#ifndef IMESH_H
#define IMESH_H

#include <glew/glew.h>
#include <vector>
#include <glm/vec3.hpp>
#include <glm/vec2.hpp>

class IMesh
{
protected:
    enum {POSITION_BUFFER, NORMAL_BUFFER, TEXCOORD_BUFFER, TANGENT_BUFFER, INDICES_BUFFER, NB_BUFFERS};

    typedef struct
    {
        glm::vec3 tangent;
        glm::vec3 bitangent;
    } Tangents;

    std::vector<glm::vec3> positions;
    std::vector<glm::vec3> normals;
    std::vector<glm::vec2> texCoords;
    std::vector<Tangents> tangents;
    std::vector<unsigned int> indices;

    GLuint vao;
    GLuint vbo[NB_BUFFERS];
    bool locked;

public:
    ~IMesh();
    void addTriangle(int i1, int i2, int i3);

    void addVertex(float x, float y, float z);
    void addVertex(glm::vec3 &position);
    void addVertex(glm::vec3 &position, glm::vec3 &normal);
    void addVertex(glm::vec3 &position, glm::vec2 &texCoord);
    void addVertex(glm::vec3 &position, glm::vec3 &normal, glm::vec2 &texCoord);

    void computeFaceNormals();
    void computeVertexNormals();
    void computeTangents();

    bool hasNormals();
    bool hasTexCoords();
    bool hasTangents();

    /*
     * When the mesh is locked, addFace and addVertex do nothing, but the mesh can be drawn
     * initGL locks the mesh
     * destroyGL unlocks the mesh
     */
    void initGL(bool isDynamic = false);
    void destroyGL();
    void draw();
    bool isLocked(){return locked;}
};

#endif // IMESH_H