#define _POSIX_C_SOURCE 199309L
#include <assert.h>
#include <time.h>
#include <stdlib.h>
#include <math.h>
#include <wlr/types/wlr_box.h>
#include <wlr/types/wlr_compositor.h>
#include <wlr/types/wlr_cursor.h>
#include <wlr/types/wlr_gamma_control.h>
#include <wlr/types/wlr_output_layout.h>
#include <wlr/types/wlr_wl_shell.h>
#include <wlr/types/wlr_xdg_shell_v6.h>
#include <wlr/util/log.h>
#include "rootston/desktop.h"
#include "rootston/server.h"

void view_destroy(struct roots_view *view) {
	struct roots_desktop *desktop = view->desktop;

	struct roots_input *input = desktop->server->input;
	if (input->active_view == view) {
		input->active_view = NULL;
		input->mode = ROOTS_CURSOR_PASSTHROUGH;
	}
	if (input->last_active_view == view) {
		input->last_active_view = NULL;
	}

	for (size_t i = 0; i < desktop->views->length; ++i) {
		struct roots_view *_view = desktop->views->items[i];
		if (view == _view) {
			list_del(desktop->views, i);
			break;
		}
	}
	free(view);
}

void view_get_size(struct roots_view *view, struct wlr_box *box) {
	if (view->get_size) {
		view->get_size(view, box);
		return;
	}
	box->x = box->y = 0;
	box->width = view->wlr_surface->current->width;
	box->height = view->wlr_surface->current->height;
}

void view_activate(struct roots_view *view, bool activate) {
	if (view->activate) {
		view->activate(view, activate);
	}
}

void view_resize(struct roots_view *view, uint32_t width, uint32_t height) {
	if (view->resize) {
		view->resize(view, width, height);
	}
}

void view_close(struct roots_view *view) {
	if (view->close) {
		view->close(view);
	}
}

bool view_center(struct roots_view *view) {
	struct wlr_box size;
	view_get_size(view, &size);
	if (size.width == 0 && size.height == 0) {
		return false;
	}

	struct roots_desktop *desktop = view->desktop;
	struct wlr_cursor *cursor = desktop->server->input->cursor;
	struct wlr_output *output = wlr_output_layout_output_at(desktop->layout,
		cursor->x, cursor->y);
	const struct wlr_output_layout_output *output_layout =
		wlr_output_layout_get(desktop->layout, output);
	if (!output) {
		return false;
	}

	view->x = (double)(output->width - size.width) / 2
		+ output_layout->x;
	view->y = (double)(output->height - size.height) / 2
		+ output_layout->y;
	return true;
}

bool view_initialize(struct roots_view *view) {
	bool centered = view_center(view);
	if (centered) {
		struct roots_input *input = view->desktop->server->input;
		set_view_focus(input, view->desktop, view);
		wlr_seat_keyboard_notify_enter(input->wl_seat, view->wlr_surface);
	}
	return centered;
}

static struct wlr_subsurface *subsurface_at(struct wlr_surface *surface,
		double sx, double sy, double *sub_x, double *sub_y) {
	struct wlr_subsurface *subsurface;
	wl_list_for_each(subsurface, &surface->subsurface_list, parent_link) {
		double _sub_x = subsurface->surface->current->subsurface_position.x;
		double _sub_y = subsurface->surface->current->subsurface_position.y;
		struct wlr_subsurface *sub =
			subsurface_at(subsurface->surface, _sub_x + sx, _sub_y + sy,
				sub_x, sub_y);
		if (sub) {
			// TODO: This won't work for nested subsurfaces. Convert sub_x and
			// sub_y to the parent coordinate system
			return sub;
		}

		int sub_width = subsurface->surface->current->buffer_width;
		int sub_height = subsurface->surface->current->buffer_height;
		if ((sx > _sub_x && sx < _sub_x + sub_width) &&
				(sy > _sub_y && sy < _sub_y + sub_height)) {
			if (pixman_region32_contains_point(
						&subsurface->surface->current->input,
						sx - _sub_x, sy - _sub_y, NULL)) {
				*sub_x = _sub_x;
				*sub_y = _sub_y;
				return subsurface;
			}
		}
	}

	return NULL;
}

static struct wlr_xdg_surface_v6 *xdg_v6_popup_at(
		struct wlr_xdg_surface_v6 *surface, double sx, double sy,
		double *popup_sx, double *popup_sy) {
	// XXX: I think this is so complicated because we're mixing geometry
	// coordinates with surface coordinates. Input handling should only deal
	// with surface coordinates.
	struct wlr_xdg_surface_v6 *popup;
	wl_list_for_each(popup, &surface->popups, popup_link) {
		double _popup_sx = surface->geometry->x + popup->popup_state->geometry.x;
		double _popup_sy =  surface->geometry->y + popup->popup_state->geometry.y;
		int popup_width =  popup->popup_state->geometry.width;
		int popup_height =  popup->popup_state->geometry.height;

