(null);
@@ -74,6 +77,7 @@ export const WorksGrid = memo(function WorksGrid({
{header}
+ {subheader}
{list.loading && !list.items && (
diff --git a/app/aweme/[awemeId]/hooks/useRelatedHashtags.ts b/app/aweme/[awemeId]/hooks/useRelatedHashtags.ts
new file mode 100644
index 0000000..9498f3e
--- /dev/null
+++ b/app/aweme/[awemeId]/hooks/useRelatedHashtags.ts
@@ -0,0 +1,37 @@
+import { useEffect, useState } from "react";
+import type { RelatedHashtagsResult } from "@/lib/hashtag-related.server";
+
+const cache = new Map();
+
+/** 取某个 hashtag 的相关 tag（按共现计算）；name 为空或 enabled 为 false 时不请求。 */
+export function useRelatedHashtags(
+ name: string | null,
+ enabled: boolean,
+): RelatedHashtagsResult | null {
+ const key = name?.toLowerCase() ?? "";
+ const [result, setResult] = useState(
+ () => cache.get(key) ?? null,
+ );
+
+ useEffect(() => {
+ if (!key || !enabled) return;
+ const cached = cache.get(key);
+ setResult(cached ?? null);
+ if (cached) return;
+
+ let cancelled = false;
+ fetch(`/api/hashtag/related?name=${encodeURIComponent(key)}`)
+ .then((res) => (res.ok ? res.json() : null))
+ .then((data: RelatedHashtagsResult | null) => {
+ if (!data) return;
+ cache.set(key, data);
+ if (!cancelled) setResult(data);
+ })
+ .catch(() => {});
+ return () => {
+ cancelled = true;
+ };
+ }, [key, enabled]);
+
+ return result?.name === key ? result : null;
+}
diff --git a/lib/hashtag-related.server.ts b/lib/hashtag-related.server.ts
new file mode 100644
index 0000000..73de87a
--- /dev/null
+++ b/lib/hashtag-related.server.ts
@@ -0,0 +1,114 @@
+import {
+ HASHTAG_EXTRACT_PG,
+ META_HASHTAG_PG,
+ META_HASHTAGS,
+} from "@/lib/hashtag";
+import { prisma } from "@/lib/prisma";
+
+export type RelatedHashtag = {
+ name: string;
+ /** 和目标 tag 一起出现的作品数 */
+ together: number;
+ /** 这个 tag 自己的作品数 */
+ count: number;
+};
+
+export type RelatedHashtagsResult = {
+ name: string;
+ count: number;
+ related: RelatedHashtag[];
+};
+
+const CACHE_MS = 60_000;
+const cache = new Map();
+
+/**
+ * 按「同一个作品描述里一起出现」计算相关 hashtag（共现图），每次实时从描述里解析，不需要额外的表。
+ *
+ * 打分取两个方向里较大的那个：
+ * - 子话题：候选 tag 大多和目标一起出现（together / 候选数），乘 ln(1+together) 防止只出现一次的巧合排到前面；
+ * 例：#明日方舟 → #明日方舟七周年、#特蕾西娅
+ * - 上位话题：目标大多和候选一起出现（together / 目标数），乘 ln(1+候选数)，让热门的上位 tag 排前面；
+ * 例：#圣聆初雪（只有 2 个作品）→ #明日方舟
+ * cos、二次元这类「万金油」tag 与平台活动 tag 不参与推荐。
+ */
+export async function relatedHashtags(
+ rawName: string,
+ limit = 12,
+): Promise {
+ const name = rawName.toLowerCase();
+ const key = `${name}:${limit}`;
+ const hit = cache.get(key);
+ if (hit && Date.now() - hit.at < CACHE_MS) return hit.value;
+
