#include "vdpau.h"

#include <SDL_syswm.h>

#define BAIL_ON_FAIL(status, something) if ((status) != VDP_STATUS_OK) { \
                                            SDL_LogWarn(SDL_LOG_CATEGORY_APPLICATION, \
                                                        #something " failed: %d", (status)); \
                                            return false; \
                                        }

#define GET_PROC_ADDRESS(id, func) status = vdpauCtx->get_proc_address(vdpauCtx->device, id, (void**)func); \
                                   BAIL_ON_FAIL(status, id)

const VdpRGBAFormat VDPAURenderer::k_OutputFormats[] = {
    VDP_RGBA_FORMAT_B8G8R8A8,
    VDP_RGBA_FORMAT_R8G8B8A8
};

VDPAURenderer::VDPAURenderer()
    : m_HwContext(nullptr),
      m_PresentationQueueTarget(0),
      m_PresentationQueue(0),
      m_VideoMixer(0),
      m_NextSurfaceIndex(0)
{
    SDL_zero(m_OutputSurface);
}

VDPAURenderer::~VDPAURenderer()
{
    for (int i = 0; i < OUTPUT_SURFACE_COUNT; i++) {
        if (m_OutputSurface[i] != 0) {
            m_VdpOutputSurfaceDestroy(m_OutputSurface[i]);
        }
    }

    if (m_VideoMixer != 0) {
        m_VdpVideoMixerDestroy(m_VideoMixer);
    }

    if (m_PresentationQueue != 0) {
        m_VdpPresentationQueueDestroy(m_PresentationQueue);
    }

    if (m_PresentationQueueTarget != 0) {
        m_VdpPresentationQueueTargetDestroy(m_PresentationQueueTarget);
    }

    // This must be done last as it frees VDPAU context required to call
    // the functions above.
    if (m_HwContext != nullptr) {
        av_buffer_unref(&m_HwContext);
    }
}

bool VDPAURenderer::initialize(SDL_Window* window, int, int width, int height)
{
    int err;
    VdpStatus status;
    SDL_SysWMinfo info;

    m_VideoWidth = width;
    m_VideoHeight = height;

    err = av_hwdevice_ctx_create(&m_HwContext,
                                 AV_HWDEVICE_TYPE_VDPAU,
                                 nullptr, nullptr, 0);
    if (err < 0) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "Failed to create VDPAU context: %d",
                     err);
        return false;
    }

    AVHWDeviceContext* devCtx = (AVHWDeviceContext*)m_HwContext->data;
    AVVDPAUDeviceContext* vdpauCtx = (AVVDPAUDeviceContext*)devCtx->hwctx;

    GET_PROC_ADDRESS(VDP_FUNC_ID_GET_ERROR_STRING, &m_VdpGetErrorString);
    GET_PROC_ADDRESS(VDP_FUNC_ID_PRESENTATION_QUEUE_TARGET_DESTROY, &m_VdpPresentationQueueTargetDestroy);
    GET_PROC_ADDRESS(VDP_FUNC_ID_VIDEO_MIXER_CREATE, &m_VdpVideoMixerCreate);
    GET_PROC_ADDRESS(VDP_FUNC_ID_VIDEO_MIXER_DESTROY, &m_VdpVideoMixerDestroy);
    GET_PROC_ADDRESS(VDP_FUNC_ID_VIDEO_MIXER_RENDER, &m_VdpVideoMixerRender);
    GET_PROC_ADDRESS(VDP_FUNC_ID_PRESENTATION_QUEUE_CREATE, &m_VdpPresentationQueueCreate);
    GET_PROC_ADDRESS(VDP_FUNC_ID_PRESENTATION_QUEUE_DESTROY, &m_VdpPresentationQueueDestroy);
    GET_PROC_ADDRESS(VDP_FUNC_ID_PRESENTATION_QUEUE_DISPLAY, &m_VdpPresentationQueueDisplay);
    GET_PROC_ADDRESS(VDP_FUNC_ID_PRESENTATION_QUEUE_SET_BACKGROUND_COLOR, &m_VdpPresentationQueueSetBackgroundColor);
    GET_PROC_ADDRESS(VDP_FUNC_ID_PRESENTATION_QUEUE_BLOCK_UNTIL_SURFACE_IDLE, &m_VdpPresentationQueueBlockUntilSurfaceIdle);
    GET_PROC_ADDRESS(VDP_FUNC_ID_OUTPUT_SURFACE_CREATE, &m_VdpOutputSurfaceCreate);
    GET_PROC_ADDRESS(VDP_FUNC_ID_OUTPUT_SURFACE_DESTROY, &m_VdpOutputSurfaceDestroy);
    GET_PROC_ADDRESS(VDP_FUNC_ID_OUTPUT_SURFACE_QUERY_CAPABILITIES, &m_VdpOutputSurfaceQueryCapabilities);

