import type { Context, Params } from 'worktop';
import type { Dict, Strict, Promisable } from 'worktop/utils';

declare global {
	interface ResponseInit {
		/** @note Cloudflare only */
		webSocket?: WebSocket;
	}
}

export interface WebSocket {
	accept(): void;
	send(message: number | string): void;
	close(code?: number, reason?: string): void;
	addEventListener(type: 'error', listener: (this: WebSocket, ev: Event) => any): void;
	addEventListener(type: 'close', listener: (this: WebSocket, ev: CloseEvent) => any): void;
	addEventListener(type: 'message', listener: (this: WebSocket, ev: MessageEvent<string>) => any): void;
}

export type State = Dict<any>;

export interface Socket<S extends State = State> {
	send: WebSocket['send'];
	close: WebSocket['close'];
	state: S; // todo: not happy w/ name
	event:
		| { type: 'close' } & CloseEvent
		| { type: 'message' } & MessageEvent<string>
		| { type: 'error' } & Event;
}

export type SocketHandler<
	C extends Context = Context,
	P extends Params = Params,
	S extends State = State,
> = (
	request: Request,
	context: C, // todo: omit
	socket: Socket<S>
) => Promisable<void>;

/**
 * Establish a Websocket connection.
 * Attach the `handler` as the 'message' event listener.
 * @NOTE Invokes the `ws.connect` middleware automatically.
 */
export function listen<
	C extends Context = Context,
	P extends Params = Params,
>(handler: SocketHandler<C, P>): (
 request: Request,
 context: Omit<C, 'params'> & {
	 params: Strict<P>;
 }
) => Response;