/**
 * @license Copyright (c) 2003-2025, CKSource Holding sp. z o.o. All rights reserved.
 * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-licensing-options
 */
/**
 * @module export-inline-styles/utils/exportinlinestylescssvariables
 */
import type { StylesMap } from 'ckeditor5/src/engine.js';
import type { ParsedCSSRule } from './exportinlinestylescollector.js';
/**
 * Collects CSS custom properties (variables) that are defined in `:root` selector rules.
 * These variables are then used as global fallback values for variable resolution in the document.
 *
 * **Note:** Since `element.matches(':root')` always returns `false` for detached DOM elements,
 * this effectively inlines all CSS custom properties defined in `:root` rules into the document,
 * making them available for variable resolution regardless of the DOM structure.
 *
 * @param rules An array of parsed CSS rules to extract variables from.
 * @returns A map containing CSS variable names as keys and their computed values.
 *
 * ```ts
 * const rules = [
 * 	{
 * 		flatSelector: ':root',
 * 		stylesMap: createStylesMap( '--primary-color: blue; --button-color: var(--primary-color);' )
 * 	},
 * 	{
 * 		flatSelector: '.button',
 * 		stylesMap: createStylesMap( 'background: var(--button-color); border: 1px solid var(--primary-color);' )
 * 	}
 * ];
 *
 * const rootVariables = collectRootStylesheetsVariables( rules );
 * // Returns: Map {
 * //	'--primary-color' => 'blue',
 * //	'--button-color' => 'blue'
 * // }
 * ```
 */
export declare function collectRootStylesheetsVariables(rules: Array<ParsedCSSRule>): CSSVariablesMap;
/**
 * Processes CSS variables in a styles map by inlining their values.
 *
 * **Note:** This function modifies the input StylesMap object. CSS variables are extracted
 * and their references are replaced with actual values in other style properties.
 *
 * @param fallbackCSSVariablesLookup A function that returns a CSS variable if not found in the local CSS variables map.
 * @param stylesMap The styles map to process. Will be modified in-place.
 * @returns The local CSS variables map containing CSS variables and their values.
 *
 * ```ts
 * const stylesMap = new StylesMap();
 * stylesMap.set( '--color', 'red' );
 * stylesMap.set( 'color', 'var(--color)' );
 *
 * inlineStylesMapCSSVariables( stylesMap );
 * // stylesMap now contains: color: red
 * ```
 */
export declare function inlineStylesMapCSSVariables(fallbackCSSVariablesLookup: CSSVariableLookupCallback, stylesMap: StylesMap): CSSVariablesMap;
/**
 * A function that returns a CSS variable value for a given variable name.
 */
export type CSSVariableLookupCallback = (name: string) => string | undefined;
/**
 * A map of CSS variables and their values.
 */
export type CSSVariablesMap = Map<string, string>;