/**
 * Diagnostics Plugin for ECSpresso
 *
 * Runtime diagnostics: FPS, entity count, per-system timing, per-phase timing,
 * and an optional DOM overlay for visual debugging.
 */
import type { SystemPhase } from 'ecspresso';
export interface DiagnosticsData {
    fps: number;
    entityCount: number;
    systemTimings: ReadonlyMap<string, number>;
    phaseTimings: Readonly<Record<SystemPhase, number>>;
    averageFrameTime: number;
}
export interface DiagnosticsResourceTypes {
    diagnostics: DiagnosticsData;
}
export interface DiagnosticsPluginOptions<G extends string = 'diagnostics'> {
    /** System group name (default: 'diagnostics') */
    systemGroup?: G;
    /** Enable timing collection on initialize (default: true) */
    enableTimingOnInit?: boolean;
    /** Number of frames to sample for FPS average (default: 60) */
    fpsSampleCount?: number;
}
export interface DiagnosticsOverlayOptions {
    /** Corner position (default: 'top-left') */
    position?: 'top-left' | 'top-right' | 'bottom-left' | 'bottom-right';
    /** Milliseconds between DOM updates (default: 200) */
    updateInterval?: number;
    /** Show per-system timings (default: true) */
    showSystemTimings?: boolean;
    /** Maximum systems to show in overlay (default: 10) */
    maxSystemsShown?: number;
}
export declare function createDiagnosticsPlugin<G extends string = 'diagnostics'>(options?: DiagnosticsPluginOptions<G>): import("ecspresso").Plugin<import("ecspresso").WithResources<import("ecspresso").EmptyConfig, DiagnosticsResourceTypes>, import("ecspresso").EmptyConfig, "diagnostics-collect", G, never, never>;
/**
 * Create a DOM overlay that displays diagnostics data.
 * Returns a cleanup function that removes the element and clears the interval.
 *
 * @param ecs An ECSpresso instance with the diagnostics resource
 * @param options Overlay configuration
 * @returns Cleanup function
 */
export declare function createDiagnosticsOverlay<R extends DiagnosticsResourceTypes>(ecs: {
    getResource<K extends keyof R>(key: K): R[K];
}, options?: DiagnosticsOverlayOptions): () => void;