#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <time.h> 
#include <stdint.h>
#include <wayland-client.h>
#include <wayland-util.h>
#include <SDL3/SDL.h>
#include <pthread.h>
#include <sys/mman.h>
#include "renderer.h"
#include "shm.h"
#include "xdg-shell-protocol.h"
#include <EGL/egl.h>
#include <wayland-egl.h>

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;
}

struct client_state {
    int width, height;
    /* Globals */
    struct wl_display *wl_display;
    struct wl_registry *wl_registry;
    struct wl_shm *wl_shm;
    struct wl_compositor *wl_compositor;
    struct xdg_wm_base *xdg_wm_base;
    /* Objects */
    struct wl_surface *wl_surface;
    struct xdg_surface *xdg_surface;
    struct xdg_toplevel *xdg_toplevel;

	struct wl_egl_window *egl_window;

	EGLDisplay egl_display;
	EGLConfig egl_config;
	EGLSurface egl_surface;
	EGLContext egl_context;
};

static void
wl_buffer_release(void *data, struct wl_buffer *wl_buffer)
{
    /* Sent by the compositor when it's no longer using this buffer */
    wl_buffer_destroy(wl_buffer);
}

static const struct wl_buffer_listener wl_buffer_listener = {
    .release = wl_buffer_release,
};


static struct wl_buffer *
draw_frame(struct client_state *state)
{
    int stride = state->width * 4;
    int size = stride * state->height;

    int fd = allocate_shm_file(size);
    if (fd == -1) {
        return NULL;
    }

    uint32_t *data = mmap(NULL, size,
            PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
    if (data == MAP_FAILED) {
        close(fd);
        return NULL;
    }

    struct wl_shm_pool *pool = wl_shm_create_pool(state->wl_shm, fd, size);
    struct wl_buffer *buffer = wl_shm_pool_create_buffer(pool, 0,
            state->width, state->height, stride, WL_SHM_FORMAT_XRGB8888);
    wl_shm_pool_destroy(pool);
    close(fd);

    /* Draw checkerboxed background */
    for (int y = 0; y < state->height; ++y) {
        for (int x = 0; x < state->width; ++x) {
            if ((x + y / 8 * 8) % 16 < 8)
                data[y * state->width + x] = 0xFF666666;
            else
                data[y * state->width + x] = 0xFFEEEEEE;
        }
    }

    munmap(data, size);
    wl_buffer_add_listener(buffer, &wl_buffer_listener, NULL);
    return buffer;
}

static void
xdg_surface_configure(void *data,
        struct xdg_surface *xdg_surface, uint32_t serial)
{
    struct client_state *state = data;
    xdg_surface_ack_configure(xdg_surface, serial);

    // TODO do egl stuff here instead?
    //struct wl_buffer *buffer = draw_frame(state);
    //wl_surface_attach(state->wl_surface, buffer, 0, 0);
    wl_surface_commit(state->wl_surface);
}

static const struct xdg_surface_listener xdg_surface_listener = {
    .configure = xdg_surface_configure,
};

static void
xdg_wm_base_ping(void *data, struct xdg_wm_base *xdg_wm_base, uint32_t serial)
{
    xdg_wm_base_pong(xdg_wm_base, serial);
}

static const struct xdg_wm_base_listener xdg_wm_base_listener = {
    .ping = xdg_wm_base_ping,
};

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 client_state *state = data;

    //if (strcmp(interface, wl_shm_interface.name) == 0) {
    //    state->wl_shm = wl_registry_bind(
    //            registry, name, &wl_shm_interface, 1);
    //}
    if (strcmp(interface, wl_compositor_interface.name) == 0) {
        state->wl_compositor = wl_registry_bind(
                registry, name, &wl_compositor_interface, 4);
    }
    if (strcmp(interface, xdg_wm_base_interface.name) == 0) {
        state->xdg_wm_base = wl_registry_bind(
                registry, name, &xdg_wm_base_interface, 1);
        xdg_wm_base_add_listener(state->xdg_wm_base,
                &xdg_wm_base_listener, state);
    }

}

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
wl_registry_listener = {
	.global = registry_handle_global,
	.global_remove = registry_handle_global_remove,
};

static void egl_init(struct client_state *state) {
    EGLint major, minor, count, n, size;
    EGLConfig *configs;
    int i;
    EGLint config_attribs[] = {
	EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
	EGL_RED_SIZE, 8,
	EGL_GREEN_SIZE, 8,
	EGL_BLUE_SIZE, 8,
	EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
	EGL_NONE
    };

    static const EGLint context_attribs[] = {
	EGL_CONTEXT_CLIENT_VERSION, 2,
	EGL_NONE
    };

    
    state->egl_display = eglGetDisplay((EGLNativeDisplayType) state->wl_display);
    if (state->egl_display == EGL_NO_DISPLAY) {
	fprintf(stderr, "Can't create egl display\n");
	exit(1);
    } else {
	fprintf(stderr, "Created egl display\n");
    }

