import { SimpleType } from '../internal/responseHandler';
/**
 * The type of arguments that can be passed in a {@link PluginMessage}.
 *
 * @hidden
 * @internal
 * Limited to Microsoft-internal use
 * @beta
 */
export type PluginMessageArg = SimpleType;
/**
 * Indicates whether the plugin capability is available in the current host.
 *
 * @remarks
 * This API validates SDK initialization and then checks runtime capability flags
 * for `supports.plugins`.
 *
 * @returns `true` if the host reports plugin support; otherwise `false`.
 *
 * @throws Error if {@linkcode app.initialize} has not successfully completed.
 *
 * @hidden
 * @internal
 * Limited to Microsoft-internal use
 * @beta
 */
export declare function isSupported(): boolean;
/**
 * Canonical message envelope used for plugin send/receive operations.
 *
 * @remarks
 * Messages are used to communicate between plugin and host.
 *
 * @property func - Function/event name for the message.
 * @property args - Optional JSON payload.
 * @property correlationId - Optional ID for request/response correlation.
 *
 * @hidden
 * @internal
 * Limited to Microsoft-internal use
 * @beta
 */
export type PluginMessage = {
    func: string;
    args?: PluginMessageArg;
    correlationId?: string;
};
/**
 * Sends a plugin message to the host.
 *
 * @remarks
 * The message payload is serialized before transmission to the host.
 * All payload data must be JSON-safe (see {@link JsonValue}).
 *
 * @returns A promise that resolves when the host acknowledges the message.
 *
 * @throws Error if SDK initialization has not completed, if the host returns
 * an error response, or if `func` is missing.
 *
 * @hidden
 * @internal
 * Limited to Microsoft-internal use
 * @beta
 */
export declare function sendPluginMessage(message: PluginMessage): Promise<void>;
/**
 * Handler signature for incoming plugin messages.
 *
 * @param message - Normalized plugin message envelope.
 *
 * @hidden
 * @internal
 * Limited to Microsoft-internal use
 * @beta
 */
export type ReceiveMessageHandler = (message: PluginMessage) => void;
/**
 * Registers a handler to receive plugin messages from the host.
 *
 * @remarks
 * This API registers the callback under the `plugin.receiveMessage` handler name.
 * When the host dispatches a plugin message, the supplied handler is invoked with
 * the received JSON payload.
 *
 * @param handler - Callback invoked for each incoming plugin message payload.
 *
 * @throws Error if plugin messaging is not supported by the current host.
 *
 * @hidden
 * @internal
 * Limited to Microsoft-internal use
 * @beta
 */
export declare function registerPluginMessage(handler: ReceiveMessageHandler): void;