#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "wayland.h"

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 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);
}

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_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");
    }
}

/// Initializes wayland and creates an opengl context
struct client_state wayland_init() {
    int width = 700, height = 700;
    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);

    return state;
}

/// Swaps front/backbuffers and dispatches pending wayland commands.
void commit(struct client_state *state) {
    wl_display_dispatch(state->wl_display);
    eglSwapBuffers(state->egl_display, state->egl_surface);
}