#include <GL/glew.h>

#include "gl.h"

void mesh_init(Mesh *mesh, u32 vertex_count)
{
	glGenVertexArrays(1, &mesh->vao);
	mesh->vbos_count = 0;
	mesh->vertex_count = vertex_count;
	glBindVertexArray(mesh->vao);
}

static void mesh_store(Mesh *mesh, void *data, u32 len, u32 dimensions, GLenum type)
{
	GLuint vbo;
	GLint index = mesh->vbos_count;
	glGenBuffers(1, &vbo);
	glBindBuffer(GL_ARRAY_BUFFER, vbo);
	glBufferData(GL_ARRAY_BUFFER, len, data, GL_STATIC_DRAW);
	glEnableVertexAttribArray(index);
	if (type == GL_FLOAT)
		glVertexAttribPointer(index, dimensions, type, GL_FALSE, 0, 0);
	else
		glVertexAttribIPointer(index, dimensions, type, 0, 0);
	mesh->vbos[mesh->vbos_count++] = vbo;
}

void mesh_store_float(Mesh *mesh, float *data, u32 count, u32 dimensions)
{
	mesh_store(mesh, data, count * sizeof(float), dimensions, GL_FLOAT);
}

void mesh_store_i32(Mesh *mesh, i32 *data, u32 count, u32 dimensions)
{
	mesh_store(mesh, data, count * sizeof(i32), dimensions, GL_INT);
}

void mesh_store_u8(Mesh *mesh, u8 *data, u32 count, u32 dimensions)
{
	mesh_store(mesh, data, count * sizeof(u8), dimensions, GL_UNSIGNED_BYTE);
}

void mesh_store_u32(Mesh *mesh, u32 *data, u32 count, u32 dimensions)
{
	mesh_store(mesh, data, count * sizeof(u32), dimensions, GL_UNSIGNED_INT);
}

void mesh_finish(void)
{
	glBindVertexArray(0);
}

void mesh_bind(Mesh *mesh)
{
	glBindVertexArray(mesh->vao);
	for (int i = 0; i < mesh->vbos_count; i++)
		glEnableVertexAttribArray(i);
}

void mesh_unbind(Mesh *mesh)
{
	for (int i = 0; i < mesh->vbos_count; i++)
		glDisableVertexAttribArray(i);
	glBindVertexArray(0);
}

void mesh_draw(Mesh *mesh)
{
	glDrawArrays(GL_TRIANGLES, 0, mesh->vertex_count);
}

void mesh_draw_instanced(Mesh *mesh, u32 count)
{
	glDrawArraysInstanced(GL_TRIANGLES, 0, mesh->vertex_count, count);
}

void mesh_free(Mesh *mesh)
{
	glDeleteBuffers(mesh->vbos_count, mesh->vbos);
	glDeleteVertexArrays(1, &mesh->vao);
}

void uniform_init(Uniform *uniform, u32 len)
{
	uniform->len = len;
	glGenBuffers(1, &uniform->id);
	glBindBuffer(GL_UNIFORM_BUFFER, uniform->id);
	glBufferData(GL_UNIFORM_BUFFER, len, NULL, GL_DYNAMIC_DRAW);
	glBindBuffer(GL_UNIFORM_BUFFER, 0);
}

void uniform_store(Uniform *uniform, u32 offset, u32 len, void *data)
{
	glBindBuffer(GL_UNIFORM_BUFFER, uniform->id);
	glBufferSubData(GL_UNIFORM_BUFFER, offset, len, data);
	glBindBuffer(GL_UNIFORM_BUFFER, 0);
}

void uniform_bind(Uniform *uniform, u32 binding)
{
	glBindBufferBase(GL_UNIFORM_BUFFER, binding, uniform->id);
}

void uniform_unbind(u32 binding)
{
	glBindBufferBase(GL_UNIFORM_BUFFER, binding, 0);
}

void uniform_free(Uniform *uniform)
{
	glDeleteBuffers(1, &uniform->id);
}