import type { CredentialRankingContext, CredentialRankingStrategy, UsageLimit, UsageLogger, UsageReport } from "../usage.js";
/** Read a string identity field from report metadata. */
export declare function usageReportMetadataValue(report: UsageReport, key: string): string | undefined;
/** Resolve a single report-scoped account ID. */
export declare function usageReportScopeAccountId(report: UsageReport): string | undefined;
/** Merge reports for the same account, logging a reduction when configured. */
export declare function dedupeUsageReports(reports: UsageReport[], logger?: UsageLogger): UsageReport[];
/** Determine whether a usage limit has exhausted its quota. */
export declare function isUsageLimitExhausted(limit: UsageLimit): boolean;
/** Return the usage limits that apply to the requested model for this strategy. */
export declare function scopedUsageLimits(strategy: CredentialRankingStrategy, report: UsageReport, context: CredentialRankingContext): UsageLimit[];
/** Returns true if usage indicates rate limit has been reached. */
export declare function isUsageLimitReached(limits: UsageLimit[]): boolean;
/** Extracts when every currently exhausted window has reset (in ms). */
export declare function usageResetAtMs(limits: UsageLimit[], nowMs: number): number | undefined;
/** Read a finite reset deadline from a usage window. */
export declare function windowResetAt(window: UsageLimit["window"]): number | undefined;
/** Normalize a window’s used fraction for ranking. */
export declare function normalizeUsageFraction(limit: UsageLimit | undefined): number;
/** Select usage limits for account reserve evaluation. */
export declare function reserveUsageLimits(strategy: CredentialRankingStrategy | undefined, report: UsageReport, rankingContext: CredentialRankingContext): UsageLimit[];
/** Measure currently available quota outside expired windows. */
export declare function remainingUsageFraction(strategy: CredentialRankingStrategy | undefined, report: UsageReport | null, rankingContext: CredentialRankingContext, nowMs: number): number | undefined;
/**
 * Computes the required drain rate: `headroomFraction / remainingHours` —
 * how fast the window's remaining quota must be consumed to fully use it
 * before it resets and expires. Higher = more headroom at risk of expiring
 * unused = ranked first, so selection chases quota that is about to be
 * wasted ("use it or lose it"). Without a reset clock, the full window
 * duration is assumed to remain so clocked and clockless scores stay comparable.
 */
export declare function windowRequiredDrain(limit: UsageLimit | undefined, nowMs: number, fallbackDurationMs: number): number;