    SDL_GetWindowSize(window, (int*)&m_DisplayWidth, (int*)&m_DisplayHeight);

    SDL_VERSION(&info.version);

    if (!SDL_GetWindowWMInfo(window, &info)) {
        SDL_LogWarn(SDL_LOG_CATEGORY_APPLICATION,
                    "SDL_GetWindowWMInfo() failed: %s",
                    SDL_GetError());
        return false;
    }

    SDL_assert(info.subsystem == SDL_SYSWM_X11);

    if (info.subsystem == SDL_SYSWM_X11) {
        GET_PROC_ADDRESS(VDP_FUNC_ID_PRESENTATION_QUEUE_TARGET_CREATE_X11,
                         &m_VdpPresentationQueueTargetCreateX11);
        status = m_VdpPresentationQueueTargetCreateX11(vdpauCtx->device,
                                                       info.info.x11.window,
                                                       &m_PresentationQueueTarget);
        if (status != VDP_STATUS_OK) {
            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                         "VdpPresentationQueueTargetCreateX11() failed: %s",
                         m_VdpGetErrorString(status));
            return false;
        }
    }
    else if (info.subsystem == SDL_SYSWM_WAYLAND) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "VDPAU backend does not currently support Wayland");
        return false;
    }
    else {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "Unsupported VDPAU rendering subsystem: %d",
                     info.subsystem);
        return false;
    }

    // Try our available output formats to find something the GPU supports
    bool foundFormat = false;
    for (int i = 0; i < OUTPUT_SURFACE_FORMAT_COUNT; i++) {
        VdpBool supported;
        uint32_t maxWidth, maxHeight;
        status = m_VdpOutputSurfaceQueryCapabilities(vdpauCtx->device, k_OutputFormats[i],
                                                     &supported, &maxWidth, &maxHeight);
        if (status != VDP_STATUS_OK) {
            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                         "VdpOutputSurfaceQueryCapabilities() failed: %s",
                         m_VdpGetErrorString(status));
            return false;
        }

        if (supported) {
            if (m_DisplayWidth <= maxWidth && m_DisplayHeight <= maxHeight) {
                m_OutputSurfaceFormat = k_OutputFormats[i];
                foundFormat = true;
                break;
            }
            else  {
                SDL_LogWarn(SDL_LOG_CATEGORY_APPLICATION,
                            "Display size not within capabilities %dx%d vs %dx%d",
                            m_DisplayWidth, m_DisplayWidth,
                            maxWidth, maxHeight);
            }
        }
    }

    if (!foundFormat) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "No compatible output surface format found!");
        return false;
    }

    // Create the output surfaces
    for (int i = 0; i < OUTPUT_SURFACE_COUNT; i++) {
        status = m_VdpOutputSurfaceCreate(vdpauCtx->device, m_OutputSurfaceFormat,
                                          m_DisplayWidth, m_DisplayHeight,
                                          &m_OutputSurface[i]);
        if (status != VDP_STATUS_OK) {
            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                         "VdpOutputSurfaceCreate() failed: %s",
                         m_VdpGetErrorString(status));
            return false;
        }
    }

    status = m_VdpPresentationQueueCreate(vdpauCtx->device, m_PresentationQueueTarget,
                                          &m_PresentationQueue);
    if (status != VDP_STATUS_OK) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "VdpPresentationQueueCreate() failed: %s",
                     m_VdpGetErrorString(status));
        return false;
    }

