/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * 
 */
import { GraphQLError } from '../../error/GraphQLError';
export function unusedVariableMessage(varName, opName) {
  return opName ? "Variable \"$".concat(varName, "\" is never used in operation \"").concat(opName, "\".") : "Variable \"$".concat(varName, "\" is never used.");
}
/**
 * No unused variables
 *
 * A GraphQL operation is only valid if all variables defined by an operation
 * are used, either directly or within a spread fragment.
 */

export function NoUnusedVariables(context) {
  var variableDefs = [];
  return {
    OperationDefinition: {
      enter: function enter() {
        variableDefs = [];
      },
      leave: function leave(operation) {
        var variableNameUsed = Object.create(null);
        var usages = context.getRecursiveVariableUsages(operation);
        var opName = operation.name ? operation.name.value : null;
        var _iteratorNormalCompletion = true;
        var _didIteratorError = false;
        var _iteratorError = undefined;

        try {
          for (var _iterator = usages[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
            var _ref2 = _step.value;
            var node = _ref2.node;
            variableNameUsed[node.name.value] = true;
          }
        } catch (err) {
          _didIteratorError = true;
          _iteratorError = err;
        } finally {
          try {
            if (!_iteratorNormalCompletion && _iterator.return != null) {
              _iterator.return();
            }
          } finally {
            if (_didIteratorError) {
              throw _iteratorError;
            }
          }
        }

        for (var _i = 0, _variableDefs = variableDefs; _i < _variableDefs.length; _i++) {
          var variableDef = _variableDefs[_i];
          var variableName = variableDef.variable.name.value;

          if (variableNameUsed[variableName] !== true) {
            context.reportError(new GraphQLError(unusedVariableMessage(variableName, opName), variableDef));
          }
        }
      }
    },
    VariableDefinition: function VariableDefinition(def) {
      variableDefs.push(def);
    }
  };
}