import type { CreateInvoiceBase64Result, CreateInvoiceOptions, CreateInvoiceResult, InvoiceData } from "./types.js";
/**
 * Creates a PDF invoice and returns a temporary download URL and calculations.
 * Requires an internet connection and is intended for server-side Node.js use.
 * The API validates invoice fields and calculates totals; this client keeps no invoice state.
 *
 * Use `.then()`/`.catch()` or `await` inside an async function. Top-level `await`
 * is also supported when the calling project's module and TypeScript settings allow it.
 * Each call has a 30-second deadline, including the PDF download for base64 output.
 *
 * @param data - Invoice fields and optional account key. Omitted or `undefined` data defaults to `{}`.
 * @param options - Client output selection. Defaults to a URL; use { output: "base64" } to download and encode.
 * @returns URL metadata by default, or a base64 PDF when explicitly requested.
 * @throws {TypeError} The promise rejects if arguments are invalid or cannot be serialized as JSON.
 * @throws {EasyInvoiceError} The promise rejects on HTTP errors, network failures, timeouts, or malformed responses.
 *
 * @example
 * import { createInvoice, saveInvoice } from "easyinvoice";
 *
 * createInvoice({
 *   mode: "development",
 *   products: [{ quantity: 2, description: "Consulting", taxRate: 8.25, price: 75 }],
 *   settings: { currency: "USD", locale: "en-US" },
 * })
 *   .then((result) => saveInvoice(result, "invoice.pdf"))
 *   .catch((error) => console.error(error));
 */
export declare function createInvoice(data?: InvoiceData, options?: {
    output?: "url";
}): Promise<CreateInvoiceResult>;
export declare function createInvoice(data: InvoiceData | undefined, options: {
    output: "base64";
}): Promise<CreateInvoiceBase64Result>;
export declare function createInvoice(data: InvoiceData | undefined, options: CreateInvoiceOptions): Promise<CreateInvoiceResult | CreateInvoiceBase64Result>;
/**
 * Downloads an existing invoice directly to a local file without base64 conversion.
 * The URL expires, so call this promptly after createInvoice().
 * Streams into a temporary file beside the destination and replaces the destination only
 * after a complete download. A failed download leaves an existing destination untouched.
 * Each save has its own 30-second deadline and never creates another invoice.
 *
 * @param invoice - The URL result returned by createInvoice().
 * @param filename - Destination path. Its parent directory must already exist.
 * @throws {EasyInvoiceError} On HTTP, network, timeout, and empty download failures.
 * @throws {Error} On filesystem failures, including a missing directory or denied access.
 */
export declare function saveInvoice(invoice: CreateInvoiceResult, filename: string): Promise<void>;