#include "blur.hpp"

#include "blur_binary.h"

static IDirect3DSurface9* rtBackup = nullptr;
static IDirect3DPixelShader9* blurShaderX = nullptr;
static IDirect3DPixelShader9* blurShaderY = nullptr;
static IDirect3DTexture9* blurTexture = nullptr;
static int backbufferWidth = 0;
static int backbufferHeight = 0;

static void BeginBlur(const ImDrawList* parent_list, const ImDrawCmd* cmd)
{
    const auto device = reinterpret_cast<IDirect3DDevice9*>(cmd->UserCallbackData);

    if (!blurShaderX)
    {
        device->CreatePixelShader(reinterpret_cast<const DWORD*>(blur_x.data()), &blurShaderX);
    }

    if (!blurShaderY)
    {
        device->CreatePixelShader(reinterpret_cast<const DWORD*>(blur_y.data()), &blurShaderY);
    }

    IDirect3DSurface9* backBuffer;
    device->GetBackBuffer(0, 0, D3DBACKBUFFER_TYPE_MONO, &backBuffer);
    D3DSURFACE_DESC desc;
    backBuffer->GetDesc(&desc);

    if (backbufferWidth != desc.Width || backbufferHeight != desc.Height)
    {
        if (blurTexture)
            blurTexture->Release();

        backbufferWidth = desc.Width;
        backbufferHeight = desc.Height;
        device->CreateTexture(desc.Width, desc.Height, 1, D3DUSAGE_RENDERTARGET, D3DFMT_A8R8G8B8, D3DPOOL_DEFAULT, &blurTexture, nullptr);
    }

    device->GetRenderTarget(0, &rtBackup);

    {
        IDirect3DSurface9* surface;
        blurTexture->GetSurfaceLevel(0, &surface);
        device->StretchRect(backBuffer, NULL, surface, NULL, D3DTEXF_NONE);
        device->SetRenderTarget(0, surface);
        surface->Release();
    }

    backBuffer->Release();

    device->SetSamplerState(0, D3DSAMP_ADDRESSU, D3DTADDRESS_CLAMP);
    device->SetSamplerState(0, D3DSAMP_ADDRESSV, D3DTADDRESS_CLAMP);
}

static void FirstBlurPass(const ImDrawList* parent_list, const ImDrawCmd* cmd)
{
    const auto device = reinterpret_cast<IDirect3DDevice9*>(cmd->UserCallbackData);

    device->SetPixelShader(blurShaderX);
    const float params[4] = { 1.0f / backbufferWidth };
    device->SetPixelShaderConstantF(0, params, 1);
}

static void SecondBlurPass(const ImDrawList* parent_list, const ImDrawCmd* cmd)
{
    const auto device = reinterpret_cast<IDirect3DDevice9*>(cmd->UserCallbackData);

    device->SetPixelShader(blurShaderY);
    const float params[4] = { 1.0f / backbufferHeight };
    device->SetPixelShaderConstantF(0, params, 1);
}

static void EndBlur(const ImDrawList* parent_list, const ImDrawCmd* cmd)
{
    const auto device = reinterpret_cast<IDirect3DDevice9*>(cmd->UserCallbackData);

    device->SetRenderTarget(0, rtBackup);
    rtBackup->Release();

    device->SetPixelShader(nullptr);
    device->SetSamplerState(0, D3DSAMP_ADDRESSU, D3DTADDRESS_WRAP);
    device->SetSamplerState(0, D3DSAMP_ADDRESSV, D3DTADDRESS_WRAP);
}

inline void DrawBackgroundBlur(ImDrawList* drawList, IDirect3DDevice9* device)
{
    drawList->AddCallback(BeginBlur, device);

    for (int i = 0; i < 8; ++i) {
        drawList->AddCallback(FirstBlurPass, device);
        drawList->AddImage(blurTexture, { 0.0f, 0.0f }, { backbufferWidth * 1.0f, backbufferHeight * 1.0f });
        drawList->AddCallback(SecondBlurPass, device);
        drawList->AddImage(blurTexture, { 0.0f, 0.0f }, { backbufferWidth * 1.0f, backbufferHeight * 1.0f });
    }

    drawList->AddCallback(EndBlur, device);
    drawList->AddImageRounded(blurTexture, { 0.0f, 0.0f }, { backbufferWidth * 1.0f, backbufferHeight * 1.0f }, { 0.0f, 0.0f }, { 1.0f, 1.0f }, IM_COL32(255, 255, 255, 255), 7.f);
}