#include <stdio.h>
#include <stdlib.h>
#include <GL/glew.h>
#include <GLFW/glfw3.h>

const uint32_t vert_spirv[] =
#include "vert_spirv.h"
;
const uint32_t frag_spirv[] =
#include "frag_spirv.h"
;
const char vert_src[] = {
#include "vert_src.h"
, 0x00 };
const char frag_src[] = {
#include "frag_src.h"
, 0x00 };

GLuint load_shader_src(GLenum type, const char* src) {
	GLuint shader = glCreateShader(type);
	glShaderSource(shader, 1, &src, NULL);
	glCompileShader(shader);
	return shader;
}
GLuint load_shader_spirv(GLenum type, const char* src, size_t size) {
	GLuint shader = glCreateShader(type);
	glShaderBinary(1, &shader, GL_SHADER_BINARY_FORMAT_SPIR_V, src, size);
	glSpecializeShader(shader, "main", 0, NULL, NULL);
	return shader;
}

GLuint link_shaders(GLuint vert, GLuint frag) {
	GLuint shader = glCreateProgram();
	glAttachShader(shader, vert);
	glAttachShader(shader, frag);
	glLinkProgram(shader);
	glUseProgram(shader); // <- use the program before getting uniform name
	glDeleteShader(vert);
	glDeleteShader(frag);
	return shader;
}

void test(const char* label, GLuint shader) {
	printf("%s:\n", label);

	// list all ACTIVE uniforms in shader
	GLint count;
	glGetProgramiv(shader, GL_ACTIVE_UNIFORMS, &count);
	printf("\tactive uniform count: %d\n", count);
	for (unsigned i = 0; i < count; i++) {
		GLchar name[80];
		GLsizei length;
		glGetActiveUniformName(shader, i, 80, &length, name);
		printf("\t(location = %u) = \"%.*s\"\n", i, length, name);
	}

	// try directly geting uniform location
	GLint uniform_location = glGetUniformLocation(shader, "test");
	printf("\t`test` uniform location = %d\n", uniform_location);
}

int main(int argc, char** argv) {
	// initialize window
	glfwInit();
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 6);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
	glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE);
	GLFWwindow* window = glfwCreateWindow(800, 600, "test", NULL, NULL);
	glfwMakeContextCurrent(window);
	glewInit();

	// print driver info
	printf("vendor:        %s\n", glGetString(GL_VENDOR));
	printf("renderer:      %s\n", glGetString(GL_RENDERER));
	printf("version:       %s\n", glGetString(GL_VERSION));
	printf("glsl version:  %s\n", glGetString(GL_SHADING_LANGUAGE_VERSION));
	printf("------------------------------\n");

	// test w/ glsl source
	GLuint src_vert = load_shader_src(GL_VERTEX_SHADER, vert_src);
	GLuint src_frag = load_shader_src(GL_FRAGMENT_SHADER, vert_src);
	GLuint src_shader = link_shaders(src_vert, src_frag);
	test("GLSL", src_shader);

	// test w/ spir-v
	GLuint spirv_vert = load_shader_spirv(GL_VERTEX_SHADER, (char*) vert_spirv, sizeof(vert_spirv));
	GLuint spirv_frag = load_shader_spirv(GL_FRAGMENT_SHADER, (char*) frag_spirv, sizeof(frag_spirv));
	GLuint spirv_shader = link_shaders(spirv_vert, spirv_frag);
	test("SPIR-V", spirv_shader);

	return 0;
}