/**
 * Slice `b1-filesplit-campaign` (wave 3B) — verbatim extraction of the
 * `peaks lease-metrics` option/kind type layer and the multi-session event
 * reader out of `./lease-metrics-commands.ts` (344 raw lines > the 300 cap) so
 * that module clears the cap. No field, no default, no message string and no
 * filter changed: `lease-metrics-commands.ts` imports the names it still uses,
 * re-exports the two public ones from its own path, and
 * `./lease-stats-commands.ts` therefore needed no edit.
 *
 * `aggregateLeaseEvents` and `recomputeRate` stayed behind on purpose — each
 * carries findings, and a NEW module in this campaign must be clean outright.
 */
import { type ObservabilityEvent } from '../../services/observability/observability-service.js';
export type LeaseMetricsOptions = {
    session?: string;
    project?: string;
    rate?: boolean;
    allSessions?: boolean;
    json?: boolean;
};
export type KindCounts = {
    spawn: number;
    renew: number;
    release: number;
    gc: number;
    autoRelease: number;
    'autoRelease-failed': number;
    'autoRelease-skipped': number;
};
export declare const EMPTY_COUNTS: KindCounts;
/**
 * Part 5: leak-rate + lifetime statistics.
 *
 * Leaks are leases that were spawned but neither released (manual)
 * nor auto-released nor gc'd. A naive count is
 * `spawn - release - gc - autoRelease`; the result is the number
 * of currently-alive leases in the absence of in-flight work
 * (the on-disk lease files in `.peaks/_runtime/<sid>/worktree-leases/`
 * are the canonical "alive" set; this aggregation is an estimate
 * for sessions whose files have been pruned but the metrics
 * stream survived).
 *
 * Lifetime: pair each spawn event with its first terminal event
 * (release / gc / autoRelease / autoRelease-failed) for the same
 * leaseId; the duration is the difference in milliseconds. The
 * result is an avg / p99 across the completed leases. p99 is the
 * 99th percentile; with 0-1 completed leases the field is null.
 */
export type RateStats = {
    readonly totalSpawn: number;
    readonly totalTerminal: number;
    /** spawn - terminal — leases still "alive" per the metrics stream alone. */
    readonly estimatedActive: number;
    /** Estimated leaked = active - autoRelease-failed. Positive = worktrees
     *  the user / CLI will need to gc manually. */
    readonly estimatedLeaked: number;
    readonly completedLifetimes: number;
    readonly avgLifetimeMs: number | null;
    readonly p99LifetimeMs: number | null;
};
/**
 * Part 5: enumerate every session under `.peaks/_runtime/` for a
 * project root and aggregate their lease events. Sessions without
 * a `metrics/slices.jsonl` are skipped silently (a clean project
 * has no lease events to report; that's not an error).
 */
export declare function readAllSessionLeaseEvents(projectRoot: string): {
    sessions: ReadonlyArray<{
        sessionId: string;
        events: ReadonlyArray<ObservabilityEvent>;
    }>;
    missingSessions: number;
};