#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include "types/wlr_xdg_shell.h"
#include "util/signal.h"

static void xdg_popup_grab_end(struct wlr_xdg_popup_grab *popup_grab) {
	struct wlr_xdg_popup *popup, *tmp;
	wl_list_for_each_safe(popup, tmp, &popup_grab->popups, grab_link) {
		xdg_popup_send_popup_done(popup->resource);
	}

	wlr_seat_pointer_end_grab(popup_grab->seat);
	wlr_seat_keyboard_end_grab(popup_grab->seat);
	wlr_seat_touch_end_grab(popup_grab->seat);
}

static void xdg_pointer_grab_enter(struct wlr_seat_pointer_grab *grab,
		struct wlr_surface *surface, double sx, double sy) {
	struct wlr_xdg_popup_grab *popup_grab = grab->data;
	if (wl_resource_get_client(surface->resource) == popup_grab->client) {
		wlr_seat_pointer_enter(grab->seat, surface, sx, sy);
	} else {
		wlr_seat_pointer_clear_focus(grab->seat);
	}
}

static void xdg_pointer_grab_clear_focus(struct wlr_seat_pointer_grab *grab) {
	wlr_seat_pointer_clear_focus(grab->seat);
}

static void xdg_pointer_grab_motion(struct wlr_seat_pointer_grab *grab,
		uint32_t time, double sx, double sy) {
	wlr_seat_pointer_send_motion(grab->seat, time, sx, sy);
}

static uint32_t xdg_pointer_grab_button(struct wlr_seat_pointer_grab *grab,
		uint32_t time, uint32_t button, uint32_t state) {
	uint32_t serial =
		wlr_seat_pointer_send_button(grab->seat, time, button, state);
	if (serial) {
		return serial;
	} else {
		xdg_popup_grab_end(grab->data);
		return 0;
	}
}

static void xdg_pointer_grab_axis(struct wlr_seat_pointer_grab *grab,
		uint32_t time, enum wlr_axis_orientation orientation, double value,
		int32_t value_discrete, enum wlr_axis_source source) {
	wlr_seat_pointer_send_axis(grab->seat, time, orientation, value,
		value_discrete, source);
}

static void xdg_pointer_grab_frame(struct wlr_seat_pointer_grab *grab) {
	wlr_seat_pointer_send_frame(grab->seat);
}

static void xdg_pointer_grab_cancel(struct wlr_seat_pointer_grab *grab) {
	xdg_popup_grab_end(grab->data);
}

static const struct wlr_pointer_grab_interface xdg_pointer_grab_impl = {
	.enter = xdg_pointer_grab_enter,
	.clear_focus = xdg_pointer_grab_clear_focus,
	.motion = xdg_pointer_grab_motion,
	.button = xdg_pointer_grab_button,
	.cancel = xdg_pointer_grab_cancel,
	.axis = xdg_pointer_grab_axis,
	.frame = xdg_pointer_grab_frame,
};

static void xdg_keyboard_grab_enter(struct wlr_seat_keyboard_grab *grab,
		struct wlr_surface *surface, uint32_t keycodes[], size_t num_keycodes,
		struct wlr_keyboard_modifiers *modifiers) {
	// keyboard focus should remain on the popup
}

static void xdg_keyboard_grab_clear_focus(struct wlr_seat_keyboard_grab *grab) {
	// keyboard focus should remain on the popup
}

static void xdg_keyboard_grab_key(struct wlr_seat_keyboard_grab *grab, uint32_t time,
		uint32_t key, uint32_t state) {
	wlr_seat_keyboard_send_key(grab->seat, time, key, state);
}

static void xdg_keyboard_grab_modifiers(struct wlr_seat_keyboard_grab *grab,
		struct wlr_keyboard_modifiers *modifiers) {
	wlr_seat_keyboard_send_modifiers(grab->seat, modifiers);
}

static void xdg_keyboard_grab_cancel(struct wlr_seat_keyboard_grab *grab) {
	wlr_seat_pointer_end_grab(grab->seat);
}

