// SPDX-License-Identifier: GPL-2.0-only
/*
 * Theme engine for labwc
 *
 * Copyright (C) Johan Malm 2020-2021
 */

#define _POSIX_C_SOURCE 200809L
#include <cairo.h>
#include <ctype.h>
#include <drm_fourcc.h>
#include <glib.h>
#include <math.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wlr/util/box.h>
#include <wlr/util/log.h>
#include <strings.h>
#include "common/dir.h"
#include "common/font.h"
#include "common/graphic-helpers.h"
#include "common/match.h"
#include "common/string-helpers.h"
#include "config/rcxml.h"
#include "theme.h"
#include "xbm/xbm.h"
#include "buffer.h"
#include "ssd.h"

static int
hex_to_dec(char c)
{
	if (c >= '0' && c <= '9') {
		return c - '0';
	}
	if (c >= 'a' && c <= 'f') {
		return c - 'a' + 10;
	}
	if (c >= 'A' && c <= 'F') {
		return c - 'A' + 10;
	}
	return 0;
}

/**
 * parse_hexstr - parse #rrggbb
 * @hex: hex string to be parsed
 * @rgba: pointer to float[4] for return value
 */
static void
parse_hexstr(const char *hex, float *rgba)
{
	if (!hex || hex[0] != '#' || strlen(hex) < 7) {
		return;
	}
	rgba[0] = (hex_to_dec(hex[1]) * 16 + hex_to_dec(hex[2])) / 255.0;
	rgba[1] = (hex_to_dec(hex[3]) * 16 + hex_to_dec(hex[4])) / 255.0;
	rgba[2] = (hex_to_dec(hex[5]) * 16 + hex_to_dec(hex[6])) / 255.0;
	if (strlen(hex) > 7) {
		rgba[3] = atoi(hex + 7) / 100.0;
	} else {
		rgba[3] = 1.0;
	}
}

static enum lab_justification
parse_justification(const char *str)
{
	if (!strcasecmp(str, "Center")) {
		return LAB_JUSTIFY_CENTER;
	} else if (!strcasecmp(str, "Right")) {
		return LAB_JUSTIFY_RIGHT;
	} else {
		return LAB_JUSTIFY_LEFT;
	}
}

/*
 * We generally use Openbox defaults, but if no theme file can be found it's
 * better to populate the theme variables with some sane values as no-one
 * wants to use openbox without a theme - it'll all just be black and white.
 *
 * Openbox doesn't actual start if it can't find a theme. As it's normally
 * packaged with Clearlooks, this is not a problem, but for labwc I thought
 * this was a bit hard-line. People might want to try labwc without having
 * Openbox (and associated themes) installed.
 *
 * theme_builtin() applies a theme that is similar to vanilla GTK
 */
static void
theme_builtin(struct theme *theme)
{
	theme->border_width = 1;
	theme->padding_height = 3;
	theme->menu_overlap_x = 0;
	theme->menu_overlap_y = 0;

	parse_hexstr("#dddad6", theme->window_active_border_color);
	parse_hexstr("#f6f5f4", theme->window_inactive_border_color);

	parse_hexstr("#dddad6", theme->window_active_title_bg_color);
	parse_hexstr("#f6f5f4", theme->window_inactive_title_bg_color);

	parse_hexstr("#000000", theme->window_active_label_text_color);
	parse_hexstr("#000000", theme->window_inactive_label_text_color);
	theme->window_label_text_justify = parse_justification("Center");

	parse_hexstr("#000000",
		theme->window_active_button_menu_unpressed_image_color);
	parse_hexstr("#000000",
		theme->window_active_button_iconify_unpressed_image_color);
	parse_hexstr("#000000",
		theme->window_active_button_max_unpressed_image_color);
	parse_hexstr("#000000",
		theme->window_active_button_close_unpressed_image_color);
	parse_hexstr("#000000",
		theme->window_inactive_button_menu_unpressed_image_color);
	parse_hexstr("#000000",
		theme->window_inactive_button_iconify_unpressed_image_color);
	parse_hexstr("#000000",
		theme->window_inactive_button_max_unpressed_image_color);
	parse_hexstr("#000000",
		theme->window_inactive_button_close_unpressed_image_color);

