// SPDX-License-Identifier: GPL-2.0-only
#include "config.h"
#include <cairo.h>
#include <drm_fourcc.h>
#include <pango/pangocairo.h>
#include <wlr/util/log.h>
#include "buffer.h"
#include "common/buf.h"
#include "common/font.h"
#include "config/rcxml.h"
#include "labwc.h"
#include "theme.h"

#define OSD_ITEM_HEIGHT (20)
#define OSD_ITEM_WIDTH (600)
#define OSD_ITEM_PADDING (10)
#define OSD_BORDER_WIDTH (6)
#define OSD_TAB1 (120)
#define OSD_TAB2 (300)

static void
set_source(cairo_t *cairo, float *c)
{
	cairo_set_source_rgba(cairo, c[0], c[1], c[2], c[3]);
}

/* is title different from app_id/class? */
static int
is_title_different(struct view *view)
{
	switch (view->type) {
	case LAB_XDG_SHELL_VIEW:
		return g_strcmp0(view_get_string_prop(view, "title"),
			view_get_string_prop(view, "app_id"));
#if HAVE_XWAYLAND
	case LAB_XWAYLAND_VIEW:
		return g_strcmp0(view_get_string_prop(view, "title"),
			view->xwayland_surface->class);
#endif
	}
	return 1;
}

static const char *
get_formatted_app_id(struct view *view)
{
	char *s = (char *)view_get_string_prop(view, "app_id");
	if (!s) {
		return NULL;
	}
	/* remove the first two nodes of 'org.' strings */
	if (!strncmp(s, "org.", 4)) {
		char *p = s + 4;
		p = strchr(p, '.');
		if (p) {
			return ++p;
		}
	}
	return s;
}

static int
get_osd_height(struct wl_list *views)
{
	int height = 0;
	struct view *view;
	wl_list_for_each(view, views, link) {
		if (!isfocusable(view)) {
			continue;
		}
		height += OSD_ITEM_HEIGHT;
	}
	height += 2 * OSD_BORDER_WIDTH;
	return height;
}

static void
destroy_osd_nodes(struct output *output)
{
	struct wlr_scene_node *child, *next;
	struct wl_list *children = &output->osd_tree->node.state.children;
	wl_list_for_each_safe(child, next, children, state.link) {
		wlr_scene_node_destroy(child);
	}
}

void
osd_finish(struct server *server)
{
	struct output *output;
	wl_list_for_each(output, &server->outputs, link) {
		destroy_osd_nodes(output);
		wlr_scene_node_set_enabled(&output->osd_tree->node, false);
	}
}

void
osd_update(struct server *server)
{
	if (wl_list_empty(&server->views)) {
		return;
	}

	struct theme *theme = server->theme;

	struct output *output;
	wl_list_for_each(output, &server->outputs, link) {
		destroy_osd_nodes(output);
		float scale = output->wlr_output->scale;
		int w = (OSD_ITEM_WIDTH + (2 * OSD_BORDER_WIDTH)) * scale;
		int h = get_osd_height(&server->views) * scale;

		if (output->osd_buffer) {
			wlr_buffer_drop(&output->osd_buffer->base);
		}
		output->osd_buffer = buffer_create_cairo(w, h, scale, true);

		cairo_t *cairo = output->osd_buffer->cairo;
		cairo_surface_t *surf = cairo_get_target(cairo);

		/* background */
		set_source(cairo, theme->osd_bg_color);
		cairo_rectangle(cairo, 0, 0, w, h);
		cairo_fill(cairo);

		/* border */
		set_source(cairo, theme->osd_label_text_color);
		cairo_rectangle(cairo, 0, 0, w, h);
		cairo_stroke(cairo);

		/* highlight current window */
		int y = OSD_BORDER_WIDTH;
		struct view *view;
		wl_list_for_each(view, &server->views, link) {
			if (!isfocusable(view)) {
				continue;
			}
			if (view == server->cycle_view) {
				set_source(cairo, theme->osd_label_text_color);
				cairo_rectangle(cairo, OSD_BORDER_WIDTH, y,
					OSD_ITEM_WIDTH, OSD_ITEM_HEIGHT);
				cairo_stroke(cairo);
				break;
			}
			y += OSD_ITEM_HEIGHT;
		}

		/* text */
		set_source(cairo, theme->osd_label_text_color);
		PangoLayout *layout = pango_cairo_create_layout(cairo);
		pango_layout_set_width(layout, w * PANGO_SCALE);
		pango_layout_set_ellipsize(layout, PANGO_ELLIPSIZE_END);

		struct font font = {
			.name = rc.font_name_osd,
			.size = rc.font_size_osd,
		};
		PangoFontDescription *desc = pango_font_description_new();
		pango_font_description_set_family(desc, font.name);
		pango_font_description_set_size(desc, font.size * PANGO_SCALE);
		pango_layout_set_font_description(layout, desc);
		pango_font_description_free(desc);

		PangoTabArray *tabs = pango_tab_array_new_with_positions(2, TRUE,
			PANGO_TAB_LEFT, OSD_TAB1, PANGO_TAB_LEFT, OSD_TAB2);
		pango_layout_set_tabs(layout, tabs);
		pango_tab_array_free(tabs);

		pango_cairo_update_layout(cairo, layout);

		struct buf buf;
		buf_init(&buf);
		y = OSD_BORDER_WIDTH;

		y += (OSD_ITEM_HEIGHT - font_height(&font)) / 2;

		wl_list_for_each(view, &server->views, link) {
			if (!isfocusable(view)) {
				continue;
			}
			buf.len = 0;
			cairo_move_to(cairo, OSD_BORDER_WIDTH + OSD_ITEM_PADDING, y);

			switch (view->type) {
			case LAB_XDG_SHELL_VIEW:
				buf_add(&buf, "[xdg-shell]\t");
				buf_add(&buf, get_formatted_app_id(view));
				buf_add(&buf, "\t");
				break;
#if HAVE_XWAYLAND
			case LAB_XWAYLAND_VIEW:
				buf_add(&buf, "[xwayland]\t");
				buf_add(&buf, view_get_string_prop(view, "class"));
				buf_add(&buf, "\t");
				break;
#endif
			}

			if (is_title_different(view)) {
				buf_add(&buf, view_get_string_prop(view, "title"));
			}

			pango_layout_set_text(layout, buf.buf, -1);
			pango_cairo_show_layout(cairo, layout);
			y += OSD_ITEM_HEIGHT;
		}
		g_object_unref(layout);
		cairo_surface_flush(surf);

		struct wlr_scene_buffer *scene_buffer = wlr_scene_buffer_create(
			&output->osd_tree->node, &output->osd_buffer->base);

		/* Center OSD */
		struct wlr_box output_box;
		wlr_output_layout_get_box(output->server->output_layout,
			output->wlr_output, &output_box);
		int lx = output->usable_area.x + output->usable_area.width / 2
			- w / 2 + output_box.x;
		int ly = output->usable_area.y + output->usable_area.height / 2
			- h / 2 + output_box.y;
		wlr_scene_node_set_position(&scene_buffer->node, lx, ly);
		wlr_scene_node_set_enabled(&output->osd_tree->node, true);
	}
}