static const struct wlr_keyboard_grab_interface xdg_keyboard_grab_impl = {
	.enter = xdg_keyboard_grab_enter,
	.clear_focus = xdg_keyboard_grab_clear_focus,
	.key = xdg_keyboard_grab_key,
	.modifiers = xdg_keyboard_grab_modifiers,
	.cancel = xdg_keyboard_grab_cancel,
};

static uint32_t xdg_touch_grab_down(struct wlr_seat_touch_grab *grab,
		uint32_t time, struct wlr_touch_point *point) {
	struct wlr_xdg_popup_grab *popup_grab = grab->data;

	if (wl_resource_get_client(point->surface->resource) != popup_grab->client) {
		xdg_popup_grab_end(grab->data);
		return 0;
	}

	return wlr_seat_touch_send_down(grab->seat, point->surface, time,
			point->touch_id, point->sx, point->sy);
}

static void xdg_touch_grab_up(struct wlr_seat_touch_grab *grab,
		uint32_t time, struct wlr_touch_point *point) {
	wlr_seat_touch_send_up(grab->seat, time, point->touch_id);
}

static void xdg_touch_grab_motion(struct wlr_seat_touch_grab *grab,
		uint32_t time, struct wlr_touch_point *point) {
	wlr_seat_touch_send_motion(grab->seat, time, point->touch_id, point->sx,
		point->sy);
}

static void xdg_touch_grab_enter(struct wlr_seat_touch_grab *grab,
		uint32_t time, struct wlr_touch_point *point) {
}

static void xdg_touch_grab_frame(struct wlr_seat_touch_grab *grab) {
	wlr_seat_touch_send_frame(grab->seat);
}

static void xdg_touch_grab_cancel(struct wlr_seat_touch_grab *grab) {
	wlr_seat_touch_end_grab(grab->seat);
}

static const struct wlr_touch_grab_interface xdg_touch_grab_impl = {
	.down = xdg_touch_grab_down,
	.up = xdg_touch_grab_up,
	.motion = xdg_touch_grab_motion,
	.enter = xdg_touch_grab_enter,
	.frame = xdg_touch_grab_frame,
	.cancel = xdg_touch_grab_cancel
};

static void destroy_xdg_popup_grab(struct wlr_xdg_popup_grab *xdg_grab) {
	if (xdg_grab == NULL) {
		return;
	}

	wl_list_remove(&xdg_grab->seat_destroy.link);

	struct wlr_xdg_popup *popup, *tmp;
	wl_list_for_each_safe(popup, tmp, &xdg_grab->popups, grab_link) {
		destroy_xdg_surface(popup->base);
	}

	wl_list_remove(&xdg_grab->link);
	free(xdg_grab);
}

static void xdg_popup_grab_handle_seat_destroy(
		struct wl_listener *listener, void *data) {
	struct wlr_xdg_popup_grab *xdg_grab =
		wl_container_of(listener, xdg_grab, seat_destroy);
	destroy_xdg_popup_grab(xdg_grab);
}

static struct wlr_xdg_popup_grab *get_xdg_shell_popup_grab_from_seat(
		struct wlr_xdg_shell *shell, struct wlr_seat *seat) {
	struct wlr_xdg_popup_grab *xdg_grab;
	wl_list_for_each(xdg_grab, &shell->popup_grabs, link) {
		if (xdg_grab->seat == seat) {
			return xdg_grab;
		}
	}

	xdg_grab = calloc(1, sizeof(struct wlr_xdg_popup_grab));
	if (!xdg_grab) {
		return NULL;
	}

	xdg_grab->pointer_grab.data = xdg_grab;
	xdg_grab->pointer_grab.interface = &xdg_pointer_grab_impl;
	xdg_grab->keyboard_grab.data = xdg_grab;
	xdg_grab->keyboard_grab.interface = &xdg_keyboard_grab_impl;
	xdg_grab->touch_grab.data = xdg_grab;
	xdg_grab->touch_grab.interface = &xdg_touch_grab_impl;

	wl_list_init(&xdg_grab->popups);

	wl_list_insert(&shell->popup_grabs, &xdg_grab->link);
	xdg_grab->seat = seat;

