main.c

#define _POSIX_C_SOURCE 200112L

#include <assert.h>
#include <unistd.h>
#include <wlr/backend/libinput.h>
#include <wlr/render/allocator.h>
#include <wlr/render/wlr_renderer.h>
#include <wlr/types/wlr_data_device.h>
#include <wlr/types/wlr_scene.h>
#include <wlr/types/wlr_subcompositor.h>
#include <wlr/types/wlr_xcursor_manager.h>
#include <wlr/types/wlr_xdg_shell.h>
#include <wlr/util/log.h>

char* keyboard_layout = "us";
char* keyboard_optns = "";
char* terminal = "alacritty";
char* browser = "firefox";
char* system_monitor = "alacritty -e btop";
bool hide_cursor_at_top_left = false;

struct tinytile_server {
  struct wl_display* wl_display;
  struct wlr_backend* backend;
  struct wlr_renderer* renderer;
  struct wlr_allocator* allocator;
  struct wlr_scene* scene;

  struct wlr_xdg_shell* xdg_shell;
  struct wl_listener new_xdg_surface;
  struct wl_list views;

  struct wlr_cursor* cursor;
  struct wlr_xcursor_manager* cursor_mgr;
  struct wl_listener cursor_motion;
  struct wl_listener cursor_motion_absolute;
  struct wl_listener cursor_button;
  struct wl_listener cursor_axis;
  struct wl_listener cursor_frame;

  struct wlr_seat* seat;
  struct wl_listener new_input;
  struct wl_listener request_cursor;
  struct wl_listener request_set_selection;
  struct wl_list keyboards;

  struct wlr_output_layout* output_layout;
  struct wl_list outputs;
  struct wl_listener new_output;
};

struct tinytile_output {
  struct wl_list link;
  struct tinytile_server* server;
  struct wlr_output* wlr_output;
  struct wl_listener frame;
  struct wl_listener destroy;
};

struct tinytile_view {
  struct wl_list link;
  struct tinytile_server* server;
  struct wlr_xdg_toplevel* xdg_toplevel;
  struct wlr_scene_tree* scene_tree;
  struct wl_listener map;
  struct wl_listener unmap;
  struct wl_listener destroy;
  struct wl_listener request_fullscreen;
};

struct tinytile_keyboard {
  struct wl_list link;
  struct tinytile_server* server;
  struct wlr_keyboard* wlr_keyboard;

  struct wl_listener modifiers;
  struct wl_listener key;
  struct wl_listener destroy;
};

static char* replace_char(char* str, char find, char replace) {
  char* current_pos = strchr(str, find);
  while (current_pos) {
    *current_pos = replace;
    current_pos = strchr(current_pos, find);
  }
  return str;
}

static inline bool yes_to_bool(char string[]) {
  if (!strcmp(string, "yes"))
    return true;
  else if (!strcmp(string, "no"))
    return false;
  else
    wlr_log(WLR_ERROR, "Please say either yes or no instead of '%s'", string);
  exit(EXIT_FAILURE);
}

static void run(const char* command) {
  if (fork() == 0) {
    system(command);
    exit(EXIT_SUCCESS);
  }
}

static void focus_view(struct tinytile_view* view,
                       struct wlr_surface* surface) {
  /* Note: this function only deals with keyboard focus. */
  if (view == NULL) {
    return;
  }
  struct tinytile_server* server = view->server;
  struct wlr_seat* seat = server->seat;
  struct wlr_surface* prev_surface = seat->keyboard_state.focused_surface;
  if (prev_surface == surface) {
    /* Don't re-focus an already focused surface. */
    return;
  }
  if (prev_surface) {
    /*
     * Deactivate the previously focused surface. This lets the client know
     * it no longer has focus and the client will repaint accordingly, e.g.
     * stop displaying a caret.
     */
    struct wlr_xdg_surface* previous =
        wlr_xdg_surface_from_wlr_surface(seat->keyboard_state.focused_surface);
    assert(previous->role == WLR_XDG_SURFACE_ROLE_TOPLEVEL);
    wlr_xdg_toplevel_set_activated(previous->toplevel, false);
  }
  struct wlr_keyboard* keyboard = wlr_seat_get_keyboard(seat);
  /* Move the view to the front */
  wlr_scene_node_raise_to_top(&view->scene_tree->node);
  wl_list_remove(&view->link);
  wl_list_insert(&server->views, &view->link);
  /* Activate the new surface */
  wlr_xdg_toplevel_set_activated(view->xdg_toplevel, true);
  /*
   * Tell the seat to have the keyboard enter this surface. wlroots will keep
   * track of this and automatically send key events to the appropriate
   * clients without additional work on your part.
   */
  if (keyboard != NULL) {
    wlr_seat_keyboard_notify_enter(seat, view->xdg_toplevel->base->surface,
                                   keyboard->keycodes, keyboard->num_keycodes,
                                   &keyboard->modifiers);
  }
}

