Comprehensive comparison for technology in applications

const { ApolloServer } = require('@apollo/server');
const { startStandaloneServer } = require('@apollo/server/standalone');
const { GraphQLError } = require('graphql');

// Type definitions for a product catalog API
const typeDefs = `#graphql
  type Product {
    id: ID!
    name: String!
    description: String
    price: Float!
    inStock: Boolean!
    category: String!
  }

  type Query {
    products(category: String): [Product!]!
    product(id: ID!): Product
  }

  type Mutation {
    updateProductPrice(id: ID!, price: Float!): Product
    updateStock(id: ID!, inStock: Boolean!): Product
  }
`;

// Mock database
const productsDB = [
  { id: '1', name: 'Laptop', description: 'High-performance laptop', price: 1299.99, inStock: true, category: 'Electronics' },
  { id: '2', name: 'Desk Chair', description: 'Ergonomic office chair', price: 349.99, inStock: true, category: 'Furniture' },
  { id: '3', name: 'Wireless Mouse', description: 'Bluetooth mouse', price: 29.99, inStock: false, category: 'Electronics' }
];

// Resolvers with error handling and validation
const resolvers = {
  Query: {
    products: (_, { category }) => {
      if (category) {
        return productsDB.filter(p => p.category === category);
      }
      return productsDB;
    },
    product: (_, { id }) => {
      const product = productsDB.find(p => p.id === id);
      if (!product) {
        throw new GraphQLError('Product not found', {
          extensions: { code: 'NOT_FOUND', id }
        });
      }
      return product;
    }
  },
  Mutation: {
    updateProductPrice: (_, { id, price }, context) => {
      // Authentication check (simplified)
      if (!context.user || !context.user.isAdmin) {
        throw new GraphQLError('Unauthorized', {
          extensions: { code: 'UNAUTHORIZED' }
        });
      }

      if (price < 0) {
        throw new GraphQLError('Price must be positive', {
          extensions: { code: 'BAD_USER_INPUT' }
        });
      }

      const product = productsDB.find(p => p.id === id);
      if (!product) {
        throw new GraphQLError('Product not found', {
          extensions: { code: 'NOT_FOUND' }
        });
      }

      product.price = price;
      return product;
    },
    updateStock: (_, { id, inStock }, context) => {
      if (!context.user) {
        throw new GraphQLError('Authentication required', {
          extensions: { code: 'UNAUTHENTICATED' }
        });
      }

      const product = productsDB.find(p => p.id === id);
      if (!product) {
        throw new GraphQLError('Product not found', {
          extensions: { code: 'NOT_FOUND' }
        });
      }

      product.inStock = inStock;
      return product;
    }
  }
};

// Create Apollo Server instance
const server = new ApolloServer({
  typeDefs,
  resolvers,
  formatError: (error) => {
    // Custom error formatting for production
    console.error('GraphQL Error:', error);
    return {
      message: error.message,
      code: error.extensions?.code || 'INTERNAL_SERVER_ERROR',
      path: error.path
    };
  }
});

// Start server with context for authentication
startStandaloneServer(server, {
  listen: { port: 4000 },
  context: async ({ req }) => {
    // Extract auth token and validate user (simplified)
    const token = req.headers.authorization || '';
    const user = token === 'admin-token' 
      ? { id: '1', isAdmin: true } 
      : token === 'user-token' 
      ? { id: '2', isAdmin: false } 
      : null;
    
    return { user };
  }
}).then(({ url }) => {
  console.log(`Server ready at ${url}`);
});