#define _POSIX_C_SOURCE 200809L
#include <stdlib.h>
#include <wlr/config.h>
#include <wlr/types/wlr_tablet_v2.h>
#include <wlr/types/wlr_tablet_tool.h>
#include <wlr/types/wlr_tablet_pad.h>
#include "log.h"
#include "sway/input/cursor.h"
#include "sway/input/seat.h"
#include "sway/input/tablet.h"

#if WLR_HAS_LIBINPUT_BACKEND
#include <wlr/backend/libinput.h>
#endif

static void handle_pad_tablet_destroy(struct wl_listener *listener, void *data) {
	struct sway_tablet_pad *pad =
		wl_container_of(listener, pad, tablet_destroy);

	pad->tablet = NULL;

	wl_list_remove(&pad->tablet_destroy.link);
	wl_list_init(&pad->tablet_destroy.link);
}

static void attach_tablet_pad(struct sway_tablet_pad *tablet_pad,
		struct sway_tablet *tablet) {
	sway_log(SWAY_DEBUG, "Attaching tablet pad \"%s\" to tablet tool \"%s\"",
		tablet_pad->seat_device->input_device->wlr_device->name,
		tablet->seat_device->input_device->wlr_device->name);

	tablet_pad->tablet = tablet;

	wl_list_remove(&tablet_pad->tablet_destroy.link);
	tablet_pad->tablet_destroy.notify = handle_pad_tablet_destroy;
	wl_signal_add(&tablet->seat_device->input_device->wlr_device->events.destroy,
		&tablet_pad->tablet_destroy);
}

struct sway_tablet *sway_tablet_create(struct sway_seat *seat,
		struct sway_seat_device *device) {
	struct sway_tablet *tablet =
		calloc(1, sizeof(struct sway_tablet));
	if (!sway_assert(tablet, "could not allocate sway tablet for seat")) {
		return NULL;
	}

	wl_list_insert(&seat->cursor->tablets, &tablet->link);

	device->tablet = tablet;
	tablet->seat_device = device;

	return tablet;
}

void sway_configure_tablet(struct sway_tablet *tablet) {
	struct wlr_input_device *device =
		tablet->seat_device->input_device->wlr_device;
	struct sway_seat *seat = tablet->seat_device->sway_seat;

	seat_configure_xcursor(seat);

	if (!tablet->tablet_v2) {
		tablet->tablet_v2 =
			wlr_tablet_create(server.tablet_v2, seat->wlr_seat, device);
	}

#if WLR_HAS_LIBINPUT_BACKEND
	/* Search for a sibling tablet pad */
	if (!wlr_input_device_is_libinput(device)) {
		/* We can only do this on libinput devices */
		return;
	}

	struct libinput_device_group *group =
		libinput_device_get_device_group(wlr_libinput_get_device_handle(device));
	struct sway_tablet_pad *tablet_pad;
	wl_list_for_each(tablet_pad, &seat->cursor->tablet_pads, link) {
		struct wlr_input_device *pad_device =
			tablet_pad->seat_device->input_device->wlr_device;
		if (!wlr_input_device_is_libinput(pad_device)) {
			continue;
		}

		struct libinput_device_group *pad_group =
			libinput_device_get_device_group(wlr_libinput_get_device_handle(pad_device));

		if (pad_group == group) {
			attach_tablet_pad(tablet_pad, tablet);
			break;
		}
	}
#endif
}

void sway_tablet_destroy(struct sway_tablet *tablet) {
	if (!tablet) {
		return;
	}
	wl_list_remove(&tablet->link);
	free(tablet);
}

static void handle_tablet_tool_set_cursor(struct wl_listener *listener, void *data) {
	struct sway_tablet_tool *tool =
		wl_container_of(listener, tool, set_cursor);
	struct wlr_tablet_v2_event_cursor *event = data;

	struct sway_cursor *cursor = tool->seat->cursor;
	if (!seatop_allows_set_cursor(cursor->seat)) {
		return;
	}

	struct wl_client *focused_client = NULL;
	struct wlr_surface *focused_surface = tool->tablet_v2_tool->focused_surface;
	if (focused_surface != NULL) {
		focused_client = wl_resource_get_client(focused_surface->resource);
	}

