export type TraceSelectionFlags = {
    trace?: string;
    last?: number;
    since?: string;
    all?: boolean;
};
/** What the picker needs to know about a trace. `TraceSummary` has both
 *  fields, so the commands pass their summaries straight in; start time
 *  is computed in one place, `traceSummaries`, and never again. */
export type Pickable = {
    traceId: string;
    startedAt: number | undefined;
};
export type TraceSelection<T extends Pickable> = {
    kind: "selected";
    picked: T[];
    total: number;
    older: number;
} | {
    kind: "refused";
    reason: string;
};
/** `30m`, `2h`, `3d`, or an ISO date, as a time in ms, or a refusal. */
export declare function parseSince(text: string, now: number): {
    at: number;
} | {
    error: string;
};
/** A flag's text as a positive whole number, or a refusal naming the flag.
 *  Undefined text is an absent flag. */
export declare function parseCount(flag: string, text: string | undefined): {
    value: number | undefined;
} | {
    error: string;
};
/**
 * The traces the flags pick, newest first by start time, by the
 * combinations table above. `defaultLast` applies only when none of the
 * four flags is given. A trace with no timestamp sorts oldest and `since`
 * never picks it. `older` counts the traces `last` (or the default) left
 * out.
 */
export declare function selectTraces<T extends Pickable>(traces: readonly T[], flags: TraceSelectionFlags, options: {
    defaultLast: number;
    now: number;
}): TraceSelection<T>;