Add randomized landing network story

src/schema.ts

@@ -112,6 +112,26 @@ export const typeDefs = `#graphql
     distanceKm: Float
   }
 
+  enum LandingNetworkKind {
+    HUB
+    SUPPLIER
+  }
+
+  type LandingNetworkPoint {
+    uuid: String!
+    kind: LandingNetworkKind!
+    name: String!
+    country: String
+    latitude: Float!
+    longitude: Float!
+    distanceKm: Float
+  }
+
+  type LandingNetworkStory {
+    focus: LandingNetworkPoint!
+    neighbors: [LandingNetworkPoint!]!
+  }
+
   type OfferNode {
     uuid: String
     productUuid: String
@@ -177,6 +197,7 @@ export const typeDefs = `#graphql
     nearestHubs(lat: Float!, lon: Float!, radius: Float, productUuid: String, limit: Int): [Node!]!
     nearestOffers(lat: Float!, lon: Float!, radius: Float, productUuid: String, hubUuid: String, limit: Int): [OfferWithRoute!]!
     nearestSuppliers(lat: Float!, lon: Float!, radius: Float, productUuid: String, limit: Int): [Supplier!]!
+    landingNetworkStory(focusKind: LandingNetworkKind!, neighborLimit: Int): LandingNetworkStory!
     routeToCoordinate(offerUuid: String!, lat: Float!, lon: Float!): ProductRouteOption
     hubsList(limit: Int, offset: Int, country: String, transportType: String, west: Float, south: Float, east: Float, north: Float): [Node!]!
     suppliersList(limit: Int, offset: Int, country: String, west: Float, south: Float, east: Float, north: Float): [Supplier!]!
@@ -237,6 +258,93 @@ function mapOffer(doc: ArangoDoc, catalog = new Map<string, ProductCatalogItem>(
   }
 }
 
+type LandingNetworkKind = 'HUB' | 'SUPPLIER'
+
+function mapLandingNetworkPoint(doc: ArangoDoc, kind: LandingNetworkKind) {
+  return {
+    uuid: doc._key,
+    kind,
+    name: doc.name,
+    country: doc.country ?? null,
+    latitude: doc.latitude,
+    longitude: doc.longitude,
+    distanceKm: doc.distance_km ?? null,
+  }
+}
+
+async function resolveLandingNetworkStory(focusKind: LandingNetworkKind, neighborLimit?: number) {
+  const db = getDb()
+  const limit = Math.max(1, Math.min(neighborLimit ?? 3, 6))
+  const focusCursor = await db.query(focusKind === 'HUB' ? `
+    FOR hub IN nodes
+      FILTER hub.node_type == 'logistics' OR hub.node_type == null
+      FILTER hub.product_uuid == null
+      FILTER hub.latitude != null AND hub.longitude != null
+      SORT RAND()
+      LIMIT 1
+      RETURN hub
+  ` : `
+    FOR supplier IN nodes
+      FILTER supplier.node_type == 'supplier'
+      FILTER supplier.latitude != null AND supplier.longitude != null
+      SORT RAND()
+      LIMIT 1
+      RETURN supplier
+  `)
+  const focus = await focusCursor.next() as ArangoDoc | undefined
+  if (!focus) throw new Error(`No ${focusKind.toLowerCase()} is available for the landing network story`)
+
+  if (focusKind === 'SUPPLIER') {
+    const neighborsCursor = await db.query(`
+      FOR hub IN nodes
+        FILTER hub.node_type == 'logistics' OR hub.node_type == null
+        FILTER hub.product_uuid == null
+        FILTER hub.latitude != null AND hub.longitude != null
+        LET dist = DISTANCE(hub.latitude, hub.longitude, @lat, @lon) / 1000
+        SORT dist ASC
+        LIMIT @limit
+        RETURN MERGE(hub, {distance_km: dist})
+    `, { lat: focus.latitude, lon: focus.longitude, limit })
+    const neighbors = await neighborsCursor.all()
+    return {
+      focus: mapLandingNetworkPoint(focus, 'SUPPLIER'),
+      neighbors: neighbors.map((neighbor: ArangoDoc) => mapLandingNetworkPoint(neighbor, 'HUB')),
+    }
+  }
+
+  const neighborsCursor = await db.query(`
+    FOR offer IN nodes
+      FILTER offer.node_type == 'offer'
+      FILTER offer.supplier_uuid != null
+      FILTER offer.latitude != null AND offer.longitude != null
+      LET dist = DISTANCE(offer.latitude, offer.longitude, @lat, @lon) / 1000
+      COLLECT supplier_uuid = offer.supplier_uuid INTO offers
+      LET first_offer = FIRST(offers).offer
+      LET supplier_dist = DISTANCE(first_offer.latitude, first_offer.longitude, @lat, @lon) / 1000
+      LET supplier_node = FIRST(
+        FOR supplier IN nodes
+          FILTER supplier._key == supplier_uuid
+          FILTER supplier.node_type == 'supplier'
+          RETURN supplier
+      )
+      SORT supplier_dist ASC
+      LIMIT @limit
+      RETURN {
+        _key: supplier_uuid,
+        name: supplier_node != null ? supplier_node.name : first_offer.supplier_name,
+        country: supplier_node != null ? supplier_node.country : first_offer.country,
+        latitude: supplier_node != null ? supplier_node.latitude : first_offer.latitude,
+        longitude: supplier_node != null ? supplier_node.longitude : first_offer.longitude,
+        distance_km: supplier_dist
+      }
+  `, { lat: focus.latitude, lon: focus.longitude, limit })
+  const neighbors = await neighborsCursor.all()
+  return {
+    focus: mapLandingNetworkPoint(focus, 'HUB'),
+    neighbors: neighbors.map((neighbor: ArangoDoc) => mapLandingNetworkPoint(neighbor, 'SUPPLIER')),
+  }
+}
+
 async function loadProductCatalog() {
   const res = await fetch(EXCHANGE_GRAPHQL_URL, {
     method: 'POST',
@@ -460,6 +568,10 @@ export const resolvers = {
   },
 
   Query: {
+    landingNetworkStory: async (_: unknown, args: { focusKind: LandingNetworkKind; neighborLimit?: number }) => {
+      return resolveLandingNetworkStory(args.focusKind, args.neighborLimit)
+    },
+
     node: async (_: unknown, args: { uuid: string }) => {
       const db = getDb()
       const nodesCol = db.collection('nodes')