max / makenotwork

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1	//! Feed page: items from followed users, projects, and tags.
2
3	use axum::extract::{Query, State};
4	use axum::response::IntoResponse;
5	use serde::Deserialize;
6	use tower_sessions::Session;
7
8	use crate::{
9	auth::AuthUser,
10	constants,
11	db,
12	error::Result,
13	helpers::get_csrf_token,
14	templates::FeedTemplate,
15	types::DiscoverItem,
16	AppState,
17	};
18
19	/// Query parameters for the feed page.
20	#[derive(Debug, Deserialize)]
21	pub struct FeedQuery {
22	pub page: Option<u32>,
23	}
24
25	/// Build a sliding window of page numbers for pagination controls.
26	pub(super) fn build_pagination_range(current_page: u32, total_pages: u32) -> Vec<u32> {
27	if total_pages <= constants::PAGINATION_WINDOW_SIZE {
28	(1..=total_pages).collect()
29	} else {
30	let start = current_page.saturating_sub(2).max(1);
31	let end = (start + 4).min(total_pages);
32	let start = end.saturating_sub(4).max(1);
33	(start..=end).collect()
34	}
35	}
36
37	/// GET /feed: paginated feed of items from followed users, projects, and tags.
38	#[tracing::instrument(skip_all, name = "feed::feed_page")]
39	pub(super) async fn feed_page(
40	State(state): State<AppState>,
41	session: Session,
42	AuthUser(user): AuthUser,
43	Query(query): Query<FeedQuery>,
44	) -> Result<impl IntoResponse> {
45	let csrf_token = get_csrf_token(&session).await;
46	let session_user = Some(user.clone());
47
48	let page = query.page.unwrap_or(1).max(1);
49	// Widen to i64 BEFORE multiplying — `(page - 1) * FEED_PAGE_SIZE` in u32
50	// overflows for a large `?page=` (garbage offset in release, panic in debug).
51	let offset = (page as i64 - 1) * constants::FEED_PAGE_SIZE as i64;
52
53	let total_items = db::follows::count_followed_feed_items(&state.db, user.id).await? as u32;
54	let total_pages = (total_items + constants::FEED_PAGE_SIZE - 1) / constants::FEED_PAGE_SIZE.max(1);
55
56	let db_items = db::follows::get_followed_feed_items(
57	&state.db,
58	user.id,
59	constants::FEED_PAGE_SIZE as i64,
60	offset,
61	)
62	.await?;
63
64	let items: Vec<DiscoverItem> = db_items.into_iter().map(DiscoverItem::from).collect();
65
66	// Compute the "showing X–Y" labels in i64 (saturating) to avoid the u32
67	// overflow `offset as u32 + FEED_PAGE_SIZE` would hit for a large `?page=`.
68	let showing_start = if total_items == 0 {
69	0
70	} else {
71	offset.saturating_add(1).clamp(0, u32::MAX as i64) as u32
72	};
73	let showing_end = offset
74	.saturating_add(constants::FEED_PAGE_SIZE as i64)
75	.min(total_items as i64)
76	.clamp(0, u32::MAX as i64) as u32;
77	let pagination_range = build_pagination_range(page, total_pages);
78
79	Ok(FeedTemplate {
80	csrf_token,
81	session_user,
82	items,
83	total_items,
84	current_page: page,
85	total_pages,
86	pagination_range,
87	showing_start,
88	showing_end,
89	})
90	}
91