#include <stdio.h>
#include <glad/gl.h>
#include <GLFW/glfw3.h>
#include <stdlib.h>

void framebuffer_size_callback(GLFWwindow* window, int width, int height) {
    glViewport(0, 0, width, height);
}

void process_input(GLFWwindow *window) {
    if(glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
        glfwSetWindowShouldClose(window, GLFW_TRUE);
}

void init_glfw(int major, int minor) {
    if(!glfwInit()) {
        fprintf(stderr, "Failed to initialize GLFW\n");
        exit(-1);
    }

    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, major);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, minor);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
}

GLFWwindow* create_window(int width, int height, const char* title) {
    GLFWwindow* window = glfwCreateWindow(width, height, title, NULL, NULL);
    if(!window) {
        fprintf(stderr, "Failed to create GLFW window\n");
        glfwTerminate();
        exit(-1);
    }
    glfwMakeContextCurrent(window);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback); 

    if (!gladLoadGL((GLADloadfunc)glfwGetProcAddress)) {
        fprintf(stderr, "Failed to initialize GLAD\n");
        exit(-1);
    }

    glViewport(0, 0, width, height);

    return window;
}

int main() {
    init_glfw(4, 6);
    GLFWwindow* window = create_window(800, 600, "gearlib");

    while (!glfwWindowShouldClose(window)) {
        process_input(window);

        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glfwTerminate();
    return 0;
}