/**
 * DeepSeek account-balance fetch (server-side only).
 *
 * The ONLY mainstream provider with a simple public balance endpoint is
 * DeepSeek official: `GET https://api.deepseek.com/user/balance` (bearer
 * token). Most other providers expose no public balance API (OpenAI removed
 * its billing endpoint; Anthropic requires an admin key), so "remaining
 * balance" is only available for DeepSeek official — every other route can
 * only show a LOCAL estimate (spend vs a user-configured budget, or the
 * in-memory ledger for providers the user funded via `initialBalance` /
 * recharges).
 *
 * The fetch MUST run server-side: the browser cannot hold the API key or
 * reach the endpoint (CORS + credential safety). This module is host-only.
 *
 * Field names match the real DeepSeek response (snake_case): `is_available`,
 * `balance_infos[].total_balance` / `granted_balance` / `topped_up_balance`.
 *
 * @module dsh-usage-meter-harness/balance
 */
/** One currency row from DeepSeek's `/user/balance`. */
export interface DeepSeekBalanceInfo {
    currency: string;
    /** Total balance (granted + topped-up). */
    total_balance: string;
    /** Granted balance portion. */
    granted_balance: string;
    /** Topped-up balance portion. */
    topped_up_balance: string;
}
export interface DeepSeekBalance {
    is_available: boolean;
    balance_infos?: DeepSeekBalanceInfo[];
}
/** Snapshot the service caches and surfaces through the projection. */
export interface BalanceSnapshot {
    provider: 'deepseek-official';
    fetchedAt: number;
    currency: string;
    totalBalance: number;
    grantedBalance: number;
    toppedUpBalance: number;
}
/**
 * Query DeepSeek's balance endpoint.
 * @param apiKey - the user's DeepSeek API key (never logged, never stored by this module).
 * @param signal - caller cancellation.
 * @returns the raw balance document (snake_case fields).
 */
export declare function fetchDeepSeekBalance(apiKey: string, signal?: AbortSignal): Promise<DeepSeekBalance>;
/** Reduce DeepSeek's raw rows into a single preferred snapshot (null when unavailable). */
export declare function toSnapshot(raw: DeepSeekBalance): BalanceSnapshot | null;