Add toast notifications for import feedback

- Implement toast notification system using Gtk::Revealer overlay
- Show success toast when books are imported ("Added N books")
- Show error toast for failed imports ("Failed to import N files")
- Show mixed results toast when partial success ("Added N, failed M")
- Auto-hide toast after 4 seconds with manual close button
- Add CSS styling for success (green) and error (red) toasts
- Track import errors in background thread and report to UI

Users now get visual feedback when importing books instead of
silent logging to stderr.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

PLAN.md

@@ -86,11 +86,19 @@ Remaining (moved to Phase 3):
 - [ ] Consider tag chips as quick filters in search UI
 
 ### 2.2 Add Error Handling and User Feedback
-**Files**: `src/BibliothecaWindow.cpp`, `src/BookDetails.cpp`, `src/BookImport.cpp`
-**Status**: Not Started
+**Files**: `src/BibliothecaWindow.cpp`, `src/BibliothecaWindow.hpp`
+**Status**: COMPLETED
 
-- [ ] Add toast notifications for import success/failure
-- [ ] Show dialog when book file is missing/deleted
+Implemented:
+- [x] Toast notification system with Gtk::Revealer overlay
+- [x] Success toast for book import ("Added N books")
+- [x] Error toast for failed imports ("Failed to import N files")
+- [x] Mixed results toast ("Added N, failed M")
+- [x] Auto-hide after 4 seconds with manual close button
+- [x] Error/success styling with CSS classes
+
+Remaining for future:
+- [ ] Show dialog when book file is missing/deleted (currently just logs)
 - [ ] Display metadata extraction warnings
 - [ ] Add loading indicator during import
 

src/BibliothecaWindow.cpp

@@ -58,6 +58,21 @@ BibliothecaWindow::BibliothecaWindow(DatabaseManager& db, BookList& bookList)
     border-radius: 16px;
     background-color: rgba(120, 180, 255, 0.12);
   }
+  .toast-box {
+    background-color: @theme_bg_color;
+    border-radius: 8px;
+    padding: 8px 12px;
+    margin: 12px;
+    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
+  }
+  .toast-box.toast-error {
+    background-color: #c01c28;
+    color: white;
+  }
+  .toast-box.toast-success {
+    background-color: #26a269;
+    color: white;
+  }
 
   )CSS");
 
@@ -66,6 +81,7 @@ BibliothecaWindow::BibliothecaWindow(DatabaseManager& db, BookList& bookList)
 
   // Build the main views
   buildPlaceholder();
+  buildToast();
 
   m_noResults.set_orientation(Gtk::Orientation::VERTICAL);
   m_noResults.set_spacing(12);
@@ -110,9 +126,13 @@ BibliothecaWindow::BibliothecaWindow(DatabaseManager& db, BookList& bookList)
     m_addBookButton.set_visible(visible_child != "details");
   });
 
+  // Use overlay to show toast on top of content
+  m_overlay.set_child(m_stack);
+  m_overlay.add_overlay(m_toastRevealer);
+
   m_mainBox.set_spacing(0);
   m_mainBox.append(m_searchBar);
-  m_mainBox.append(m_stack);
+  m_mainBox.append(m_overlay);
 
   set_child(m_mainBox);
 
@@ -176,13 +196,64 @@ void BibliothecaWindow::buildPlaceholder() {
   m_placeholderLabel.set_xalign(0.5);
   m_placeholderLabel.set_markup(
     "<span size='large' weight='bold'>Your Library is Empty</span>\n"
-    "<small>Click the ‘+’ button to add your first book.</small>"
+    "<small>Click the '+' button to add your first book.</small>"
   );
 
   m_placeholder.append(m_placeholderIcon);
   m_placeholder.append(m_placeholderLabel);
 }
 
