import { FormGroupDirective, NgControl, NgForm } from '@angular/forms';
import { Subject } from 'rxjs';
import { ErrorStateMatcher } from '../error/error-state-matcher';
import { AbstractConstructor, Constructor } from './constructor';
/** @docs-private */
export interface CanUpdateErrorState {
    /** Whether the component is in an error state. */
    errorState: boolean;
    /** An object used to control the error state of the component. */
    errorStateMatcher: ErrorStateMatcher;
    /** Updates the error state based on the provided error state matcher. */
    updateErrorState(): void;
}
/** @docs-private */
export type CanUpdateErrorStateCtor = Constructor<CanUpdateErrorState>;
/** @docs-private */
export interface HasErrorState {
    parentFormGroup: FormGroupDirective | null;
    parentForm: NgForm | null;
    defaultErrorStateMatcher: ErrorStateMatcher;
    ngControl: NgControl | null;
    stateChanges: Subject<void>;
}
/**
 * Mixin to augment a directive with updateErrorState method.
 * For component with `errorState` and need to update `errorState`.
 */
export declare function mixinErrorState<T extends AbstractConstructor<HasErrorState>>(base: T): CanUpdateErrorStateCtor & T;
/**
 * Class that tracks the error state of a component.
 * @docs-private
 */
export declare class KbqErrorStateTracker implements CanUpdateErrorState {
    private defaultMatcher;
    ngControl: NgControl | null;
    private parentFormGroup;
    private parentForm;
    private stateChanges;
    /** Whether the tracker is currently in an error state. */
    errorState: boolean;
    /** User-defined matcher for the error state. */
    errorStateMatcher: ErrorStateMatcher;
    constructor(defaultMatcher: ErrorStateMatcher | null, ngControl: NgControl | null, parentFormGroup: FormGroupDirective | null, parentForm: NgForm | null, stateChanges: Subject<void>);
    /** Updates the error state based on the provided error state matcher. */
    updateErrorState(): void;
}