/**
 * AdaptiveQualityManager - FPS-based automatic quality adjustment
 *
 * Monitors frame rate via a rolling window average and steps quality up or down
 * based on sustained performance. Integrated into the BackgroundController's
 * animation loop so consumers get adaptive quality for free.
 *
 * Design decisions:
 * - Rolling window of ~60 frames for stable FPS estimation
 * - Downgrades after sustained low FPS (default: <30 for 3s)
 * - Upgrades after sustained high FPS (default: >55 for 10s)
 * - Steps one level at a time to avoid oscillation
 * - 5-second cooldown between adjustments
 * - Respects a quality ceiling set by device detection
 */
import type { QualityLevel } from "../domain/types.js";
export interface AdaptiveQualityOptions {
    /** FPS threshold below which quality downgrades. Default: 30. */
    downgradeThresholdFps?: number;
    /** FPS threshold above which quality upgrades. Default: 55. */
    upgradeThresholdFps?: number;
    /** How long FPS must stay below downgrade threshold before acting. Default: 3000ms. */
    downgradeSustainMs?: number;
    /** How long FPS must stay above upgrade threshold before acting. Default: 10000ms. */
    upgradeSustainMs?: number;
    /** Minimum time between quality adjustments. Default: 5000ms. */
    cooldownMs?: number;
    /** Whether adaptive quality is active. Default: true. */
    enabled?: boolean;
}
type QualityChangeCallback = (newQuality: QualityLevel, oldQuality: QualityLevel) => void;
/**
 * Tracks FPS and auto-adjusts quality level.
 *
 * Call `tick(timestamp)` every animation frame. The manager handles the rest.
 */
export declare class AdaptiveQualityManager {
    private currentQuality;
    private qualityCeiling;
    private enabled;
    private readonly frameTimes;
    private readonly maxFrameSamples;
    private lastTimestamp;
    private lowFpsSince;
    private highFpsSince;
    private lastAdjustmentTime;
    private readonly downgradeThresholdFps;
    private readonly upgradeThresholdFps;
    private readonly downgradeSustainMs;
    private readonly upgradeSustainMs;
    private readonly cooldownMs;
    private readonly callbacks;
    constructor(initialQuality: QualityLevel, options?: AdaptiveQualityOptions);
    /**
     * Called every animation frame with the rAF timestamp.
     * Computes rolling FPS and triggers quality changes when thresholds are sustained.
     */
    tick(timestamp: number): void;
    getCurrentQuality(): QualityLevel;
    setQualityCeiling(level: QualityLevel): void;
    setEnabled(enabled: boolean): void;
    onQualityChange(callback: QualityChangeCallback): void;
    /**
     * Reset tracking state. Optionally set a new quality level.
     * Call this after background switches to avoid stale FPS data
     * from the old background triggering adjustments.
     */
    reset(quality?: QualityLevel): void;
    dispose(): void;
    private evaluateQuality;
    private applyQualityChange;
}
export {};
//# sourceMappingURL=AdaptiveQualityManager.d.ts.map