    if (eglInitialize(state->egl_display, &major, &minor) != EGL_TRUE) {
	fprintf(stderr, "Can't initialise egl display\n");
	exit(1);
    }
    printf("EGL major: %d, minor %d\n", major, minor);

    eglGetConfigs(state->egl_display, NULL, 0, &count);
    printf("EGL has %d configs\n", count);

    configs = calloc(count, sizeof *configs);
    
    eglChooseConfig(state->egl_display, config_attribs,
			  configs, count, &n);
    
    for (i = 0; i < n; i++) {
	eglGetConfigAttrib(state->egl_display,
			   configs[i], EGL_BUFFER_SIZE, &size);
	printf("Buffer size for config %d is %d\n", i, size);
	eglGetConfigAttrib(state->egl_display,
			   configs[i], EGL_RED_SIZE, &size);
	printf("Red size for config %d is %d\n", i, size);
	
	// just choose the first one
	state->egl_config = configs[i];
	break;
    }

    state->egl_context =
	eglCreateContext(state->egl_display,
			 state->egl_config,
			 EGL_NO_CONTEXT, context_attribs);


    // EGL window
    state->egl_window = wl_egl_window_create(state->wl_surface,
                              state->width, state->height);
    if (state->egl_window == EGL_NO_SURFACE) {
        fprintf(stderr, "Can't create egl window\n");
        exit(1);
    } else {
        fprintf(stderr, "Created egl window\n");
    }

    state->egl_surface =
        eglCreateWindowSurface(state->egl_display,
                               state->egl_config,
                               (unsigned long) state->egl_window, NULL);

    if (eglMakeCurrent(state->egl_display, state->egl_surface,
                       state->egl_surface, state->egl_context)) {
        fprintf(stderr, "Made current\n");
    } else {
        fprintf(stderr, "Made current failed\n");
    }
}

int
main(int argc, char *argv[])
{
    char *shader_path = NULL;
    if (argc >= 2) {
        shader_path = argv[1];
    } else {
        printf("need to supply path to shader\n");
        exit(1);
    }
    int width = 700, height = 450;
    struct client_state state = { width, height, 0 };
    state.wl_display = wl_display_connect(NULL);
    state.wl_registry = wl_display_get_registry(state.wl_display);
    wl_registry_add_listener(state.wl_registry, &wl_registry_listener, &state);
    wl_display_roundtrip(state.wl_display);

    state.wl_surface = wl_compositor_create_surface(state.wl_compositor);
    state.xdg_surface = xdg_wm_base_get_xdg_surface(
            state.xdg_wm_base, state.wl_surface);
    xdg_surface_add_listener(state.xdg_surface, &xdg_surface_listener, &state);
    state.xdg_toplevel = xdg_surface_get_toplevel(state.xdg_surface);
    xdg_toplevel_set_title(state.xdg_toplevel, "GLONKERS!");
    wl_surface_commit(state.wl_surface);

	egl_init(&state);

    Renderer renderer = new_renderer();

    while (wl_display_dispatch(state.wl_display)) {
        double time = time_since_start();
        render(&renderer, state.width, state.height, time, shader_path, false);
	    eglSwapBuffers(state.egl_display, state.egl_surface);
    }

    return 0;
}

//
//_Atomic bool running = true;
//
//void intHandler(int dummy) {
//    printf("exiting\n");
//    running = false;
//    fclose(stdin);
//}
//
//bool reload_shader = false;
//
///// reads stdin on a separate thread.
//void *read_stdin(void *ptr) {
//    char buff[10];
//    while (running) {
//        fgets(buff, 10, stdin);
//        if (strcmp(buff, "r\n") == 0) {
//            printf("reloading shader\n");
//            reload_shader = true;
//        }
//    }
//    return NULL;
//}
//
//int main(int argc, char *argv[]) {
//    signal(SIGINT, intHandler);
//    pthread_t stdin_thread;
//    pthread_create( &stdin_thread, NULL, read_stdin, NULL);
//
//    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);
//
//    if (!glContext) {
//        printf("GL Context Error: %s\n", SDL_GetError());
//        SDL_DestroyWindow(window);
//        SDL_Quit();
//        return 1;
//    }
//
//    Renderer renderer = new_renderer();
//
//    SDL_Event e;
//    int w, h;
//    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);
//            }
//        }
//
//        char *shader_path = NULL;
//        if (argc >= 2) {
//            shader_path = argv[1];
//        } else {
//            printf("need to supply path to shader\n");
//            exit(1);
//        }
//
//        double time = time_since_start();
//        render(&renderer, w, h, time, shader_path, reload_shader);
//        if (reload_shader) reload_shader = false;
//
//        SDL_GL_SwapWindow(window);
//    }
//
//    pthread_join(stdin_thread, NULL);
//}
//