/*         +------------------------------------------------------+ 
  ____/  \____   /| - Open source game framework licensed to freely use, |
  \          /  / |   copy, modify and sell without restriction          |
+--\ ^__^   /--+  |                                                      |
| ~/        \~ |  | - created for <https://foam.shampoo.ooo>             |
| ~~~~~~~~~~~~ |  +------------------------------------------------------+
| SPACE ~~~~~  | /
|  ~~~~~~~ BOX |/
+-------------*/

#pragma once

/* GL functions */
#if defined(__EMSCRIPTEN__)
#include <GL/glew.h>
#elif defined(__ANDROID__) || defined(ANDROID)
#include <GLES3/gl3.h>
#include <GLES3/gl3ext.h>
#else
#include "glew/glew.h"
#endif

#include <iostream>
#include <string>
#include <map>
#include <memory>
#include <iterator>
#include <stdexcept>
#include "glm/glm.hpp"
#include "Attributes.hpp"
#include "Texture.hpp"
#include "Carousel.hpp"

namespace sb
{

    class Model
    {

    private:

        inline static const std::string DEFAULT_TEXTURE_NAME = "default";
        std::map<std::string, sb::Texture> _textures;
        std::map<std::string, std::shared_ptr<sb::Attributes>> _attributes;
        glm::mat4 _transformation {1.0f};

    public:

        Model();
        Model(const std::map<std::string, std::shared_ptr<sb::Attributes>>&);
        Model(const std::map<std::string, sb::Attributes>&);
        Model(const std::initializer_list<std::string>&);
        std::map<std::string, std::shared_ptr<sb::Attributes>>& attributes();
        std::shared_ptr<sb::Attributes>& attributes(const std::string&);
        void attributes(const sb::Attributes&, const std::string&);
        void attributes(const std::shared_ptr<sb::Attributes>&, const std::string&);
        std::shared_ptr<sb::Attributes>& operator[](const std::string&);
        void enable();
        void disable();
        std::map<std::string, sb::Texture>& textures();
        sb::Texture& texture(const std::string&);
        sb::Texture& texture();
        void texture(const sb::Texture&, const std::string&);
        void texture(const sb::Texture&);

        /*!
         * @return   a constanst reference to the model's transformation matrix
         */
        const glm::mat4& transformation() const;

        /*!
         * Apply the given transformation matrix to the model's current transformation matrix.
         *
         * @return   the model's new transformation matrix
         */
        const glm::mat4& transform(const glm::mat4& transformation);

        /*!
         * Resets the model's transformation to the identity matrix.
         *
         * @return   the model's new transformation matrix, the identity matrix
         */
        const glm::mat4& untransform();

        /*!
         * Specialized version of transform(const glm::mat4&) that builds a scale transformation from an x, y, z vector and
         * applies it to the model's transformation matrix.
         *
         * @param scale   x, y, z scale
         * @return        the model's new transformation matrix
         */
        const glm::mat4& scale(const glm::vec3& scale);

        /*!
         * Scale all dimensions by the same amount.

         * @overload scale(const glm::vec3&)
         */
        const glm::mat4& scale(float scale);

        /*!
         * Specialized version of transform(const glm::mat4&) that builds a rotation matrix from an angle in radians and an axis
         * vector and applies it to the model's transformation matrix.
         *
         * The axis is the vector around which the model will be rotated. For example, to rotate a 2D plane around the origin, use
         * the z-axis: `glm::vec3(0.0f, 0.0f, 1.0f)`.
         *
         * @param angle   angle in radians
         * @param axis    axis to rotate the model around
         * @return        the model's new transformation matrix
         */
        const glm::mat4& rotate(float angle, glm::vec3 axis);

        /*!
         * Specialized version of transform(const glm::mat4&) that builds a translation matrix from a 3D translation vector
         * indicating the distance to translate along each axis and applies it to the model's transformation matrix.
         *
         * @param translation   distance to translate in the x, y, and z dimensions
         * @return              the model's new transformation matrix
         */
        const glm::mat4& translate(glm::vec3 translation);

        std::size_t size();
        operator glm::mat4() const;

    };

    class Plane : public Model
    {

    public:

        /* A plane in the X and Y dimensions, from (-1.0, -1.0) to (1.0, 1.0) */
        inline const static std::shared_ptr<sb::Attributes> position = std::make_shared<sb::Attributes>(sb::Attributes{
                {-1.0f, 1.0f}, {1.0f, 1.0f}, {-1.0f, -1.0f},
                {1.0f, 1.0f}, {1.0f, -1.0f}, {-1.0f, -1.0f}
            });

        /* Map a texture to fill the plane */
        inline const static std::shared_ptr<sb::Attributes> uv = std::make_shared<sb::Attributes>(sb::Attributes{
                {0.0f, 1.0f}, {1.0f, 1.0f}, {0.0f, 0.0f},
                {1.0f, 1.0f}, {1.0f, 0.0f}, {0.0f, 0.0f}
            });

        /* A gradient from magenta to yellow */
        inline const static std::shared_ptr<sb::Attributes> color = std::make_shared<sb::Attributes>(sb::Attributes{
                {1.0f, 1.0f, 0.0f, 1.0f}, {1.0f, 1.0f, 0.0f, 1.0f}, {0.8f, 0.0f, 0.3f, 1.0f},
                {1.0f, 1.0f, 0.0f, 1.0f}, {0.8f, 0.0f, 0.3f, 1.0f}, {0.8f, 0.0f, 0.3f, 1.0f}
            });

        Plane() : Model(std::map<std::string, std::shared_ptr<sb::Attributes>>({{"position", position}, {"uv", uv}, {"color", color}})) {}

    };

    /*!
     * A version of `Plane` which contains two texture objects, one of which is active at a time. A reference
     * to the active `sb::Texture` object is available from `PlaneDoubleBuffer.active`, and the inactive object is
     * available from `PlaneDoubleBuffer.inactive`. The buffers can be swapped using `PlaneDoubleBuffer.swap`.
     */
    class PlaneDoubleBuffer : public Plane
    {

    private:

        bool swapped = false;

    public:

        PlaneDoubleBuffer();
        void generate(const glm::vec2&);
        sb::Texture& active();
        sb::Texture& inactive();
        void swap();

    };
}