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 unusedFragMessage(fragName) {
  return 'Fragment "' + fragName + '" is never used.';
}

/**
 * No unused fragments
 *
 * A GraphQL document is only valid if all fragment definitions are spread
 * within operations, or spread within other fragments spread within operations.
 */
export function NoUnusedFragments(context) {
  var operationDefs = [];
  var fragmentDefs = [];

  return {
    OperationDefinition: function OperationDefinition(node) {
      operationDefs.push(node);
      return false;
    },
    FragmentDefinition: function FragmentDefinition(node) {
      fragmentDefs.push(node);
      return false;
    },

    Document: {
      leave: function leave() {
        var fragmentNameUsed = Object.create(null);
        operationDefs.forEach(function (operation) {
          context.getRecursivelyReferencedFragments(operation).forEach(function (fragment) {
            fragmentNameUsed[fragment.name.value] = true;
          });
        });

        fragmentDefs.forEach(function (fragmentDef) {
          var fragName = fragmentDef.name.value;
          if (fragmentNameUsed[fragName] !== true) {
            context.reportError(new GraphQLError(unusedFragMessage(fragName), [fragmentDef]));
          }
        });
      }
    }
  };
}