		struct wlr_xdg_surface_v6 *_popup =
			xdg_v6_popup_at(popup, sx - _popup_sx + popup->geometry->x,
				sy - _popup_sy + popup->geometry->y, popup_sx, popup_sy);
		if (_popup) {
			*popup_sx = *popup_sx + _popup_sx - popup->geometry->x;
			*popup_sy = *popup_sy + _popup_sy - popup->geometry->y;
			return _popup;
		}

		if ((sx > _popup_sx && sx < _popup_sx + popup_width) &&
				(sy > _popup_sy && sy < _popup_sy + popup_height)) {
			if (pixman_region32_contains_point(&popup->surface->current->input,
						sx - _popup_sx + popup->geometry->x,
						sy - _popup_sy + popup->geometry->y, NULL)) {
				*popup_sx = _popup_sx - popup->geometry->x;
				*popup_sy = _popup_sy - popup->geometry->y;
				return popup;
			}
		}
	}

	return NULL;
}

struct roots_view *view_at(struct roots_desktop *desktop, double lx, double ly,
		struct wlr_surface **surface, double *sx, double *sy) {
	for (int i = desktop->views->length - 1; i >= 0; --i) {
		struct roots_view *view = desktop->views->items[i];

		double view_sx = lx - view->x;
		double view_sy = ly - view->y;

		struct wlr_box box = {
			.x = 0,
			.y = 0,
			.width = view->wlr_surface->current->buffer_width,
			.height = view->wlr_surface->current->buffer_height,
		};
		if (view->rotation != 0.0) {
			// Coordinates relative to the center of the view
			double ox = view_sx - (double)box.width/2,
				oy = view_sy - (double)box.height/2;
			// Rotated coordinates
			double rx = cos(view->rotation)*ox - sin(view->rotation)*oy,
				ry = cos(view->rotation)*oy + sin(view->rotation)*ox;
			view_sx = rx + (double)box.width/2;
			view_sy = ry + (double)box.height/2;
		}

		if (view->type == ROOTS_XDG_SHELL_V6_VIEW) {
			// TODO: test if this works with rotated views
			double popup_sx, popup_sy;
			struct wlr_xdg_surface_v6 *popup =
				xdg_v6_popup_at(view->xdg_surface_v6, view_sx, view_sy,
					&popup_sx, &popup_sy);

			if (popup) {
				*sx = view_sx - popup_sx;
				*sy = view_sy - popup_sy;
				*surface = popup->surface;
				return view;
			}
		}

		double sub_x, sub_y;
		struct wlr_subsurface *subsurface =
			subsurface_at(view->wlr_surface, view_sx, view_sy, &sub_x, &sub_y);
		if (subsurface) {
			*sx = view_sx - sub_x;
			*sy = view_sy - sub_y;
			*surface = subsurface->surface;
			return view;
		}

		if (wlr_box_contains_point(&box, view_sx, view_sy) &&
				pixman_region32_contains_point(
					&view->wlr_surface->current->input,
					view_sx, view_sy, NULL)) {
			*sx = view_sx;
			*sy = view_sy;
			*surface = view->wlr_surface;
			return view;
		}
	}
	return NULL;
}

struct roots_desktop *desktop_create(struct roots_server *server,
		struct roots_config *config) {
	struct roots_desktop *desktop = calloc(1, sizeof(struct roots_desktop));
	wlr_log(L_DEBUG, "Initializing roots desktop");

	assert(desktop->views = list_create());
	wl_list_init(&desktop->outputs);
	wl_list_init(&desktop->output_add.link);
	desktop->output_add.notify = output_add_notify;
	wl_list_init(&desktop->output_remove.link);
	desktop->output_remove.notify = output_remove_notify;

	wl_signal_add(&server->backend->events.output_add, &desktop->output_add);
	wl_signal_add(&server->backend->events.output_remove,
		&desktop->output_remove);

	desktop->server = server;
	desktop->config = config;
	desktop->layout = wlr_output_layout_create();
	desktop->compositor = wlr_compositor_create(server->wl_display,
		server->renderer);

	desktop->xdg_shell_v6 = wlr_xdg_shell_v6_create(server->wl_display);
	wl_signal_add(&desktop->xdg_shell_v6->events.new_surface,
		&desktop->xdg_shell_v6_surface);
	desktop->xdg_shell_v6_surface.notify = handle_xdg_shell_v6_surface;

	desktop->wl_shell = wlr_wl_shell_create(server->wl_display);
	wl_signal_add(&desktop->wl_shell->events.new_surface,
		&desktop->wl_shell_surface);
	desktop->wl_shell_surface.notify = handle_wl_shell_surface;

#ifdef HAS_XWAYLAND
	if (config->xwayland) {
		desktop->xwayland = wlr_xwayland_create(server->wl_display,
			desktop->compositor);
		wl_signal_add(&desktop->xwayland->events.new_surface,
			&desktop->xwayland_surface);
		desktop->xwayland_surface.notify = handle_xwayland_surface;
	}
#endif

	desktop->gamma_control_manager = wlr_gamma_control_manager_create(
		server->wl_display);
	desktop->screenshooter = wlr_screenshooter_create(server->wl_display,
		server->renderer);

	return desktop;
}

void desktop_destroy(struct roots_desktop *desktop) {
	// TODO
}