type Middleware<TContext, TReturn> = (
  context: TContext,
  next: () => Promise<TReturn>
) => Promise<TReturn>;

export type MiddlewareChain<TContext, TReturn> = {
  use: (middleware: Middleware<TContext, TReturn>) => void;
  execute: (context: TContext) => Promise<TReturn>;
};

export function createMiddlewareChain<TContext extends object, TReturn=TContext>(
  fallback?: (context: TContext) => Promise<TReturn>
): MiddlewareChain<TContext, TReturn> {
  const middlewares: Middleware<TContext, TReturn>[] = [];

  return {
    use(middleware: Middleware<TContext, TReturn>) {
      middlewares.push(middleware);
    },
    async execute(context: TContext) {
      let index = 0;

      async function dispatch(ctx: TContext): Promise<TReturn> {
        if (index >= middlewares.length) {
          return fallback ? fallback(ctx) : ctx as unknown as TReturn;
        }
        const current = middlewares[index++];
        return current(ctx, () => dispatch(ctx));
      }

      return dispatch(context);
    },
  };
}