#include "BlendingPipelineManagementContext.h"
#include "../PrimitivesBuilder/PipelineBuilder.h"
#include "../PrimitivesBuilder/VertexInputStateBuilder.h"
#include "../Assets.h"

std::unordered_map<Blendmode, GraphicsPipeline*> BlendingPipelineManagementContext::Pipelines;

GraphicsPipeline* BlendingPipelineManagementContext::createPipeline(Blendmode blendmode)
{
    auto* vertShader = new Shader(Assets::Path("shaders/CanvasRenderingTarget.vert.spirv"), "main", 0, 0, 0, 0);
    auto* fragShader = new Shader(Assets::Path("shaders/CanvasRenderingTarget.frag.spirv"), "main", 1, 0, 0, 1);

    SDL_GPUColorTargetBlendState blendState = {};
    blendState.enable_blend = true;
    switch (blendmode) {
    default:
    case NORMAL:
        blendState.alpha_blend_op = SDL_GPU_BLENDOP_ADD;
        blendState.color_blend_op = SDL_GPU_BLENDOP_ADD;
        blendState.src_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ONE;
        blendState.src_color_blendfactor = SDL_GPU_BLENDFACTOR_ONE;
        blendState.dst_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ONE_MINUS_SRC_ALPHA;
        blendState.dst_color_blendfactor = SDL_GPU_BLENDFACTOR_ONE_MINUS_SRC_ALPHA;
        break;
    case ADDITIVE:
        blendState.alpha_blend_op = SDL_GPU_BLENDOP_ADD;
        blendState.color_blend_op = SDL_GPU_BLENDOP_ADD;
        blendState.src_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ONE;
        blendState.src_color_blendfactor = SDL_GPU_BLENDFACTOR_ONE;
        blendState.dst_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ONE_MINUS_SRC_ALPHA;
        blendState.dst_color_blendfactor = SDL_GPU_BLENDFACTOR_ONE;
        break;
    case SUBTRACT:
        blendState.alpha_blend_op = SDL_GPU_BLENDOP_SUBTRACT;
        blendState.color_blend_op = SDL_GPU_BLENDOP_SUBTRACT;
        blendState.src_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ONE;
        blendState.src_color_blendfactor = SDL_GPU_BLENDFACTOR_ONE;
        blendState.dst_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ONE;
        blendState.dst_color_blendfactor = SDL_GPU_BLENDFACTOR_ONE;
        break;
    case MULTIPLY:
        blendState.alpha_blend_op = SDL_GPU_BLENDOP_ADD;
        blendState.color_blend_op = SDL_GPU_BLENDOP_ADD;
        blendState.src_alpha_blendfactor = SDL_GPU_BLENDFACTOR_DST_COLOR;
        blendState.src_color_blendfactor = SDL_GPU_BLENDFACTOR_ZERO;
        blendState.dst_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ONE_MINUS_SRC_ALPHA;
        blendState.dst_color_blendfactor = SDL_GPU_BLENDFACTOR_ONE_MINUS_SRC_ALPHA;
        break;
    case SCREEN:
        blendState.alpha_blend_op = SDL_GPU_BLENDOP_ADD;
        blendState.color_blend_op = SDL_GPU_BLENDOP_ADD;
        blendState.src_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ONE;
        blendState.src_color_blendfactor = SDL_GPU_BLENDFACTOR_ONE;
        blendState.dst_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ONE_MINUS_SRC_ALPHA;
        blendState.dst_color_blendfactor = SDL_GPU_BLENDFACTOR_ONE_MINUS_SRC_ALPHA;
        break;
    case DARKEN:
        blendState.alpha_blend_op = SDL_GPU_BLENDOP_ADD;
        blendState.color_blend_op = SDL_GPU_BLENDOP_ADD;
        blendState.src_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ONE;
        blendState.src_color_blendfactor = SDL_GPU_BLENDFACTOR_ZERO;
        blendState.dst_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ONE_MINUS_SRC_ALPHA;
        blendState.dst_color_blendfactor = SDL_GPU_BLENDFACTOR_ONE_MINUS_SRC_ALPHA;
        break;
    case LIGHTEN:
        blendState.alpha_blend_op = SDL_GPU_BLENDOP_ADD;
        blendState.color_blend_op = SDL_GPU_BLENDOP_ADD;
        blendState.src_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ONE;
        blendState.src_color_blendfactor = SDL_GPU_BLENDFACTOR_ONE;
        blendState.dst_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ONE_MINUS_SRC_ALPHA;
        blendState.dst_color_blendfactor = SDL_GPU_BLENDFACTOR_ONE_MINUS_SRC_ALPHA;
        break;
    case LINEAR_DODGE:
        blendState.alpha_blend_op = SDL_GPU_BLENDOP_ADD;
        blendState.color_blend_op = SDL_GPU_BLENDOP_ADD;
        blendState.src_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ONE;
        blendState.src_color_blendfactor = SDL_GPU_BLENDFACTOR_ONE;
        blendState.dst_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ONE_MINUS_SRC_ALPHA;
        blendState.dst_color_blendfactor = SDL_GPU_BLENDFACTOR_ONE_MINUS_SRC_ALPHA;
        break;
    }


    auto vertexInputState = VertexInputStateBuilder()
        .AddAttribute(0, SDL_GPU_VERTEXELEMENTFORMAT_FLOAT2)
        .AddAttribute(1, SDL_GPU_VERTEXELEMENTFORMAT_FLOAT2)
        .BuildDeferred();

    GraphicsPipeline* pipeline = PipelineBuilder()
        .Shaders(vertShader, fragShader)
        .Blend(blendState)
        .Format(SDL_GPU_TEXTUREFORMAT_R8G8B8A8_UNORM)
        .Vertex(vertexInputState.Use())
        .Primitive(SDL_GPU_PRIMITIVETYPE_TRIANGLESTRIP)
        .Build();

    Pipelines[blendmode] = pipeline;
    return pipeline;
}

GraphicsPipeline* BlendingPipelineManagementContext::GetPipeline(Blendmode blendmode)
{
    if (Pipelines.find(blendmode) != Pipelines.end())
        return Pipelines[blendmode];
    return createPipeline(blendmode);
}