import type { AppContext } from './context';
export type DynamicConfigFetcher = (ctx: AppContext) => Promise<unknown>;
interface DynamicConfigBase {
    interval?: number;
    /**
     * Transform raw response data into the stored config value.
     * Use this to apply defaults, remap fields, or coerce types.
     */
    transform?: (raw: unknown) => unknown;
    /**
     * Environment variable containing the final config as JSON.
     * When non-empty, skips loading from url/filePath/fetch and does not apply transform.
     * Defaults to NODEKIT_DYNAMIC_CONFIG_<NAMESPACE> in uppercase, replacing characters
     * outside A-Z, 0-9, and _ with _. An explicit envVarName is used as-is.
     */
    envVarName?: string;
}
interface DynamicConfigWithUrl extends DynamicConfigBase {
    /** Source URL fetched via the built-in HTTP GET. */
    url: string;
    /** Tried in order when the request to `url` fails. Headers are sent to every url. */
    fallbackUrls?: string[];
    /** Per-request timeout in ms. Without it a hanging host blocks fallbacks and the next poll. */
    timeout?: number;
    /** Static headers. */
    headers?: Record<string, string>;
    /** Dynamic headers. */
    dynamicHeaders?: Record<string, () => Promise<string>>;
    fetch?: never;
    filePath?: never;
}
interface DynamicConfigWithFetch extends DynamicConfigBase {
    url?: never;
    fallbackUrls?: never;
    timeout?: never;
    headers?: never;
    dynamicHeaders?: never;
    /** Custom fetcher for the raw config value. */
    fetch: DynamicConfigFetcher;
    filePath?: never;
}
interface DynamicConfigWithFile extends DynamicConfigBase {
    url?: never;
    fallbackUrls?: never;
    timeout?: never;
    headers?: never;
    dynamicHeaders?: never;
    fetch?: never;
    /** Path to the file to read the config from. */
    filePath: string;
}
export type DynamicConfigSetup = DynamicConfigWithUrl | DynamicConfigWithFetch | DynamicConfigWithFile;
export declare class DynamicConfigPoller {
    ctx: AppContext;
    private namespace;
    private dynamicConfigSetup;
    constructor(ctx: AppContext, namespace: string, dynamicConfigSetup: DynamicConfigSetup);
    startPolling: () => Promise<unknown>;
    private getPollTimeout;
    private onSuccess;
    private onError;
}
export {};