import { GraphQLError } from '../../error'; /**
                                             * Copyright (c) 2015-present, Facebook, Inc.
                                             *
                                             * This source code is licensed under the MIT license found in the
                                             * LICENSE file in the root directory of this source tree.
                                             *
                                             *  strict
                                             */

export function duplicateOperationNameMessage(operationName) {
  return 'There can be only one operation named "' + operationName + '".';
}

/**
 * Unique operation names
 *
 * A GraphQL document is only valid if all defined operations have unique names.
 */
export function UniqueOperationNames(context) {
  var knownOperationNames = Object.create(null);
  return {
    OperationDefinition: function OperationDefinition(node) {
      var operationName = node.name;
      if (operationName) {
        if (knownOperationNames[operationName.value]) {
          context.reportError(new GraphQLError(duplicateOperationNameMessage(operationName.value), [knownOperationNames[operationName.value], operationName]));
        } else {
          knownOperationNames[operationName.value] = operationName;
        }
      }
      return false;
    },

    FragmentDefinition: function FragmentDefinition() {
      return false;
    }
  };
}