#pragma once

#include <array>
#include <cstdint>
#include <memory>
#include <mutex>
#include <string>
#include <vector>

namespace boundard {

// 渲染组件：描述 Actor 的几何形状、颜色和可选 PNG 纹理。
class Mesh {
   public:
    struct Vertex {
        std::array<float, 2> position;
        std::array<float, 4> color;
        std::array<float, 2> uv;
    };

    std::vector<Vertex> vertices;
    std::vector<uint32_t> indices;
    std::string texture;  // PNG 纹理路径；为空时使用白色纹理。

    std::array<float, 4> color() const {
        std::lock_guard<std::mutex> lock(*color_mutex_);
        return color_;
    }

    void set_color(std::array<float, 4> color) {
        std::lock_guard<std::mutex> lock(*color_mutex_);
        color_ = color;
    }

    static Mesh quad() {
        Mesh mesh;
        mesh.vertices = {
            {{-1.0F, -1.0F}, {1.0F, 1.0F, 1.0F, 1.0F}, {0.0F, 0.0F}},
            {{1.0F, -1.0F}, {1.0F, 1.0F, 1.0F, 1.0F}, {1.0F, 0.0F}},
            {{1.0F, 1.0F}, {1.0F, 1.0F, 1.0F, 1.0F}, {1.0F, 1.0F}},
            {{-1.0F, 1.0F}, {1.0F, 1.0F, 1.0F, 1.0F}, {0.0F, 1.0F}},
        };
        mesh.indices = {0, 1, 2, 2, 3, 0};
        return mesh;
    }

    static Mesh grid(int half_cells = 12) {
        Mesh mesh;
        const float world_to_local = 1.0F / 0.35F;
        const float half_extent = static_cast<float>(half_cells) * world_to_local;
        const float line_half_width = 0.012F * world_to_local;
        const std::array<float, 4> line_color{1.0F, 1.0F, 1.0F, 1.0F};
        auto add_rect = [&](float left, float bottom, float right, float top) {
            const uint32_t base = static_cast<uint32_t>(mesh.vertices.size());
            mesh.vertices.insert(mesh.vertices.end(), {
                {{left, bottom}, line_color, {0.0F, 0.0F}},
                {{right, bottom}, line_color, {1.0F, 0.0F}},
                {{right, top}, line_color, {1.0F, 1.0F}},
                {{left, top}, line_color, {0.0F, 1.0F}},
            });
            mesh.indices.insert(mesh.indices.end(),
                                {base, base + 1, base + 2, base + 2, base + 3, base});
        };
        for (int cell = -half_cells; cell <= half_cells; ++cell) {
            const float coordinate = static_cast<float>(cell) * world_to_local;
            add_rect(coordinate - line_half_width, -half_extent, coordinate + line_half_width,
                     half_extent);
            add_rect(-half_extent, coordinate - line_half_width, half_extent,
                     coordinate + line_half_width);
        }
        return mesh;
    }

   private:
    std::unique_ptr<std::mutex> color_mutex_ = std::make_unique<std::mutex>();
    std::array<float, 4> color_{1.0F, 1.0F, 1.0F, 1.0F};
};

}  // namespace boundard