/**
 * Enum for authentication credential types.
 */
export declare enum AuthCredentialTypes {
    /**
     * API Key credential
     * https://swagger.io/docs/specification/v3_0/authentication/api-keys/
     */
    API_KEY = "apiKey",
    /**
     * Credentials for HTTP Auth schemes
     * https://www.iana.org/assignments/http-authschemes/http-authschemes.xhtml
     */
    HTTP = "http",
    /**
     * OAuth2 credentials
     * https://swagger.io/docs/specification/v3_0/authentication/oauth2/
     */
    OAUTH2 = "oauth2",
    /**
     * OpenID Connect credentials
     * https://swagger.io/docs/specification/v3_0/authentication/openid-connect-discovery/
     */
    OPEN_ID_CONNECT = "openIdConnect",
    /**
     * Service Account credentials
     * https://cloud.google.com/iam/docs/service-account-creds
     */
    SERVICE_ACCOUNT = "serviceAccount"
}
/**
 * Interface for HTTP credentials like username, password, token
 */
export interface HttpCredentials {
    username?: string;
    password?: string;
    token?: string;
}
/**
 * Interface for HTTP Authentication
 */
export interface HttpAuth {
    /**
     * The name of the HTTP Authorization scheme to be used in the Authorization
     * header as defined in RFC7235. The values used SHOULD be registered in the
     * IANA Authentication Scheme registry.
     * Examples: 'basic', 'bearer'
     */
    scheme: string;
    credentials: HttpCredentials;
}
/**
 * Interface for OAuth2 Authentication
 */
export interface OAuth2Auth {
    client_id?: string;
    client_secret?: string;
    /**
     * Tool or ADK can generate the auth_uri with the state info thus client
     * can verify the state
     */
    auth_uri?: string;
    state?: string;
    /**
     * Tool or ADK can decide the redirect_uri if they don't want client to decide
     */
    redirect_uri?: string;
    auth_response_uri?: string;
    auth_code?: string;
    /**
     * OAuth2 access token
     */
    access_token?: string;
    /**
     * OAuth2 refresh token
     */
    refresh_token?: string;
}
/**
 * Interface for Google Service Account configuration
 */
export interface ServiceAccountCredential {
    /**
     * The type should be "service_account"
     */
    type: string;
    project_id: string;
    private_key_id: string;
    private_key: string;
    client_email: string;
    client_id: string;
    auth_uri: string;
    token_uri: string;
    auth_provider_x509_cert_url: string;
    client_x509_cert_url: string;
    universe_domain: string;
}
/**
 * Interface for Google Service Account with scopes
 */
export interface ServiceAccount {
    service_account_credential?: ServiceAccountCredential;
    scopes: string[];
    use_default_credential?: boolean;
}
/**
 * Interface for authentication credentials
 *
 * Examples:
 *
 * API Key Auth:
 * ```
 * {
 *   auth_type: AuthCredentialTypes.API_KEY,
 *   api_key: "1234"
 * }
 * ```
 *
 * HTTP Auth:
 * ```
 * {
 *   auth_type: AuthCredentialTypes.HTTP,
 *   http: {
 *     scheme: "basic",
 *     credentials: { username: "user", password: "password" }
 *   }
 * }
 * ```
 *
 * OAuth2 Bearer Token in HTTP Header:
 * ```
 * {
 *   auth_type: AuthCredentialTypes.HTTP,
 *   http: {
 *     scheme: "bearer",
 *     credentials: { token: "eyAkaknabna...." }
 *   }
 * }
 * ```
 *
 * OAuth2 Auth with Authorization Code Flow:
 * ```
 * {
 *   auth_type: AuthCredentialTypes.OAUTH2,
 *   oauth2: {
 *     client_id: "1234",
 *     client_secret: "secret"
 *   }
 * }
 * ```
 *
 * OpenID Connect Auth:
 * ```
 * {
 *   auth_type: AuthCredentialTypes.OPEN_ID_CONNECT,
 *   oauth2: {
 *     client_id: "1234",
 *     client_secret: "secret",
 *     redirect_uri: "https://example.com",
 *     scopes: ["scope1", "scope2"]
 *   }
 * }
 * ```
 *
 * Auth with resource reference:
 * ```
 * {
 *   auth_type: AuthCredentialTypes.API_KEY,
 *   resource_ref: "projects/1234/locations/us-central1/resources/resource1"
 * }
 * ```
 */
export interface AuthCredential {
    auth_type: AuthCredentialTypes;
    /**
     * Resource reference for the credential.
     * This will be supported in the future.
     */
    resource_ref?: string;
    api_key?: string;
    http?: HttpAuth;
    service_account?: ServiceAccount;
    oauth2?: OAuth2Auth;
}
/**
 * API key credential implementation
 */
export declare class ApiKeyCredential {
    readonly auth_type = AuthCredentialTypes.API_KEY;
    private apiKey;
    /**
     * Initialize the API key credential
     * @param apiKey The API key value
     */
    constructor(apiKey: string);
    /**
     * Convert to AuthCredential interface
     */
    toAuthCredential(): AuthCredential;
}
/**
 * Bearer token credential implementation
 */
export declare class BearerCredential {
    readonly auth_type = AuthCredentialTypes.HTTP;
    private access_token;
    /**
     * Initialize the bearer token credential
     * @param token The bearer token value
     */
    constructor(token: string);
    /**
     * Convert to AuthCredential interface
     */
    toAuthCredential(): AuthCredential;
}
/**
 * Basic auth credential implementation
 */
export declare class BasicCredential {
    readonly auth_type = AuthCredentialTypes.HTTP;
    private username;
    private password;
    /**
     * Initialize the basic auth credential
     * @param username The username
     * @param password The password
     */
    constructor(username: string, password: string);
    /**
     * Convert to AuthCredential interface
     */
    toAuthCredential(): AuthCredential;
}