From cbb294dbc21dc6128d3cc7221f3a4ee928d7d332 Mon Sep 17 00:00:00 2001
From: Alex Gleason <alex@alexgleason.me>
Date: Tue, 25 Jul 2023 17:44:38 -0500
Subject: [PATCH] Trends: support `limit` param

---
 src/controllers/api/trends.ts | 8 +++++++-
 src/trends.ts                 | 6 +++---
 src/utils.ts                  | 2 +-
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/controllers/api/trends.ts b/src/controllers/api/trends.ts
index d4a4f7e..a8d74bc 100644
--- a/src/controllers/api/trends.ts
+++ b/src/controllers/api/trends.ts
@@ -1,13 +1,19 @@
 import { type AppController } from '@/app.ts';
 import { Conf } from '@/config.ts';
+import { z } from '@/deps.ts';
 import { trends } from '@/trends.ts';
 import { Time } from '@/utils.ts';
 
+const limitSchema = z.coerce.number().catch(10).transform((value) => Math.min(Math.max(value, 0), 20));
+
 const trendingTagsController: AppController = (c) => {
+  const limit = limitSchema.parse(c.req.query('limit'));
+  if (limit < 1) return c.json([]);
+
   const now = new Date();
   const yesterday = new Date(now.getTime() - Time.days(1));
 
-  const tags = trends.getTrendingTags(yesterday, now);
+  const tags = trends.getTrendingTags(yesterday, now, limit);
 
   return c.json(tags.map(({ name, accounts, uses }) => ({
     name,
diff --git a/src/trends.ts b/src/trends.ts
index 86a2873..2c28396 100644
--- a/src/trends.ts
+++ b/src/trends.ts
@@ -25,7 +25,7 @@ class TrendsDB {
     }, Time.days(1));
   }
 
-  getTrendingTags(since: Date, until: Date) {
+  getTrendingTags(since: Date, until: Date, limit = 10) {
     return this.#db.query<string[]>(
       `
       SELECT tag, COUNT(DISTINCT pubkey8), COUNT(*)
@@ -33,9 +33,9 @@ class TrendsDB {
         WHERE inserted_at >= ? AND inserted_at < ?
         GROUP BY tag
         ORDER BY COUNT(DISTINCT pubkey8)
-        DESC LIMIT 10;
+        DESC LIMIT ?;
     `,
-      [since, until],
+      [since, until, limit],
     ).map((row) => ({
       name: row[0],
       accounts: Number(row[1]),
diff --git a/src/utils.ts b/src/utils.ts
index 7a91fc2..a81c0fd 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -81,7 +81,7 @@ async function parseBody(req: Request): Promise<unknown> {
 const paginationSchema = z.object({
   since: z.coerce.number().optional().catch(undefined),
   until: z.lazy(() => z.coerce.number().catch(nostrNow())),
-  limit: z.coerce.number().min(0).max(40).catch(20),
+  limit: z.coerce.number().catch(20).transform((value) => Math.min(Math.max(value, 0), 40)),
 });
 
 type PaginationParams = z.infer<typeof paginationSchema>;