import { 
    buildSchema, 
    visit, 
    Kind, 
    GraphQLError, 
    GraphQLObjectType, 
    GraphQLList 
  } from 'graphql';
  
  const schemaString = `
    type User {
      id: ID!
      name: String!
      friends: [User!]! 
    }
  
    type Query {
      user(id: ID!): User
      allUsers: [User!]!
    }
  `;
  
  const schema = buildSchema(schemaString);
  
  const visitedTypes = new Set();
  
  function detectCircularReferences(type, fieldPath = []) {
    if (visitedTypes.has(type.name)) {
      throw new GraphQLError(
        `Circular reference detected for type "${type.name}" at field path: ${fieldPath.join(".")}`
      );
    }
  
    visitedTypes.add(type.name);
  
    if (type instanceof GraphQLObjectType) {
      const fields = type.getFields();
      for (const fieldName in fields) {
        const field = fields[fieldName];
        const fieldType = field.type;
  
        detectCircularReferences(fieldType.ofType || fieldType, [
          ...fieldPath,
          fieldName,
        ]);
      }
    }
  
    if (type instanceof GraphQLList) {
      detectCircularReferences(type.ofType, [...fieldPath, "[]"]);
    }
  
    visitedTypes.delete(type.name);
  }
  
  try {
    const queryType = schema.getQueryType();
    detectCircularReferences(queryType);
  
    console.log('No circular references detected in the schema.');
  } catch (error) {
    if (error instanceof GraphQLError) {
      console.error(error.message);
    } else {
      console.error('An unexpected error occurred:', error);
    }
  }