static void keyboard_handle_modifiers(struct wl_listener* listener,
                                      void* data) {
  /* This event is raised when a modifier key, such as shift or alt, is
   * pressed. We simply communicate this to the client. */
  struct tinytile_keyboard* keyboard =
      wl_container_of(listener, keyboard, modifiers);
  /*
   * A seat can only have one keyboard, but this is a limitation of the
   * Wayland protocol - not wlroots. We assign all connected keyboards to the
   * same seat. You can swap out the underlying wlr_keyboard like this and
   * wlr_seat handles this transparently.
   */
  wlr_seat_set_keyboard(keyboard->server->seat, keyboard->wlr_keyboard);
  /* Send modifiers to the client. */
  wlr_seat_keyboard_notify_modifiers(keyboard->server->seat,
                                     &keyboard->wlr_keyboard->modifiers);
}

static void keyboard_handle_key(struct wl_listener* listener, void* data) {
  /* This event is raised when a key is pressed or released. */
  struct tinytile_keyboard* keyboard = wl_container_of(listener, keyboard, key);
  struct tinytile_server* server = keyboard->server;
  struct wlr_keyboard_key_event* event = data;
  struct wlr_seat* seat = server->seat;

  /* Translate libinput keycode -> xkbcommon */
  uint32_t keycode = event->keycode + 8;
  /* Get a list of keysyms based on the keymap for this keyboard */
  const xkb_keysym_t* syms;
  int nsyms =
      xkb_state_key_get_syms(keyboard->wlr_keyboard->xkb_state, keycode, &syms);

  uint32_t modifiers = wlr_keyboard_get_modifiers(keyboard->wlr_keyboard);
  if (event->state == WL_KEYBOARD_KEY_STATE_PRESSED) {
    if (modifiers == WLR_MODIFIER_ALT) {
      /* If alt is held down and this button was _pressed_, we attempt to
       * process it as a compositor keybinding. */
      switch (syms[nsyms - 1]) {
        case XKB_KEY_Escape:
          wl_display_terminate(server->wl_display);
          return;
        case XKB_KEY_j:
          /* Cycle to the next view */
          if (wl_list_length(&server->views) >= 2) {
            struct tinytile_view* next_view =
                wl_container_of(server->views.prev, next_view, link);
            focus_view(next_view, next_view->xdg_toplevel->base->surface);
          }
          return;
        case XKB_KEY_q:
          if (wl_list_length(&server->views) >= 1) {
            struct tinytile_view* focused_view =
                wl_container_of(server->views.next, focused_view, link);
            wlr_xdg_toplevel_send_close(focused_view->xdg_toplevel);
          }
          return;
        case XKB_KEY_Return:
          run(terminal);
          return;
        case XKB_KEY_b:
          run(browser);
          return;
        case XKB_KEY_m:
          run(system_monitor);
          return;
        case XKB_KEY_x:
          run("/bin/systemctl suspend");
          return;
        case XKB_KEY_p:
          run("/bin/systemctl poweroff");
          return;
        case XKB_KEY_r:
          run("/bin/systemctl reboot");
          return;
      }
    } else if (modifiers == (WLR_MODIFIER_ALT | WLR_MODIFIER_CTRL)) {
      switch (syms[nsyms - 1]) {
        case XKB_KEY_XF86Switch_VT_1:
          wlr_session_change_vt(wlr_backend_get_session(server->backend), 1);
          return;
        case XKB_KEY_XF86Switch_VT_2:
          wlr_session_change_vt(wlr_backend_get_session(server->backend), 2);
          return;
        case XKB_KEY_XF86Switch_VT_3:
          wlr_session_change_vt(wlr_backend_get_session(server->backend), 3);
          return;
        case XKB_KEY_XF86Switch_VT_4:
          wlr_session_change_vt(wlr_backend_get_session(server->backend), 4);
          return;
        case XKB_KEY_XF86Switch_VT_5:
          wlr_session_change_vt(wlr_backend_get_session(server->backend), 5);
          return;
        case XKB_KEY_XF86Switch_VT_6:
          wlr_session_change_vt(wlr_backend_get_session(server->backend), 6);
          return;
        case XKB_KEY_XF86Switch_VT_7:
          wlr_session_change_vt(wlr_backend_get_session(server->backend), 7);
          return;
        case XKB_KEY_XF86Switch_VT_8:
          wlr_session_change_vt(wlr_backend_get_session(server->backend), 8);
          return;
        case XKB_KEY_XF86Switch_VT_9:
          wlr_session_change_vt(wlr_backend_get_session(server->backend), 9);
          return;
        case XKB_KEY_XF86Switch_VT_10:
          wlr_session_change_vt(wlr_backend_get_session(server->backend), 10);
          return;
        case XKB_KEY_XF86Switch_VT_11:
          wlr_session_change_vt(wlr_backend_get_session(server->backend), 11);
          return;
        case XKB_KEY_XF86Switch_VT_12:
          wlr_session_change_vt(wlr_backend_get_session(server->backend), 12);
          return;
      }
    }
  }