	parse_hexstr("#fcfbfa", theme->menu_items_bg_color);
	parse_hexstr("#000000", theme->menu_items_text_color);
	parse_hexstr("#dddad6", theme->menu_items_active_bg_color);
	parse_hexstr("#000000", theme->menu_items_active_text_color);

	theme->menu_item_padding_x = 7;
	theme->menu_item_padding_y = 4;

	theme->menu_min_width = 20;
	theme->menu_max_width = 200;

	theme->menu_separator_line_thickness = 1;
	theme->menu_separator_padding_width = 6;
	theme->menu_separator_padding_height = 3;
	parse_hexstr("#888888", theme->menu_separator_color);

	/* inherit settings in post_processing() if not set elsewhere */
	theme->osd_bg_color[0] = FLT_MIN;
	theme->osd_border_width = INT_MIN;
	theme->osd_border_color[0] = FLT_MIN;
	theme->osd_label_text_color[0] = FLT_MIN;
}

static void
entry(struct theme *theme, const char *key, const char *value)
{
	if (!key || !value) {
		return;
	}

	/*
	 * Note that in order for the pattern match to apply to more than just
	 * the first instance, "else if" cannot be used throughout this function
	 */
	if (match_glob(key, "border.width")) {
		theme->border_width = atoi(value);
	}
	if (match_glob(key, "padding.height")) {
		theme->padding_height = atoi(value);
	}
	if (match_glob(key, "menu.items.padding.x")) {
		theme->menu_item_padding_x = atoi(value);
	}
	if (match_glob(key, "menu.items.padding.y")) {
		theme->menu_item_padding_y = atoi(value);
	}
	if (match_glob(key, "menu.overlap.x")) {
		theme->menu_overlap_x = atoi(value);
	}
	if (match_glob(key, "menu.overlap.y")) {
		theme->menu_overlap_y = atoi(value);
	}

	if (match_glob(key, "window.active.border.color")) {
		parse_hexstr(value, theme->window_active_border_color);
	}
	if (match_glob(key, "window.inactive.border.color")) {
		parse_hexstr(value, theme->window_inactive_border_color);
	}
	/* border.color is obsolete, but handled for backward compatibility */
	if (match_glob(key, "border.color")) {
		parse_hexstr(value, theme->window_active_border_color);
		parse_hexstr(value, theme->window_inactive_border_color);
	}

	if (match_glob(key, "window.active.title.bg.color")) {
		parse_hexstr(value, theme->window_active_title_bg_color);
	}
	if (match_glob(key, "window.inactive.title.bg.color")) {
		parse_hexstr(value, theme->window_inactive_title_bg_color);
	}

	if (match_glob(key, "window.active.label.text.color")) {
		parse_hexstr(value, theme->window_active_label_text_color);
	}
	if (match_glob(key, "window.inactive.label.text.color")) {
		parse_hexstr(value, theme->window_inactive_label_text_color);
	}
	if (match_glob(key, "window.label.text.justify")) {
		theme->window_label_text_justify = parse_justification(value);
	}

	/* universal button */
	if (match_glob(key, "window.active.button.unpressed.image.color")) {
		parse_hexstr(value,
			theme->window_active_button_menu_unpressed_image_color);
		parse_hexstr(value,
			theme->window_active_button_iconify_unpressed_image_color);
		parse_hexstr(value,
			theme->window_active_button_max_unpressed_image_color);
		parse_hexstr(value,
			theme->window_active_button_close_unpressed_image_color);
	}
	if (match_glob(key, "window.inactive.button.unpressed.image.color")) {
		parse_hexstr(value,
			theme->window_inactive_button_menu_unpressed_image_color);
		parse_hexstr(value,
			theme->window_inactive_button_iconify_unpressed_image_color);
		parse_hexstr(value,
			theme->window_inactive_button_max_unpressed_image_color);
		parse_hexstr(value,
			theme->window_inactive_button_close_unpressed_image_color);
	}

