#pragma once
#ifndef _NB_DRAW
#define _NB_DRAW

#include <exception>
#include <string>
#include <vector>

#include <glad/glad.h>
#include <GLFW/glfw3.h>

#include "Buffers.h"
#include "Shader.h"

namespace NB{

class DrawWarning : public std::runtime_error {
public:
    DrawWarning(const std::string&);
};

uint8_t GLSLTypeSize(GLenum);

uint8_t GLSLPrimitiveVertexSize(GLenum, unsigned int num_prims=1);

template<typename T>
std::vector<unsigned char> rawDataVector(const std::vector<T>& vec) {
    unsigned int num_bytes = vec.size() * sizeof(T);
    std::vector<unsigned char> ret(num_bytes);
    memcpy(ret.data(), vec.data(), num_bytes);

    return ret;
}

struct VertexAttributePointer {
    int32_t offset;
    GLsizei stride = -1;
};

struct VertexAttribute {
    const GLint GLSLSize;
    const GLenum GLSLType;
    const GLboolean GLSLNormalization;
    VertexAttributePointer ptr;
};

class DrawBuffer {
public:
    DrawBuffer(std::vector<VertexAttribute>, const Shader&);
    //DrawBuffer(std::initializer_list<VertexAttribute>, std::initializer_list<VertexAttributePointer>);

    unsigned int vertSize() const;
    std::vector<VertexAttributePointer> getLayout() const;
    const Shader shader() const;
    bool keepLocalElement() const;
    bool keepLocalVertex() const;
    unsigned int elementBufferID() const;
    unsigned int vertexBufferID() const;
    virtual void draw() const;

    bool keepLocalElement(bool);
    bool keepLocalVertex(bool);
    const Shader shader(const Shader&);
    virtual std::vector<VertexAttributePointer> setLayout();
    virtual std::vector<VertexAttributePointer> setLayout(std::vector<VertexAttributePointer>);
    virtual void generateElementBuffer(std::vector<unsigned int>, GLenum gl_primitive_type=GL_TRIANGLES);
    virtual void generateElementBuffer(unsigned int, GLenum gl_primitive_type=GL_TRIANGLES);
    virtual void generateVertexBuffer(std::vector<unsigned char>);
    virtual void generateVertexBuffer(unsigned int);
    virtual void loadElementBuffer(const std::vector<unsigned int>&, unsigned int offset=0, GLenum gl_primitive_type=GL_TRIANGLES);
    virtual void loadVertexBuffer(const std::vector<unsigned char>&, unsigned int offset=0);

protected:
    std::vector<VertexAttribute> _vertex_attributes;
    BufferManager<unsigned char> _vert_data;
    BufferManager<unsigned int> _elmt_data;
    Shader _shader;
    unsigned int _num_verts, _num_prims, _VAO;
    GLenum _gl_primitive_type;
};

}
#endif