#include "PaintLayerNode.h"
#include "../GPU.h"
#include <stdexcept>


SDL_GPUSampler* PaintLayerNode::sampler = nullptr;
GPUBuffer* PaintLayerNode::vertexBuffer = nullptr;

void PaintLayerNode::setupPipeline()
{
    // TODO: abstract this too, but not as important as the Graphics plr_pipeline
    SDL_GPUSamplerCreateInfo samplerInfo = {};
    samplerInfo.min_filter = SDL_GPU_FILTER_LINEAR;
    samplerInfo.mag_filter = SDL_GPU_FILTER_LINEAR;
    samplerInfo.mipmap_mode = SDL_GPU_SAMPLERMIPMAPMODE_LINEAR;
    samplerInfo.address_mode_u = SDL_GPU_SAMPLERADDRESSMODE_CLAMP_TO_EDGE;
    samplerInfo.address_mode_v = SDL_GPU_SAMPLERADDRESSMODE_CLAMP_TO_EDGE;
    samplerInfo.address_mode_w = SDL_GPU_SAMPLERADDRESSMODE_CLAMP_TO_EDGE;
    samplerInfo.mip_lod_bias = 0.0f;
    samplerInfo.max_anisotropy = 1.0f;
    samplerInfo.compare_op = SDL_GPU_COMPAREOP_NEVER;
    samplerInfo.min_lod = 0.0f;
    samplerInfo.max_lod = 1000.0f;

    sampler = SDL_CreateGPUSampler(GPU::GetDevice(), &samplerInfo);
    if (!sampler) {
        throw std::runtime_error(SDL_GetError());
    }


    // diabolical copypaste from CanvasAppLayer
    float previewVertices[16];

    SDL_FRect fullRect = { 0.0f, 0.0f, 1.0f, 1.0f };
    SDL_FRect previewRect = { 0.0f, 0.0f, 1.0f, 1.0f };

#define NDC_TO_SCREEN * 2.0f - 1.0f
    // parameters are using screen space
    // bottom left
    previewVertices[0] = (previewRect.x - fullRect.x) / fullRect.w NDC_TO_SCREEN;
    previewVertices[1] = (previewRect.y - fullRect.y) / fullRect.h NDC_TO_SCREEN;
    previewVertices[2] = (previewRect.x - fullRect.x) / fullRect.w; // match 0
    previewVertices[3] = (previewRect.y - fullRect.y) / fullRect.h; // match 13
    // bottom right
    previewVertices[4] = (previewRect.x + previewRect.w - fullRect.x) / fullRect.w NDC_TO_SCREEN;
    previewVertices[5] = (previewRect.y - fullRect.y) / fullRect.h NDC_TO_SCREEN;
    previewVertices[6] = (previewRect.x + previewRect.w - fullRect.x) / fullRect.w; // match 4
    previewVertices[7] = (previewRect.y - fullRect.y) / fullRect.h; // match 13
    // top left
    previewVertices[8] = (previewRect.x - fullRect.x) / fullRect.w NDC_TO_SCREEN;
    previewVertices[9] = (previewRect.y + previewRect.h - fullRect.y) / fullRect.h NDC_TO_SCREEN;
    previewVertices[10] = (previewRect.x - fullRect.x) / fullRect.w; // match 8
    previewVertices[11] = (previewRect.y + previewRect.h - fullRect.y) / fullRect.h; // match 1
    // top right
    previewVertices[12] = (previewRect.x + previewRect.w - fullRect.x) / fullRect.w NDC_TO_SCREEN;
    previewVertices[13] = (previewRect.y + previewRect.h - fullRect.y) / fullRect.h NDC_TO_SCREEN;
    previewVertices[14] = (previewRect.x + previewRect.w - fullRect.x) / fullRect.w; // match 12
    previewVertices[15] = (previewRect.y + previewRect.h - fullRect.y) / fullRect.h; // match 1

    // invert y
    for (int i = 1; i < 16; i += 4) {
        previewVertices[i] = -1.0f * previewVertices[i];
    }
#undef NDC_TO_SCREEN

    SDL_GPUBufferCreateInfo buf_info = {
        .usage = SDL_GPU_BUFFERUSAGE_VERTEX,
        .size = sizeof(previewVertices),
        .props = {}
    };
    vertexBuffer = new GPUBuffer(&buf_info);
    if (!vertexBuffer) {
        throw std::runtime_error(SDL_GetError());
    }

    vertexBuffer->Transfer(previewVertices);
}


PaintLayerNode::PaintLayerNode() {
    if (!vertexBuffer) {
        setupPipeline();
    }
}

PaintLayerNode::~PaintLayerNode()
{
    delete Target;
}

void PaintLayerNode::Composite(Texture* target)
{
    GPU::AquirePushCommandBuffer();
    GraphicsPipeline* pipeline = BlendingPipelineManagementContext::GetPipeline(BlendMode);
    GPU::SubmitCommandsPopCommandBuffer();
    SDL_GPUViewport viewport = {};
    viewport.x = 0;
    viewport.y = 0;
    viewport.w = (float)target->GetWidth();
    viewport.h = (float)target->GetHeight();
    SDL_GPUColorTargetInfo colorTarget = {};
    colorTarget.texture = target->Get();
    colorTarget.clear_color = { 0.0f, 0.0f, 0.0f, 0.0f };
    colorTarget.load_op = SDL_GPU_LOADOP_LOAD;
    colorTarget.store_op = SDL_GPU_STOREOP_STORE;
    colorTarget.mip_level = 0;
    colorTarget.layer_or_depth_plane = 0;
    colorTarget.cycle = false;
    GPU::AquirePushCommandBuffer();
    GPU::BeginRendering({ &colorTarget }, nullptr);
    SDL_SetGPUViewport(GPU::GetRenderPass(), &viewport);
    pipeline->Bind();
    SDL_GPUBufferBinding vertexBufferBinding = { .buffer = vertexBuffer->Get(), .offset = 0 };
    SDL_BindGPUVertexBuffers(GPU::GetRenderPass(), 0, &vertexBufferBinding, 1);
    SDL_GPUTextureSamplerBinding textureSamplerBinding = { .texture = Target->Get(), .sampler = sampler };
    SDL_BindGPUFragmentSamplers(GPU::GetRenderPass(), 0, &textureSamplerBinding, 1);
    float pushConstants[1] = { (float)Opacity };
    SDL_PushGPUFragmentUniformData(GPU::GetCommandBuffer(), 0, pushConstants, sizeof(pushConstants));
    SDL_DrawGPUPrimitives(GPU::GetRenderPass(), 4, 1, 0, 0); // draw canvas
    GPU::EndRendering();
    GPU::SubmitCommandsPopCommandBuffer();
}