export interface BeatClockConfig {
    bpm: number;
    /** Beats per bar/measure, for bar-relative UI (rhythm-game combo windows). Default 4. */
    beatsPerBar?: number;
}
export interface BeatSnapshot {
    /** Fractional beat count since the clock started. */
    beat: number;
    beatIndex: number;
    bar: number;
    beatInBar: number;
    /** 0..1 fractional position within the current beat. */
    phase: number;
}
export interface BeatClock {
    /** Advance by a game-time delta (already scaled by ctx.time — never wall-clock). Returns the resulting snapshot and fires onBeat once per newly crossed integer beat. */
    advance(gameDt: number): BeatSnapshot;
    snapshot(): BeatSnapshot;
    /** Elapsed game-seconds since the clock started. */
    now(): number;
    beatDurationSec(): number;
    bpm(): number;
}
/** @internal */
export declare function createBeatClock(config: BeatClockConfig, onBeat?: (beatIndex: number) => void): BeatClock;
/** Signed offset (game-seconds) from `nowSec` to the nearest beat boundary — negative = early, positive = late (#286.12).
 * @internal
 */
export declare function nearestBeatDelta(nowSec: number, beatDurationSec: number): number;
export interface BeatAccuracyTier {
    id: string;
    /** Maximum absolute delta (game-seconds) from the beat that still earns this tier. */
    windowSec: number;
}
export interface BeatJudgement {
    /** The matched tier id, or `"miss"` beyond every tier. */
    tier: string;
    /** Signed delta to the nearest beat — negative = early, positive = late. */
    deltaSec: number;
}
export declare const DEFAULT_BEAT_TIERS: readonly BeatAccuracyTier[];
/** Classify a press against the nearest beat into tiered judgements (perfect/good/miss by default). Tiers must be ordered tightest-first.
 * @internal
 */
export declare function classifyBeatAccuracy(nowSec: number, beatDurationSec: number, tiers?: readonly BeatAccuracyTier[]): BeatJudgement;
/** Whether a snapshot sits inside a bar-relative open window `[fromBeat, toBeat)` — e.g. "act on beats 2-4 of every bar" (#286.12).
 * @internal
 */
export declare function inBarWindow(snapshot: BeatSnapshot, fromBeat: number, toBeat: number): boolean;
/** The absolute beat-time (game-seconds) that a press at `nowSec` quantizes to: the same instant if it lands on a beat boundary, else the next one.
 * @internal
 */
export declare function nextBeatTime(nowSec: number, beatDurationSec: number, epsilon?: number): number;
export interface BufferedAction<T> {
    action: T;
    bufferedAtSec: number;
    fireAtSec: number;
}
export interface BeatInputBuffer<T> {
    /** Buffer an action; it quantizes to fire on the next beat tick (or immediately if `nowSec` is already on a beat). Returns the resolved fire time. */
    buffer(action: T, nowSec: number): number;
    /** Drain and return every action whose fire time has arrived, in the order they were buffered. */
    advance(nowSec: number): T[];
    pendingCount(): number;
    clear(): void;
}
/** @internal */
export declare function createBeatInputBuffer<T>(beatDurationSec: number): BeatInputBuffer<T>;