export interface DateParts {
    day: number;
    month: number;
    year: number;
}
export interface CalendarDayCell {
    date: string;
    day: number;
    isCurrentMonth: boolean;
    isToday: boolean;
}
/**
 * Full month names for display in calendars.
 */
export declare const MONTH_NAMES: string[];
/**
 * Abbreviated weekday names (Sunday through Saturday).
 */
export declare const WEEKDAY_SHORT_NAMES: string[];
/**
 * Parses a "YYYY-MM-DD" string into its parts, or null if it isn't a real calendar date.
 */
export declare function parseDate(value: string): DateParts | null;
/**
 * Formats date parts as "YYYY-MM-DD".
 */
export declare function formatDate(parts: DateParts): string;
/**
 * Compares two "YYYY-MM-DD" strings chronologically (safe because the format is
 * zero-padded and lexicographic order matches chronological order).
 */
export declare function compareDates(a: string, b: string): number;
/**
 * Returns whether a date falls within optional inclusive min/max bounds.
 */
export declare function isDateInRange(value: string, minDate?: string, maxDate?: string): boolean;
/**
 * Clamps a date to optional inclusive min/max bounds.
 */
export declare function clampDate(value: string, minDate?: string, maxDate?: string): string;
/**
 * Parses, validates, and clamps a typed value to "YYYY-MM-DD", or returns null if unparseable.
 */
export declare function normalizeDate(value: string, minDate?: string, maxDate?: string): string | null;
/**
 * Returns the given date's weekday, 0=Sunday..6=Saturday, matching the `Date#getUTCDay()`
 * convention already used by `RecurringShiftTemplate.byDay`.
 */
export declare function weekdayOf(value: string): number;
/**
 * Adds (or subtracts, if negative) whole days to a date.
 */
export declare function addDays(value: string, delta: number): string;
/**
 * Adds (or subtracts) whole months, clamping the day if the target month is shorter.
 */
export declare function addMonths(value: string, delta: number): string;
/**
 * Adds (or subtracts) whole years.
 */
export declare function addYears(value: string, delta: number): string;
/**
 * Returns today's local calendar date as "YYYY-MM-DD".
 */
export declare function todayString(): string;
/**
 * Returns the first day of the given date's month.
 */
export declare function startOfMonth(value: string): string;
/**
 * Generates a 42-cell (6-week) month grid for the month containing `monthValue`, starting on
 * `weekStartsOn` (0=Sunday..6=Saturday). Cells outside the target month are included (dimmed by
 * the caller) so the grid always has full weeks.
 */
export declare function generateMonthGrid(monthValue: string, weekStartsOn?: number): CalendarDayCell[];
/**
 * Formats a month value as "Month YYYY", e.g. "July 2026".
 */
export declare function monthLabel(monthValue: string): string;
/**
 * Rotates the short weekday labels to start on `weekStartsOn`.
 */
export declare function orderedWeekdayLabels(weekStartsOn?: number): string[];
/**
 * Returns all 12 months of the given year, for the month drill-down grid.
 */
export declare function generateYearMonths(year: number): {
    label: string;
    monthValue: string;
}[];
/**
 * Returns a 12-year page containing the given year, aligned to a 12-year boundary, for the
 * year drill-down grid.
 */
export declare function generateDecadeYears(year: number): number[];