  /* If we haven't return yet, pass the keypress along to the client. */
  wlr_seat_set_keyboard(seat, keyboard->wlr_keyboard);
  wlr_seat_keyboard_notify_key(seat, event->time_msec, event->keycode,
                               event->state);
}

static void keyboard_handle_destroy(struct wl_listener* listener, void* data) {
  /* This event is raised by the keyboard base wlr_input_device to signal
   * the destruction of the wlr_keyboard. It will no longer receive events
   * and should be destroyed.
   */
  struct tinytile_keyboard* keyboard =
      wl_container_of(listener, keyboard, destroy);
  wl_list_remove(&keyboard->modifiers.link);
  wl_list_remove(&keyboard->key.link);
  wl_list_remove(&keyboard->destroy.link);
  wl_list_remove(&keyboard->link);
  free(keyboard);
}

static void server_new_keyboard(struct tinytile_server* server,
                                struct wlr_input_device* device) {
  struct wlr_keyboard* wlr_keyboard = wlr_keyboard_from_input_device(device);

  struct tinytile_keyboard* keyboard =
      calloc(1, sizeof(struct tinytile_keyboard));
  keyboard->server = server;
  keyboard->wlr_keyboard = wlr_keyboard;

  /* We need to prepare an XKB keymap and assign it to the keyboard. */
  struct xkb_context* context = xkb_context_new(XKB_CONTEXT_NO_FLAGS);
  struct xkb_keymap* keymap = xkb_keymap_new_from_names(
      context,
      &(struct xkb_rule_names){.layout = keyboard_layout,
                               .options = keyboard_optns},
      XKB_KEYMAP_COMPILE_NO_FLAGS);

  wlr_keyboard_set_keymap(wlr_keyboard, keymap);
  xkb_keymap_unref(keymap);
  xkb_context_unref(context);
  wlr_keyboard_set_repeat_info(wlr_keyboard, 25, 600);

  /* Here we set up listeners for keyboard events. */
  keyboard->modifiers.notify = keyboard_handle_modifiers;
  wl_signal_add(&wlr_keyboard->events.modifiers, &keyboard->modifiers);
  keyboard->key.notify = keyboard_handle_key;
  wl_signal_add(&wlr_keyboard->events.key, &keyboard->key);
  keyboard->destroy.notify = keyboard_handle_destroy;
  wl_signal_add(&device->events.destroy, &keyboard->destroy);

  wlr_seat_set_keyboard(server->seat, keyboard->wlr_keyboard);

  /* And add the keyboard to our list of keyboards */
  wl_list_insert(&server->keyboards, &keyboard->link);
}

static void server_new_pointer(struct tinytile_server* server,
                               struct wlr_input_device* device) {
  /* We don't do anything special with pointers; all of our pointer handling
   * consists of setting up mouse accelaration on libinput and then getting
   * wlroots to do the dirty work. */
  struct wlr_pointer* pointer = wlr_pointer_from_input_device(device);
  if (wlr_input_device_is_libinput(&pointer->base)) {
    struct libinput_device* libinput_device =
        (struct libinput_device*)wlr_libinput_get_device_handle(&pointer->base);
    if (libinput_device_config_accel_is_available(libinput_device)) {
      libinput_device_config_accel_set_profile(
          libinput_device, LIBINPUT_CONFIG_ACCEL_PROFILE_ADAPTIVE);
      libinput_device_config_accel_set_speed(libinput_device, 0.75);
    }
    wlr_cursor_attach_input_device(server->cursor, device);
  }
}

static void server_new_input(struct wl_listener* listener, void* data) {
  /* This event is raised by the backend when a new input device becomes
   * available. */
  struct tinytile_server* server = wl_container_of(listener, server, new_input);
  struct wlr_input_device* device = data;
  switch (device->type) {
    case WLR_INPUT_DEVICE_KEYBOARD:
      server_new_keyboard(server, device);
      break;
    case WLR_INPUT_DEVICE_POINTER:
      server_new_pointer(server, device);
      break;
    default:
      break;
  }
  /* We need to let the wlr_seat know what our capabilities are, which is
   * communiciated to the client. In tinytile we always have a cursor, even if
   * there are no pointer devices, so we always include that capability. */
  uint32_t caps = WL_SEAT_CAPABILITY_POINTER;
  if (!wl_list_empty(&server->keyboards)) {
    caps |= WL_SEAT_CAPABILITY_KEYBOARD;
  }
  wlr_seat_set_capabilities(server->seat, caps);
}

static void seat_request_cursor(struct wl_listener* listener, void* data) {
  struct tinytile_server* server =
      wl_container_of(listener, server, request_cursor);
  /* This event is raised by the seat when a client provides a cursor image */
  struct wlr_seat_pointer_request_set_cursor_event* event = data;
  struct wlr_seat_client* focused_client =
      server->seat->pointer_state.focused_client;
  /* This can be sent by any client, so we check to make sure this one is
   * actually has pointer focus first. */
  if (focused_client == event->seat_client) {
    /* Once we've vetted the client, we can tell the cursor to use the
     * provided surface as the cursor image. It will set the hardware cursor
     * on the output that it's currently on and continue to do so as the
     * cursor moves between outputs. */
    wlr_cursor_set_surface(server->cursor, event->surface, event->hotspot_x,
                           event->hotspot_y);
  }
}

