import { GanttDateCell, GanttWeekGroup, GanttViewMode, GanttTask, FlatTask } from './gantt-types';
declare function normalizeDate(d: Date | string): Date;
declare function addDays(date: Date, days: number): Date;
declare function diffDays(a: Date, b: Date): number;
declare function isSameDay(a: Date, b: Date): boolean;
export declare function generateDateCells(start: Date, end: Date, isHoliday: (date: Date) => boolean): GanttDateCell[];
export declare function generateWeekGroups(dateCells: GanttDateCell[], viewMode: GanttViewMode): GanttWeekGroup[];
export declare function generateSecondaryHeaders(dateCells: GanttDateCell[], viewMode: GanttViewMode): GanttWeekGroup[];
export declare function generateMonthCells(start: Date, end: Date, _isHoliday?: (date: Date) => boolean): GanttDateCell[];
export declare function generateQuarterCells(start: Date, end: Date): GanttDateCell[];
export declare function generateYearCells(start: Date, end: Date): GanttDateCell[];
export declare function flattenTasks(tasks: GanttTask[], collapsedIds: Set<string>, depth?: number, parentId?: string): FlatTask[];
export declare function getTaskBarPosition(task: GanttTask, startDate: Date, columnWidth: number, viewMode: GanttViewMode): {
    left: number;
    width: number;
    startCol: number;
    endCol: number;
} | null;
export declare function columnToDate(_columnIndex: number, startDate: Date, columnWidth: number, pixelOffset: number, viewMode: GanttViewMode): Date;
export declare function getDefaultColumnWidth(viewMode: GanttViewMode): number;
export declare function computeDateRange(tasks: GanttTask[], viewMode: GanttViewMode, startDate?: Date | string, endDate?: Date | string): {
    start: Date;
    end: Date;
};
export declare function getTodayColumnIndex(_startDate: Date, dateCells: GanttDateCell[]): number;
export declare function getMarkerPosition(markerDate: Date | string, startDate: Date, columnWidth: number, viewMode: GanttViewMode): number;
export { normalizeDate, addDays, diffDays, isSameDay };