import type { SqliteAdapter as Database } from '../db/sqlite-adapter.js';
import type { Period } from '../types/index.js';
export interface BillingDiffRow {
    agent: string;
    estimated_usd: number;
    actual_usd: number;
    delta_usd: number;
    delta_pct: number;
}
/**
 * Why a drift percentage could not be computed. `null` means it could.
 *
 * - `no_billing_records` — no provider billing rows exist for the period at
 *   all. Nothing was imported; there is no "actual" to compare against.
 * - `zero_actual_billing` — rows exist but total $0.00, so the denominator is
 *   still absent even though the import ran.
 */
export type BillingDiffIncomparableReason = 'no_billing_records' | 'zero_actual_billing';
/**
 * Estimated-vs-actual drift as a percentage, or `null` when there is no actual
 * to divide by.
 *
 * Returning `null` rather than `0` is the point. Three call sites independently
 * wrote `actual > 0 ? (delta / actual) * 100 : 0`, and every one of them then
 * rendered the fallback as a measured "0.0%" — reporting perfect agreement for
 * the case where nothing was there to agree with.
 */
export declare function billingDeltaPct(estimatedUsd: number, actualUsd: number): number | null;
export interface BillingDiffSummary {
    period: Period;
    estimated_usd: number;
    actual_usd: number;
    delta_usd: number;
    delta_pct: number;
    threshold_pct: number;
    is_alert: boolean;
    /**
     * Whether `delta_pct` is a measurement at all. False means the two sides
     * could not be compared, and `delta_pct` carries 0 only because the type is
     * a number — read this before reporting the percentage as agreement.
     */
    comparable: boolean;
    incomparable_reason: BillingDiffIncomparableReason | null;
    by_agent: BillingDiffRow[];
    by_provider: Record<string, number>;
}
export declare function queryBillingDiff(db: Database, period: Period, thresholdPct?: number): BillingDiffSummary;
/**
 * The health verdict `economy doctor` reports for billing drift.
 *
 * Kept beside the diff rather than in the CLI because the interesting case is
 * a semantic one: an unmeasurable drift must not render as a measured 0.0%.
 * A check that cannot distinguish "the sides agree" from "there is nothing to
 * compare" cannot fail, and this one is consulted to decide whether the rest
 * of the tool's numbers are trustworthy.
 */
export declare function billingDriftCheck(diff: BillingDiffSummary): {
    ok: boolean;
    msg: string;
};
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