static void seat_request_set_selection(struct wl_listener* listener,
                                       void* data) {
  /* This event is raised by the seat when a client wants to set the selection,
   * usually when the user copies something. wlroots allows compositors to
   * ignore such requests if they so choose, but in tinytile we always honor
   */
  struct tinytile_server* server =
      wl_container_of(listener, server, request_set_selection);
  struct wlr_seat_request_set_selection_event* event = data;
  wlr_seat_set_selection(server->seat, event->source, event->serial);
}

static struct tinytile_view* desktop_view_at(struct tinytile_server* server,
                                             double lx,
                                             double ly,
                                             struct wlr_surface** surface,
                                             double* sx,
                                             double* sy) {
  /* This returns the topmost node in the scene at the given layout coords.
   * we only care about surface nodes as we are specifically looking for a
   * surface in the surface tree of a tinytile_view. */
  struct wlr_scene_node* node =
      wlr_scene_node_at(&server->scene->tree.node, lx, ly, sx, sy);
  if (node == NULL || node->type != WLR_SCENE_NODE_BUFFER) {
    return NULL;
  }
  struct wlr_scene_buffer* scene_buffer = wlr_scene_buffer_from_node(node);
  struct wlr_scene_surface* scene_surface =
      wlr_scene_surface_from_buffer(scene_buffer);
  if (!scene_surface) {
    return NULL;
  }

  *surface = scene_surface->surface;
  /* Find the node corresponding to the tinytile_view at the root of this
   * surface tree, it is the only one for which we set the data field. */
  struct wlr_scene_tree* tree = node->parent;
  while (tree != NULL && tree->node.data == NULL) {
    tree = tree->node.parent;
  }
  return tree->node.data;
}

static void process_cursor_motion(struct tinytile_server* server,
                                  uint32_t time) {
  if (hide_cursor_at_top_left && server->cursor->x <= 3 &&
      server->cursor->y <= 3) {
    wlr_cursor_set_image(server->cursor, NULL, 0, 0, 0, 0, 0, 0);
    wlr_seat_pointer_notify_clear_focus(server->seat);
    return;
  }
  /* Find the view under the pointer and send the event along. */
  double sx, sy;
  struct wlr_seat* seat = server->seat;
  struct wlr_surface* surface = NULL;
  struct tinytile_view* view = desktop_view_at(
      server, server->cursor->x, server->cursor->y, &surface, &sx, &sy);
  if (!view) {
    /* If there's no view under the cursor, set the cursor image to a
     * default. This is what makes the cursor image appear when you move it
     * around the screen, not over any views. */
    wlr_xcursor_manager_set_cursor_image(server->cursor_mgr, "left_ptr",
                                         server->cursor);
  }
  if (surface) {
    /*
     * Send pointer enter and motion events.
     *
     * The enter event gives the surface "pointer focus", which is distinct
     * from keyboard focus. You get pointer focus by moving the pointer over
     * a window.
     *
     * Note that wlroots will avoid sending duplicate enter/motion events if
     * the surface has already has pointer focus or if the client is already
     * aware of the coordinates passed.
     */
    wlr_seat_pointer_notify_enter(seat, surface, sx, sy);
    wlr_seat_pointer_notify_motion(seat, time, sx, sy);
  } else {
    /* Clear pointer focus so future button events and such are not sent to
     * the last client to have the cursor over it. */
    wlr_seat_pointer_clear_focus(seat);
  }
}

static void server_cursor_motion(struct wl_listener* listener, void* data) {
  /* This event is forwarded by the cursor when a pointer emits a _relative_
   * pointer motion event (i.e. a delta) */
  struct tinytile_server* server =
      wl_container_of(listener, server, cursor_motion);
  struct wlr_pointer_motion_event* event = data;
  /* The cursor doesn't move unless we tell it to. The cursor automatically
   * handles constraining the motion to the output layout, as well as any
   * special configuration applied for the specific input device which
   * generated the event. You can pass NULL for the device if you want to move
   * the cursor around without any input. */
  wlr_cursor_move(server->cursor, &event->pointer->base, event->delta_x,
                  event->delta_y);
  process_cursor_motion(server, event->time_msec);
}

static void server_cursor_motion_absolute(struct wl_listener* listener,
                                          void* data) {
  /* This event is forwarded by the cursor when a pointer emits an _absolute_
   * motion event, from 0..1 on each axis. This happens, for example, when
   * wlroots is running under a Wayland window rather than KMS+DRM, and you
   * move the mouse over the window. You could enter the window from any edge,
   * so we have to warp the mouse there. There is also some hardware which
   * emits these events. */
  struct tinytile_server* server =
      wl_container_of(listener, server, cursor_motion_absolute);
  struct wlr_pointer_motion_absolute_event* event = data;
  wlr_cursor_warp_absolute(server->cursor, &event->pointer->base, event->x,
                           event->y);
  process_cursor_motion(server, event->time_msec);
}

