import { is_array, as_func, o_defprop } from './builtins.jsy'

export function bind_codec(codec) ::
  // For use with `codec_channel` of 'code/channel.jsy'

  // Also see plugins/standard/json_codec.jsy
  //  and see plugins/cbor/cbor_codec.jsy

  as_func @ codec.encode
  as_func @ codec.decode
  const cache = new WeakMap()
  return @{}
    codec

    encode_pkt(pkt) ::
      let pkt_data = cache.get(pkt)
      if undefined === pkt_data ::
        let id_route, id_target, meta, body, on_sent
        if is_array(pkt) ::
          if 3 === pkt.length ::
            ([ id_route, id_target, body ] = pkt);
          else 
            ([ id_route, id_target, meta, body ] = pkt);

        else ::
          ({ 0: id_route, 1: id_target, meta, body, on_sent } = pkt);

        pkt_data = codec.encode @#
          id_route, id_target, meta, body

        if on_sent ::
          if 'string' === typeof pkt_data ::
            // transform into a string object
            pkt_data = new String(pkt_data)

          o_defprop @ pkt_data, @{} on_sent: {value: on_sent}

        cache.set(pkt, pkt_data)
      return pkt_data

    decode_pkt(pkt_data) ::
      let pkt_vec = codec.decode(pkt_data)
      let [id_route, id_target, meta, body] = pkt_vec
      let pkt = {0: id_route, 1: id_target, meta, body}
      cache.set(pkt, pkt_data)
      return pkt