import type { BalanceEntry } from "../balance-providers";
export declare const CURRENCIES: Record<string, string>;
/** Approximate USD exchange rates — used as defaults when switching currency.
 *  Users can override via /cache-rate.  Last updated 2026-05. */
export declare const DEFAULT_RATES: Record<string, number>;
/**
 * 将余额从来源币种换算为目标币种。
 * DEFAULT_RATES 以 USD=1 为基准：先折算为 USD，再换算到目标币种。
 */
export declare function convertBalance(target: string, targetRate: number, amount: number, from: string): number;
/** 货币符号：优先取 /cache-currency 内置映射，未知币种回退为代码。 */
export declare function balanceSymbol(currency: string): string;
/**
 * 将余额列表格式化为单行文本。
 * 优先直接显示偏好币种（CNY/USD…）；偏好币种为换算币种时按汇率折算第一条余额。
 */
export declare function formatBalanceText(list: BalanceEntry[], pref: string, rate: number): string;