferReadyCond.wait(lock, [this] {
            return !m_isRunning.load() || m_buffer1Available || m_buffer2Available;
        });

        if (!m_isRunning.load()) {
            break;
        }

        WAVEHDR* targetHeader = nullptr;
        std::vector<int16_t>* targetBuffer = nullptr;

        if (m_buffer1Available) {
            targetHeader = &m_waveHeader1;
            targetBuffer = &m_audioBuffer1;
            m_buffer1Available = false;
        } else if (m_buffer2Available) {
            targetHeader = &m_waveHeader2;
            targetBuffer = &m_audioBuffer2;
            m_buffer2Available = false;
        } else {
            continue;
        }

        RenderCallback renderCallback;
        const uint32 frameCount = m_config.bufferSize;
        const uint32 channels = m_config.channels;
        const uint32 sampleRate = m_config.sampleRate;
        const size_t sampleCount = static_cast<size_t>(frameCount) * channels;

        if (targetBuffer->size() != sampleCount) {
            targetBuffer->assign(sampleCount, 0);
        } else {
            std::fill(targetBuffer->begin(), targetBuffer->end(), 0);
        }

        if (m_renderBuffer.size() != sampleCount) {
            m_renderBuffer.assign(sampleCount, 0.0f);
        } else {
            std::fill(m_renderBuffer.begin(), m_renderBuffer.end(), 0.0f);
        }
        renderCallback = m_renderCallback;
        lock.unlock();

        if (renderCallback && !m_renderBuffer.empty()) {
            renderCallback(m_renderBuffer.data(), frameCount, channels, sampleRate);
        }
        FillPcm16Buffer(*targetBuffer, m_renderBuffer);

        if (SubmitBuffer(*targetHeader, *targetBuffer) != MMSYSERR_NOERROR) {
            std::lock_guard<std::mutex> restoreLock(m_bufferMutex);
            if (targetHeader == &m_waveHeader1) {
                m_buffer1Available = true;
            } else {
                m_buffer2Available = true;
            }
            m_bufferReadyCond.notify_one();
        }
    }
}

void WaveOutBackend::OnAudioCallback(HWAVEOUT hwo, UINT uMsg, DWORD_PTR dwInstance,
                                    DWORD_PTR dwParam1, DWORD_PTR dwParam2) {
    (void)hwo;
    (void)dwInstance;
    (void)dwParam2;

    if (uMsg == WOM_DONE) {
        std::lock_guard<std::mutex> lock(m_bufferMutex);
        WAVEHDR* completedHeader = reinterpret_cast<WAVEHDR*>(dwParam1);
        if (completedHeader == &m_waveHeader1) {
            m_buffer1Available = true;
        } else if (completedHeader == &m_waveHeader2) {
            m_buffer2Available = true;
        }
        m_bufferReadyCond.notify_one();
    }
}

void CALLBACK WaveOutBackend::StaticAudioCallback(HWAVEOUT hwo, UINT uMsg,
                                                DWORD_PTR dwInstance,
                                                DWORD_PTR dwParam1, DWORD_PTR dwParam2) {
    WaveOutBackend* backend = reinterpret_cast<WaveOutBackend*>(dwInstance);
    if (backend != nullptr) {
        backend->OnAudioCallback(hwo, uMsg, dwInstance, dwParam1, dwParam2);
    }
}

MMRESULT WaveOutBackend::SubmitBuffer(WAVEHDR& header, std::vector<int16_t>& samples) {
    header.lpData = reinterpret_cast<LPSTR>(samples.data());
    header.dwBufferLength = static_cast<DWORD>(samples.size() * sizeof(int16_t));
    header.dwFlags &= ~WHDR_DONE;

    MMRESULT result = waveOutWrite(m_hWaveOut, &header, sizeof(WAVEHDR));
    if (result != MMSYSERR_NOERROR) {
        std::cout << "Failed to write audio data" << std::endl;
    }
    return result;
}

} // namespace WaveOut
} // namespace Audio
} // namespace XCEngine