/** A pluggable fiat FX rate oracle consumed by the valuation endpoint. */
export type Oracle = {
    /** Returns the cache-key suffix for the oracle's current publication window. */
    cacheKey?: (() => string) | undefined;
    /** Oracle identifier, surfaced as valuation rate provenance (e.g. `ecb`). */
    name: string;
    /** Fetches the oracle's current rate set. */
    rates: () => Promise<RateSet>;
    /** Cache lifetime for a fetched rate set, in milliseconds. */
    ttl: number;
};
/** One oracle-published set of exchange rates quoted against a base currency. */
export type RateSet = {
    /** Publication date of the rate set as an ISO 8601 timestamp. */
    asOf: string;
    /** Currency the rates are quoted against (e.g. `EUR`). */
    base: string;
    /** Currency code to units of that currency per one `base` unit, as decimal strings. */
    rates: Record<string, string>;
};
/** Fixed-point scale (decimal places) of cross rates returned by {@link rate}. */
export declare const precision = 18;
/** Canonical ECB daily reference-rate feed (public, no key required). */
export declare const ecbUrl = "https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml";
/**
 * Normalizes an oracle definition into an {@link Oracle}: applies the default
 * `ttl` and rethrows `rates()` failures as {@link RatesError}.
 */
export declare function from(oracle: from.Value): Oracle;
export declare namespace from {
    /** Oracle definition accepted by {@link from}. */
    type Value = Pick<Oracle, 'cacheKey' | 'name' | 'rates'> & {
        /** Cache lifetime for a fetched rate set, in milliseconds. @default `Ttl.hours(1)` */
        ttl?: number | undefined;
    };
}
/** European Central Bank reference rates, cached for one day to match their publication cadence. */
export declare function ecb(options?: ecb.Options): Oracle;
export declare namespace ecb {
    /** Options for the ECB oracle. */
    type Options = {
        /** Fetch implementation used to retrieve the feed. @default `globalThis.fetch` */
        fetch?: typeof globalThis.fetch | undefined;
        /** Feed URL. @default {@link ecbUrl} */
        url?: string | undefined;
    };
}
/**
 * Derives the cross rate from one currency to another through the set's base,
 * scaled to {@link precision} decimal places. Returns `undefined` when the set
 * prices neither leg of a currency.
 */
export declare function rate(set: RateSet, options: rate.Options): bigint | undefined;
export declare namespace rate {
    /** Options for deriving a cross rate. */
    type Options = {
        /** Currency code to convert from. */
        from: string;
        /** Currency code to convert to. */
        to: string;
    };
}
/** Thrown when an oracle fails to produce its rate set. */
export declare class RatesError extends Error {
    name: string;
    constructor(oracle: string, options: {
        cause: unknown;
    });
}
//# sourceMappingURL=FxOracle.d.ts.map