static void server_cursor_button(struct wl_listener* listener, void* data) {
  /* This event is forwarded by the cursor when a pointer emits a button
   * event. */
  struct tinytile_server* server =
      wl_container_of(listener, server, cursor_button);
  struct wlr_pointer_button_event* event = data;
  /* Notify the client with pointer focus that a button press has occurred */
  wlr_seat_pointer_notify_button(server->seat, event->time_msec, event->button,
                                 event->state);
  double sx, sy;
  struct wlr_surface* surface = NULL;
  struct tinytile_view* view = desktop_view_at(
      server, server->cursor->x, server->cursor->y, &surface, &sx, &sy);
  if (event->state == WLR_BUTTON_PRESSED) {
    /* Focus that client if the button was _pressed_ */
    focus_view(view, surface);
  }
}

static void server_cursor_axis(struct wl_listener* listener, void* data) {
  /* This event is forwarded by the cursor when a pointer emits an axis event,
   * for example when you move the scroll wheel. */
  struct tinytile_server* server =
      wl_container_of(listener, server, cursor_axis);
  struct wlr_pointer_axis_event* event = data;
  /* Notify the client with pointer focus of the axis event. */
  wlr_seat_pointer_notify_axis(server->seat, event->time_msec,
                               event->orientation, event->delta,
                               event->delta_discrete, event->source);
}

static void server_cursor_frame(struct wl_listener* listener, void* data) {
  /* This event is forwarded by the cursor when a pointer emits an frame
   * event. Frame events are sent after regular pointer events to group
   * multiple events together. For instance, two axis events may happen at the
   * same time, in which case a frame event won't be sent in between. */
  struct tinytile_server* server =
      wl_container_of(listener, server, cursor_frame);
  /* Notify the client with pointer focus of the frame event. */
  wlr_seat_pointer_notify_frame(server->seat);
}

static void output_frame(struct wl_listener* listener, void* data) {
  /* This function is called every time an output is ready to display a frame,
   * generally at the output's refresh rate (e.g. 60Hz). */
  struct tinytile_output* output = wl_container_of(listener, output, frame);
  struct wlr_scene* scene = output->server->scene;

  struct wlr_scene_output* scene_output =
      wlr_scene_get_scene_output(scene, output->wlr_output);

  /* Render the scene if needed and commit the output */
  wlr_scene_output_commit(scene_output);

  struct timespec now;
  clock_gettime(CLOCK_MONOTONIC, &now);
  wlr_scene_output_send_frame_done(scene_output, &now);
}

static void output_destroy(struct wl_listener* listener, void* data) {
  struct tinytile_output* output = wl_container_of(listener, output, destroy);

  wl_list_remove(&output->frame.link);
  wl_list_remove(&output->destroy.link);
  wl_list_remove(&output->link);
  free(output);
}

static void server_new_output(struct wl_listener* listener, void* data) {
  /* This event is raised by the backend when a new output (aka a display or
   * monitor) becomes available. */
  struct tinytile_server* server =
      wl_container_of(listener, server, new_output);
  struct wlr_output* wlr_output = data;

  /* Configures the output created by the backend to use our allocator
   * and our renderer. Must be done once, before commiting the output */
  wlr_output_init_render(wlr_output, server->allocator, server->renderer);

  /* Some backends don't have modes. DRM+KMS does, and we need to set a mode
   * before we can use the output. The mode is a tuple of (width, height,
   * refresh rate), and each monitor supports only a specific set of modes. We
   * just pick the monitor's preferred mode, a more sophisticated compositor
   * would let the user configure it. */
  if (!wl_list_empty(&wlr_output->modes)) {
    struct wlr_output_mode* mode = wlr_output_preferred_mode(wlr_output);
    wlr_output_set_mode(wlr_output, mode);
    wlr_output_enable(wlr_output, true);
    if (!wlr_output_commit(wlr_output)) {
      return;
    }
  }

  /* Allocates and configures our state for this output */
  struct tinytile_output* output = calloc(1, sizeof(struct tinytile_output));
  output->wlr_output = wlr_output;
  output->server = server;
  /* Sets up a listener for the frame notify event. */
  output->frame.notify = output_frame;
  wl_signal_add(&wlr_output->events.frame, &output->frame);

  /* Sets up a listener for the destroy notify event. */
  output->destroy.notify = output_destroy;
  wl_signal_add(&wlr_output->events.destroy, &output->destroy);

  wl_list_insert(&server->outputs, &output->link);