+ const rows = await prisma.$queryRaw<
+ { name: string; together: number; count: number; target: number }[]
+ >`
+ WITH ht AS (
+ SELECT DISTINCT w.aweme_id, lower(m[1]) AS tag
+ FROM (
+ SELECT aweme_id, "desc" FROM "Video"
+ UNION ALL
+ SELECT aweme_id, "desc" FROM "ImagePost"
+ ) w,
+ regexp_matches(w."desc", ${HASHTAG_EXTRACT_PG}, 'g') m
+ ),
+ target AS (SELECT aweme_id FROM ht WHERE tag = ${name}),
+ target_count AS (SELECT count(*)::int AS c FROM target),
+ co AS (
+ SELECT ht.tag, count(*)::int AS together
+ FROM ht JOIN target USING (aweme_id)
+ WHERE ht.tag <> ${name}
+ GROUP BY ht.tag
+ ),
+ counts AS (
+ SELECT tag, count(*)::int AS c FROM ht
+ WHERE tag IN (SELECT tag FROM co)
+ GROUP BY tag
+ )
+ SELECT
+ co.tag AS name,
+ co.together,
+ counts.c AS count,
+ tc.c AS target
+ FROM co
+ JOIN counts USING (tag)
+ CROSS JOIN target_count tc
+ WHERE co.together >= CASE WHEN tc.c >= 4 THEN 2 ELSE 1 END
+ AND co.tag <> ALL (${META_HASHTAGS}::text[])
+ AND co.tag !~ ${META_HASHTAG_PG}
+ ORDER BY GREATEST(
+ co.together::float8 / counts.c * ln(1 + co.together),
+ co.together::float8 / tc.c * ln(1 + counts.c)
+ ) DESC, co.together DESC, co.tag
+ LIMIT ${limit}
+ `;
+
+ let count = rows[0]?.target;
+ if (count === undefined) {
+ // 没有相关 tag 时单独数一下目标 tag 的作品数
+ const [{ c }] = await prisma.$queryRaw<{ c: number }[]>`
+ SELECT count(DISTINCT w.aweme_id)::int AS c
+ FROM (
+ SELECT aweme_id, "desc" FROM "Video"
+ UNION ALL
+ SELECT aweme_id, "desc" FROM "ImagePost"
+ ) w,
+ regexp_matches(w."desc", ${HASHTAG_EXTRACT_PG}, 'g') m
+ WHERE lower(m[1]) = ${name}
+ `;
+ count = c;
+ }
+
+ const value: RelatedHashtagsResult = {
+ name,
+ count,
+ related: rows.map(({ name, together, count }) => ({
+ name,
+ together,
+ count,
+ })),
+ };
+ cache.set(key, { at: Date.now(), value });
+ return value;
+}
diff --git a/lib/hashtag.ts b/lib/hashtag.ts
index 5a1396a..f8df1d3 100644
--- a/lib/hashtag.ts
+++ b/lib/hashtag.ts
@@ -47,3 +47,21 @@ export function hashtagToPgPattern(name: string): string {
const escaped = name.toLowerCase().replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
return `#${escaped}([\\s${STOP_CHARS}]|$)`;
}
+
+/** 从描述里提取全部 hashtag 名的 Postgres 正则（ARE），配合 regexp_matches(..., 'g') 使用 */
+export const HASHTAG_EXTRACT_PG = `#([^\\s${STOP_CHARS}]+)`;
+
+// 「万金油」tag：几乎和什么都一起出现，不提供话题信息，不作为相关 tag 推荐
+export const META_HASHTAGS = [
+ "cos",
+ "cosplay",
+ "coser",
+ "二次元",
+ "ooc致歉",
+ "搞笑",
+ "抽象",
+ "vlog日常",
+ "内容过于真实",
+];
+/** 平台活动类 tag（xx计划、xx挑战赛…）和纯数字 tag 的 Postgres 正则 */
+export const META_HASHTAG_PG = "(计划|挑战赛|大赛|扶持|热门|浪潮)$|^[0-9]+$";