	/* individual buttons */
	if (match_glob(key, "window.active.button.menu.unpressed.image.color")) {
		parse_hexstr(value,
			theme->window_active_button_menu_unpressed_image_color);
	}
	if (match_glob(key, "window.active.button.iconify.unpressed.image.color")) {
		parse_hexstr(value,
			theme->window_active_button_iconify_unpressed_image_color);
	}
	if (match_glob(key, "window.active.button.max.unpressed.image.color")) {
		parse_hexstr(value,
			theme->window_active_button_max_unpressed_image_color);
	}
	if (match_glob(key, "window.active.button.close.unpressed.image.color")) {
		parse_hexstr(value,
			theme->window_active_button_close_unpressed_image_color);
	}
	if (match_glob(key, "window.inactive.button.menu.unpressed.image.color")) {
		parse_hexstr(value,
			theme->window_inactive_button_menu_unpressed_image_color);
	}
	if (match_glob(key, "window.inactive.button.iconify.unpressed.image.color")) {
		parse_hexstr(value,
			theme->window_inactive_button_iconify_unpressed_image_color);
	}
	if (match_glob(key, "window.inactive.button.max.unpressed.image.color")) {
		parse_hexstr(value,
			theme->window_inactive_button_max_unpressed_image_color);
	}
	if (match_glob(key, "window.inactive.button.close.unpressed.image.color")) {
		parse_hexstr(value,
			theme->window_inactive_button_close_unpressed_image_color);
	}

	if (match_glob(key, "menu.width.min")) {
		theme->menu_min_width = atoi(value);
	}
	if (match_glob(key, "menu.width.max")) {
		theme->menu_max_width = atoi(value);
	}

	if (match_glob(key, "menu.items.bg.color")) {
		parse_hexstr(value, theme->menu_items_bg_color);
	}
	if (match_glob(key, "menu.items.text.color")) {
		parse_hexstr(value, theme->menu_items_text_color);
	}
	if (match_glob(key, "menu.items.active.bg.color")) {
		parse_hexstr(value, theme->menu_items_active_bg_color);
	}
	if (match_glob(key, "menu.items.active.text.color")) {
		parse_hexstr(value, theme->menu_items_active_text_color);
	}

	if (match_glob(key, "menu.separator.width")) {
		theme->menu_separator_line_thickness = atoi(value);
	}
	if (match_glob(key, "menu.separator.padding.width")) {
		theme->menu_separator_padding_width = atoi(value);
	}
	if (match_glob(key, "menu.separator.padding.height")) {
		theme->menu_separator_padding_height = atoi(value);
	}
	if (match_glob(key, "menu.separator.color")) {
		parse_hexstr(value, theme->menu_separator_color);
	}

	if (match_glob(key, "osd.bg.color")) {
		parse_hexstr(value, theme->osd_bg_color);
	}
	if (match_glob(key, "osd.border.width")) {
		theme->osd_border_width = atoi(value);
	}
	if (match_glob(key, "osd.border.color")) {
		parse_hexstr(value, theme->osd_border_color);
	}
	if (match_glob(key, "osd.label.text.color")) {
		parse_hexstr(value, theme->osd_label_text_color);
	}
}

static void
parse_config_line(char *line, char **key, char **value)
{
	char *p = strchr(line, ':');
	if (!p) {
		return;
	}
	*p = '\0';
	*key = string_strip(line);
	*value = string_strip(++p);
}

static void
process_line(struct theme *theme, char *line)
{
	if (line[0] == '\0' || line[0] == '#') {
		return;
	}
	char *key = NULL, *value = NULL;
	parse_config_line(line, &key, &value);
	entry(theme, key, value);
}

static void
theme_read(struct theme *theme, const char *theme_name)
{
	FILE *stream = NULL;
	char *line = NULL;
	size_t len = 0;
	char themerc[4096];

	if (strlen(theme_dir(theme_name))) {
		snprintf(themerc, sizeof(themerc), "%s/themerc",
			theme_dir(theme_name));
		stream = fopen(themerc, "r");
	}
	if (!stream) {
		if (theme_name) {
			wlr_log(WLR_INFO, "cannot find theme %s", theme_name);
		}
		return;
	}
	wlr_log(WLR_INFO, "read theme %s", themerc);
	while (getline(&line, &len, stream) != -1) {
		char *p = strrchr(line, '\n');
		if (p) {
			*p = '\0';
		}
		process_line(theme, line);
	}
	free(line);
	fclose(stream);
}

static void
theme_read_override(struct theme *theme)
{
	char f[4096] = { 0 };
	snprintf(f, sizeof(f), "%s/themerc-override", rc.config_dir);

