initial commit

shared/updates.js

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+// Decides what a saved schedule needs after the catalog was read again.
+// Runs in the browser; kept free of DOM code so the rules are testable in Node.
+
+const escape = (s) => s.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+const time = (value) => Date.parse(value || "") || 0;
+
+/** "23-БА" matches "23-ЛГ_23-БА.docx" but not "23-БАз" or "123-БА". */
+export function namesGroup(fileName, group) {
+  if (!group) return false;
+  const base = fileName.replace(/\.docx?$/i, "");
+  return new RegExp(
+    `(^|[^0-9A-Za-zА-ЯЁа-яё])${escape(group)}(?![0-9A-Za-zА-ЯЁа-яё])`,
+    "iu",
+  ).test(base);
+}
+
+/**
+ * changed: the same document was republished (or parsed by an older version) — reload it quietly.
+ * newer:   another document for this group appeared later, e.g. the next semester — offer it.
+ * missing: the document left the catalog, e.g. a new academic year began.
+ */
+export function scheduleUpdate(saved, catalog, group, options = {}) {
+  const { dismissed = [], schemaVersion = 0 } = options;
+  const fileId = saved?.source?.fileId;
+  if (!fileId || !catalog?.files || catalog.stale) return null;
+  const current = catalog.files.find((f) => f.id === fileId) || null;
+  const savedTime = time(saved.source.modified) || time(saved.source.importedAt);
+  const newer =
+    catalog.files
+      .filter(
+        (f) =>
+          f.id !== fileId &&
+          !dismissed.includes(f.id) &&
+          namesGroup(f.name, group) &&
+          time(f.modified) > savedTime &&
+          (!saved.source.faculty || f.faculty === saved.source.faculty),
+      )
+      .sort((a, b) => time(b.modified) - time(a.modified))[0] || null;
+  const changed =
+    current &&
+    (current.modified !== saved.source.modified ||
+      (saved.schemaVersion || 0) < schemaVersion)
+      ? current
+      : null;
+  if (!changed && !newer && current) return null;
+  return { changed, newer, missing: !current };
+}