import { AdapterMetadata } from "./interfaces.js";
/**
 * Overrides the user's Next Config file (next.config.[ts|mts|js|mjs]) to add configs
 * optimized for Firebase App Hosting.
 */
export declare function overrideNextConfig(projectRoot: string, nextConfigFileName: string): Promise<void>;
/**
 * This function is used to validate the state of an app after running the
 * overrideNextConfig. It validates that:
 *  1. original next config is preserved
 *  2. a new next config is created
 *  3. new next config can be loaded by NextJs without any issues.
 */
export declare function validateNextConfigOverride(root: string, projectRoot: string, originalConfigFileName: string): Promise<void>;
/**
 * Restores the user's original Next Config file (next.config.original.[ts|mts|js|mjs])
 * to leave user code the way we found it.
 */
export declare function restoreNextConfig(projectRoot: string, nextConfigFileName: string): Promise<void>;
/**
 * Modifies the app's route manifest (routes-manifest.json) to add Firebase App Hosting
 * specific overrides (i.e headers).
 *
 * It adds the following headers to all routes:
 * - x-fah-adapter: The Firebase App Hosting adapter version used to build the app.
 *
 * It also adds the following headers to all routes for which middleware is enabled:
 * - x-fah-middleware: When middleware is enabled.
 * @param appPath The path to the app directory.
 * @param distDir The path to the dist directory.
 * @param adapterMetadata The adapter metadata.
 */
export declare function addRouteOverrides(appPath: string, distDir: string, adapterMetadata: AdapterMetadata): Promise<void>;