	// TODO: check cursor mode
	if (focused_client == NULL ||
			event->seat_client->client != focused_client) {
		sway_log(SWAY_DEBUG, "denying request to set cursor from unfocused client");
		return;
	}

	cursor_set_image_surface(cursor, event->surface, event->hotspot_x,
			event->hotspot_y, focused_client);
}

static void handle_tablet_tool_destroy(struct wl_listener *listener, void *data) {
	struct sway_tablet_tool *tool =
		wl_container_of(listener, tool, tool_destroy);

	wl_list_remove(&tool->tool_destroy.link);
	wl_list_remove(&tool->set_cursor.link);

	free(tool);
}

void sway_tablet_tool_configure(struct sway_tablet *tablet,
		struct wlr_tablet_tool *wlr_tool) {
	struct sway_tablet_tool *tool =
		calloc(1, sizeof(struct sway_tablet_tool));
	if (!sway_assert(tool, "could not allocate sway tablet tool for tablet")) {
		return;
	}

	switch (wlr_tool->type) {
	case WLR_TABLET_TOOL_TYPE_LENS:
	case WLR_TABLET_TOOL_TYPE_MOUSE:
		tool->mode = SWAY_TABLET_TOOL_MODE_RELATIVE;
		break;
	default:
		tool->mode = SWAY_TABLET_TOOL_MODE_ABSOLUTE;

		struct input_config *ic = input_device_get_config(
			tablet->seat_device->input_device);
		if (!ic) {
			break;
		}

		for (int i = 0; i < ic->tools->length; i++) {
			struct input_config_tool *tool_config = ic->tools->items[i];
			if (tool_config->type == wlr_tool->type) {
				tool->mode = tool_config->mode;
				break;
			}
		}
	}

	tool->seat = tablet->seat_device->sway_seat;
	tool->tablet = tablet;
	tool->tablet_v2_tool =
		wlr_tablet_tool_create(server.tablet_v2,
			tablet->seat_device->sway_seat->wlr_seat, wlr_tool);

	tool->tool_destroy.notify = handle_tablet_tool_destroy;
	wl_signal_add(&wlr_tool->events.destroy, &tool->tool_destroy);

	tool->set_cursor.notify = handle_tablet_tool_set_cursor;
	wl_signal_add(&tool->tablet_v2_tool->events.set_cursor,
		&tool->set_cursor);

	wlr_tool->data = tool;
}

static void handle_tablet_pad_attach(struct wl_listener *listener,
		void *data) {
	struct sway_tablet_pad *pad = wl_container_of(listener, pad, attach);
	struct wlr_tablet_tool *wlr_tool = data;
	struct sway_tablet_tool *tool = wlr_tool->data;

	if (!tool) {
		return;
	}

	attach_tablet_pad(pad, tool->tablet);
}

static void handle_tablet_pad_ring(struct wl_listener *listener, void *data) {
	struct sway_tablet_pad *pad = wl_container_of(listener, pad, ring);
	struct wlr_tablet_pad_ring_event *event = data;

	if (!pad->current_surface) {
		return;
	}

	wlr_tablet_v2_tablet_pad_notify_ring(pad->tablet_v2_pad,
		event->ring, event->position,
		event->source == WLR_TABLET_PAD_RING_SOURCE_FINGER,
		event->time_msec);
}

static void handle_tablet_pad_strip(struct wl_listener *listener, void *data) {
	struct sway_tablet_pad *pad = wl_container_of(listener, pad, strip);
	struct wlr_tablet_pad_strip_event *event = data;

	if (!pad->current_surface) {
		return;
	}

	wlr_tablet_v2_tablet_pad_notify_strip(pad->tablet_v2_pad,
		event->strip, event->position,
		event->source == WLR_TABLET_PAD_STRIP_SOURCE_FINGER,
		event->time_msec);
}

static void handle_tablet_pad_button(struct wl_listener *listener, void *data) {
	struct sway_tablet_pad *pad = wl_container_of(listener, pad, button);
	struct wlr_tablet_pad_button_event *event = data;

	if (!pad->current_surface) {
		return;
	}

	wlr_tablet_v2_tablet_pad_notify_mode(pad->tablet_v2_pad,
		event->group, event->mode, event->time_msec);

	wlr_tablet_v2_tablet_pad_notify_button(pad->tablet_v2_pad,
		event->button, event->time_msec,
		(enum zwp_tablet_pad_v2_button_state)event->state);
}

struct sway_tablet_pad *sway_tablet_pad_create(struct sway_seat *seat,
		struct sway_seat_device *device) {
	struct sway_tablet_pad *tablet_pad =
		calloc(1, sizeof(struct sway_tablet_pad));
	if (!sway_assert(tablet_pad, "could not allocate sway tablet")) {
		return NULL;
	}

	tablet_pad->wlr = wlr_tablet_pad_from_input_device(device->input_device->wlr_device);
	tablet_pad->seat_device = device;
	wl_list_init(&tablet_pad->attach.link);
	wl_list_init(&tablet_pad->button.link);
	wl_list_init(&tablet_pad->strip.link);
	wl_list_init(&tablet_pad->ring.link);
	wl_list_init(&tablet_pad->surface_destroy.link);
	wl_list_init(&tablet_pad->tablet_destroy.link);

