import { Option } from "scats";
import { MissedRunStrategy, TaskPeriodType } from "./tasks-model.js";
import type { ScheduleCronTaskDetails, SchedulePeriodicTaskDetails } from "./tasks-model.js";
export interface PeriodicScheduleConfig {
    repeatType: TaskPeriodType;
    repeatInterval: Option<number>;
    cronExpression: Option<string>;
    startAfter: Date;
    initialStart: Date;
    missedRunsStrategy: MissedRunStrategy;
}
export declare class PeriodicScheduleUtils {
    /**
     * Resolves persisted repeat interval based on periodic type.
     *
     * For `cron` schedules interval is not used and `null` is returned.
     * For fixed schedules, `period` must be present.
     *
     * @param task task schedule request
     * @param periodType requested period type
     * @returns repeat interval in milliseconds or `null` for cron
     */
    static resolveRepeatInterval(task: SchedulePeriodicTaskDetails | ScheduleCronTaskDetails, periodType: TaskPeriodType): number | null;
    /**
     * Resolves persisted cron expression based on periodic type.
     *
     * For fixed schedules cron expression is not used and `null` is returned.
     * For `cron` schedules a non-blank `cronExpression` is required.
     *
     * Supported expression formats:
     * - 5 fields: minute, hour, day-of-month, month, day-of-week
     * - 6 fields: second, minute, hour, day-of-month, month, day-of-week
     *
     * @param task task schedule request
     * @param periodType requested period type
     * @returns normalized cron expression or `null` for fixed schedules
     */
    static resolveCronExpression(task: SchedulePeriodicTaskDetails | ScheduleCronTaskDetails, periodType: TaskPeriodType): string | null;
    /**
     * Calculates the next task start time for periodic tasks.
     *
     * Supported schedule sources:
     * - fixed interval (`fixed_rate`, `fixed_delay`)
     * - cron expression (`cron`)
     *
     * @param task periodic scheduling configuration
     * @param now current timestamp used as a base for delay and skip-missed semantics
     * @returns next start time
     */
    static calculateNextStartAfter(task: PeriodicScheduleConfig, now: Date): Date;
    /**
     * Calculates next start for cron-based periodic tasks.
     *
     * Supported cron formats:
     * - 5 fields: minute, hour, day-of-month, month, day-of-week
     * - 6 fields: second, minute, hour, day-of-month, month, day-of-week
     *
     * Cron expressions are evaluated in UTC in the current implementation.
     *
     * @param task cron scheduling config
     * @param now current timestamp
     * @returns next start time for cron schedule
     */
    private static calculateNextCronStartAfter;
    /**
     * Calculates next start for interval-based periodic tasks.
     *
     * @param task interval scheduling config
     * @param now current timestamp
     * @returns next start time for fixed-rate or fixed-delay schedule
     */
    private static calculateNextIntervalStartAfter;
    /**
     * Calculates fixed-rate next start for skip-missed behavior.
     *
     * @param initialStart initial schedule anchor
     * @param now current timestamp
     * @param repeatInterval schedule period in milliseconds
     * @returns nearest fixed-rate slot at or after `now`
     */
    private static calculateFixedRateSkipMissedNextStartAfter;
}