    // Set the background to black
    VdpColor color;
    SDL_zero(color);
    m_VdpPresentationQueueSetBackgroundColor(m_PresentationQueue, &color);

#define PARAM_COUNT 2
    const VdpVideoMixerParameter params[PARAM_COUNT] = {
        VDP_VIDEO_MIXER_PARAMETER_VIDEO_SURFACE_WIDTH,
        VDP_VIDEO_MIXER_PARAMETER_VIDEO_SURFACE_HEIGHT,
    };
    const void* const paramValues[PARAM_COUNT] = {
        &m_VideoWidth,
        &m_VideoHeight,
    };

    status = m_VdpVideoMixerCreate(vdpauCtx->device, 0, nullptr,
                                   PARAM_COUNT, params, paramValues,
                                   &m_VideoMixer);
    if (status != VDP_STATUS_OK) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "VdpVideoMixerCreate() failed: %s",
                     m_VdpGetErrorString(status));
        return false;
    }

    return true;
}

bool VDPAURenderer::prepareDecoderContext(AVCodecContext* context)
{
    context->hw_device_ctx = av_buffer_ref(m_HwContext);

    SDL_LogInfo(SDL_LOG_CATEGORY_APPLICATION,
                "Using VDPAU accelerated renderer");

    return true;
}

void VDPAURenderer::renderFrame(AVFrame* frame)
{
    VdpStatus status;
    VdpVideoSurface videoSurface = (VdpVideoSurface)(uintptr_t)frame->data[3];

    // This is safe without locking because this is always called on the main thread
    VdpOutputSurface chosenSurface = m_OutputSurface[m_NextSurfaceIndex];
    m_NextSurfaceIndex = (m_NextSurfaceIndex + 1) % OUTPUT_SURFACE_COUNT;

    // Wait for this frame to be off the screen
    VdpTime pts;
    m_VdpPresentationQueueBlockUntilSurfaceIdle(m_PresentationQueue, chosenSurface, &pts);

    VdpRect outputRect;

    // Center in frame and preserve aspect ratio
    double srcAspectRatio = (double)m_VideoWidth / (double)m_VideoHeight;
    double dstAspectRatio = (double)m_DisplayWidth / (double)m_DisplayHeight;
    if (dstAspectRatio < srcAspectRatio) {
        // Greater height per width
        uint32_t drawHeight = (uint32_t)(m_DisplayWidth / srcAspectRatio);
        outputRect.y0 = (m_DisplayHeight - drawHeight) / 2;
        outputRect.y1 = outputRect.y0 + drawHeight;
        outputRect.x0 = 0;
        outputRect.x1 = outputRect.x0 + m_DisplayWidth;
    }
    else {
        // Greater width per height
        uint32_t drawWidth = (uint32_t)(m_DisplayHeight * srcAspectRatio);
        outputRect.y0 = 0;
        outputRect.y1 = outputRect.y0 + m_DisplayHeight;
        outputRect.x0 = (m_DisplayWidth - drawWidth) / 2;
        outputRect.x1 = outputRect.x0 + drawWidth;
    }

    // Render the next frame into the output surface
    status = m_VdpVideoMixerRender(m_VideoMixer,
                                   VDP_INVALID_HANDLE, nullptr,
                                   VDP_VIDEO_MIXER_PICTURE_STRUCTURE_FRAME,
                                   0, nullptr,
                                   videoSurface,
                                   0, nullptr,
                                   nullptr,
                                   chosenSurface,
                                   &outputRect,
                                   nullptr,
                                   0,
                                   nullptr);

    // The decoder can have this surface back now
    av_frame_free(&frame);

    if (status != VDP_STATUS_OK) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "VdpVideoMixerRender() failed: %s",
                     m_VdpGetErrorString(status));
        return;
    }

    // Queue the frame for display immediately
    status = m_VdpPresentationQueueDisplay(m_PresentationQueue, chosenSurface, 0, 0, 0);
    if (status != VDP_STATUS_OK) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "VdpPresentationQueueDisplay() failed: %s",
                     m_VdpGetErrorString(status));
        return;
    }
}