type Matrix = {

  baseUrl: string;

  token: string;

};

export async function main(matrix_res: Matrix, room: string) {

  if (!matrix_res.token) {

    throw Error("Joining a room requires an access token.");

  }

  const resp = await fetch(

    `${matrix_res.baseUrl}/_matrix/client/v3/join/${encodeURIComponent(room)}`,

    {

      method: "POST",

      headers: {

        Authorization: `Bearer ${matrix_res.token}`,

      },

    },

  );

  if (!resp.ok) {

    throw Error(`Failed to join room: Error HTTP${resp.status}`);

  }

}