	xdg_grab->seat_destroy.notify = xdg_popup_grab_handle_seat_destroy;
	wl_signal_add(&seat->events.destroy, &xdg_grab->seat_destroy);

	return xdg_grab;
}

void handle_xdg_popup_committed(struct wlr_xdg_popup *popup) {
	if (!popup->parent) {
		wl_resource_post_error(popup->base->resource,
			XDG_SURFACE_ERROR_NOT_CONSTRUCTED,
			"xdg_popup has no parent");
		return;
	}

	if (!popup->committed) {
		wlr_xdg_surface_schedule_configure(popup->base);
		popup->committed = true;
	}
}

static const struct xdg_popup_interface xdg_popup_implementation;

struct wlr_xdg_popup *wlr_xdg_popup_from_resource(
		struct wl_resource *resource) {
	assert(wl_resource_instance_of(resource, &xdg_popup_interface,
		&xdg_popup_implementation));
	return wl_resource_get_user_data(resource);
}

static void xdg_popup_handle_grab(struct wl_client *client,
		struct wl_resource *resource, struct wl_resource *seat_resource,
		uint32_t serial) {
	struct wlr_xdg_popup *popup =
		wlr_xdg_popup_from_resource(resource);
	if (!popup) {
		return;
	}

	struct wlr_seat_client *seat_client =
		wlr_seat_client_from_resource(seat_resource);
	if (popup->committed) {
		wl_resource_post_error(popup->resource,
			XDG_POPUP_ERROR_INVALID_GRAB,
			"xdg_popup is already mapped");
		return;
	}

	struct wlr_xdg_popup_grab *popup_grab = get_xdg_shell_popup_grab_from_seat(
		popup->base->client->shell, seat_client->seat);

	if (!wl_list_empty(&popup->base->popups)) {
		wl_resource_post_error(popup->base->client->resource,
			XDG_WM_BASE_ERROR_NOT_THE_TOPMOST_POPUP,
			"xdg_popup was not created on the topmost popup");
		return;
	}

	popup_grab->client = popup->base->client->client;
	popup->seat = seat_client->seat;

	wl_list_insert(&popup_grab->popups, &popup->grab_link);

	wlr_seat_pointer_start_grab(seat_client->seat,
		&popup_grab->pointer_grab);
	wlr_seat_keyboard_start_grab(seat_client->seat,
		&popup_grab->keyboard_grab);
	wlr_seat_touch_start_grab(seat_client->seat,
		&popup_grab->touch_grab);
}

static void xdg_popup_handle_destroy(struct wl_client *client,
		struct wl_resource *resource) {
	struct wlr_xdg_popup *popup =
		wlr_xdg_popup_from_resource(resource);

	if (popup && !wl_list_empty(&popup->base->popups)) {
		wl_resource_post_error(popup->base->client->resource,
			XDG_WM_BASE_ERROR_NOT_THE_TOPMOST_POPUP,
			"xdg_popup was destroyed while it was not the topmost popup");
		return;
	}

	wl_resource_destroy(resource);
}

static const struct xdg_popup_interface xdg_popup_implementation = {
	.destroy = xdg_popup_handle_destroy,
	.grab = xdg_popup_handle_grab,
};

static void xdg_popup_handle_resource_destroy(struct wl_resource *resource) {
	struct wlr_xdg_popup *popup =
		wlr_xdg_popup_from_resource(resource);
	if (popup == NULL) {
		return;
	}
	wlr_xdg_popup_destroy(popup);
}

const struct wlr_surface_role xdg_popup_surface_role = {
	.name = "xdg_popup",
	.commit = xdg_surface_role_commit,
	.precommit = xdg_surface_role_precommit,
};

void create_xdg_popup(struct wlr_xdg_surface *surface,
		struct wlr_xdg_surface *parent,
		struct wlr_xdg_positioner_resource *positioner, uint32_t id) {
	if (positioner->attrs.size.width == 0 ||
			positioner->attrs.anchor_rect.width == 0) {
		wl_resource_post_error(surface->client->resource,
			XDG_WM_BASE_ERROR_INVALID_POSITIONER,
			"positioner object is not complete");
		return;
	}

