feat: Enhance group selection logic to exclude duplicates for main schedules and past documents

server/directory.js

@@ -382,8 +382,26 @@ export function examsOf(idx, group, faculty) {
 export const groupKey = (s) =>
   (s || "").toLowerCase().replace(/ё/g, "е").replace(/[\s\-–_.]/g, "");
 
-/** Every group of every document, with the catalog place it came from. */
-export function groupEntries(idx) {
+/**
+ * Documents that only add to a group's timetable: their credits, exams and consultations reach
+ * the student through the session countdown (/api/exams), so the group picker offers them only
+ * when the group has nothing else.
+ */
+const SUPPLEMENTS = new Set(["Зачёты", "Экзаменационная сессия"]);
+
+/** The last date of a document whose every lesson is dated ("Введение в высшее образование"), else null. */
+function lastDate(schedule) {
+  const dates = schedule.lessons.flatMap((l) => (l.date ? [l.date] : l.dates || []));
+  return dates.length && schedule.lessons.every((l) => l.date || l.dates?.length)
+    ? dates.sort().at(-1)
+    : null;
+}
+
+/**
+ * Every group of every document, with the catalog place it came from. A group with a main
+ * timetable is not offered its supplements, nor dated documents that are already over.
+ */
+export function groupEntries(idx, today = todayIso()) {
   const list = [];
   for (const { file, schedule } of idx.docs)
     for (const group of schedule.groups)
@@ -397,8 +415,11 @@ export function groupEntries(idx) {
         form: file.form || "",
         period: schedule.period || "",
         modified: file.modified || null,
+        over: (lastDate(schedule) ?? "9999") < today,
       });
-  return list;
+  const secondary = (e) => SUPPLEMENTS.has(e.period) || e.over;
+  const main = new Set(list.filter((e) => !secondary(e)).map((e) => e.key));
+  return list.filter((e) => !secondary(e) || !main.has(e.key)).map(({ over, ...e }) => e);
 }
 
 const count = (items, pick) => {
@@ -416,8 +437,8 @@ const count = (items, pick) => {
  * Groups matching a query and/or catalog filters. The query ignores filters on
  * purpose: a student typing their group must find it in any faculty.
  */
-export function findGroups(idx, { q = "", faculty = "", course = "", form = "" } = {}) {
-  const all = groupEntries(idx);
+export function findGroups(idx, { q = "", faculty = "", course = "", form = "", today } = {}) {
+  const all = groupEntries(idx, today);
   const key = groupKey(q);
   let results;
   if (key.length >= 2) {