#ifndef slic3r_GLModel_hpp_
#define slic3r_GLModel_hpp_

#include "libslic3r/Point.hpp"
#include "libslic3r/Color.hpp"
#include "libslic3r/BoundingBox.hpp"
#include <vector>
#include <string>

struct indexed_triangle_set;

namespace Slic3r {

class TriangleMesh;
class Polygon;
using Polygons = std::vector<Polygon>;

namespace GUI {

    class GLModel
    {
    public:
        enum class PrimitiveType : unsigned char
        {
            Triangles,
            Lines,
            LineStrip,
            LineLoop
        };

        struct Geometry
        {
            // enum class EPrimitiveType : unsigned char { Points, Triangles, TriangleStrip, TriangleFan, Lines, LineStrip, LineLoop };
            enum class EVertexLayout : unsigned char {
                P2,     // position 2 floats
                P2T2,   // position 2 floats + texture coords 2 floats
                P3,     // position 3 floats
                P3T2,   // position 3 floats + texture coords 2 floats
                P3N3,   // position 3 floats + normal 3 floats
                P3N3T2, // position 3 floats + normal 3 floats + texture coords 2 floats
                P4,     // position 4 floats
            };

            enum class EIndexType : unsigned char {
                UINT,   // unsigned int
                USHORT, // unsigned short
                UBYTE   // unsigned byte
            };

            struct Format
            {
                PrimitiveType type{PrimitiveType::Triangles};
                EVertexLayout vertex_layout{EVertexLayout::P3N3};
            };

            Format                    format;
            std::vector<float>        vertices;
            std::vector<unsigned int> indices;
            EIndexType                index_type{EIndexType::UINT};
            ColorRGBA                 color{ColorRGBA::BLACK()};

            void reserve_vertices(size_t vertices_count) { vertices.reserve(vertices_count * vertex_stride_floats(format)); }
            void reserve_indices(size_t indices_count) { indices.reserve(indices_count); }

            void add_vertex(const Vec2f &position);                                              // EVertexLayout::P2
            void add_vertex(const Vec2f &position, const Vec2f &tex_coord);                      // EVertexLayout::P2T2
            void add_vertex(const Vec3f &position);                                              // EVertexLayout::P3
            void add_vertex(const Vec3f &position, const Vec2f &tex_coord);                      // EVertexLayout::P3T2
            void add_vertex(const Vec3f &position, const Vec3f &normal);                         // EVertexLayout::P3N3
            void add_vertex(const Vec3f &position, const Vec3f &normal, const Vec2f &tex_coord); // EVertexLayout::P3N3T2
            void add_vertex(const Vec4f &position);                                              // EVertexLayout::P4

            void set_vertex(size_t id, const Vec3f &position, const Vec3f &normal); // EVertexLayout::P3N3

            void set_index(size_t id, unsigned int index);

            void add_index(unsigned int id);
            void add_line(unsigned int id1, unsigned int id2);
            void add_triangle(unsigned int id1, unsigned int id2, unsigned int id3);

            Vec2f extract_position_2(size_t id) const;
            Vec3f extract_position_3(size_t id) const;
            Vec3f extract_normal_3(size_t id) const;
            Vec2f extract_tex_coord_2(size_t id) const;

            unsigned int extract_index(size_t id) const;

            void remove_vertex(size_t id);

            bool is_empty() const { return vertices_count() == 0 || indices_count() == 0; }

            size_t vertices_count() const { return vertices.size() / vertex_stride_floats(format); }
            size_t indices_count() const { return indices.size(); }

            size_t vertices_size_floats() const { return vertices.size(); }
            size_t vertices_size_bytes() const { return vertices_size_floats() * sizeof(float); }
            size_t indices_size_bytes() const { return indices.size() * index_stride_bytes(*this); }

            indexed_triangle_set get_as_indexed_triangle_set() const;

            static size_t vertex_stride_floats(const Format &format);
            static size_t vertex_stride_bytes(const Format &format) { return vertex_stride_floats(format) * sizeof(float); }

            static size_t position_stride_floats(const Format &format);
            static size_t position_stride_bytes(const Format &format) { return position_stride_floats(format) * sizeof(float); }
            static size_t position_offset_floats(const Format &format);
            static size_t position_offset_bytes(const Format &format) { return position_offset_floats(format) * sizeof(float); }

            static size_t normal_stride_floats(const Format &format);
            static size_t normal_stride_bytes(const Format &format) { return normal_stride_floats(format) * sizeof(float); }
            static size_t normal_offset_floats(const Format &format);
            static size_t normal_offset_bytes(const Format &format) { return normal_offset_floats(format) * sizeof(float); }

            static size_t tex_coord_stride_floats(const Format &format);
            static size_t tex_coord_stride_bytes(const Format &format) { return tex_coord_stride_floats(format) * sizeof(float); }
            static size_t tex_coord_offset_floats(const Format &format);
            static size_t tex_coord_offset_bytes(const Format &format) { return tex_coord_offset_floats(format) * sizeof(float); }

            static size_t index_stride_bytes(const Geometry &data);

            static bool has_position(const Format &format);
            static bool has_normal(const Format &format);
            static bool has_tex_coord(const Format &format);
        };

        struct RenderData
        {
            Geometry geometry;

