export type SegmentType = "year" | "month" | "day" | "hour" | "minute" | "dayPeriod";
/** Accessible names per segment. Keys match {@link SegmentType} so `labels[type]` resolves. */
export interface SegmentLabels {
    year: string;
    month: string;
    day: string;
    hour: string;
    minute: string;
    dayPeriod: string;
}
export type LayoutSegment = {
    kind: "field";
    type: SegmentType;
} | {
    kind: "literal";
    value: string;
};
export interface DateLayout {
    /** Field + literal segments in locale display order. */
    segments: LayoutSegment[];
    hour12: boolean;
    /** Localized AM/PM strings (only meaningful when hour12). */
    amText: string;
    pmText: string;
}
/** Committed segment values. `hour` is canonical 0–23 regardless of display. */
export interface SegmentBuffer {
    year: number | null;
    month: number | null;
    day: number | null;
    hour: number | null;
    minute: number | null;
}
export declare function emptyBuffer(): SegmentBuffer;
/** The Intl options a TIME reads under — 12-vs-24-hour follows from the locale's
 *  own resolution of these. Exported because the segments and the picker list
 *  that fills them (`time_options`) must agree. */
export declare const TIME_FORMAT_OPTIONS: Intl.DateTimeFormatOptions;
export declare function getDateLayout(locale: string, hasTime: boolean): DateLayout;
/** Time-only layout (hour / minute / dayPeriod), for a standalone time field. */
export declare function getTimeLayout(locale: string): DateLayout;
/** Editable field segments in display order (literals dropped). */
export declare function fieldOrder(layout: DateLayout): SegmentType[];
export declare function to12h(hour24: number): {
    h12: number;
    pm: boolean;
};
export declare function from12h(h12: number, pm: boolean): number;
export declare function placeholderFor(type: SegmentType): string;
export interface DigitResult {
    /** In-progress text for the segment. */
    text: string;
    /** Parsed numeric value (display domain — for `hour` in 12h mode this is 1–12). */
    value: number;
    /** When true the segment is full and focus should advance to the next field. */
    complete: boolean;
}
/** Apply a typed digit to a numeric segment's in-progress text. */
export declare function typeDigit(type: SegmentType, currentText: string, digit: string, hour12: boolean): DigitResult;
/** A typed separator advances to the next segment — "1" alone cannot
 *  auto-advance (it might be "12"), so the separator is the typist's explicit
 *  "done here". A leading one is a no-op, matching native date inputs. */
export declare function separatorAdvances(key: string, segmentHasContent: boolean): boolean;
/** Step a numeric segment up/down, wrapping within its range. */
export declare function incrementSegment(type: SegmentType, current: number | null, delta: number, hour12: boolean): number;
/** Convert a typed `hour` segment value (display domain) to a canonical 0–23 hour. */
export declare function setHourField(buffer: SegmentBuffer, typed: number, hour12: boolean): number;
/** Set the AM/PM half-day, preserving the displayed 12-hour value. */
export declare function withDayPeriod(buffer: SegmentBuffer, pm: boolean): number;
/** Zero-padded display text for a committed segment, or null when unset. */
export declare function displayValue(type: SegmentType, buffer: SegmentBuffer, layout: DateLayout): string | null;
export declare function valueToSegments(iso: string, hasTime: boolean): SegmentBuffer;
export declare function isBufferEmpty(buffer: SegmentBuffer, hasTime: boolean): boolean;
/** Compose a canonical ISO value, or null when the buffer is incomplete/invalid. */
export declare function segmentsToValue(buffer: SegmentBuffer, hasTime: boolean): string | null;
/** The layout + value↔buffer mapping the segment engine drives a field with. */
export interface SegmentsConfig {
    layout: DateLayout;
    toBuffer: (value: string) => SegmentBuffer;
    toValue: (buffer: SegmentBuffer) => string | null;
    isEmpty: (buffer: SegmentBuffer) => boolean;
    /** Parse loosely-typed/pasted text to a canonical value, or null. */
    parse: (text: string) => string | null;
}
export declare function dateSegmentsConfig(locale: string, hasTime: boolean): SegmentsConfig;
/** "HH:mm" → buffer. Anything unparseable or out of range reads as empty. */
export declare function timeToSegments(time: string): SegmentBuffer;
/** Buffer → canonical "HH:mm", or null while either half is still missing. */
export declare function segmentsToTime(buffer: SegmentBuffer): string | null;
export declare function timeSegmentsConfig(locale: string): SegmentsConfig;