#define GL_GLEXT_PROTOTYPES

#include <stdio.h>
#include <time.h> 
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <EGL/egl.h>
#include <GL/gl.h>
#include <wayland-client.h>
#include <wayland-util.h>
#include <SDL3/SDL.h>

//int main() {
//    struct wl_display *display = wl_display_connect(NULL);
//    if (!display) {
//        fprintf(stderr, "Failed to connect to Wayland display.\n");
//        return 1;
//    }
//    fprintf(stderr, "Connection established!\n");
//
//    while (wl_display_dispatch(display) != -1) {
//    }
//
//    wl_display_disconnect(display);
//}
//struct our_state {
//    // ...
//    struct wl_compositor *compositor;
//    // ...
//};
//
//static void
//registry_handle_global(void *data, struct wl_registry *registry,
//		uint32_t name, const char *interface, uint32_t version)
//{
//	printf("interface: '%s', version: %d, name: %d\n",
//			interface, version, name);
//
//    struct our_state *state = data;
//
//    if (strcmp(interface, wl_compositor_interface.name) == 0) {
//        state->compositor = wl_registry_bind(
//            registry, name, &wl_compositor_interface, 4);
//    }
//}
//
//static void
//registry_handle_global_remove(void *data, struct wl_registry *registry,
//		uint32_t name)
//{
//	// This space deliberately left blank
//}
//
//static const struct wl_registry_listener
//registry_listener = {
//	.global = registry_handle_global,
//	.global_remove = registry_handle_global_remove,
//};
//
//int
//main(int argc, char *argv[])
//{
//    struct our_state state = { 0 };
//	struct wl_display *display = wl_display_connect(NULL);
//	struct wl_registry *registry = wl_display_get_registry(display);
//    wl_registry_add_listener(registry, &registry_listener, &state);
//	wl_display_roundtrip(display);
//	return 0;
//}

void checkGlError() {
    const char *err = SDL_GetError();
    if (*err != 0) {
        printf("OpenGL error: %s", err);
    }
}

/// returns 0 if failed.
GLuint compile_shader(GLuint type, const char *src) {
    GLuint id = glCreateShader(type);
    glShaderSource(id, 1, &src, 0);
    glCompileShader(id);

    int result;
    glGetShaderiv(id, GL_COMPILE_STATUS, &result);
    if (result == GL_FALSE) {
        int length;
        glGetShaderiv(id, GL_INFO_LOG_LENGTH, &result);
        char *message = alloca(length * sizeof(char));
        glGetShaderInfoLog(id, length, &length, message);
        printf("failed to compile %s shader\n", type == GL_VERTEX_SHADER ? "vertex" : "fragment");
        printf("%s\n", message);
        glDeleteShader(id);
        return 0;
    }

    return id;
}

const char *vertex_shader_src =
//"attribute vec4 vPosition; \n"
//"void main() \n"
//"{ \n"
//" gl_Position = vPosition; \n"
//"} \n";
"#version 320 es\n"
"\n"
"layout(location = 0) in vec2 aPos;\n"
"\n"
"void main() {\n"
"    gl_Position = vec4(aPos, 0.0, 1.0);\n"
"}\n";

/// returns 0 if failed.
GLuint create_shader(const char *fragment_src) {
    GLuint program = glCreateProgram();
    GLuint vertex_shader = compile_shader(GL_VERTEX_SHADER, vertex_shader_src);
    GLuint fragment_shader = compile_shader(GL_FRAGMENT_SHADER, fragment_src);
    if (!((fragment_shader == 0) || (vertex_shader == 0))) {
        glAttachShader(program, vertex_shader);
        glAttachShader(program, fragment_shader);
        glLinkProgram(program);
        glValidateProgram(program);
        glDeleteShader(vertex_shader);
        glDeleteShader(fragment_shader);
        return program;
    } else {
        return 0;
    }
}

GLuint load_shader(const char *path) {
    FILE *handle = fopen(path, "r");
    fseek(handle, 0L, SEEK_END);
    long length = ftell(handle);
    fseek(handle, 0L, SEEK_SET);
    char *string = malloc(length * sizeof(char));
    if (!fread(string, sizeof(char), length, handle)) {
        printf("failed to read shader file");
        exit(1);
    }
    fclose(handle);

