let comments influence ranking

api/resolvers/item.js

@@ -88,14 +88,15 @@ export async function orderByNumerator (me, models) {
   if (me) {
     const user = await models.user.findUnique({ where: { id: me.id } })
     if (user.wildWestMode) {
-      return 'GREATEST("Item"."weightedVotes", POWER("Item"."weightedVotes", 1.2))'
+      return 'GREATEST("Item"."weightedVotes", POWER("Item"."weightedVotes", 1.2)) + "Item"."weightedComments"/2'
     }
   }
 
   return `(CASE WHEN "Item"."weightedVotes" > "Item"."weightedDownVotes"
                 THEN 1
                 ELSE -1 END
-          * GREATEST(ABS("Item"."weightedVotes" - "Item"."weightedDownVotes"), POWER(ABS("Item"."weightedVotes" - "Item"."weightedDownVotes"), 1.2)))`
+          * GREATEST(ABS("Item"."weightedVotes" - "Item"."weightedDownVotes"), POWER(ABS("Item"."weightedVotes" - "Item"."weightedDownVotes"), 1.2))
+          + "Item"."weightedComments"/2)`
 }
 
 export async function filterClause (me, models) {
@@ -1246,7 +1247,7 @@ export const SELECT =
   "Item"."subName", "Item".status, "Item"."uploadId", "Item"."pollCost", "Item".boost, "Item".msats,
   "Item".ncomments, "Item"."commentMsats", "Item"."lastCommentAt", "Item"."weightedVotes",
   "Item"."weightedDownVotes", "Item".freebie, "Item"."otsHash", "Item"."bountyPaidTo",
-  ltree2text("Item"."path") AS "path"`
+  ltree2text("Item"."path") AS "path", "Item"."weightedComments"`
 
 async function newTimedOrderByWeightedSats (me, models, num) {
   return `

prisma/migrations/20230508232041_comment_weight/migration.sql

@@ -0,0 +1,2 @@
+-- AlterTable
+ALTER TABLE "Item" ADD COLUMN "weightedComments" DOUBLE PRECISION NOT NULL DEFAULT 0;

prisma/migrations/20230509171046_comment_weight_funcs/migration.sql

@@ -0,0 +1,50 @@
+UPDATE "Item"
+SET "weightedComments" = sub."weightedComments"
+FROM (
+    SELECT subsub."itemId", SUM(subsub."userTrust") AS "weightedComments"
+    FROM
+    (SELECT p.id AS "itemId", u.id AS "userId", u.trust AS "userTrust"
+        FROM "Item" p
+        -- all decendants of p that aren't from the same author
+        JOIN "Item" c ON c.path <@ p.path AND c.id <> p.id AND c."userId" <> p."userId"
+        JOIN users u ON u.id = c."userId"
+        WHERE u.trust > 0
+        GROUP BY p.id, u.id, u.trust) subsub
+    GROUP BY subsub."itemId") sub
+WHERE "Item".id = sub."itemId";
+
+-- TODO: this could be better, e.g. testing for comment length or using comment votes instead
+-- of just comment presence ... this is just an mvp
+CREATE OR REPLACE FUNCTION ncomments_after_comment() RETURNS TRIGGER AS $$
+DECLARE
+    user_trust DOUBLE PRECISION;
+BEGIN
+    -- grab user's trust who is commenting
+    SELECT trust INTO user_trust FROM users WHERE id = NEW."userId";
+
+    UPDATE "Item"
+    SET "lastCommentAt" = now_utc(), "ncomments" = "ncomments" + 1
+    WHERE id <> NEW.id and path @> NEW.path;
+
+    -- we only want to add the user's trust to weightedComments if they aren't
+    -- already the author of a descendant comment
+    UPDATE "Item"
+    SET "weightedComments" = "weightedComments" + user_trust
+    FROM (
+        -- for every ancestor of the new comment, return the ones that don't have
+        -- the same author in their descendants
+        SELECT p.id
+        FROM "Item" p
+        -- all decendants of p that aren't the new comment
+        JOIN "Item" c ON c.path <@ p.path AND c.id <> NEW.id
+        -- p is an ancestor of this comment, it isn't itself, and it doesn't have the same author
+        WHERE p.path @> NEW.path AND p.id <> NEW.id AND p."userId" <> NEW."userId"
+        GROUP BY p.id
+        -- only return p if it doesn't have any descendants with the same author as the comment
+        HAVING bool_and(c."userId" <> NEW."userId")
+    ) fresh
+    WHERE "Item".id = fresh.id;
+
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;

prisma/schema.prisma

@@ -276,9 +276,10 @@ model Item {
   upvotes           Int    @default(0)
 
   // denormalized comment stats
-  ncomments     Int       @default(0)
-  commentMsats  BigInt    @default(0)
-  lastCommentAt DateTime?
+  ncomments        Int       @default(0)
+  commentMsats     BigInt    @default(0)
+  lastCommentAt    DateTime?
+  weightedComments Float     @default(0)
 
   // if sub is null, this is the main sub
   sub     Sub?    @relation(fields: [subName], references: [name])