+void BibliothecaWindow::buildToast() {
+  m_toastRevealer.set_transition_type(Gtk::RevealerTransitionType::SLIDE_UP);
+  m_toastRevealer.set_transition_duration(200);
+  m_toastRevealer.set_halign(Gtk::Align::CENTER);
+  m_toastRevealer.set_valign(Gtk::Align::END);
+  m_toastRevealer.set_reveal_child(false);
+
+  m_toastBox.set_spacing(8);
+  m_toastBox.add_css_class("toast-box");
+
+  m_toastLabel.set_hexpand(true);
+
+  m_toastCloseButton.set_icon_name("window-close-symbolic");
+  m_toastCloseButton.add_css_class("flat");
+  m_toastCloseButton.add_css_class("circular");
+  m_toastCloseButton.signal_clicked().connect(sigc::mem_fun(*this, &BibliothecaWindow::hideToast));
+
+  m_toastBox.append(m_toastLabel);
+  m_toastBox.append(m_toastCloseButton);
+  m_toastRevealer.set_child(m_toastBox);
+}
+
+void BibliothecaWindow::showToast(const Glib::ustring& message, bool is_error) {
+  // Cancel any pending hide timeout
+  if (m_toastTimeout.connected()) {
+    m_toastTimeout.disconnect();
+  }
+
+  m_toastLabel.set_text(message);
+
+  // Update styling
+  m_toastBox.remove_css_class("toast-error");
+  m_toastBox.remove_css_class("toast-success");
+  m_toastBox.add_css_class(is_error ? "toast-error" : "toast-success");
+
+  m_toastRevealer.set_reveal_child(true);
+
+  // Auto-hide after 4 seconds
+  m_toastTimeout = Glib::signal_timeout().connect([this]() {
+    hideToast();
+    return false; // Don't repeat
+  }, 4000);
+}
+
+void BibliothecaWindow::hideToast() {
+  if (m_toastTimeout.connected()) {
+    m_toastTimeout.disconnect();
+  }
+  m_toastRevealer.set_reveal_child(false);
+}
+
 void BibliothecaWindow::showPlaceholderIfEmpty() {
   updateVisibleView();
 }
@@ -195,7 +266,7 @@ void BibliothecaWindow::updateVisibleView() {
       m_noResultsLabel.set_markup(
         Glib::ustring::compose(
           "<span size='large' weight='bold'>No matches</span>\n"
-          "<small>No books match “%1”.</small>", escaped));
+          "<small>No books match \"%1\".</small>", escaped));
       m_stack.set_visible_child("noresults");
     } else {
       m_stack.set_visible_child("shelf");
@@ -269,14 +340,20 @@ void BibliothecaWindow::onAddBookClicked() {
       try {
         files = dialog->open_multiple_finish(res);
       } catch (const Glib::Error& e) {
-        std::cerr << "File dialog error: " << e.what() << "\n";
+        // User cancelled or error
+        if (e.code() != 2) { // 2 = GTK_DIALOG_ERROR_DISMISSED
+          showToast("Failed to open file dialog", true);
+        }
         return;
       }
       if (files.empty()) return;
 
+      const size_t total_files = files.size();
+
       // Hash and create Book objects off the GTK thread
-      std::thread([this, files = std::move(files)]() {
+      std::thread([this, files = std::move(files), total_files]() {
         std::vector<Book> imported;
+        std::vector<std::string> errors;
         imported.reserve(files.size());
 
         for (const auto& f : files) {
@@ -299,16 +376,29 @@ void BibliothecaWindow::onAddBookClicked() {
 
             imported.push_back(std::move(b));
           } catch (const std::exception& e) {
+            errors.push_back(Glib::path_get_basename(f->get_path()) + ": " + e.what());
             std::cerr << "Import failed: " << e.what() << "\n";
           }
         }
 
         // Push to model on the GTK main loop
-        Glib::signal_idle().connect_once([this, books = std::move(imported)]() mutable {
+        Glib::signal_idle().connect_once([this, books = std::move(imported), errors = std::move(errors), total_files]() mutable {
           if (!books.empty()) {
             m_bookList.upsertMany(books);
             updateVisibleView();
           }
+
+          // Show toast with import results
+          const size_t success_count = books.size();
+          const size_t error_count = errors.size();
+
+          if (error_count == 0 && success_count > 0) {
+            showToast(Glib::ustring::compose("Added %1 book%2", success_count, success_count == 1 ? "" : "s"), false);
+          } else if (success_count == 0 && error_count > 0) {
+            showToast(Glib::ustring::compose("Failed to import %1 file%2", error_count, error_count == 1 ? "" : "s"), true);
+          } else if (success_count > 0 && error_count > 0) {
+            showToast(Glib::ustring::compose("Added %1, failed %2", success_count, error_count), true);
+          }
         });
       }).detach();
     }

src/BibliothecaWindow.hpp

@@ -10,6 +10,8 @@
 #include <gtkmm/label.h>
 #include <gtkmm/searchbar.h>
 #include <gtkmm/searchentry.h>
+#include <gtkmm/overlay.h>
+#include <gtkmm/revealer.h>
 
 #include "BookList.hpp"
 #include "BookShelf.hpp"
@@ -33,9 +35,14 @@ private:
   // UI setup helpers
   void buildHeaderBar();
   void buildPlaceholder();
+  void buildToast();
   void showPlaceholderIfEmpty();
   void updateVisibleView();
 
+  // Toast notification
+  void showToast(const Glib::ustring& message, bool is_error = false);
+  void hideToast();
+
   // Callbacks
   void onAddBookClicked();
   void onBookActivated(const Book& book);
@@ -56,8 +63,16 @@ private:
   Gtk::Box       m_mainBox {Gtk::Orientation::VERTICAL};
   Gtk::SearchBar m_searchBar;
   Gtk::SearchEntry m_searchEntry;
+  Gtk::Overlay   m_overlay;
   Gtk::Stack     m_stack;
 
+  // Toast notification widgets
+  Gtk::Revealer  m_toastRevealer;
+  Gtk::Box       m_toastBox {Gtk::Orientation::HORIZONTAL};
+  Gtk::Label     m_toastLabel;
+  Gtk::Button    m_toastCloseButton;
+  sigc::connection m_toastTimeout;
+
   Gtk::Box       m_placeholder {Gtk::Orientation::VERTICAL};
   Gtk::Image     m_placeholderIcon;
   Gtk::Label     m_placeholderLabel;