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

// Settings
constexpr unsigned int SCR_WIDTH = 800;
constexpr unsigned int SCR_HEIGHT = 600;

// Shader sources (usually from file, kept here for simplicity)
const char* vertexShaderSource = "#version 330 core\n"
    "layout (location = 0) in vec3 aPos;\n"
    "void main() {\n"
    "   gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
    "}\0";

const char* fragmentShaderSource = "#version 330 core\n"
    "out vec4 FragColor;\n"
    "void main() {\n"
    "   FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
    "}\n\0";

int main() {
    // 1. Init
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "OpenGL Triangle", nullptr, nullptr);
    if (window == nullptr) {
        std::cout << "Failed to create GLDW window" << std::endl;
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);

    // 2. Load OpenGL function pointers
    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
        std::cout << "Failed to initialize GLAD" << std::endl;
        return -1;
    }

    // 3. Build and compile shaders
    // Vertex Shader
    unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vertexShaderSource, nullptr);
    glCompileShader(vertexShader);

    // Fragment Shader
    unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentShaderSource, nullptr);
    glCompileShader(fragmentShader);

    // Link shaders into a program
    unsigned int shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);

    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);

    // 4. Set up vertex data (Normalized Device Coordinates)
    float verticies[] = {
        -0.5f, -0.5f, 0.0f, // Left
         0.5f, -0.5f, 0.0f, // Right
         0.0f,  0.5f, 0.0f  // Top
    };

    unsigned int VBO, VAO;
    glCenVertextArrays(1, &VAO);

}