Refactor trending tags history, make it more correct

src/controllers/api/trends.ts

@@ -3,6 +3,7 @@ import { Conf } from '@/config.ts';
 import { z } from '@/deps.ts';
 import { trends } from '@/trends.ts';
 import { Time } from '@/utils.ts';
+import { stripTime } from '@/utils/time.ts';
 
 const limitSchema = z.coerce.number().catch(10).transform((value) => Math.min(Math.max(value, 0), 20));
 
@@ -25,11 +26,11 @@ const trendingTagsController: AppController = (c) => {
     url: Conf.local(`/tags/${name}`),
     history: [
       {
-        day: String(Math.floor(now.getTime() / 1000)),
+        day: String(Math.floor(stripTime(now).getTime() / 1000)),
         accounts: String(accounts),
         uses: String(uses),
       },
-      ...getTagHistoryWithGapsFilled({
+      ...trends.getTagHistory({
         tag: name,
         since: lastWeek,
         until: now,
@@ -44,28 +45,4 @@ const trendingTagsController: AppController = (c) => {
   })));
 };
 
-function generateDateRange(since: Date, until: Date): Date[] {
-  const dates = [];
-
-  const sinceDate = new Date(Date.UTC(since.getUTCFullYear(), since.getUTCMonth(), since.getUTCDate() + 1));
-  const untilDate = new Date(Date.UTC(until.getUTCFullYear(), until.getUTCMonth(), until.getUTCDate()));
-
-  while (sinceDate < untilDate) {
-    dates.push(new Date(sinceDate));
-    sinceDate.setUTCDate(sinceDate.getUTCDate() + 1);
-  }
-
-  return dates.reverse();
-}
-
-function getTagHistoryWithGapsFilled(params: Parameters<typeof trends.getTagHistory>[0]) {
-  const history = trends.getTagHistory(params);
-  const dateRange = generateDateRange(params.since, params.until);
-
-  return dateRange.map((day) => {
-    const data = history.find((item) => item.day.getTime() === day.getTime());
-    return data || { day, accounts: 0, uses: 0 };
-  });
-}
-
 export { trendingTagsController };

src/trends.ts

@@ -1,6 +1,7 @@
 import { Sqlite } from '@/deps.ts';
 import { hashtagSchema, hexIdSchema } from '@/schema.ts';
-import { Time } from './utils.ts';
+import { Time } from '@/utils.ts';
+import { generateDateRange } from '@/utils/time.ts';
 
 interface GetTrendingTagsOpts {
   since: Date;
@@ -63,7 +64,7 @@ class TrendsDB {
   }
 
   getTagHistory({ tag, since, until, limit = 7, offset = 0 }: GetTagHistoryOpts) {
-    return this.#db.query<string[]>(
+    const result = this.#db.query<string[]>(
       `
       SELECT date(inserted_at), COUNT(DISTINCT pubkey8), COUNT(*)
         FROM tag_usages
@@ -79,6 +80,16 @@ class TrendsDB {
       accounts: Number(row[1]),
       uses: Number(row[2]),
     }));
+
+    const dateRange = generateDateRange(
+      new Date(since.getTime() + Time.days(1)),
+      new Date(until.getTime() - Time.days(offset)),
+    ).reverse();
+
+    return dateRange.map((day) => {
+      const data = result.find((item) => item.day.getTime() === day.getTime());
+      return data || { day, accounts: 0, uses: 0 };
+    });
   }
 
   addTagUsages(pubkey: string, hashtags: string[], date = new Date()): void {

src/utils/time.test.ts

@@ -0,0 +1,23 @@
+import { assertEquals } from '@/deps-test.ts';
+
+import { generateDateRange } from './time.ts';
+
+Deno.test('generateDateRange', () => {
+  const since = new Date('2023-07-03T16:30:00.000Z');
+  const until = new Date('2023-07-07T09:01:00.000Z');
+
+  const expected = [
+    new Date('2023-07-03T00:00:00.000Z'),
+    new Date('2023-07-04T00:00:00.000Z'),
+    new Date('2023-07-05T00:00:00.000Z'),
+    new Date('2023-07-06T00:00:00.000Z'),
+    new Date('2023-07-07T00:00:00.000Z'),
+  ];
+
+  const result = generateDateRange(since, until);
+
+  assertEquals(
+    result.map((d) => d.getTime()),
+    expected.map((d) => d.getTime()),
+  );
+});

src/utils/time.ts

@@ -9,4 +9,24 @@ const Time = {
   years: (y: number) => y * Time.days(365),
 };
 
-export { Time };
+/** Strips the time off the date, giving 12am UTC. */
+function stripTime(date: Date): Date {
+  return new Date(Date.UTC(date.getUTCFullYear(), date.getUTCMonth(), date.getUTCDate()));
+}
+
+/** Strips times off the dates and generates all 24h intervals between them, inclusive of both inputs. */
+function generateDateRange(since: Date, until: Date): Date[] {
+  const dates = [];
+
+  const sinceDate = stripTime(since);
+  const untilDate = stripTime(until);
+
+  while (sinceDate <= untilDate) {
+    dates.push(new Date(sinceDate));
+    sinceDate.setUTCDate(sinceDate.getUTCDate() + 1);
+  }
+
+  return dates;
+}
+
+export { generateDateRange, stripTime, Time };