From 3984f9c9baaf820a7b7ebf28254ec24bde0a05ad Mon Sep 17 00:00:00 2001
From: Matchu <matchu1993@gmail.com>
Date: Tue, 23 Mar 2021 18:32:22 -0700
Subject: [PATCH] Filter trade counts to the last 6 months

---
 src/server/loaders.js    | 50 ----------------------------------------
 src/server/types/Item.js | 49 ++++++++++++++++++++++++++++++++++-----
 2 files changed, 43 insertions(+), 56 deletions(-)

diff --git a/src/server/loaders.js b/src/server/loaders.js
index f017eef..4fd01ef 100644
--- a/src/server/loaders.js
+++ b/src/server/loaders.js
@@ -535,55 +535,6 @@ const buildItemAllOccupiedZonesLoader = (db) =>
     });
   });
 
-const buildItemTradeCountsLoader = (db) =>
-  new DataLoader(
-    async (itemIdOwnedPairs) => {
-      const qs = itemIdOwnedPairs
-        .map((_) => "(closet_hangers.item_id = ? AND closet_hangers.owned = ?)")
-        .join(" OR ");
-      const values = itemIdOwnedPairs
-        .map(({ itemId, isOwned }) => [itemId, isOwned])
-        .flat();
-      const [rows, _] = await db.execute(
-        `
-        SELECT
-          closet_hangers.item_id AS item_id, closet_hangers.owned AS is_owned,
-            count(DISTINCT closet_hangers.user_id) AS users_count
-          FROM closet_hangers
-          INNER JOIN users ON users.id = closet_hangers.user_id
-          LEFT JOIN closet_lists ON closet_lists.id = closet_hangers.list_id
-          WHERE (
-            (${qs})
-            AND (
-              (closet_hangers.list_id IS NOT NULL AND closet_lists.visibility >= 2)
-              OR (
-                closet_hangers.list_id IS NULL AND closet_hangers.owned = 1
-                AND users.owned_closet_hangers_visibility >= 2
-              )
-              OR (
-                closet_hangers.list_id IS NULL AND closet_hangers.owned = 0
-                AND users.wanted_closet_hangers_visibility >= 2
-              )
-            )
-          )
-          GROUP BY closet_hangers.item_id, closet_hangers.owned;
-      `,
-        values
-      );
-
-      const entities = rows.map(normalizeRow);
-
-      return itemIdOwnedPairs.map(({ itemId, isOwned }) => {
-        // NOTE: There may be no matching row, if there are 0 such trades.
-        const entity = entities.find(
-          (e) => e.itemId === itemId && Boolean(e.isOwned) === isOwned
-        );
-        return entity ? entity.usersCount : 0;
-      });
-    },
-    { cacheKeyFn: ({ itemId, isOwned }) => `${itemId}-${isOwned}` }
-  );
-
 const buildItemTradesLoader = (db, loaders) =>
   new DataLoader(
     async (itemIdOwnedPairs) => {
@@ -1261,7 +1212,6 @@ function buildLoaders(db) {
     db
   );
   loaders.itemAllOccupiedZonesLoader = buildItemAllOccupiedZonesLoader(db);
-  loaders.itemTradeCountsLoader = buildItemTradeCountsLoader(db);
   loaders.itemTradesLoader = buildItemTradesLoader(db, loaders);
   loaders.petTypeLoader = buildPetTypeLoader(db, loaders);
   loaders.petTypeBySpeciesAndColorLoader = buildPetTypeBySpeciesAndColorLoader(
diff --git a/src/server/types/Item.js b/src/server/types/Item.js
index 8f55824..e4a4605 100644
--- a/src/server/types/Item.js
+++ b/src/server/types/Item.js
@@ -29,6 +29,7 @@ const typeDefs = gql`
     currentUserWantsThis: Boolean! @cacheControl(scope: PRIVATE)
 
     # How many users are offering/seeking this in their public trade lists.
+    # Excludes users that seem relatively inactive.
     numUsersOfferingThis: Int! @cacheControl(maxAge: ${oneHour})
     numUsersSeekingThis: Int! @cacheControl(maxAge: ${oneHour})
 
@@ -268,19 +269,55 @@ const resolvers = {
       return closetHangers.some((h) => h.itemId === id && !h.owned);
     },
 
-    numUsersOfferingThis: async ({ id }, _, { itemTradeCountsLoader }) => {
-      const count = await itemTradeCountsLoader.load({
+    numUsersOfferingThis: async (
+      { id },
+      _,
+      { itemTradesLoader, userLastTradeActivityLoader }
+    ) => {
+      // First, get the trades themselves. TODO: Optimize into one query?
+      const trades = await itemTradesLoader.load({
         itemId: id,
         isOwned: true,
       });
-      return count;
+
+      // Then, get the last active dates for those users.
+      const userIds = trades.map((t) => t.user.id);
+      const lastActiveDates = await userLastTradeActivityLoader.loadMany(
+        userIds
+      );
+
+      // Finally, count how many of those dates were in the last 6 months.
+      // Those trades get to be in the count!
+      const sixMonthsAgo = new Date();
+      sixMonthsAgo.setMonth(sixMonthsAgo.getMonth() - 6);
+      const numTrades = lastActiveDates.filter((d) => d > sixMonthsAgo).length;
+
+      return numTrades;
     },
-    numUsersSeekingThis: async ({ id }, _, { itemTradeCountsLoader }) => {
-      const count = await itemTradeCountsLoader.load({
+    numUsersSeekingThis: async (
+      { id },
+      _,
+      { itemTradesLoader, userLastTradeActivityLoader }
+    ) => {
+      // First, get the trades themselves. TODO: Optimize into one query?
+      const trades = await itemTradesLoader.load({
         itemId: id,
         isOwned: false,
       });
-      return count;
+
+      // Then, get the last active dates for those users.
+      const userIds = trades.map((t) => t.user.id);
+      const lastActiveDates = await userLastTradeActivityLoader.loadMany(
+        userIds
+      );
+
+      // Finally, count how many of those dates were in the last 6 months.
+      // Those trades get to be in the count!
+      const sixMonthsAgo = new Date();
+      sixMonthsAgo.setMonth(sixMonthsAgo.getMonth() - 6);
+      const numTrades = lastActiveDates.filter((d) => d > sixMonthsAgo).length;
+
+      return numTrades;
     },
 
     tradesOffering: async ({ id }, _, { itemTradesLoader }) => {