Add product price summaries

src/schema.ts

@@ -99,6 +99,11 @@ export const typeDefs = `#graphql
     name: String
     imageUrl: String
     offersCount: Int
+    averagePrice: Float
+    priceVariationPercent: Float
+    priceSeries: [Float!]!
+    currency: String
+    unit: String
   }
 
   type Supplier {
@@ -255,6 +260,11 @@ function productView(doc: ArangoDoc, catalog: Map<string, ProductCatalogItem>) {
     name: product?.name ?? doc.product_name ?? doc.name ?? null,
     imageUrl: product?.imageUrl ?? null,
     offersCount: doc.offers_count ?? doc.offersCount ?? null,
+    averagePrice: doc.average_price ?? null,
+    priceVariationPercent: doc.price_variation_percent ?? null,
+    priceSeries: doc.price_series ?? [],
+    currency: doc.currency ?? null,
+    unit: doc.unit ?? null,
   }
 }
 
@@ -1368,9 +1378,30 @@ export const resolvers = {
           ${bounds.filter}
           COLLECT product_uuid = node.product_uuid INTO offers
           LET first_offer = FIRST(offers).node
+          LET price_series = (
+            FOR offer_row IN offers
+              LET price = TO_NUMBER(offer_row.node.price_per_unit)
+              FILTER price > 0
+              SORT price ASC
+              RETURN price
+          )
+          LET average_price = LENGTH(price_series) > 0 ? AVERAGE(price_series) : null
+          LET price_variation_percent = average_price > 0
+            ? ((LAST(price_series) - FIRST(price_series)) / 2 / average_price) * 100
+            : 0
           SORT first_offer.product_name ASC
           LIMIT @offset, @limit
-          RETURN { uuid: product_uuid, product_uuid, product_name: first_offer.product_name, offers_count: LENGTH(offers) }
+          RETURN {
+            uuid: product_uuid,
+            product_uuid,
+            product_name: first_offer.product_name,
+            offers_count: LENGTH(offers),
+            average_price,
+            price_variation_percent,
+            price_series,
+            currency: first_offer.currency,
+            unit: first_offer.unit
+          }
       `, { offset: args.offset ?? 0, limit: args.limit ?? 50, ...bounds.vars })
       const products = await cursor.all()
       return products.map((product: ArangoDoc) => productView(product, productCatalog))