	FILE *stream = fopen(f, "r");
	if (!stream) {
		wlr_log(WLR_INFO, "no theme override '%s'", f);
		return;
	}

	wlr_log(WLR_INFO, "read theme-override %s", f);
	char *line = NULL;
	size_t len = 0;
	while (getline(&line, &len, stream) != -1) {
		char *p = strrchr(line, '\n');
		if (p) {
			*p = '\0';
		}
		process_line(theme, line);
	}
	free(line);
	fclose(stream);
}

struct rounded_corner_ctx {
	struct wlr_box *box;
	double radius;
	double line_width;
	float *fill_color;
	float *border_color;
	enum {
		LAB_CORNER_UNKNOWN = 0,
		LAB_CORNER_TOP_LEFT,
		LAB_CORNER_TOP_RIGHT,
	} corner;
};

static struct lab_data_buffer *
rounded_rect(struct rounded_corner_ctx *ctx)
{
	/* 1 degree in radians (=2π/360) */
	double deg = 0.017453292519943295;

	if (ctx->corner == LAB_CORNER_UNKNOWN) {
		return NULL;
	}

	double w = ctx->box->width;
	double h = ctx->box->height;
	double r = ctx->radius;

	struct lab_data_buffer *buffer;
	/* TODO: scale */
	buffer = buffer_create_cairo(w, h, 1, true);

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

	/* set transparent background */
	cairo_set_operator(cairo, CAIRO_OPERATOR_CLEAR);
	cairo_paint(cairo);

	/* fill */
	cairo_set_line_width(cairo, 0.0);
	cairo_new_sub_path(cairo);
	switch (ctx->corner) {
	case LAB_CORNER_TOP_LEFT:
		cairo_arc(cairo, r, r, r, 180 * deg, 270 * deg);
		cairo_line_to(cairo, w, 0);
		cairo_line_to(cairo, w, h);
		cairo_line_to(cairo, 0, h);
		break;
	case LAB_CORNER_TOP_RIGHT:
		cairo_arc(cairo, w - r, r, r, -90 * deg, 0 * deg);
		cairo_line_to(cairo, w, h);
		cairo_line_to(cairo, 0, h);
		cairo_line_to(cairo, 0, 0);
		break;
	default:
		wlr_log(WLR_ERROR, "unknown corner type");
	}
	cairo_close_path(cairo);
	cairo_set_operator(cairo, CAIRO_OPERATOR_SOURCE);
	set_cairo_color(cairo, ctx->fill_color);
	cairo_fill_preserve(cairo);
	cairo_stroke(cairo);

	/* border */
	cairo_set_line_cap(cairo, CAIRO_LINE_CAP_ROUND);
	set_cairo_color(cairo, ctx->border_color);
	cairo_set_line_width(cairo, ctx->line_width);
	double half_line_width = ctx->line_width / 2.0;
	switch (ctx->corner) {
	case LAB_CORNER_TOP_LEFT:
		cairo_move_to(cairo, half_line_width, h);
		cairo_line_to(cairo, half_line_width, r + half_line_width);
		cairo_arc(cairo, r, r, r - half_line_width, 180 * deg, 270 * deg);
		cairo_line_to(cairo, w, half_line_width);
		break;
	case LAB_CORNER_TOP_RIGHT:
		cairo_move_to(cairo, 0, half_line_width);
		cairo_line_to(cairo, w - r, half_line_width);
		cairo_arc(cairo, w - r, r, r - half_line_width, -90 * deg, 0 * deg);
		cairo_line_to(cairo, w - half_line_width, h);
		break;
	default:
		wlr_log(WLR_ERROR, "unknown corner type");
	}
	cairo_stroke(cairo);
	cairo_surface_flush(surf);

