/** Which candidates a file field takes, how many, and what it refuses. */
export interface MdyFileCandidate {
    readonly name: string;
    readonly type: string;
    readonly size: number;
}
export interface MdyFileSelectionOptions {
    readonly accept?: string;
    readonly multiple: boolean;
    readonly maxFileSize?: number;
    readonly maxFiles?: number;
}
export interface MdyFileSelectionTransition<TFile extends MdyFileCandidate> {
    /** What the field holds: always a list, as `MDY_VALUE_CONTRACTS.file` declares. */
    readonly value: readonly TFile[] | null | undefined;
    readonly accepted: readonly TFile[];
    readonly rejected: readonly TFile[];
    readonly touched: boolean;
}
/** Shared picker/drop policy. `undefined` means no accepted candidate and preserves the committed value. */
export declare function fileSelectionTransition<TFile extends MdyFileCandidate>(candidates: readonly TFile[], options: MdyFileSelectionOptions): MdyFileSelectionTransition<TFile>;
export declare function clearFileSelection<TFile extends MdyFileCandidate>(): MdyFileSelectionTransition<TFile>;