var modes = require('../lib/modes');

module.exports = function (local, remote) {
  var loadAs = local.loadAs;
  local.loadAs = newLoadAs;
  function newLoadAs(type, hash, callback) {
    if (!callback) return newLoadAs.bind(local. type, hash);
    loadAs.call(local, type, hash, function (err, body) {
      if (err) return callback(err);
      if (body === undefined) return remote.loadAs(type, hash, callback);
      callback(null, body);
    });
  }

  var readRef = local.readRef;
  local.readRef = newReadRef;
  function newReadRef(ref, callback) {
    if (!callback) return newReadRef.bind(local. ref);
    readRef.call(local, ref, function (err, body) {
      if (err) return callback(err);
      if (body === undefined) return remote.readRef(ref, callback);
      callback(null, body);
    });
  }

};