#include "render_context.h"

#include "LLGL/Utils/VertexFormat.h"
#include "mirage.h"
#include "rendering_common.h"
#include "shader_loader.h"
#include "LLGL/Utils/Parse.h"

struct pipeline_param {
    Eigen::Matrix4f mvp;
};

namespace mirage {
    render_context::~render_context() {
        if (command_buffer) {
            get_renderer()->Release(*command_buffer);
        }
        if (swap_chain) {
            get_renderer()->Release(*swap_chain);
        }
    }

    bool render_context::init(const swap_chain_descriptor& in_desc, const std::shared_ptr<LLGL::Surface>& in_surface) {
        LLGL::SwapChainDescriptor temp = in_desc;
        temp.resolution                = in_surface->GetContentSize();
        swap_chain                     = get_renderer()->CreateSwapChain(temp, in_surface);
        if (swap_chain == nullptr) {
            spdlog::error("无法创建交换链");
            return false;
        }

        command_buffer = get_renderer()->CreateCommandBuffer(LLGL::CommandBufferFlags::ImmediateSubmit);
        if (command_buffer == nullptr) {
            spdlog::error("无法创建命令缓冲区");
            return false;
        }
        set_vsync(in_desc.vsync);
        vertex_buffer = create_vertex_buffer(64);
        index_buffer  = create_index_buffer(64);
        param_buffer  = create_constant_buffer<pipeline_param>();

        pipeline_param param;
        param.mvp = get_projection_matrix();
        param_buffer->set(param);

        LLGL::PipelineLayoutDescriptor pipeline_layout_desc;
        // pipeline_layout_desc.bindings.emplace_back(
        //     LLGL::ResourceType::Buffer,
        //     LLGL::BindFlags::VertexBuffer,
        //     LLGL::StageFlags::VertexStage,
        //     0
        //     );
        pipeline_layout_desc.bindings.emplace_back(
            LLGL::ResourceType::Buffer,
            LLGL::BindFlags::ConstantBuffer,
            LLGL::StageFlags::VertexStage | LLGL::StageFlags::FragmentStage,
            1
            );
        pipeline = generated_pipelines::create_aorii_rect_pipeline(get_renderer(), swap_chain->GetRenderPass(), pipeline_layout_desc);

        push_rectangle({0, 0}, {100, 100}, linear_color::white);
        return true;
    }

    render_context::update_status render_context::render_update(const duration_type& in_delta_time) {
        if (!command_buffer || !swap_chain) {
            return update_status::fail;
        }
        if (!swap_chain->IsPresentable()) {
            return update_status::wait_for_present;
        }

        if (new_size) {
            swap_chain->ResizeBuffers(new_size.value());
            pipeline_param param;
            param.mvp = get_projection_matrix();
            param_buffer->set(param);
            new_size.reset();
        }

        command_buffer->Begin(); {
            command_buffer->SetViewport(swap_chain->GetResolution());

            command_buffer->SetIndexBuffer(index_buffer->get_raw());
            command_buffer->SetVertexBuffer(vertex_buffer->get_raw());

            command_buffer->BeginRenderPass(*swap_chain); {
                command_buffer->Clear(LLGL::ClearFlags::Color, {0.1f, 0.1f, 0.2f, 1.0f});
                command_buffer->SetPipelineState(*pipeline.pipeline_state);

                command_buffer->SetResource(0, param_buffer->get_raw());
                
                command_buffer->DrawIndexed(index_buffer->get_size() / sizeof(uint32_t), 0);
            }
            command_buffer->EndRenderPass();
        }
        command_buffer->End();
        get_renderer()->GetCommandQueue()->Submit(*command_buffer);
        swap_chain->Present();
        return update_status::success;
    }

    void render_context::resize_swap_chain(const LLGL::Extent2D& in_size, long in_flag) {
        if (!swap_chain)
            return;
        new_size = in_size;
    }

    void render_context::set_vsync(bool in_vsync) {
        if (!swap_chain)
            return;
        swap_chain->SetVsyncInterval(in_vsync ? 1 : 0);
        vsync = in_vsync;
        spdlog::info("垂直同步: {}", vsync);
    }

    void render_context::push_rectangle(const Eigen::Vector2f& in_pos, const Eigen::Vector2f& in_size,
        const linear_color_type& in_color) {
        vertex va{};
        vertex vb{};
        vertex vc{};
        vertex vd{};
        va.color = in_color;
        vb.color = in_color;
        vc.color = in_color;
        vd.color = in_color;

        va.position = in_pos;
        vb.position = {in_pos.x() + in_size.x(), in_pos.y()};
        vc.position = in_pos + in_size;
        vd.position = {in_pos.x(), in_pos.y() + in_size.y()};

        va.uv = {0.0f, 0.0f};
        vb.uv = {1.0f, 0.0f};
        vc.uv = {1.0f, 1.0f};
        vd.uv = {0.0f, 1.0f};

        const auto index_offset = static_cast<uint32_t>(vertex_buffer->get_size() / sizeof(vertex));

        // 根据index_offset计算索引
        const triangle_index_t ta = {0 + index_offset, 1 + index_offset, 2 + index_offset};
        const triangle_index_t tb = {0 + index_offset, 2 + index_offset, 3 + index_offset};

        std::vector quad_indices  = {ta, tb};
        std::vector quad_vertices = {va, vb, vc, vd};
        vertex_buffer->push(quad_vertices);
        index_buffer->push(quad_indices);
    }

    Eigen::Matrix4f render_context::get_projection_matrix() const {
        const bool is_clip_range_unit_cube = get_renderer()->GetRenderingCaps().clippingRange ==
                                             LLGL::ClippingRange::MinusOneToOne;
        const auto& size = swap_chain->GetResolution();

        Eigen::Matrix4f matrix = Eigen::Matrix4f::Identity();

        if (is_clip_range_unit_cube) {
            // 对于 [-1, 1] 的裁剪范围
            matrix(0, 0) = 2.0f / size.width;
            matrix(1, 1) = -2.0f / size.height;
            matrix(2, 2) = 1.0f;
            matrix(3, 3) = 1.0f;
            matrix(3, 0) = -1.0f;
            matrix(3, 1) = 1.0f;

            // 调整Z轴范围从[-1,1]
            matrix(2, 2) = 2.0f;
            matrix(3, 2) = -1.0f;
        } else {
            // 对于 [0, 1] 的裁剪范围
            matrix(0, 0) = 2.0f / size.width;
            matrix(1, 1) = -2.0f / size.height;
            matrix(2, 2) = 1.0f;
            matrix(3, 3) = 1.0f;
            matrix(3, 0) = -1.0f;
            matrix(3, 1) = 1.0f;
            // 调整Z轴范围从[0,1]
            matrix(2, 2) = 1.0f;
            matrix(3, 2) = 0.0f;
        }
        return matrix;
    }

} // namespace mirage