/**
 * Copyright (c) 2026 Dominic Masters
 * 
 * This software is released under the MIT License.
 * https://opensource.org/licenses/MIT
 */

#pragma once
#include "error/error.h"
#include "display/mesh/meshvertex.h"

typedef enum {
  MESH_PRIMITIVE_TYPE_TRIANGLES = GL_TRIANGLES,
  MESH_PRIMITIVE_TYPE_LINES = GL_LINES,
  MESH_PRIMITIVE_TYPE_POINTS = GL_POINTS,
} meshprimitivetypegl_t;

typedef struct {
  int32_t vertexCount;
  meshprimitivetypegl_t primitiveType;
  const meshvertex_t *vertices;
  
  #ifdef DUSK_OPENGL_LEGACY
    // Nothing needed
  #else
    GLuint vaoId;
    GLuint vboId;
  #endif
} meshgl_t;

/**
 * Initializes a mesh for OpenGL.
 * 
 * @param mesh The mesh to initialize.
 * @param primitiveType The OpenGL primitive type (e.g., GL_TRIANGLES).
 * @param vertexCount The number of vertices in the mesh.
 * @param vertices The vertex data for the mesh.
 * @return An errorret_t indicating success or failure.
 */
errorret_t meshInitGL(
  meshgl_t *mesh,
  const meshprimitivetypegl_t primitiveType,
  const int32_t vertexCount,
  const meshvertex_t *vertices
);

/**
 * Flushes the vertices (stored in memory) to the GPU.
 * 
 * @param mesh Mesh to flush vertices for.
 * @param vertOffset First vertice index to flush.
 * @param vertCount Count of vertices to flush.
 * @return Error state.
 */
errorret_t meshFlushGL(
  meshgl_t *mesh,
  const int32_t vertOffset,
  const int32_t vertCount
);

/**
 * Draws a mesh using OpenGL.
 * 
 * @param mesh The mesh to draw.
 * @param vertexOffset The offset in the vertex array to start drawing from.
 * @param vertexCount The number of vertices to draw. If -1, draws all vertices.
 * @return An errorret_t indicating success or failure.
 */
errorret_t meshDrawGL(
  const meshgl_t *mesh,
  const int32_t vertexOffset,
  const int32_t vertexCount
);

/**
 * Gets the vertex count of a mesh used for OpenGL.
 * 
 * @param mesh The mesh to get the vertex count from.
 * @return The vertex count of the mesh.
 */
int32_t meshGetVertexCountGL(const meshgl_t *mesh);

/**
 * Disposes a mesh used for OpenGL.
 * 
 * @param mesh The mesh to dispose.
 * @return An errorret_t indicating success or failure.
 */
errorret_t meshDisposeGL(meshgl_t *mesh);