#include "labwc.h"

#include <wlr/types/wlr_export_dmabuf_v1.h>
#include <wlr/types/wlr_screencopy_v1.h>
#include <wlr/types/wlr_data_control_v1.h>
#include <wlr/types/wlr_gamma_control_v1.h>
#include <wlr/types/wlr_primary_selection_v1.h>

static struct tinywl_view *last_toplevel(struct tinywl_server *server) {
	struct tinywl_view *view;

	wl_list_for_each_reverse(view, &server->views, link) {
		if (!view->been_mapped) {
			continue;
		}
		if (is_toplevel(view)) {
			return view;
		}
	}
	fprintf(stderr, "warn: found no toplevel view (%s)\n", __func__);
	return NULL;
}

static void view_focus_last_toplevel(struct tinywl_server *server) {
	/* TODO: write view_nr_toplevel_views() */
	if (wl_list_length(&server->views) < 2) {
		return;
	}
	struct tinywl_view *view = last_toplevel(server);
	focus_view(view, view->surface);
}

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 tinywl_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->device);
	/* Send modifiers to the client. */
	wlr_seat_keyboard_notify_modifiers(keyboard->server->seat,
		&keyboard->device->keyboard->modifiers);
}

static void xdg_debug_show_one_view(struct tinywl_view *view) {
	fprintf(stderr, "XDG  ");
	switch (view->xdg_surface->role) {
	case WLR_XDG_SURFACE_ROLE_NONE:
		fprintf(stderr, "- ");
		break;
	case WLR_XDG_SURFACE_ROLE_TOPLEVEL:
		fprintf(stderr, "0 ");
		break;
	case WLR_XDG_SURFACE_ROLE_POPUP:
		fprintf(stderr, "? ");
		break;
	}
	fprintf(stderr, "                   %p %s", (void *)view,
		view->xdg_surface->toplevel->app_id);
	fprintf(stderr, "  {%d, %d, %d, %d}\n",
		view->xdg_surface->geometry.x,
		view->xdg_surface->geometry.y,
		view->xdg_surface->geometry.height,
		view->xdg_surface->geometry.width);
}

static void xwl_debug_show_one_view(struct tinywl_view *view) {
	fprintf(stderr, "XWL  ");
	if (!view->been_mapped) {
		fprintf(stderr, "- ");
	} else {
		fprintf(stderr, "%d ", xwl_nr_parents(view));
	}
	fprintf(stderr, "     %d      ", wl_list_length(&view->xwayland_surface->children));
	if (view->mapped) {
		fprintf(stderr, "Y");
	} else {
		fprintf(stderr, "-");
	}
	fprintf(stderr, "      %p %s {%d,%d,%d,%d}\n",
		(void *)view,
		view->xwayland_surface->class,
		view->xwayland_surface->x,
		view->xwayland_surface->y,
		view->xwayland_surface->width,
		view->xwayland_surface->height);
	/*
	 * Other variables to consider printing:
	 *
	 * view->mapped,
	 * view->been_mapped,
	 * view->xwayland_surface->override_redirect,
	 * wlr_xwayland_or_surface_wants_focus(view->xwayland_surface));
	 * view->xwayland_surface->saved_width,
	 * view->xwayland_surface->saved_height);
	 * view->xwayland_surface->surface->sx,
	 * view->xwayland_surface->surface->sy);
	 */
}

static void debug_show_one_view(struct tinywl_view *view) {
	if (view->type == LAB_XDG_SHELL_VIEW)
		xdg_debug_show_one_view(view);
	else if (view->type == LAB_XWAYLAND_VIEW)
		xwl_debug_show_one_view(view);
}

static void debug_show_views(struct tinywl_server *server) {
	struct tinywl_view *view;

	fprintf(stderr, "---\n");
	fprintf(stderr, "TYPE NR_PNT NR_CLD MAPPED VIEW-POINTER   NAME\n");
	wl_list_for_each_reverse(view, &server->views, link)
		debug_show_one_view(view);
}

static bool handle_keybinding(struct tinywl_server *server, xkb_keysym_t sym) {
	/*
	 * Here we handle compositor keybindings. This is when the compositor is
	 * processing keys, rather than passing them on to the client for its own
	 * processing.
	 *
	 * This function assumes Alt is held down.
	 */
	switch (sym) {
	case XKB_KEY_Escape:
		wl_display_terminate(server->wl_display);
		break;
	case XKB_KEY_F1:
	case XKB_KEY_F2:
		view_focus_last_toplevel(server);
		break;
	case XKB_KEY_F3:
		if (fork() == 0) {
			execl("/bin/dmenu_run", "/bin/dmenu_run", (void *)NULL);
		}
		break;
	case XKB_KEY_F6:
		begin_interactive(first_toplevel(server),
			TINYWL_CURSOR_MOVE, 0);
		break;
	case XKB_KEY_F12:
		debug_show_views(server);
		break;
	default:
		return false;
	}
	return true;
}

static void keyboard_handle_key(
		struct wl_listener *listener, void *data) {
	/* This event is raised when a key is pressed or released. */
	struct tinywl_keyboard *keyboard =
		wl_container_of(listener, keyboard, key);
	struct tinywl_server *server = keyboard->server;
	struct wlr_event_keyboard_key *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->device->keyboard->xkb_state, keycode, &syms);

	bool handled = false;
	uint32_t modifiers = wlr_keyboard_get_modifiers(keyboard->device->keyboard);
	if ((modifiers & WLR_MODIFIER_ALT) && event->state == WLR_KEY_PRESSED) {
		/* If alt is held down and this button was _pressed_, we attempt to
		 * process it as a compositor keybinding. */
		for (int i = 0; i < nsyms; i++) {
			handled = handle_keybinding(server, syms[i]);
		}
	}

	if (!handled) {
		/* Otherwise, we pass it along to the client. */
		wlr_seat_set_keyboard(seat, keyboard->device);
		wlr_seat_keyboard_notify_key(seat, event->time_msec,
			event->keycode, event->state);
	}
}

static void server_new_keyboard(struct tinywl_server *server,
		struct wlr_input_device *device) {
	struct tinywl_keyboard *keyboard =
		calloc(1, sizeof(struct tinywl_keyboard));
	keyboard->server = server;
	keyboard->device = device;

