import { type Oauth2AccessToken, type Oauth2ClientConfig, type Oauth2PkceMethod, type ApiRequestContract, type RedirectRequestContract } from '../../types.ts';
import { HttpClient } from '../../http_client.ts';
import { UrlBuilder } from '../../url_builder.ts';
/**
 * Generic implementation of OAuth2.
 */
export declare class Oauth2Client<Token extends Oauth2AccessToken> {
    options: Oauth2ClientConfig;
    constructor(options: Oauth2ClientConfig);
    /**
     * Define the authorize url. Can be overridden by config
     */
    protected authorizeUrl: string;
    /**
     * Define the access token url. Can be overridden by config
     */
    protected accessTokenUrl: string;
    /**
     * Returns the PKCE code verifier for building the authorization redirect.
     * Child classes can override this method to generate and persist a verifier.
     */
    protected getPkceCodeVerifierForRedirect(): string | null;
    /**
     * Returns the PKCE code verifier for the access token exchange.
     * Child classes can override this method to load a previously persisted verifier.
     */
    protected getPkceCodeVerifierForAccessToken(): string | null;
    /**
     * Returns the PKCE code challenge. Child classes can override this method
     * to customize the challenge derivation or persistence strategy.
     */
    protected getPkceCodeChallenge(codeVerifier: string): string;
    /**
     * Returns the PKCE code challenge method.
     */
    protected getPkceCodeChallengeMethod(): Oauth2PkceMethod;
    /**
     * Processing the API client response. The child class can overwrite it
     * for more control
     */
    protected processClientResponse(client: HttpClient, response: any): any;
    /**
     * Configure the redirect request. Invoked before
     * the user callback.
     *
     * The client defaults can be removed using the `clearParam` method
     */
    protected configureRedirectRequest(_: RedirectRequestContract): void;
    /**
     * Configure the access token request. Invoked before
     * the user callback.
     *
     * The client defaults can be removed using the `clearParam` or
     * `clearOauth1Param` methods
     */
    protected configureAccessTokenRequest(_: ApiRequestContract): void;
    /**
     * Returns the instance of the HTTP client for internal use
     */
    protected httpClient(url: string): HttpClient;
    /**
     * Returns the instance of the URL builder
     */
    protected urlBuilder(url: string): UrlBuilder;
    /**
     * Generates a random PKCE code verifier.
     */
    protected makeCodeVerifier(): string;
    /**
     * Generates a PKCE code challenge from the given verifier.
     */
    protected makeCodeChallenge(codeVerifier: string, method?: Oauth2PkceMethod): string;
    /**
     * Returns the redirect url for redirecting the user. Pre-defines
     * the following params
     *
     * - redirect_uri
     * - client_id
     */
    getRedirectUrl(callback?: (request: RedirectRequestContract) => void): string | Promise<string>;
    /**
     * Generates a random token to be stored as a state and to be sent along
     * for later verification
     */
    getState(): string;
    /**
     * Verifies the redirect input with the state input
     */
    verifyState(state: string, inputValue?: string): void;
    /**
     * Get the access token from the authorization code. One must define
     * the authorization code using the callback input.
     *
     * ```ts
     * client.getAccessToken((request) => {
     *   request.field('code', authorizationCode)
     * })
     * ```
     *
     * Pre-defines the following form fields
     *
     * - grant_type = 'authorization_code'
     * - redirect_uri
     * - client_id
     * - client_secret
     */
    getAccessToken(callback?: (request: ApiRequestContract) => void): Promise<Token>;
}