import { ApolloClient, InMemoryCache, createHttpLink, from, ApolloLink } from '@apollo/client'
import { setContext } from '@apollo/client/link/context'
import { onError } from '@apollo/client/link/error'
import { handleApiError, getUserFriendlyMessage } from '@/lib/error-handler'

// HTTP Link - configured to use the GraphQL API
const httpLink = createHttpLink({
  uri: process.env.NEXT_PUBLIC_GRAPHQL_ENDPOINT || 'http://localhost:4000/graphql',
})

// Auth Link - for adding authentication headers
const authLink = setContext((_, { headers }) => {
  // Get the authentication token from secure storage
  let token: string | null = null
  if (typeof window !== 'undefined') {
    // Try to get from secure storage
    token = sessionStorage.getItem('auth_token')
  }
  
  return {
    headers: {
      ...headers,
      authorization: token ? `Bearer ${token}` : '',
    },
  }
})

// Error Link - handle GraphQL and network errors
const errorLink = onError(({ graphQLErrors, networkError, operation, forward }) => {
  if (graphQLErrors) {
    graphQLErrors.forEach(({ message, locations, path }) => {
      const error = handleApiError(new Error(message))
      console.error(
        `[GraphQL error]: Message: ${getUserFriendlyMessage(error)}, Location: ${locations}, Path: ${path}`
      )
    })
  }

  if (networkError) {
    const error = handleApiError(networkError)
    console.error(`[Network error]: ${getUserFriendlyMessage(error)}`)
  }
})

// Create Apollo Client
export const apolloClient = new ApolloClient({
  link: from([errorLink, authLink, httpLink]),
  cache: new InMemoryCache(),
  defaultOptions: {
    watchQuery: {
      errorPolicy: 'all',
    },
    query: {
      errorPolicy: 'all',
    },
  },
})