import { type Address, type CalculationResult, type CapabilitiesResponse, type HealthResponse, type LineItem, type RateStack, type ShippingInput, type StatesResponse } from './models.js';
/** A `fetch`-shaped function. Injected for unit tests. */
export type FetchFn = (input: string | URL, init?: RequestInit) => Promise<Response>;
export interface OpenSalesTaxClientOptions {
    /** Base URL of the engine, e.g. `"http://10.32.161.126:8080"`. */
    baseUrl: string;
    /** Optional API key; sent as `Authorization: Bearer <key>`. */
    apiKey?: string | null;
    /** Per-request timeout in milliseconds. Default 10_000. */
    timeoutMs?: number;
    /** Suffix appended to the SDK's default User-Agent header. */
    userAgent?: string | null;
    /** When false, skip TLS verification (dev only — engine self-signed cert). Default true. */
    verify?: boolean;
    /**
     * Permit loopback / RFC-1918 / link-local engine URLs. Default false.
     * Set to true for dev or merchants running the engine on a private
     * network (e.g. inside the same Docker compose stack).
     */
    allowPrivate?: boolean;
    /**
     * Inject a `fetch` implementation. Defaults to `globalThis.fetch`.
     * Useful for unit tests, polyfills, and HTTP instrumentation.
     */
    fetch?: FetchFn;
}
interface HealthCheckSuccess {
    ok: true;
    version: string;
    databaseConnected: boolean;
    rttMs: number;
}
interface HealthCheckFailure {
    ok: false;
    rttMs: number;
    error: string;
}
/**
 * Result of the convenience `healthCheck()` wrapper — never throws.
 * Used by connector startup probes that want to log-and-continue
 * rather than crash on engine-unreachable.
 */
export type HealthCheckResult = HealthCheckSuccess | HealthCheckFailure;
export declare class OpenSalesTaxClient {
    private readonly baseUrl;
    private readonly apiKey;
    private readonly timeoutMs;
    private readonly userAgent;
    private readonly fetchImpl;
    /**
     * Per-instance cache for `capabilitiesCached()`. `null` until the
     * first call resolves; subsequent calls return the same Promise.
     * Invalidate by creating a new client.
     */
    private cachedCapabilities;
    constructor(options: OpenSalesTaxClientOptions);
    /** No-op close hook for parity with the Python SDK's context-manager API. */
    close(): void;
    /** GET /v1/health — liveness + DB-connection check. */
    health(): Promise<HealthResponse>;
    /** GET /v1/states — coverage tier per state. */
    states(): Promise<StatesResponse>;
    /** GET /v1/rates?zip5=...&zip4=... — rate stack only (no calculation). */
    rates(zip5: string, zip4?: string | null): Promise<RateStack>;
    /**
     * GET /v1/capabilities — engine version, endpoint manifest, feature flags.
     *
     * Always fetches fresh. For connector tier code that wants a single
     * fetch per client lifetime, use {@link capabilitiesCached}.
     */
    capabilities(): Promise<CapabilitiesResponse>;
    /**
     * Same as {@link capabilities} but memoized per-client-instance.
     * Resolves with the same `CapabilitiesResponse` for every call
     * after the first; suitable for connector setup-time checks where
     * the capability snapshot will not change within the process
     * lifetime.
     *
     * Cache invalidation: create a new `OpenSalesTaxClient` instance.
     * (Long-running processes that need to detect engine version
     * bumps should bypass this and call {@link capabilities} directly.)
     */
    capabilitiesCached(): Promise<CapabilitiesResponse>;
    /**
     * POST /v1/calculate — full per-line, per-jurisdiction calculation.
     *
     * @param address Destination address (US ZIP).
     * @param lineItems Pre-tax product line items.
     * @param shipping Optional top-level shipping segment. Engine v0.59.0+
     *   applies per-state shipping-taxability rules; older engines silently
     *   ignore the field. Pass `undefined` (or omit) for product-only carts.
     */
    calculate(address: Address, lineItems: LineItem[], shipping?: ShippingInput | null): Promise<CalculationResult>;
    /**
     * Liveness probe wrapper with RTT measurement and never-throws
     * contract. Used by connector startup probes that want to log a
     * warning and continue booting rather than crash on engine-down.
     */
    healthCheck(): Promise<HealthCheckResult>;
    private buildHeaders;
    private sendRequest;
    private handleErrorResponse;
    private parseSuccessBody;
    private requestJSON;
}
export {};
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