  /* Adds this to the output layout. The add_auto function arranges outputs
   * from left-to-right in the order they appear. A more sophisticated
   * compositor would let the user configure the arrangement of outputs in the
   * layout.
   *
   * The output layout utility automatically adds a wl_output global to the
   * display, which Wayland clients can see to find out information about the
   * output (such as DPI, scale factor, manufacturer, etc).
   */
  wlr_output_layout_add_auto(server->output_layout, wlr_output);
}

static void xdg_toplevel_map(struct wl_listener* listener, void* data) {
  /* Called when the surface is mapped, or ready to display on-screen. */
  struct tinytile_view* view = wl_container_of(listener, view, map);

  // Make the client tile
  wlr_xdg_toplevel_set_tiled(
      view->xdg_toplevel,
      WLR_EDGE_TOP | WLR_EDGE_BOTTOM | WLR_EDGE_LEFT | WLR_EDGE_RIGHT);

  // Resize the client to be the size of the monitor that the cursor is
  // currently at
  struct wlr_output* monitor = wlr_output_layout_output_at(
      view->server->output_layout, view->server->cursor->x,
      view->server->cursor->y);
  struct wlr_output_layout_output* monitor_pos =
      wlr_output_layout_get(view->server->output_layout, monitor);
  wlr_scene_node_set_position(&view->scene_tree->node, monitor_pos->x,
                              monitor_pos->y);
  wlr_xdg_toplevel_set_size(view->xdg_toplevel, monitor->width,
                            monitor->height);

  wl_list_insert(&view->server->views, &view->link);

  focus_view(view, view->xdg_toplevel->base->surface);
}

static void xdg_toplevel_unmap(struct wl_listener* listener, void* data) {
  /* Called when the surface is unmapped, and should no longer be shown. */
  struct tinytile_view* view = wl_container_of(listener, view, unmap);

  /* Update the focused view */
  struct tinytile_view* focused_view =
      wl_container_of(view->server->views.next, focused_view, link);
  if (view == focused_view && wl_list_length(&view->server->views) >= 2) {
    struct tinytile_view* view_to_be_focused = wl_container_of(
        view->server->views.next->next, view_to_be_focused, link);
    focus_view(view_to_be_focused,
               view_to_be_focused->xdg_toplevel->base->surface);
  }

  /* Remove the view */
  process_cursor_motion(view->server, 0);
  wl_list_remove(&view->link);
}

static void xdg_toplevel_destroy(struct wl_listener* listener, void* data) {
  /* Called when the surface is destroyed and should never be shown again. */
  struct tinytile_view* view = wl_container_of(listener, view, destroy);

  wl_list_remove(&view->map.link);
  wl_list_remove(&view->unmap.link);
  wl_list_remove(&view->destroy.link);
  wl_list_remove(&view->request_fullscreen.link);

  free(view);
}

static void xdg_toplevel_request_fullscreen(struct wl_listener* listener,
                                            void* data) {
  struct tinytile_view* view =
      wl_container_of(listener, view, request_fullscreen);
  wlr_xdg_toplevel_set_fullscreen(view->xdg_toplevel,
                                  view->xdg_toplevel->requested.fullscreen);
  wlr_xdg_surface_schedule_configure(view->xdg_toplevel->base);
}

static void server_new_xdg_surface(struct wl_listener* listener, void* data) {
  /* This event is raised when wlr_xdg_shell receives a new xdg surface from a
   * client, either a toplevel (application window) or popup. */
  struct tinytile_server* server =
      wl_container_of(listener, server, new_xdg_surface);
  struct wlr_xdg_surface* xdg_surface = data;

  /* We must add xdg popups to the scene graph so they get rendered. The
   * wlroots scene graph provides a helper for this, but to use it we must
   * provide the proper parent scene node of the xdg popup. To enable this,
   * we always set the user data field of xdg_surfaces to the corresponding
   * scene node. */
  if (xdg_surface->role == WLR_XDG_SURFACE_ROLE_POPUP) {
    struct wlr_xdg_surface* parent =
        wlr_xdg_surface_from_wlr_surface(xdg_surface->popup->parent);
    struct wlr_scene_tree* parent_tree = parent->data;
    xdg_surface->data = wlr_scene_xdg_surface_create(parent_tree, xdg_surface);
    struct wlr_output* monitor_view_is_on = wlr_output_layout_output_at(
        server->output_layout, xdg_surface->surface->sx,
        xdg_surface->surface->sy);
    wlr_xdg_popup_unconstrain_from_box(
        xdg_surface->popup,
        &(struct wlr_box){.x = 0,
                          .y = 0,
                          .width = monitor_view_is_on->width,
                          .height = monitor_view_is_on->height});
    return;
  }
  assert(xdg_surface->role == WLR_XDG_SURFACE_ROLE_TOPLEVEL);

  /* Allocate a tinytile_view for this surface */
  struct tinytile_view* view = calloc(1, sizeof(struct tinytile_view));
  view->server = server;
  view->xdg_toplevel = xdg_surface->toplevel;
  view->scene_tree = wlr_scene_xdg_surface_create(&view->server->scene->tree,
                                                  view->xdg_toplevel->base);
  view->scene_tree->node.data = view;
  xdg_surface->data = view->scene_tree;