	/* We need to prepare an XKB keymap and assign it to the keyboard. This
	 * assumes the defaults (e.g. layout = "us"). */
	struct xkb_rule_names rules = { 0 };
	struct xkb_context *context = xkb_context_new(XKB_CONTEXT_NO_FLAGS);
	struct xkb_keymap *keymap = xkb_map_new_from_names(context, &rules,
		XKB_KEYMAP_COMPILE_NO_FLAGS);

	wlr_keyboard_set_keymap(device->keyboard, keymap);
	xkb_keymap_unref(keymap);
	xkb_context_unref(context);
	wlr_keyboard_set_repeat_info(device->keyboard, 25, 600);

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

	wlr_seat_set_keyboard(server->seat, device);

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

static void server_new_pointer(struct tinywl_server *server,
		struct wlr_input_device *device) {
	/* We don't do anything special with pointers. All of our pointer handling
	 * is proxied through wlr_cursor. On another compositor, you might take this
	 * opportunity to do libinput configuration on the device to set
	 * acceleration, etc. */
	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 tinywl_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 TinyWL 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 tinywl_server *server = wl_container_of(
			listener, server, request_cursor);
	/* This event is rasied 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);
	}
}

int main(int argc, char *argv[]) {
	wlr_log_init(WLR_ERROR, NULL);
	char *startup_cmd = NULL;

	int c;
	while ((c = getopt(argc, argv, "s:h")) != -1) {
		switch (c) {
		case 's':
			startup_cmd = optarg;
			break;
		default:
			printf("Usage: %s [-s startup command]\n", argv[0]);
			return 0;
		}
	}
	if (optind < argc) {
		printf("Usage: %s [-s startup command]\n", argv[0]);
		return 0;
	}

	struct tinywl_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. The NULL argument here optionally allows you
	 * to pass in a custom renderer if wlr_renderer doesn't meet your needs. The
	 * backend uses the renderer, for example, to fall back to software cursors
	 * if the backend does not support hardware cursors (some older GPUs
	 * don't). */
	server.backend = wlr_backend_autocreate(server.wl_display, NULL);

	/* If we don't provide a renderer, autocreate makes a GLES2 renderer for us.
	 * The renderer is responsible for defining the various pixel formats it
	 * supports for shared memory, this configures that for clients. */
	server.renderer = wlr_backend_get_renderer(server.backend);
	wlr_renderer_init_wl_display(server.renderer, server.wl_display);

	/* This creates some hands-off wlroots interfaces. The compositor is
	 * necessary for clients to allocate 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. */
	server.compositor = wlr_compositor_create(server.wl_display, server.renderer);
	wlr_data_device_manager_create(server.wl_display);

	wlr_export_dmabuf_manager_v1_create(server.wl_display);
	wlr_screencopy_manager_v1_create(server.wl_display);
	wlr_data_control_manager_v1_create(server.wl_display);
	wlr_gamma_control_manager_v1_create(server.wl_display);
	wlr_primary_selection_v1_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);

	/* Set up our list of views and the xdg-shell. 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);
	server.new_xdg_surface.notify = xdg_surface_new;
	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);

	/*
	 * 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);

	/* 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;
	}

	/* Set the WAYLAND_DISPLAY environment variable to our socket and run the
	 * startup command if requested. */
	setenv("WAYLAND_DISPLAY", socket, true);

	wl_display_init_shm(server.wl_display);

	/* Init xwayland */
	server.xwayland = wlr_xwayland_create(server.wl_display, server.compositor, false);
	server.new_xwayland_surface.notify = xwl_surface_new;
	wl_signal_add(&server.xwayland->events.new_surface, &server.new_xwayland_surface);
	setenv("DISPLAY", server.xwayland->display_name, true);
	wlr_xwayland_set_seat(server.xwayland, server.seat);

	/* 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(XCURSOR_DEFAULT, XCURSOR_SIZE);
	wlr_xcursor_manager_load(server.cursor_mgr, 1);

	struct wlr_xcursor *xcursor =
		wlr_xcursor_manager_get_xcursor(server.cursor_mgr, XCURSOR_DEFAULT, 1);
	if (xcursor) {
		struct wlr_xcursor_image *image = xcursor->images[0];
		wlr_xwayland_set_cursor(server.xwayland, image->buffer,
					image->width * 4, image->width, image->height,
					image->hotspot_x, image->hotspot_y);
	}

	if (startup_cmd) {
		if (fork() == 0) {
			execl("/bin/sh", "/bin/sh", "-c", startup_cmd, (void *)NULL);
		}
	}
	/* 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. */
	wlr_xwayland_destroy(server.xwayland);
	wlr_xcursor_manager_destroy(server.cursor_mgr);
	wl_display_destroy_clients(server.wl_display);
	wl_display_destroy(server.wl_display);
	return 0;
}