var $ = require('../internals/export');
var uncurryThis = require('../internals/function-uncurry-this');
var ReflectMetadataModule = require('../internals/reflect-metadata');
var anObject = require('../internals/an-object');
var getPrototypeOf = require('../internals/object-get-prototype-of');
var $arrayUniqueBy = require('../internals/array-unique-by');

var arrayUniqueBy = uncurryThis($arrayUniqueBy);
var concat = uncurryThis([].concat);
var ordinaryOwnMetadataKeys = ReflectMetadataModule.keys;
var toMetadataKey = ReflectMetadataModule.toKey;

var ordinaryMetadataKeys = function (O, P) {
  var oKeys = ordinaryOwnMetadataKeys(O, P);
  var parent = getPrototypeOf(O);
  if (parent === null) return oKeys;
  var pKeys = ordinaryMetadataKeys(parent, P);
  return pKeys.length ? oKeys.length ? arrayUniqueBy(concat(oKeys, pKeys)) : pKeys : oKeys;
};

// `Reflect.getMetadataKeys` method
// https://github.com/rbuckton/reflect-metadata
$({ target: 'Reflect', stat: true }, {
  getMetadataKeys: function getMetadataKeys(target /* , targetKey */) {
    var targetKey = arguments.length < 2 ? undefined : toMetadataKey(arguments[1]);
    return ordinaryMetadataKeys(anObject(target), targetKey);
  }
});