/**
 * Pluggable per-user payment-link lookup.
 *
 * Parallel to `TierProvider`: where `TierProvider.getTier` answers "is this
 * user paid?", `PaymentLinkProvider.getPaymentLink` answers "where do I send
 * a free-tier user to upgrade?". Returns null when no link is available
 * (provider down, user ineligible, free product, etc.) — callers must handle
 * null gracefully.
 *
 * Wires into `expandTokens` so an outbound message body can carry a
 * `{{subscription_link}}` placeholder that's resolved at send time:
 *
 *   const body = await expandTokens(template, {
 *     '{{subscription_link}}': () => paymentLinks.getPaymentLink(whatsapp),
 *   });
 */
export interface PaymentLinkContext {
    whatsapp: string;
    name?: string | null;
    /** Optional campaign/source so the gateway can attribute the click. */
    campaign?: string | null;
}
export declare abstract class PaymentLinkProvider {
    abstract getPaymentLink(ctx: PaymentLinkContext): Promise<string | null>;
}
export interface HttpPaymentLinkProviderOptions {
    baseUrl: string;
    token?: string;
    /** Override URL construction. Default: `${baseUrl}/${whatsapp}/payment_link`. */
    urlFor?: (whatsapp: string) => string;
    /** Cache successful lookups for this many ms. 0 disables. Default 60_000. */
    cacheMs?: number;
    /** Pull the link out of the JSON response. Default: `(d) => d.payment_link`. */
    extract?: (data: unknown) => string | null;
}
interface CacheEntry {
    t: number;
    v: string | null;
}
export declare class HttpPaymentLinkProvider extends PaymentLinkProvider {
    readonly baseUrl: string;
    readonly token: string | undefined;
    readonly urlFor: (whatsapp: string) => string;
    readonly cacheMs: number;
    readonly extract: (data: unknown) => string | null;
    readonly cache: Map<string, CacheEntry>;
    constructor({ baseUrl, token, urlFor, cacheMs, extract }: HttpPaymentLinkProviderOptions);
    getPaymentLink(ctx: PaymentLinkContext): Promise<string | null>;
    invalidate(whatsapp: string): void;
}
/**
 * Async token-expansion utility. Resolves any token whose value is a function
 * — lazy, so providers that throw or 404 only run when the placeholder is
 * actually present in `text`.
 *
 * Tokens whose resolver returns null leave the placeholder intact, so the
 * caller can detect a failed expansion and react (drop the message, fall
 * back to a static URL, etc.).
 */
export type TokenResolver = string | null | (() => Promise<string | null> | string | null);
export declare function expandTokens(text: string, tokens: Record<string, TokenResolver>): Promise<string>;
export {};
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