fix: prune books missing form sd card in recent books list (#1959)

src/RecentBooksStore.cpp

@@ -22,6 +22,9 @@ RecentBooksStore RecentBooksStore::instance;
 
 void RecentBooksStore::addBook(const std::string& path, const std::string& title, const std::string& author,
                                const std::string& coverBmpPath) {
+  // Drop stale entries first so a new add can't evict a valid book in their stead.
+  pruneMissing();
+
   // Remove existing entry if present
   auto it =
       std::find_if(recentBooks.begin(), recentBooks.end(), [&](const RecentBook& book) { return book.path == path; });
@@ -53,6 +56,14 @@ void RecentBooksStore::updateBook(const std::string& path, const std::string& ti
   }
 }
 
+bool RecentBooksStore::isMissing(const RecentBook& book) { return !Storage.exists(book.path.c_str()); }
+
+bool RecentBooksStore::pruneMissing() {
+  const size_t before = recentBooks.size();
+  recentBooks.erase(std::remove_if(recentBooks.begin(), recentBooks.end(), &isMissing), recentBooks.end());
+  return recentBooks.size() != before;
+}
+
 bool RecentBooksStore::saveToFile() const {
   Storage.mkdir("/.crosspoint");
   return JsonSettingsIO::saveRecentBooks(*this, RECENT_BOOKS_FILE_JSON);

src/RecentBooksStore.h

@@ -37,6 +37,13 @@ class RecentBooksStore {
   void updateBook(const std::string& path, const std::string& title, const std::string& author,
                   const std::string& coverBmpPath);
 
+  // True if the book's backing file is no longer present on the SD card.
+  static bool isMissing(const RecentBook& book);
+
+  // Remove entries whose backing file is no longer on the SD card.
+  // Returns true if any entry was removed. Does not persist — caller decides.
+  bool pruneMissing();
+
   // Get the list of recent books (most recent first)
   const std::vector<RecentBook>& getBooks() const { return recentBooks; }
 

src/activities/home/HomeActivity.cpp

@@ -43,7 +43,7 @@ void HomeActivity::loadRecentBooks(int maxBooks) {
     }
 
     // Skip if file no longer exists
-    if (!Storage.exists(book.path.c_str())) {
+    if (RecentBooksStore::isMissing(book)) {
       continue;
     }
 

src/activities/home/RecentBooksActivity.cpp

@@ -15,23 +15,17 @@ namespace {
 constexpr unsigned long GO_HOME_MS = 1000;
 }  // namespace
 
-void RecentBooksActivity::loadRecentBooks() {
-  recentBooks.clear();
-  const auto& books = RECENT_BOOKS.getBooks();
-  recentBooks.reserve(books.size());
-
-  for (const auto& book : books) {
-    // Skip if file no longer exists
-    if (!Storage.exists(book.path.c_str())) {
-      continue;
-    }
-    recentBooks.push_back(book);
-  }
-}
+void RecentBooksActivity::loadRecentBooks() { recentBooks = RECENT_BOOKS.getBooks(); }
 
 void RecentBooksActivity::onEnter() {
   Activity::onEnter();
 
+  // Prune entries whose backing files are gone; this is one of two interaction
+  // points where the persistent store gets cleaned (the other is addBook).
+  if (RECENT_BOOKS.pruneMissing()) {
+    RECENT_BOOKS.saveToFile();
+  }
+
   // Load data
   loadRecentBooks();