{
  "data": {
    "listing": {
      "title": "Cave campsite in snowy MoundiiX",
      "moneyValueGuaranteed": true
    }
  }
}

extend schema
  @link(
    url: "https://specs.apollo.dev/federation/v2.7"
    import: ["@key", "@requires", "@external"]
  )

type Query {
  "A list of the most recent reviews in the database"
  recentReviews: [Review!]!
}

"A comment and a rating submitted by a guest about a particular listing"
type Review {
  id: ID!
  "Comment the author has written"
  text: String!
  "The numerical rating for the review target, on a scale of 1-5, with 5 being excellent."
  rating: Float!
  listing: Listing
}

type Listing @key(fields: "id") {
  id: ID!
  overallRating: Float
  reviews: [Review!]!
  costPerNight: Float @external
  moneyValueGuaranteed: Boolean @requires(fields: "costPerNight")
}

export const resolvers = {
  Query: {
    recentReviews: async (_, __, { dataSources }) => {
      return dataSources.reviewsDb.getMostRecentReviews();
    },
  },
  Listing: {
    // Exercise: Contributing to an entity
    __resolveReference: (listing) => {
      return listing;
    },
    overallRating: ({ id }, __, { dataSources }) => {
      return dataSources.reviewsDb.getOverallRatingForListing(id);
    },
    reviews: ({ id }, __, { dataSources }) => {
      return dataSources.reviewsDb.getReviewsByListing(id);
    },
    // Exercise: Using requires/external
    moneyValueGuaranteed: (listing, _, { dataSources }) => {
      return dataSources.reviewsDb.calculateMoneyValueGuarantee(
        listing.costPerNight,
        listing.id
      );
    },
  },
  // Exercise: Reference an entity
  Review: {
    listing: (review) => {
      return { id: review.listingId };
    },
  },
};