            PrimitiveType        type;
            unsigned int         vbo_id{0};
            unsigned int         ibo_id{0};
            size_t               indices_count{0};
            std::array<float, 4> color{1.0f, 1.0f, 1.0f, 1.0f};
        };

        struct InitializationData
        {
            struct Entity
            {
                PrimitiveType type;
                std::vector<Vec3f> positions;
                std::vector<Vec3f> normals;
                std::vector<unsigned int> indices;
                std::array<float, 4> color{ 1.0f, 1.0f, 1.0f, 1.0f };
            };

            std::vector<Entity> entities;

            size_t vertices_count() const;
            size_t vertices_size_floats() const { return vertices_count() * 6; }
            size_t vertices_size_bytes() const { return vertices_size_floats() * sizeof(float); }

            size_t indices_count() const;
            size_t indices_size_bytes() const { return indices_count() * sizeof(unsigned int); }
        };

    private:
        std::vector<RenderData> m_render_data;

        BoundingBoxf3 m_bounding_box;
        std::string m_filename;

    public:
        GLModel() = default;
        virtual ~GLModel();

        TriangleMesh *mesh{nullptr};

        void init_from(Geometry &&data, bool generate_mesh = false);
        void init_from(const InitializationData& data);
        void init_from(const indexed_triangle_set& its, const BoundingBoxf3& bbox);
        void init_from(const indexed_triangle_set& its);
        void init_from(const Polygons& polygons, float z);
        bool init_from_file(const std::string& filename);

        // if entity_id == -1 set the color of all entities
        void set_color(int entity_id, const std::array<float, 4>& color);

        void reset();
        void render() const;
        void render_instanced(unsigned int instances_vbo, unsigned int instances_count) const;

        bool is_initialized() const { return !m_render_data.empty(); }

        const BoundingBoxf3& get_bounding_box() const { return m_bounding_box; }
        const std::string& get_filename() const { return m_filename; }

    private:
        bool send_to_gpu(RenderData &data, const std::vector<float> &vertices, const std::vector<unsigned int> &indices) const;
    };

    // create an arrow with cylindrical stem and conical tip, with the given dimensions and resolution
    // the origin of the arrow is in the center of the stem cap
    // the arrow has its axis of symmetry along the Z axis and is pointing upward
    // used to render bed axes and sequential marker
    GLModel::InitializationData stilized_arrow(int resolution, float tip_radius, float tip_height, float stem_radius, float stem_height);

    // create an arrow whose stem is a quarter of circle, with the given dimensions and resolution
    // the origin of the arrow is in the center of the circle
    // the arrow is contained in the 1st quadrant of the XY plane and is pointing counterclockwise
    // used to render sidebar hints for rotations
    GLModel::InitializationData circular_arrow(int resolution, float radius, float tip_height, float tip_width, float stem_width, float thickness);

    // create an arrow with the given dimensions
    // the origin of the arrow is in the center of the stem cap
    // the arrow is contained in XY plane and has its main axis along the Y axis
    // used to render sidebar hints for position and scale
    GLModel::InitializationData straight_arrow(float tip_width, float tip_height, float stem_width, float stem_height, float thickness);

    // create a diamond with the given resolution
    // the origin of the diamond is in its center
    // the diamond is contained into a box with size [1, 1, 1]
    GLModel::InitializationData diamond(int resolution);

    // create a sphere with smooth normals
    // the origin of the sphere is in its center
    GLModel::Geometry smooth_sphere(unsigned int resolution, float radius);
    // create a cylinder with smooth normals
    // the axis of the cylinder is the Z axis
    // the origin of the cylinder is the center of its bottom cap face
    GLModel::Geometry smooth_cylinder(unsigned int resolution, float radius, float height);
    // create a torus with smooth normals
    // the axis of the torus is the Z axis
    // the origin of the torus is in its center
    GLModel::Geometry smooth_torus(unsigned int primary_resolution, unsigned int secondary_resolution, float radius, float thickness);

    std::shared_ptr<GLModel> init_plane_data(const indexed_triangle_set &its, const std::vector<int> &triangle_indices,float normal_offset = 0.0f);
    std::shared_ptr<GLModel> init_torus_data(unsigned int       primary_resolution,
                                             unsigned int       secondary_resolution,
                                             const Vec3f &      center,
                                             float              radius,
                                             float              thickness,
                                             const Vec3f &      model_axis,
                                             const Transform3f &world_trafo);
    } // namespace GUI
} // namespace Slic3r

#endif // slic3r_GLModel_hpp_