  /* Listen to the various events it can emit */
  view->map.notify = xdg_toplevel_map;
  wl_signal_add(&xdg_surface->events.map, &view->map);
  view->unmap.notify = xdg_toplevel_unmap;
  wl_signal_add(&xdg_surface->events.unmap, &view->unmap);
  view->destroy.notify = xdg_toplevel_destroy;
  wl_signal_add(&xdg_surface->events.destroy, &view->destroy);

  /* cotd */
  struct wlr_xdg_toplevel* toplevel = xdg_surface->toplevel;
  view->request_fullscreen.notify = xdg_toplevel_request_fullscreen;
  wl_signal_add(&toplevel->events.request_fullscreen,
                &view->request_fullscreen);
}

int main(int argc, char* argv[]) {
  wlr_log_init(WLR_DEBUG, NULL);

  if (argc > 1) {
    for (int _ = 1; _ < (argc - 1); _ += 2) {
      if (!strcmp(argv[_], "terminal"))
        terminal = replace_char(argv[_ + 1], '_', ' ');
      else if (!strcmp(argv[_], "browser"))
        browser = replace_char(argv[_ + 1], '_', ' ');
      else if (!strcmp(argv[_], "hideCursor"))
        hide_cursor_at_top_left = yes_to_bool(argv[_ + 1]);
      else if (!strcmp(argv[_], "systemMonitor"))
        system_monitor = replace_char(argv[_ + 1], '_', ' ');
      else if (!strcmp(argv[_], "keyboardLayout"))
        keyboard_layout = argv[_ + 1];
      else if (!strcmp(argv[_], "keyboardOptns"))
        keyboard_optns = replace_char(argv[_ + 1], '_', ' ');
      else {
        wlr_log(
            WLR_ERROR,
            "The option '%s' is not a valid option please choose from either "
            "browser, terminal, systemMonitor, keyboardLayout, hideCursor or "
            "keyboardOptns.",
            argv[_]);
        exit(1);
      }
    }
  }

  struct tinytile_server server;
  /* The Wayland display is managed by libwayland. It handles accepting
   * clients from the Unix socket, manging Wayland globals, and so on. */
  server.wl_display = wl_display_create();
  /* The backend is a wlroots feature which abstracts the underlying input and
   * output hardware. The autocreate option will choose the most suitable
   * backend based on the current environment, such as opening an X11 window
   * if an X11 server is running. */
  server.backend = wlr_backend_autocreate(server.wl_display);
  if (server.backend == NULL) {
    wlr_log(WLR_ERROR, "failed to create wlr_backend");
    return 1;
  }

  /* Autocreates a renderer, either Pixman, GLES2 or Vulkan for us. The user
   * can also specify a renderer using the WLR_RENDERER env var.
   * The renderer is responsible for defining the various pixel formats it
   * supports for shared memory, this configures that for clients. */
  server.renderer = wlr_renderer_autocreate(server.backend);
  if (server.renderer == NULL) {
    wlr_log(WLR_ERROR, "failed to create wlr_renderer");
    return 1;
  }

  wlr_renderer_init_wl_display(server.renderer, server.wl_display);

  /* Autocreates an allocator for us.
   * The allocator is the bridge between the renderer and the backend. It
   * handles the buffer creation, allowing wlroots to render onto the
   * screen */
  server.allocator = wlr_allocator_autocreate(server.backend, server.renderer);
  if (server.allocator == NULL) {
    wlr_log(WLR_ERROR, "failed to create wlr_allocator");
    return 1;
  }

  /* This creates some hands-off wlroots interfaces. The compositor is
   * necessary for clients to allocate surfaces, the subcompositor allows to
   * assign the role of subsurfaces to surfaces and the data device manager
   * handles the clipboard. Each of these wlroots interfaces has room for you
   * to dig your fingers in and play with their behavior if you want. Note that
   * the clients cannot set the selection directly without compositor approval,
   * see the handling of the request_set_selection event below.*/
  wlr_compositor_create(server.wl_display, server.renderer);
  wlr_subcompositor_create(server.wl_display);
  wlr_data_device_manager_create(server.wl_display);

  /* Creates an output layout, which a wlroots utility for working with an
   * arrangement of screens in a physical layout. */
  server.output_layout = wlr_output_layout_create();

  /* Configure a listener to be notified when new outputs are available on the
   * backend. */
  wl_list_init(&server.outputs);
  server.new_output.notify = server_new_output;
  wl_signal_add(&server.backend->events.new_output, &server.new_output);

  /* Create a scene graph. This is a wlroots abstraction that handles all
   * rendering and damage tracking. All the compositor author needs to do
   * is add things that should be rendered to the scene graph at the proper
   * positions and then call wlr_scene_output_commit() to render a frame if
   * necessary.
   */
  server.scene = wlr_scene_create();
  wlr_scene_attach_output_layout(server.scene, server.output_layout);