	wl_list_insert(&seat->cursor->tablet_pads, &tablet_pad->link);

	return tablet_pad;
}

void sway_configure_tablet_pad(struct sway_tablet_pad *tablet_pad) {
	struct wlr_input_device *wlr_device =
		tablet_pad->seat_device->input_device->wlr_device;
	struct sway_seat *seat = tablet_pad->seat_device->sway_seat;

	if (!tablet_pad->tablet_v2_pad) {
		tablet_pad->tablet_v2_pad =
			wlr_tablet_pad_create(server.tablet_v2, seat->wlr_seat, wlr_device);
	}

	wl_list_remove(&tablet_pad->attach.link);
	tablet_pad->attach.notify = handle_tablet_pad_attach;
	wl_signal_add(&tablet_pad->wlr->events.attach_tablet,
		&tablet_pad->attach);

	wl_list_remove(&tablet_pad->button.link);
	tablet_pad->button.notify = handle_tablet_pad_button;
	wl_signal_add(&tablet_pad->wlr->events.button, &tablet_pad->button);

	wl_list_remove(&tablet_pad->strip.link);
	tablet_pad->strip.notify = handle_tablet_pad_strip;
	wl_signal_add(&tablet_pad->wlr->events.strip, &tablet_pad->strip);

	wl_list_remove(&tablet_pad->ring.link);
	tablet_pad->ring.notify = handle_tablet_pad_ring;
	wl_signal_add(&tablet_pad->wlr->events.ring, &tablet_pad->ring);

#if WLR_HAS_LIBINPUT_BACKEND
	/* Search for a sibling tablet */
	if (!wlr_input_device_is_libinput(wlr_device)) {
		/* We can only do this on libinput devices */
		return;
	}

	struct libinput_device_group *group =
		libinput_device_get_device_group(wlr_libinput_get_device_handle(wlr_device));
	struct sway_tablet *tool;
	wl_list_for_each(tool, &seat->cursor->tablets, link) {
		struct wlr_input_device *tablet =
			tool->seat_device->input_device->wlr_device;
		if (!wlr_input_device_is_libinput(tablet)) {
			continue;
		}

		struct libinput_device_group *tablet_group =
			libinput_device_get_device_group(wlr_libinput_get_device_handle(tablet));

		if (tablet_group == group) {
			attach_tablet_pad(tablet_pad, tool);
			break;
		}
	}
#endif
}

void sway_tablet_pad_destroy(struct sway_tablet_pad *tablet_pad) {
	if (!tablet_pad) {
		return;
	}

	wl_list_remove(&tablet_pad->link);
	wl_list_remove(&tablet_pad->attach.link);
	wl_list_remove(&tablet_pad->button.link);
	wl_list_remove(&tablet_pad->strip.link);
	wl_list_remove(&tablet_pad->ring.link);
	wl_list_remove(&tablet_pad->surface_destroy.link);
	wl_list_remove(&tablet_pad->tablet_destroy.link);

	free(tablet_pad);
}

static void handle_pad_tablet_surface_destroy(struct wl_listener *listener,
		void *data) {
	struct sway_tablet_pad *tablet_pad =
		wl_container_of(listener, tablet_pad, surface_destroy);

	sway_tablet_pad_set_focus(tablet_pad, NULL);
}

void sway_tablet_pad_set_focus(struct sway_tablet_pad *tablet_pad,
		struct wlr_surface *surface) {
	if (!tablet_pad || !tablet_pad->tablet) {
		return;
	}

	if (surface == tablet_pad->current_surface) {
		return;
	}

	/* Leave current surface */
	if (tablet_pad->current_surface) {
		wlr_tablet_v2_tablet_pad_notify_leave(tablet_pad->tablet_v2_pad,
			tablet_pad->current_surface);
		wl_list_remove(&tablet_pad->surface_destroy.link);
		wl_list_init(&tablet_pad->surface_destroy.link);
		tablet_pad->current_surface = NULL;
	}

	if (surface == NULL ||
			!wlr_surface_accepts_tablet_v2(tablet_pad->tablet->tablet_v2, surface)) {
		return;
	}

	wlr_tablet_v2_tablet_pad_notify_enter(tablet_pad->tablet_v2_pad,
		tablet_pad->tablet->tablet_v2, surface);

	tablet_pad->current_surface = surface;
	tablet_pad->surface_destroy.notify = handle_pad_tablet_surface_destroy;
	wl_signal_add(&surface->events.destroy, &tablet_pad->surface_destroy);
}
