max / makenotwork

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1	use super::{PgPool, Uuid};
2
3	#[derive(sqlx::FromRow)]
4	pub struct EndorsementRow {
5	pub post_id: Uuid,
6	pub endorser_id: Uuid,
7	}
8
9	/// One post's total endorsement count (from an aggregated `GROUP BY`).
10	#[derive(sqlx::FromRow)]
11	pub struct EndorsementCount {
12	pub post_id: Uuid,
13	pub count: i64,
14	}
15
16	/// Batch-fetch endorsements for a set of post IDs.
17	///
18	/// Loads one row per endorsement, fine when the caller needs the endorser ids,
19	/// but the thread view must NOT use this: a hot post with thousands of
20	/// endorsements would stream every row on every (unauthenticated, unthrottled)
21	/// page load. That path uses [`count_endorsements_for_posts`] +
22	/// [`list_user_endorsed_posts`] instead.
23	#[tracing::instrument(skip_all)]
24	pub async fn list_endorsements_for_posts(
25	pool: &PgPool,
26	post_ids: &[Uuid],
27	) -> Result<Vec<EndorsementRow>, sqlx::Error> {
28	sqlx::query_as!(
29	EndorsementRow,
30	"SELECT post_id, endorser_id FROM post_endorsements WHERE post_id = ANY($1)",
31	post_ids,
32	)
33	.fetch_all(pool)
34	.await
35	}
36
37	/// Per-post endorsement counts, aggregated in Postgres.
38	///
39	/// Replaces streaming every endorsement row into the app just to `len()` them:
40	/// a `GROUP BY` returns at most one row per visible post regardless of how many
41	/// endorsements a post has (fuzz-2026-07-06 endorsement fan-out). Posts with
42	/// zero endorsements are absent; the caller defaults them to 0.
43	#[tracing::instrument(skip_all)]
44	pub async fn count_endorsements_for_posts(
45	pool: &PgPool,
46	post_ids: &[Uuid],
47	) -> Result<Vec<EndorsementCount>, sqlx::Error> {
48	sqlx::query_as!(
49	EndorsementCount,
50	r#"SELECT post_id, COUNT(*) AS "count!"
51	FROM post_endorsements
52	WHERE post_id = ANY($1)
53	GROUP BY post_id"#,
54	post_ids,
55	)
56	.fetch_all(pool)
57	.await
58	}
59
60	/// The subset of `post_ids` the given user has endorsed. Bounded by the page's
61	/// post count (not the endorsement total), so the thread view can mark the
62	/// viewer's own endorsements without loading every endorser id.
63	#[tracing::instrument(skip_all)]
64	pub async fn list_user_endorsed_posts(
65	pool: &PgPool,
66	post_ids: &[Uuid],
67	user_id: Uuid,
68	) -> Result<Vec<Uuid>, sqlx::Error> {
69	sqlx::query_scalar!(
70	"SELECT post_id FROM post_endorsements WHERE post_id = ANY($1) AND endorser_id = $2",
71	post_ids,
72	user_id,
73	)
74	.fetch_all(pool)
75	.await
76	}
77