  /* Set up xdg-shell version 3. The xdg-shell is a Wayland protocol which is
   * used for application windows. For more detail on shells, refer to my
   * article:
   *
   * https://drewdevault.com/2018/07/29/Wayland-shells.html
   */
  wl_list_init(&server.views);
  server.xdg_shell = wlr_xdg_shell_create(server.wl_display, 3);
  server.new_xdg_surface.notify = server_new_xdg_surface;
  wl_signal_add(&server.xdg_shell->events.new_surface, &server.new_xdg_surface);

  /*
   * Creates a cursor, which is a wlroots utility for tracking the cursor
   * image shown on screen.
   */
  server.cursor = wlr_cursor_create();
  wlr_cursor_attach_output_layout(server.cursor, server.output_layout);

  /* Creates an xcursor manager, another wlroots utility which loads up
   * Xcursor themes to source cursor images from and makes sure that cursor
   * images are available at all scale factors on the screen (necessary for
   * HiDPI support). We add a cursor theme at scale factor 1 to begin with. */
  server.cursor_mgr = wlr_xcursor_manager_create(NULL, 24);
  wlr_xcursor_manager_load(server.cursor_mgr, 1);

  /*
   * wlr_cursor *only* displays an image on screen. It does not move around
   * when the pointer moves. However, we can attach input devices to it, and
   * it will generate aggregate events for all of them. In these events, we
   * can choose how we want to process them, forwarding them to clients and
   * moving the cursor around. More detail on this process is described in my
   * input handling blog post:
   *
   * https://drewdevault.com/2018/07/17/Input-handling-in-wlroots.html
   *
   * And more comments are sprinkled throughout the notify functions above.
   */
  server.cursor_motion.notify = server_cursor_motion;
  wl_signal_add(&server.cursor->events.motion, &server.cursor_motion);
  server.cursor_motion_absolute.notify = server_cursor_motion_absolute;
  wl_signal_add(&server.cursor->events.motion_absolute,
                &server.cursor_motion_absolute);
  server.cursor_button.notify = server_cursor_button;
  wl_signal_add(&server.cursor->events.button, &server.cursor_button);
  server.cursor_axis.notify = server_cursor_axis;
  wl_signal_add(&server.cursor->events.axis, &server.cursor_axis);
  server.cursor_frame.notify = server_cursor_frame;
  wl_signal_add(&server.cursor->events.frame, &server.cursor_frame);

  /*
   * Configures a seat, which is a single "seat" at which a user sits and
   * operates the computer. This conceptually includes up to one keyboard,
   * pointer, touch, and drawing tablet device. We also rig up a listener to
   * let us know when new input devices are available on the backend.
   */
  wl_list_init(&server.keyboards);
  server.new_input.notify = server_new_input;
  wl_signal_add(&server.backend->events.new_input, &server.new_input);
  server.seat = wlr_seat_create(server.wl_display, "seat0");
  server.request_cursor.notify = seat_request_cursor;
  wl_signal_add(&server.seat->events.request_set_cursor,
                &server.request_cursor);
  server.request_set_selection.notify = seat_request_set_selection;
  wl_signal_add(&server.seat->events.request_set_selection,
                &server.request_set_selection);

  /* Add a Unix socket to the Wayland display. */
  const char* socket = wl_display_add_socket_auto(server.wl_display);
  if (!socket) {
    wlr_backend_destroy(server.backend);
    return 1;
  }

  /* Start the backend. This will enumerate outputs and inputs, become the DRM
   * master, etc */
  if (!wlr_backend_start(server.backend)) {
    wlr_backend_destroy(server.backend);
    wl_display_destroy(server.wl_display);
    return 1;
  }

  /* Either creates the cursor in its pocket if that is enabled, otherwise
   * it is shown on the screen */
  if (hide_cursor_at_top_left)
    wlr_cursor_warp_closest(server.cursor, NULL, 0, 0);
  else {
    /* HACK: creates the cursor image which is normaly hidden */
    wlr_cursor_warp_closest(server.cursor, NULL, 100, 100);
    wlr_xcursor_manager_set_cursor_image(server.cursor_mgr, "left_ptr",
                                         server.cursor);
  }

  /* Set the WAYLAND_DISPLAY environment variable to our socket */
  setenv("WAYLAND_DISPLAY", socket, true);

  /* Run the Wayland event loop. This does not return until you exit the
   * compositor. Starting the backend rigged up all of the necessary event
   * loop configuration to listen to libinput events, DRM events, generate
   * frame events at the refresh rate, and so on. */
  wlr_log(WLR_INFO, "Running Wayland compositor on WAYLAND_DISPLAY=%s", socket);
  wl_display_run(server.wl_display);

  /* Once wl_display_run returns, we shut down the server. */
  wl_display_destroy_clients(server.wl_display);
  wl_display_destroy(server.wl_display);
  return EXIT_SUCCESS;
}