feat(thread-stats): show board page number in post stats via cache-first lookup

src/lib/utils/post-page-resolution.ts

@@ -0,0 +1,96 @@
+/**
+ * Post page resolution utilities.
+ * Page semantics are board pagination pages (not catalog ordering, not fetch-chunk index).
+ */
+
+/** Minimal Comment shape with cid */
+export interface CommentWithCid {
+  cid?: string;
+  [key: string]: unknown;
+}
+
+/** Minimal FeedOptions shape for board-feed filtering */
+export interface FeedOptionsLike {
+  subplebbitAddresses: string[];
+  sortType: string;
+  postsPerPage?: number;
+  filter?: unknown;
+  newerThan?: number;
+  modQueue?: unknown;
+  accountComments?: unknown;
+}
+
+/** FeedsOptions-like map */
+export type FeedsOptionsLike = Record<string, FeedOptionsLike>;
+
+/** Loaded feeds map: feedName -> Comment[] */
+export type LoadedFeedsLike = Record<string, CommentWithCid[]>;
+
+/**
+ * Find the board pagination page (1-based) containing postCid in a feed.
+ * Pure index math: page = floor(index / guiPostsPerPage) + 1.
+ *
+ * @param feed - Array of comments (posts) in feed order
+ * @param postCid - CID of the post (OP) to locate
+ * @param guiPostsPerPage - Posts per GUI page
+ * @returns 1-based page number, or undefined if post not found
+ */
+export function findPostPageInFeed(feed: CommentWithCid[], postCid: string, guiPostsPerPage: number): number | undefined {
+  if (!postCid || guiPostsPerPage <= 0) return undefined;
+  const index = feed.findIndex((c) => c.cid === postCid);
+  if (index < 0) return undefined;
+  return Math.floor(index / guiPostsPerPage) + 1;
+}
+
+/**
+ * Strict board-feed filter criteria.
+ * A feed is a "board feed" iff:
+ * - sortType === 'active'
+ * - single-sub feed (subplebbitAddresses.length === 1)
+ * - no filter, no newerThan, no modQueue, no accountComments
+ */
+export function isBoardFeedOptions(opts: FeedOptionsLike, subplebbitAddress: string): boolean {
+  return (
+    opts.sortType === 'active' &&
+    opts.subplebbitAddresses?.length === 1 &&
+    opts.subplebbitAddresses[0] === subplebbitAddress &&
+    !opts.filter &&
+    opts.newerThan == null &&
+    !opts.modQueue &&
+    !opts.accountComments
+  );
+}
+
+/**
+ * Find the board pagination page for postCid by searching loaded board feeds.
+ * Only considers feeds matching strict board-feed criteria.
+ *
+ * @param feedsOptions - Feeds store feedsOptions
+ * @param loadedFeeds - Feeds store loadedFeeds
+ * @param subplebbitAddress - Board subplebbit address
+ * @param postCid - CID of the post (OP) to locate
+ * @param guiPostsPerPage - Posts per GUI page
+ * @returns 1-based page number, or undefined if not found in any matching feed
+ */
+export function findPostPageInLoadedBoardFeeds(
+  feedsOptions: FeedsOptionsLike,
+  loadedFeeds: LoadedFeedsLike,
+  subplebbitAddress: string,
+  postCid: string,
+  guiPostsPerPage: number,
+): number | undefined {
+  if (!subplebbitAddress || !postCid || guiPostsPerPage <= 0) return undefined;
+
+  for (const feedName of Object.keys(feedsOptions)) {
+    const opts = feedsOptions[feedName];
+    if (!opts || !isBoardFeedOptions(opts, subplebbitAddress)) continue;
+
+    const feed = loadedFeeds[feedName];
+    if (!feed || !Array.isArray(feed)) continue;
+
+    const page = findPostPageInFeed(feed, postCid, guiPostsPerPage);
+    if (page !== undefined) return page;
+  }
+
+  return undefined;
+}