#include "PipelineBuilder.h"
#include "../GPU.h"

PipelineBuilder& PipelineBuilder::Shaders(Shader* vertShader, Shader* fragShader)
{
    this->vertShader = vertShader;
    this->fragShader = fragShader;
    return *this;
}

PipelineBuilder& PipelineBuilder::Format(SDL_GPUTextureFormat format)
{
    this->format = format;
    return *this;
}

PipelineBuilder& PipelineBuilder::FormatSwapchain()
{
    this->format = GPU::GetSwapchainFormat();
    return *this;
}

PipelineBuilder& PipelineBuilder::Blend(SDL_GPUColorTargetBlendState blendState)
{
    this->blendState = blendState;
    return *this;
}

PipelineBuilder& PipelineBuilder::BlendPremultiplied()
{
    blendState = {};
    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;
    blendState.enable_blend = true;
    return *this;
}

PipelineBuilder& PipelineBuilder::BlendAlpha()
{
    blendState = {};
    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_SRC_ALPHA;
    blendState.dst_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ONE_MINUS_SRC_ALPHA;
    blendState.dst_color_blendfactor = SDL_GPU_BLENDFACTOR_ONE_MINUS_SRC_ALPHA;
    blendState.enable_blend = true;
    return *this;
}

PipelineBuilder& PipelineBuilder::BlendErase()
{
    blendState = {};
    blendState.alpha_blend_op = SDL_GPU_BLENDOP_ADD;
    blendState.color_blend_op = SDL_GPU_BLENDOP_ADD;
    blendState.src_alpha_blendfactor = SDL_GPU_BLENDFACTOR_ZERO;
    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;
    blendState.enable_blend = true;
    return *this;
}

PipelineBuilder& PipelineBuilder::BlendAlphaKeepColor()
{
    blendState = {};
    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;
    blendState.enable_blend = true;
    return *this;
}

PipelineBuilder& PipelineBuilder::Vertex(SDL_GPUVertexInputState vertexInputState)
{
    this->vertexInputState = vertexInputState;
    return *this;
}

PipelineBuilder& PipelineBuilder::Primitive(SDL_GPUPrimitiveType primitiveType)
{
    this->primitiveType = primitiveType;
    return *this;
}

GraphicsPipeline* PipelineBuilder::Build()
{

    SDL_GPUColorTargetDescription colorTargetDesciption = {};
    colorTargetDesciption.format = format;
    colorTargetDesciption.blend_state = blendState;
    SDL_GPUGraphicsPipelineTargetInfo targetInfo = {};
    targetInfo.num_color_targets = 1;
    targetInfo.color_target_descriptions = &colorTargetDesciption;
    SDL_GPUGraphicsPipelineCreateInfo createInfo = {};
    createInfo.vertex_shader = vertShader->Get();
    createInfo.fragment_shader = fragShader->Get();
    createInfo.target_info = targetInfo;
    createInfo.vertex_input_state = vertexInputState;
    createInfo.primitive_type = primitiveType;

    SDL_GPUGraphicsPipeline* pipeline = SDL_CreateGPUGraphicsPipeline(GPU::GetDevice(), &createInfo);
    return new GraphicsPipeline(pipeline);
}