import { type TradingSignals, TrendIndicatorSeries } from '../../base/Indicator.js';
import type { HilbertCycleState } from './HilbertTransform.js';
type HTTrendlineState = HilbertCycleState & {
    barsTotal: number;
    cycleAverages: number[];
    prices: number[];
    smoothPeriod: number;
};
export declare class HTTrendline extends TrendIndicatorSeries<number, TradingSignals, HTTrendlineState> {
    readonly inputShape: "price";
    protected state: HTTrendlineState;
    getRequiredInputs(): number;
    update(price: number, replace: boolean): number | null;
    protected calculateSignalState(result?: number | null): "BEARISH" | "BULLISH" | "SIDEWAYS" | "UNKNOWN";
}
export {};