	return buffer;
}

static void
create_corners(struct theme *theme)
{
	struct wlr_box box = {
		.x = 0,
		.y = 0,
		.width = SSD_BUTTON_WIDTH + theme->border_width,
		.height = theme->title_height + theme->border_width,
	};

	struct rounded_corner_ctx ctx = {
		.box = &box,
		.radius = rc.corner_radius,
		.line_width = theme->border_width,
		.fill_color = theme->window_active_title_bg_color,
		.border_color = theme->window_active_border_color,
		.corner = LAB_CORNER_TOP_LEFT,
	};
	theme->corner_top_left_active_normal = rounded_rect(&ctx);

	ctx.fill_color = theme->window_inactive_title_bg_color,
	ctx.border_color = theme->window_inactive_border_color,
	theme->corner_top_left_inactive_normal = rounded_rect(&ctx);

	ctx.corner = LAB_CORNER_TOP_RIGHT;
	ctx.fill_color = theme->window_active_title_bg_color,
	ctx.border_color = theme->window_active_border_color,
	theme->corner_top_right_active_normal = rounded_rect(&ctx);

	ctx.fill_color = theme->window_inactive_title_bg_color,
	ctx.border_color = theme->window_inactive_border_color,
	theme->corner_top_right_inactive_normal = rounded_rect(&ctx);
}

static void
post_processing(struct theme *theme)
{
	theme->title_height = font_height(&rc.font_activewindow)
		+ 2 * theme->padding_height;

	if (rc.corner_radius >= theme->title_height) {
		theme->title_height = rc.corner_radius + 1;
	}

	if (theme->menu_max_width < theme->menu_min_width) {
		wlr_log(WLR_ERROR,
			"Adjusting menu.width.max: .max (%d) lower than .min (%d)",
			theme->menu_max_width, theme->menu_min_width);
		theme->menu_max_width = theme->menu_min_width;
	}

	/* Inherit OSD settings if not set */
	if (theme->osd_bg_color[0] == FLT_MIN) {
		memcpy(theme->osd_bg_color,
			theme->window_active_title_bg_color,
			sizeof(theme->osd_bg_color));
	}
	if (theme->osd_border_width == INT_MIN) {
		theme->osd_border_width = theme->border_width;
	}
	if (theme->osd_label_text_color[0] == FLT_MIN) {
		memcpy(theme->osd_label_text_color,
			theme->window_active_label_text_color,
			sizeof(theme->osd_label_text_color));
	}
	if (theme->osd_border_color[0] == FLT_MIN) {
		/*
		 * As per http://openbox.org/wiki/Help:Themes#osd.border.color
		 * we should fall back to window_active_border_color but
		 * that is usually the same as window_active_title_bg_color
		 * and thus the fallback for osd_bg_color. Which would mean
		 * they are both the same color and thus the border is invisible.
		 *
		 * Instead, we fall back to osd_label_text_color which in turn
		 * falls back to window_active_label_text_color.
		 */
		memcpy(theme->osd_border_color, theme->osd_label_text_color,
			sizeof(theme->osd_border_color));
	}
}

void
theme_init(struct theme *theme, const char *theme_name)
{
	/*
	 * Set some default values. This is particularly important on
	 * reconfigure as not all themes set all options
	 */
	theme_builtin(theme);

	/* Read <data-dir>/share/themes/$theme_name/openbox-3/themerc */
	theme_read(theme, theme_name);

	/* Read <config-dir>/labwc/themerc-override */
	theme_read_override(theme);

	post_processing(theme);
	create_corners(theme);
	xbm_load(theme);
}

void
theme_finish(struct theme *theme)
{
	wlr_buffer_drop(&theme->corner_top_left_active_normal->base);
	wlr_buffer_drop(&theme->corner_top_left_inactive_normal->base);
	wlr_buffer_drop(&theme->corner_top_right_active_normal->base);
	wlr_buffer_drop(&theme->corner_top_right_inactive_normal->base);
	theme->corner_top_left_active_normal = NULL;
	theme->corner_top_left_inactive_normal = NULL;
	theme->corner_top_right_active_normal = NULL;
	theme->corner_top_right_inactive_normal = NULL;
}