#ifndef _RENDERER_H_
#define _RENDERER_H_

#include <linmath.h>

#include <stdbool.h>
#include <stdlib.h>

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


#define UNIFORMS_COUNT 1
#define PROGRAMS_COUNT 2

#define DEFAULT_PROGRAM 0
#define NUKLEAR_PROGRAM 1

typedef int RENDERER_ERROR;
#define RENDERER_ERROR_OK 0
#define RENDERER_ERROR_GLFW -1
#define RENDERER_ERROR_GLAD -2

#define ERROR_AND_QUIT(R, ...) \
( R==RENDERER_ERROR_GLFW ? fprintf(stderr, "GLFW: %s\n", __VA_ARGS__) \
 : R==RENDERER_ERROR_GLAD ? fprintf(stderr, "GLAD: %s\n", __VA_ARGS__) \
 : fprintf(stderr, "%s\n", __VA_ARGS__)); exit(1)


#if 0
struct nk_glfw_vertex {
	float position[2];
	float uv[2];
	nk_byte col[4];
};
#endif

typedef struct {

	GLFWwindow *window;
	int width;
	int height;


	GLuint vao;
	GLuint vbo;
	GLuint ebo;

	mat4x4 projection;

	GLuint texture_color;
	
	GLuint uniforms[UNIFORMS_COUNT];
	GLuint programs[PROGRAMS_COUNT];

	GLint attrib_pos;
	GLint attrib_uv;
	GLint attrib_col;

#if 0
	/* nuklear */
	struct nk_context *ctx;
	GLuint font_tex;
	struct nk_draw_null_texture tex_null;
	struct nk_buffer cmds;
#endif


} Renderer;


RENDERER_ERROR renderer_init(Renderer *renderer, int width, int height);
RENDERER_ERROR renderer_init_glfw(Renderer* renderer, int width, int height);

void renderer_init_shaders(Renderer *renderer);
void renderer_init_textures(Renderer *renderer);
void renderer_init_quad(Renderer *renderer);
void renderer_destroy(Renderer* renderer);

void render_quad(Renderer* renderer, vec2 pos, vec2 size, vec4 color);
void renderer_init_nk(Renderer* renderer);


void read_shader_source(GLchar* source, const char* file_path);
static const char* shader_type_as_cstr(GLuint shader);
static bool compile_shader_source(const GLchar* source, GLenum shader_type, GLuint* shader);
static void attach_shaders_to_program(GLuint* shaders, size_t shaders_count, GLuint program);
static bool link_program(GLuint program, const char* file_path, size_t line);
static void renderer_upload_atlas(Renderer* renderer, const void* image, int width, int height);

#endif // _RENDERER_H_