feat: long-press back button on MainMenu to delete a book with confirmation

lib/microreader/screens/MainMenu.cpp

@@ -46,19 +46,141 @@ void MainMenu::update(const ButtonState& buttons, DrawBuffer& buf, IRuntime& run
     buf.full_refresh();
   }
 
+  // === DELETE CONFIRMATION MODE ===
+  if (delete_pending_) {
+    Button btn;
+    while (buttons.next_press(btn)) {
+      if (btn == Button::Button1) {
+        do_delete_(buf, runtime);
+        return;
+      }
+      if (btn == Button::Button0) {
+        cancel_delete_(buf, runtime);
+        return;
+      }
+    }
+    draw_all_(buf, runtime.battery_percentage());
+    buf.refresh();
+    return;
+  }
+
+  // === NORMAL MODE ===
+
+  // Track Button1 hold duration (time-based for frame-rate independence)
+  if (buttons.is_down(Button::Button1))
+    button1_hold_ms_ += runtime.frame_time_ms();
+  else
+    button1_hold_ms_ = 0;
+
+  // Let parent handle up/down/back navigation.
+  // on_select() stores the index but no longer opens the book immediately.
   ListMenuScreen::update(buttons, buf, runtime);
+
+  // Handle pending selection (set by on_select above)
+  if (pending_select_idx_ >= 0) {
+    // Button released → short press → open the book
+    if (!buttons.is_down(Button::Button1)) {
+      pending_select_idx_ = -1;
+      app_->push_screen(ScreenId::Reader);
+      return;
+    }
+    // Long press threshold reached → enter delete confirmation
+    if (button1_hold_ms_ >= kLongPressMs) {
+      const int idx = pending_select_idx_;
+      pending_select_idx_ = -1;
+      button1_hold_ms_ = 0;
+      delete_pending_ = true;
+      delete_index_ = idx;
+      delete_book_label_ = entries_[idx].label;
+      title_ = "Delete?";
+      set_item_label(idx, "Back=No  Sel=Yes");
+      draw_all_(buf, runtime.battery_percentage());
+      buf.refresh();
+      return;
+    }
+    // Button still held but not yet long enough — wait another frame
+  }
 }
 
 void MainMenu::on_select(int index) {
+  // Don't open the book immediately — update() handles short-press vs long-press
   last_selected_path_ = entries_[index].path;
   app_->reader()->set_path(entries_[index].path.c_str());
-  app_->push_screen(ScreenId::Reader);
+  pending_select_idx_ = index;
 }
 
 void MainMenu::on_back() {
   app_->push_screen(ScreenId::Settings);
 }
 
+void MainMenu::do_delete_(DrawBuffer& buf, IRuntime& runtime) {
+  const std::string& epub_path = entries_[delete_index_].path;
+  const char* path_cstr = epub_path.c_str();
+
+  MR_LOGI("menu", "deleting %s", path_cstr);
+
+  // 1. Delete the EPUB file
+  (void)std::remove(path_cstr);
+
+  // 2. Delete the MRB cache directory (<data_dir>/cache/<basename>/)
+  if (app_ && app_->data_dir_) {
+    std::string cache_dir = std::string(app_->data_dir_) + "/cache/";
+    const char* name = path_cstr;
+    const char* sep = std::strrchr(name, '/');
+#ifdef _WIN32
+    const char* bsep = std::strrchr(name, '\\');
+    if (bsep && (!sep || bsep > sep))
+      sep = bsep;
+#endif
+    if (sep)
+      name = sep + 1;
+    const char* dot = std::strrchr(name, '.');
+    if (dot)
+      cache_dir.append(name, static_cast<size_t>(dot - name));
+    else
+      cache_dir.append(name);
+
+#ifdef ESP_PLATFORM
+    DIR* d = opendir(cache_dir.c_str());
+    if (d) {
+      struct dirent* ent;
+      char fpath[300];
+      while ((ent = readdir(d)) != nullptr) {
+        if (ent->d_name[0] == '.')
+          continue;
+        std::snprintf(fpath, sizeof(fpath), "%s/%s", cache_dir.c_str(), ent->d_name);
+        std::remove(fpath);
+      }
+      closedir(d);
+      rmdir(cache_dir.c_str());
+    }
+#else
+    if (fs::exists(cache_dir))
+      fs::remove_all(cache_dir);
+#endif
+  }
+
+  // Reset state and rescan
+  button1_hold_ms_ = 0;
+  delete_pending_ = false;
+  delete_index_ = -1;
+  title_ = "Microreader";
+  scan_directory_(buf);
+  populate_list_();
+  draw_all_(buf, runtime.battery_percentage());
+  buf.full_refresh();
+}
+
+void MainMenu::cancel_delete_(DrawBuffer& buf, IRuntime& runtime) {
+  set_item_label(delete_index_, delete_book_label_);
+  button1_hold_ms_ = 0;
+  delete_pending_ = false;
+  delete_index_ = -1;
+  title_ = "Microreader";
+  draw_all_(buf, runtime.battery_percentage());
+  buf.refresh();
+}
+
 void MainMenu::scan_directory_(DrawBuffer& buf) {
   if (!books_dir_ || !app_->data_dir_)
     return;

lib/microreader/screens/MainMenu.h

@@ -20,6 +20,11 @@ class MainMenu final : public ListMenuScreen {
     books_dir_ = dir;
   }
 
+  // Force the book list to rescan on the next update.
+  void request_rescan() {
+    needs_scan_ = true;
+  }
+
   // Restore the book list selection to the entry matching this path.
   // Call before start(); applied after directory scan.
   void set_initial_selection(const char* path) {
@@ -83,6 +88,17 @@ class MainMenu final : public ListMenuScreen {
   BookListFormat list_format_ = BookListFormat::TitleOnly;
   bool needs_scan_ = false;
 
+  // Long-press delete state
+  int pending_select_idx_ = -1;   // index selected via on_select, pending resolution
+  int delete_index_ = -1;         // book to delete when confirmed
+  bool delete_pending_ = false;   // waiting for confirm/cancel on delete prompt
+  uint32_t button1_hold_ms_ = 0;  // accumulated hold time for Button1
+  std::string delete_book_label_; // original label of book pending deletion
+  static constexpr uint32_t kLongPressMs = 800;
+
+  void do_delete_(DrawBuffer& buf, IRuntime& runtime);
+  void cancel_delete_(DrawBuffer& buf, IRuntime& runtime);
+
   struct BookEntry {
     std::string path;
     std::string label;