import { GraphQLError } from "../../error/GraphQLError.mjs";

/**
 * 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 NoUnusedVariablesRule(context) {
  var variableDefs = [];
  return {
    OperationDefinition: {
      enter: function enter() {
        variableDefs = [];
      },
      leave: function leave(operation) {
        var variableNameUsed = Object.create(null);
        var usages = context.getRecursiveVariableUsages(operation);

        for (var _i2 = 0; _i2 < usages.length; _i2++) {
          var _ref2 = usages[_i2];
          var node = _ref2.node;
          variableNameUsed[node.name.value] = true;
        }

        for (var _i4 = 0, _variableDefs2 = variableDefs; _i4 < _variableDefs2.length; _i4++) {
          var variableDef = _variableDefs2[_i4];
          var variableName = variableDef.variable.name.value;

          if (variableNameUsed[variableName] !== true) {
            context.reportError(new GraphQLError(operation.name ? "Variable \"$".concat(variableName, "\" is never used in operation \"").concat(operation.name.value, "\".") : "Variable \"$".concat(variableName, "\" is never used."), variableDef));
          }
        }
      }
    },
    VariableDefinition: function VariableDefinition(def) {
      variableDefs.push(def);
    }
  };
}