import type { UnknownEnum, UnknownMessage, UnknownOneofGroup, UnknownScalar } from "./unknown-types";
/**
 * Is the given value a valid oneof group?
 *
 * We represent protobuf `oneof` as algebraic data types (ADT) in generated
 * code. But when working with messages of unknown type, the ADT does not
 * help us.
 *
 * This type guard checks if the given object adheres to the ADT rules, which
 * are as follows:
 *
 * 1) Must be an object.
 *
 * 2) Must have a "oneofKind" discriminator property.
 *
 * 3) If "oneofKind" is `undefined`, no member field is selected. The object
 * must not have any other properties.
 *
 * 4) If "oneofKind" is a `string`, the member field with this name is
 * selected.
 *
 * 5) If a member field is selected, the object must have a second property
 * with this name. The property must not be `undefined`.
 *
 * 6) No extra properties are allowed. The object has either one property
 * (no selection) or two properties (selection).
 *
 */
export declare function isOneofGroup(any: any): any is UnknownOneofGroup;
/**
 * Returns the value of the given field in a oneof group.
 */
export declare function getOneofValue<T extends UnknownOneofGroup, K extends T extends {
    oneofKind: keyof T;
} ? T["oneofKind"] : never, V extends T extends {
    oneofKind: K;
} ? T[K] : never>(oneof: T, kind: K): V | undefined;
/**
 * Selects the given field in a oneof group.
 *
 * Note that the recommended way to modify a oneof group is to set
 * a new object:
 *
 * ```ts
 * message.result = {
 *   oneofKind: "error",
 *   error: "foo"
 * };
 * ```
 */
export declare function setOneofValue<T extends UnknownOneofGroup, K extends T extends {
    oneofKind: keyof T;
} ? T["oneofKind"] : never, V extends T extends {
    oneofKind: K;
} ? T[K] : never>(oneof: T, kind: K, value: V): void;
export declare function setOneofValue<T extends UnknownOneofGroup>(oneof: T, kind: undefined, value?: undefined): void;
/**
 * Selects the given field in a oneof group, just like `setOneofValue()`,
 * but works with unknown oneof groups.
 */
export declare function setUnknownOneofValue(oneof: UnknownOneofGroup, kind: string, value: UnknownScalar | UnknownEnum | UnknownMessage): void;
export declare function setUnknownOneofValue(oneof: UnknownOneofGroup, kind: undefined, value?: undefined): void;
/**
 * Removes the selected field in a oneof group.
 *
 * Note that the recommended way to modify a oneof group is to set
 * a new object:
 *
 * ```ts
 * message.result = { oneofKind: undefined };
 * ```
 */
export declare function clearOneofValue<T extends UnknownOneofGroup>(oneof: T): void;
/**
 * Returns the selected value of the given oneof group.
 *
 * Not that the recommended way to access a oneof group is to check
 * the "oneofKind" property and let TypeScript narrow down the union
 * type for you:
 *
 * ```ts
 * if (message.result.oneofKind === "error") {
 *   message.result.error; // string
 * }
 * ```
 *
 * In the rare case you just need the value, and do not care about
 * which protobuf field is selected, you can use this function
 * for convenience.
 */
export declare function getSelectedOneofValue<T extends UnknownOneofGroup, V extends string extends keyof T ? UnknownOneofGroup[string] : T extends {
    oneofKind: keyof T;
} ? T[T["oneofKind"]] : never>(oneof: T): V | undefined;