	if (surface->role != WLR_XDG_SURFACE_ROLE_NONE) {
		wl_resource_post_error(surface->resource,
			XDG_SURFACE_ERROR_ALREADY_CONSTRUCTED,
			"xdg-surface has already been constructed");
		return;
	}

	if (!wlr_surface_set_role(surface->surface, &xdg_popup_surface_role,
			surface, surface->resource, XDG_WM_BASE_ERROR_ROLE)) {
		return;
	}

	assert(surface->popup == NULL);
	surface->popup = calloc(1, sizeof(struct wlr_xdg_popup));
	if (!surface->popup) {
		wl_resource_post_no_memory(surface->resource);
		return;
	}
	surface->popup->base = surface;

	surface->popup->resource = wl_resource_create(
		surface->client->client, &xdg_popup_interface,
		wl_resource_get_version(surface->resource), id);
	if (surface->popup->resource == NULL) {
		free(surface->popup);
		surface->popup = NULL;
		wl_resource_post_no_memory(surface->resource);
		return;
	}
	wl_resource_set_implementation(surface->popup->resource,
		&xdg_popup_implementation, surface->popup,
		xdg_popup_handle_resource_destroy);

	surface->role = WLR_XDG_SURFACE_ROLE_POPUP;

	// positioner properties
	memcpy(&surface->popup->positioner, &positioner->attrs,
		sizeof(struct wlr_xdg_positioner));
	surface->popup->geometry =
		wlr_xdg_positioner_get_geometry(&positioner->attrs);

	if (parent) {
		surface->popup->parent = parent->surface;
		wl_list_insert(&parent->popups, &surface->popup->link);
		wlr_signal_emit_safe(&parent->events.new_popup, surface->popup);
	} else {
		wl_list_init(&surface->popup->link);
	}
}

void unmap_xdg_popup(struct wlr_xdg_popup *popup) {
	if (popup->seat != NULL) {
		struct wlr_xdg_popup_grab *grab =
			get_xdg_shell_popup_grab_from_seat(
				popup->base->client->shell, popup->seat);

		wl_list_remove(&popup->grab_link);

		if (wl_list_empty(&grab->popups)) {
			if (grab->seat->pointer_state.grab == &grab->pointer_grab) {
				wlr_seat_pointer_end_grab(grab->seat);
			}
			if (grab->seat->keyboard_state.grab == &grab->keyboard_grab) {
				wlr_seat_keyboard_end_grab(grab->seat);
			}
			if (grab->seat->touch_state.grab == &grab->touch_grab) {
				wlr_seat_touch_end_grab(grab->seat);
			}
			
			destroy_xdg_popup_grab(grab);
		}

		popup->seat = NULL;
	}
}

void wlr_xdg_popup_destroy(struct wlr_xdg_popup *popup) {
	if (popup == NULL) {
		return;
	}

	struct wlr_xdg_popup *child, *child_tmp;
	wl_list_for_each_safe(child, child_tmp, &popup->base->popups, link) {
		wlr_xdg_popup_destroy(child);
	}

	xdg_popup_send_popup_done(popup->resource);
	wl_resource_set_user_data(popup->resource, NULL);
	reset_xdg_surface(popup->base);
}

void wlr_xdg_popup_get_anchor_point(struct wlr_xdg_popup *popup,
		int *root_sx, int *root_sy) {
	struct wlr_box rect = popup->positioner.anchor_rect;
	enum xdg_positioner_anchor anchor = popup->positioner.anchor;
	int sx = 0, sy = 0;

