import { type CpuInfo } from "os";
import { monitorEventLoopDelay } from "perf_hooks";
import type { HostPressureLevel, HostPressureOs, HostPressureReason, WSMessage } from "../../types";
import type { WSHub } from "../../ws-hub";
export type CpuTimesSnapshot = CpuInfo["times"];
type EventLoopHistogram = ReturnType<typeof monitorEventLoopDelay>;
export declare const HOST_PRESSURE_SAMPLE_MS = 5000;
/**
 * Enter a level at the more extreme bar; leave at the less extreme bar so a
 * value sitting between them does not flicker. The elevated→ok leave bars sit
 * a little past the enter bars so a 7.9% ↔ 8.1% free-mem wiggle stays put.
 *
 * Tune these only together with `__tests__/host-pressure.test.ts`.
 */
export declare const HOST_PRESSURE_BARS: {
    readonly memFreeRatio: {
        readonly enterElevated: 0.08;
        readonly leaveElevated: 0.1;
        readonly enterCritical: 0.04;
        readonly leaveCritical: 0.08;
    };
    readonly eventLoopP99Ms: {
        readonly enterElevated: 250;
        readonly leaveElevated: 200;
        readonly enterCritical: 500;
        readonly leaveCritical: 250;
    };
    readonly loadPerCpu: {
        readonly enterElevated: 2;
        readonly leaveElevated: 1.5;
        readonly enterCritical: 3;
        readonly leaveCritical: 2;
    };
    readonly cpuBusy: {
        readonly enterElevated: 0.95;
        readonly leaveElevated: 0.85;
        readonly enterCritical: 0.99;
        readonly leaveCritical: 0.95;
    };
    readonly liveAgentsPair: 8;
};
export type HostSample = {
    liveAgents: number;
    memFreeRatio?: number;
    eventLoopP99Ms: number;
    load1: number;
    ncpu: number;
    /** 0–1 CPU busy from consecutive os.cpus() times snapshots. Used on win32 only. */
    cpuBusyRatio?: number;
};
export type HostPressureState = "ok" | HostPressureLevel;
export type HostPressureClassification = {
    level: HostPressureState;
    reasons: HostPressureReason[];
};
export type HostPressureWsMessage = Extract<WSMessage, {
    type: "host_pressure";
}>;
export declare function parseMacMemoryPressureFreeRatio(output: string): number | undefined;
export declare function readMacMemoryPressureFreeRatio(run?: () => Promise<string>): Promise<number | undefined>;
export declare class MacMemoryPressureProbe {
    private readonly read;
    private current;
    private pending;
    constructor(read: () => Promise<number | undefined>);
    refresh(): void;
    value(): number | undefined;
}
export declare function hostMemoryFreeRatio(platform: NodeJS.Platform, totalBytes: number, freeBytes: number, macPressureFreeRatio?: number): number | undefined;
/** Node reports win32 for every Windows build. Other platforms are omitted on the wire. */
export declare function hostPressureOs(platform: NodeJS.Platform): HostPressureOs | undefined;
/** Fraction of CPU that was busy between two os.cpus() snapshots. 0 when there is no delta. */
export declare function cpuBusyRatio(previous: readonly CpuTimesSnapshot[] | null, next: readonly CpuTimesSnapshot[]): number;
export declare function classifyHostPressure(sample: HostSample, previous: HostPressureState, platform: NodeJS.Platform): HostPressureClassification;
export type HostPressureMonitorOpts = {
    wsHub: Pick<WSHub, "broadcast">;
    readSample: () => HostSample;
    now?: () => Date;
    platform?: NodeJS.Platform;
    histogram?: EventLoopHistogram;
    intervalMs?: number;
};
export declare class HostPressureMonitor {
    private readonly opts;
    private timer;
    private level;
    private lastWarning;
    constructor(opts: HostPressureMonitorOpts);
    start(): void;
    tick(): void;
    wsMessage(): HostPressureWsMessage | null;
    dispose(): void;
}
export declare function createHostPressureMonitor(wsHub: WSHub, liveAgents: () => number): HostPressureMonitor;
export {};
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