/**
* @license Copyright (c) 2003-2026, CKSource Holding sp. z o.o. All rights reserved.
* For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-licensing-options
*/
/**
* Handles a configuration dictionary.
*
* @typeParam Cfg A type of the configuration dictionary.
*/
export declare class Config<Cfg> {
	/**
	* Store for the whole configuration.
	*/
	private readonly _config;
	/**
	* Creates an instance of the {@link ~Config} class.
	*
	* @param configurations The initial configurations to be set. Usually, provided by the user.
	* @param defaultConfigurations The default configurations. Usually, provided by the system.
	*/
	constructor(configurations?: Partial<Cfg>, defaultConfigurations?: Partial<Cfg>);
	/**
	* Set configuration values.
	*
	* It also accepts setting a "deep configuration" by using dots in the name. For example, `'resize.width'` sets
	* the value for the `width` configuration in the `resize` subset.
	*
	* ```ts
	* config.set( 'resize.width', 500 );
	* ```
	*
	* It accepts both a name/value pair or an object, which properties and values will be used to set
	* configurations. See {@link #set:CONFIG_OBJECT}.
	*
	* @label KEY_VALUE
	* @param name The configuration name. Configuration names are case-sensitive.
	* @param value The configuration value.
	*/
	set<K extends string>(name: K, value: GetSubConfig<Cfg, K>): void;
	/**
	* Set configuration values.
	*
	* It accepts an object, which properties and values will be used to set configurations.
	*
	* ```ts
	* config.set( {
	* 	width: 500
	* 	toolbar: {
	* 		collapsed: true
	* 	}
	* } );
	*
	* // Equivalent to:
	* config.set( 'width', 500 );
	* config.set( 'toolbar.collapsed', true );
	* ```
	*
	* Passing an object as the value will amend the configuration, not replace it.
	*
	* ```ts
	* config.set( 'toolbar', {
	* 	collapsed: true,
	* } );
	*
	* config.set( 'toolbar', {
	* 	color: 'red',
	* } );
	*
	* config.get( 'toolbar.collapsed' ); // true
	* config.get( 'toolbar.color' ); // 'red'
	* ```
	*
	* It accepts both a name/value pair or an object, which properties and values will be used to set
	* configurations. See {@link #set:KEY_VALUE}.
	*
	* @label CONFIG_OBJECT
	* @param config The configuration object from which take properties as
	* configuration entries. Configuration names are case-sensitive.
	*/
	set(config: Partial<Cfg>): void;
	/**
	* Does exactly the same as {@link #set:KEY_VALUE} with one exception – passed configuration extends
	* existing one, but does not overwrite already defined values.
	*
	* This method is supposed to be called by plugin developers to setup plugin's configurations. It would be
	* rarely used for other needs.
	*
	* @label KEY_VALUE
	* @param name The configuration name. Configuration names are case-sensitive.
	* @param value The configuration value.
	*/
	define<K extends string>(name: K, value: GetSubConfig<Cfg, K>): void;
	/**
	* Does exactly the same as {@link #set:CONFIG_OBJECT} with one exception – passed configuration extends
	* existing one, but does not overwrite already defined values.
	*
	* This method is supposed to be called by plugin developers to setup plugin's configurations. It would be
	* rarely used for other needs.
	*
	* @label CONFIG_OBJECT
	* @param config The configuration object from which take properties as
	* configuration entries. Configuration names are case-sensitive.
	*/
	define(config: Partial<Cfg>): void;
	/**
	* Gets the value for a configuration entry.
	*
	* ```ts
	* config.get( 'name' );
	* ```
	*
	* Deep configurations can be retrieved by separating each part with a dot.
	*
	* ```ts
	* config.get( 'toolbar.collapsed' );
	* ```
	*
	* @param name The configuration name. Configuration names are case-sensitive.
	* @returns The configuration value or `undefined` if the configuration entry was not found.
	*/
	get<K extends string>(name: K): GetSubConfig<Cfg, K> | undefined;
	/**
	* Iterates over all top level configuration names.
	*/
	names(): Iterable<string>;
	/**
	* Saves passed configuration to the specified target (nested object).
	*
	* @param target Nested config object.
	* @param name The configuration name or an object from which take properties as
	* configuration entries. Configuration names are case-sensitive.
	* @param value The configuration value. Used if a name is passed.
	* @param isDefine Define if passed configuration should overwrite existing one.
	*/
	private _setToTarget;
	/**
	* Get specified configuration from specified source (nested object).
	*
	* @param source level of nested object.
	* @param name The configuration name. Configuration names are case-sensitive.
	* @returns The configuration value or `undefined` if the configuration entry was not found.
	*/
	private _getFromSource;
	/**
	* Iterates through passed object and calls {@link #_setToTarget} method with object key and value for each property.
	*
	* @param target Nested config object.
	* @param configuration Configuration data set
	* @param isDefine Defines if passed configuration is default configuration or not.
	*/
	private _setObjectToTarget;
}
/**
* An utility type excluding primitive values and arrays from the union.
*/
export type OnlyObject<T> = Exclude<T, undefined | null | string | number | boolean | Array<any>>;
/**
* An utility type extracting configuration value from the given name.
*
* @typeParam T The type of a configuration dictionary.
* @typeParam K The literal type of configuration name (dot-separated path).
*/
export type GetSubConfig<
	T,
	K
> = K extends keyof T ? T[K] : K extends `${infer K1}.${infer K2}` ? K1 extends keyof T ? GetSubConfig<OnlyObject<T[K1]>, K2> : unknown : unknown;