	if (anchor == XDG_POSITIONER_ANCHOR_NONE) {
		sx = (rect.x + rect.width) / 2;
		sy = (rect.y + rect.height) / 2;
	} else if (anchor == XDG_POSITIONER_ANCHOR_TOP) {
		sx = (rect.x + rect.width) / 2;
		sy = rect.y;
	} else if (anchor == XDG_POSITIONER_ANCHOR_BOTTOM) {
		sx = (rect.x + rect.width) / 2;
		sy = rect.y + rect.height;
	} else if (anchor == XDG_POSITIONER_ANCHOR_LEFT) {
		sx = rect.x;
		sy = (rect.y + rect.height) / 2;
	} else if (anchor == XDG_POSITIONER_ANCHOR_RIGHT) {
		sx = rect.x + rect.width;
		sy = (rect.y + rect.height) / 2;
	} else if (anchor == XDG_POSITIONER_ANCHOR_TOP_LEFT) {
		sx = rect.x;
		sy = rect.y;
	} else if (anchor == XDG_POSITIONER_ANCHOR_TOP_RIGHT) {
		sx = rect.x + rect.width;
		sy = rect.y;
	} else if (anchor == XDG_POSITIONER_ANCHOR_BOTTOM_LEFT) {
		sx = rect.x;
		sy = rect.y + rect.height;
	} else if (anchor == XDG_POSITIONER_ANCHOR_BOTTOM_RIGHT) {
		sx = rect.x + rect.width;
		sy = rect.y + rect.height;
	}

	*root_sx = sx;
	*root_sy = sy;
}

void wlr_xdg_popup_get_toplevel_coords(struct wlr_xdg_popup *popup,
		int popup_sx, int popup_sy, int *toplevel_sx, int *toplevel_sy) {
	struct wlr_surface *parent = popup->parent;
	while (wlr_surface_is_xdg_surface(parent)) {
		struct wlr_xdg_surface *xdg_surface =
			wlr_xdg_surface_from_wlr_surface(parent);

		if (xdg_surface->role == WLR_XDG_SURFACE_ROLE_POPUP) {
			popup_sx += xdg_surface->popup->geometry.x;
			popup_sy += xdg_surface->popup->geometry.y;
			parent = xdg_surface->popup->parent;
		} else {
			popup_sx += xdg_surface->current.geometry.x;
			popup_sy += xdg_surface->current.geometry.y;
			break;
		}
	}
	assert(parent);

	*toplevel_sx = popup_sx;
	*toplevel_sy = popup_sy;
}

static void xdg_popup_box_constraints(struct wlr_xdg_popup *popup,
		const struct wlr_box *toplevel_sx_box, int *offset_x, int *offset_y) {
	int popup_width = popup->geometry.width;
	int popup_height = popup->geometry.height;
	int anchor_sx = 0, anchor_sy = 0;
	wlr_xdg_popup_get_anchor_point(popup, &anchor_sx, &anchor_sy);
	int popup_sx = 0, popup_sy = 0;
	wlr_xdg_popup_get_toplevel_coords(popup, popup->geometry.x,
		popup->geometry.y, &popup_sx, &popup_sy);
	*offset_x = 0, *offset_y = 0;

	if (popup_sx < toplevel_sx_box->x) {
		*offset_x = toplevel_sx_box->x - popup_sx;
	} else if (popup_sx + popup_width >
			toplevel_sx_box->x + toplevel_sx_box->width) {
		*offset_x = toplevel_sx_box->x + toplevel_sx_box->width -
			(popup_sx + popup_width);
	}

	if (popup_sy < toplevel_sx_box->y) {
		*offset_y = toplevel_sx_box->y - popup_sy;
	} else if (popup_sy + popup_height >
			toplevel_sx_box->y + toplevel_sx_box->height) {
		*offset_y = toplevel_sx_box->y + toplevel_sx_box->height -
			(popup_sy + popup_height);
	}
}

static bool xdg_popup_unconstrain_flip(struct wlr_xdg_popup *popup,
		const struct wlr_box *toplevel_sx_box) {
	int offset_x = 0, offset_y = 0;
	xdg_popup_box_constraints(popup, toplevel_sx_box,
		&offset_x, &offset_y);

	if (!offset_x && !offset_y) {
		return true;
	}

	bool flip_x = offset_x &&
		(popup->positioner.constraint_adjustment &
		 XDG_POSITIONER_CONSTRAINT_ADJUSTMENT_FLIP_X);