    GLuint shader = create_shader(string);

    //if (shader == 0) {
    //    // print file
    //    int line_count = 1;
    //    printf("%i\t", line_count);
    //    line_count++;
    //    for (int i = 0; i < length; i++) {
    //        printf("%c", string[i]);
    //        if (string[i] == '\n') {
    //            printf("%i\t", line_count);
    //            line_count++;
    //        }
    //    }
    //    printf("\n");
    //}

    free(string);
    return shader;
}

struct timespec program_start;

void init_timer() {
    clock_gettime(CLOCK_MONOTONIC, &program_start);
}

double time_since_start() {
    struct timespec now;
    clock_gettime(CLOCK_MONOTONIC, &now);

    return (now.tv_sec - program_start.tv_sec) +
           (now.tv_nsec - program_start.tv_nsec) / 1e9;
}

int main() {
    init_timer();

    printf("Good Morning 🍵\n");
    SDL_Init(SDL_INIT_VIDEO);
    SDL_SetHint(SDL_HINT_OPENGL_ES_DRIVER, "1");
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK,
        SDL_GL_CONTEXT_PROFILE_ES);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
    SDL_Window* window = SDL_CreateWindow("SDL3 OpenGL Cube",
    800, 600, SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE);
    if (!window) {
        printf("CreateWindow Error: %s\n", SDL_GetError());
        SDL_Quit();
        return 1;
    }
    
    SDL_GLContext glContext = SDL_GL_CreateContext(window);
const char *version = (const char *)glGetString(GL_VERSION);
const char *renderer = (const char *)glGetString(GL_RENDERER);

SDL_Log("GL_VERSION: %s", version);
SDL_Log("GL_RENDERER: %s", renderer);

    if (!glContext) {
        printf("GL Context Error: %s\n", SDL_GetError());
        SDL_DestroyWindow(window);
        SDL_Quit();
        return 1;
    }
    glEnable(GL_DEPTH_TEST);

    SDL_Event e;
    int running = 1;

    GLuint shader = load_shader("fragment.glsl"); //create_shader(fragment_shader_source);


    // buffers
    // Load the vertex data
    GLfloat vertices[] = {
        -1.0, 1.0,
        -1.0, -1.0,
        1.0, -1.0,

        1.0, -1.0,
        1.0, 1.0,
        -1.0, 1.0,
    };
    GLuint vao, vbo;
    glGenVertexArrays(1, &vao);
    glBindVertexArray(vao);
    glGenBuffers(1, &vbo);
    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    glBufferData(GL_ARRAY_BUFFER,
                 sizeof(vertices),
                 vertices,
                 GL_STATIC_DRAW);
    
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(
        0,              // location
        2,              // vec2
        GL_FLOAT,
        GL_FALSE,
        0,
        (void *)0
    );




    int w, h;
    double time;
    while (running) {
        while (SDL_PollEvent(&e)) {
            if (e.type == SDL_EVENT_QUIT) running = false;
            if (e.type == SDL_EVENT_WINDOW_RESIZED) {
                SDL_GetWindowSize(window, &w, &h);
            }
        }
        checkGlError();

        // Rendorrrr
        glViewport(0, 0, w, h);

        glClearColor(0.1f, 0.1f, 0.1f, 1.0f);  // Dark gray background
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        // Shader parameters.
        glUseProgram(shader);

        int uniform_WindowSize = glGetUniformLocation(shader, "WindowSize");
        glUniform2f(uniform_WindowSize, w, h);

        time = time_since_start();
        int uniform_time = glGetUniformLocation(shader, "time");
        glUniform1f(uniform_time, (float)time);

        //glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, vVertices);
        //glEnableVertexAttribArray(0);
        //glDrawArrays(GL_TRIANGLES, 0, 6);

        glBindVertexArray(vao);
        glDrawArrays(GL_TRIANGLES, 0, 6);

        SDL_GL_SwapWindow(window);
        checkGlError();
    }

    checkGlError();
}