	bool flip_y = offset_y &&
		(popup->positioner.constraint_adjustment &
		 XDG_POSITIONER_CONSTRAINT_ADJUSTMENT_FLIP_Y);

	if (flip_x) {
		wlr_positioner_invert_x(&popup->positioner);
	}
	if (flip_y) {
		wlr_positioner_invert_y(&popup->positioner);
	}

	popup->geometry =
		wlr_xdg_positioner_get_geometry(&popup->positioner);

	xdg_popup_box_constraints(popup, toplevel_sx_box,
		&offset_x, &offset_y);

	if (!offset_x && !offset_y) {
		// no longer constrained
		return true;
	}

	// revert the positioner back if it didn't fix it and go to the next part
	if (offset_x && flip_x) {
		wlr_positioner_invert_x(&popup->positioner);
	}
	if (offset_y && flip_y) {
		wlr_positioner_invert_y(&popup->positioner);
	}

	popup->geometry =
		wlr_xdg_positioner_get_geometry(&popup->positioner);

	return false;
}

static bool xdg_popup_unconstrain_slide(struct wlr_xdg_popup *popup,
		const struct wlr_box *toplevel_sx_box) {
	int offset_x = 0, offset_y = 0;
	xdg_popup_box_constraints(popup, toplevel_sx_box,
		&offset_x, &offset_y);

	if (!offset_x && !offset_y) {
		return true;
	}

	bool slide_x = offset_x &&
		(popup->positioner.constraint_adjustment &
		 XDG_POSITIONER_CONSTRAINT_ADJUSTMENT_SLIDE_X);

	bool slide_y = offset_y &&
		(popup->positioner.constraint_adjustment &
		 XDG_POSITIONER_CONSTRAINT_ADJUSTMENT_SLIDE_Y);

	if (slide_x) {
		popup->geometry.x += offset_x;
	}

	if (slide_y) {
		popup->geometry.y += offset_y;
	}

	int toplevel_x = 0, toplevel_y = 0;
	wlr_xdg_popup_get_toplevel_coords(popup, popup->geometry.x,
		popup->geometry.y, &toplevel_x, &toplevel_y);

	if (slide_x && toplevel_x < toplevel_sx_box->x) {
		popup->geometry.x += toplevel_sx_box->x - toplevel_x;
	}
	if (slide_y && toplevel_y < toplevel_sx_box->y) {
		popup->geometry.y += toplevel_sx_box->y - toplevel_y;
	}

	xdg_popup_box_constraints(popup, toplevel_sx_box,
		&offset_x, &offset_y);

	return !offset_x && !offset_y;
}

static bool xdg_popup_unconstrain_resize(struct wlr_xdg_popup *popup,
		const struct wlr_box *toplevel_sx_box) {
	int offset_x, offset_y;
	xdg_popup_box_constraints(popup, toplevel_sx_box,
		&offset_x, &offset_y);

	if (!offset_x && !offset_y) {
		return true;
	}

	bool resize_x = offset_x &&
		(popup->positioner.constraint_adjustment &
		 XDG_POSITIONER_CONSTRAINT_ADJUSTMENT_RESIZE_X);

	bool resize_y = offset_y &&
		(popup->positioner.constraint_adjustment &
		 XDG_POSITIONER_CONSTRAINT_ADJUSTMENT_RESIZE_Y);

	if (resize_x) {
		popup->geometry.width -= offset_x;
	}
	if (resize_y) {
		popup->geometry.height -= offset_y;
	}

	xdg_popup_box_constraints(popup, toplevel_sx_box,
		&offset_x, &offset_y);

	return !offset_x && !offset_y;
}

void wlr_xdg_popup_unconstrain_from_box(struct wlr_xdg_popup *popup,
		const struct wlr_box *toplevel_sx_box) {
	if (xdg_popup_unconstrain_flip(popup, toplevel_sx_box)) {
		return;
	}
	if (xdg_popup_unconstrain_slide(popup, toplevel_sx_box)) {
		return;
	}
	if (xdg_popup_unconstrain_resize(popup, toplevel_sx_box)) {
		return;
	}
}