Merge 66e69e750e into f67c544e16

## Summary

Resolves #562 

Implements regex change to support valid characters discussed by
@daveallie in issue
[here](https://github.com/crosspoint-reader/crosspoint-reader/issues/562#issuecomment-3830809156).

Also rejects `.` and `..` as folder names which are invalid in FAT32 and
exFAT filesystems

## Additional Context
- Unsure on the wording for the alert, it feels overly explicit, but
that might be a good thing. Happy to change.

---

### AI Usage

While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.

Did you use AI tools to help write this code? _**< PARTIALLY >**_

docs/webserver.md

@@ -153,7 +153,7 @@ Click **File Manager** to access file management features.
 
 1. Click the **+ Add** button in the top-right corner
 2. Select **New Folder** from the dropdown menu
-3. Enter a folder name (letters, numbers, underscores, and hyphens only)
+3. Enter a folder name (must not contain characters \" * : < > ? / \\ | and must not be . or ..)
 4. Click **Create Folder**
 
 This is useful for organizing your ebooks by genre, author, or series.

src/activities/browser/OpdsBookBrowserActivity.cpp

@@ -17,7 +17,6 @@
 
 namespace {
 constexpr int PAGE_ITEMS = 23;
-constexpr int SKIP_PAGE_MS = 700;
 }  // namespace
 
 void OpdsBookBrowserActivity::taskTrampoline(void* param) {
@@ -118,12 +117,6 @@ void OpdsBookBrowserActivity::loop() {
 
   // Handle browsing state
   if (state == BrowserState::BROWSING) {
-    const bool prevReleased = mappedInput.wasReleased(MappedInputManager::Button::Up) ||
-                              mappedInput.wasReleased(MappedInputManager::Button::Left);
-    const bool nextReleased = mappedInput.wasReleased(MappedInputManager::Button::Down) ||
-                              mappedInput.wasReleased(MappedInputManager::Button::Right);
-    const bool skipPage = mappedInput.getHeldTime() > SKIP_PAGE_MS;
-
     if (mappedInput.wasReleased(MappedInputManager::Button::Confirm)) {
       if (!entries.empty()) {
         const auto& entry = entries[selectorIndex];
@@ -135,20 +128,29 @@ void OpdsBookBrowserActivity::loop() {
       }
     } else if (mappedInput.wasReleased(MappedInputManager::Button::Back)) {
       navigateBack();
-    } else if (prevReleased && !entries.empty()) {
-      if (skipPage) {
-        selectorIndex = ((selectorIndex / PAGE_ITEMS - 1) * PAGE_ITEMS + entries.size()) % entries.size();
-      } else {
-        selectorIndex = (selectorIndex + entries.size() - 1) % entries.size();
-      }
-      updateRequired = true;
-    } else if (nextReleased && !entries.empty()) {
-      if (skipPage) {
-        selectorIndex = ((selectorIndex / PAGE_ITEMS + 1) * PAGE_ITEMS) % entries.size();
-      } else {
-        selectorIndex = (selectorIndex + 1) % entries.size();
-      }
-      updateRequired = true;
+    }
+
+    // Handle navigation
+    if (!entries.empty()) {
+      buttonNavigator.onNextRelease([this] {
+        selectorIndex = ButtonNavigator::nextIndex(selectorIndex, entries.size());
+        updateRequired = true;
+      });
+
+      buttonNavigator.onPreviousRelease([this] {
+        selectorIndex = ButtonNavigator::previousIndex(selectorIndex, entries.size());
+        updateRequired = true;
+      });
+
+      buttonNavigator.onNextContinuous([this] {
+        selectorIndex = ButtonNavigator::nextPageIndex(selectorIndex, entries.size(), PAGE_ITEMS);
+        updateRequired = true;
+      });
+
+      buttonNavigator.onPreviousContinuous([this] {
+        selectorIndex = ButtonNavigator::previousPageIndex(selectorIndex, entries.size(), PAGE_ITEMS);
+        updateRequired = true;
+      });
     }
   }
 }

src/activities/browser/OpdsBookBrowserActivity.h

@@ -9,6 +9,7 @@
 #include <vector>
 
 #include "../ActivityWithSubactivity.h"
+#include "util/ButtonNavigator.h"
 
 /**
  * Activity for browsing and downloading books from an OPDS server.
@@ -37,6 +38,7 @@ class OpdsBookBrowserActivity final : public ActivityWithSubactivity {
  private:
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
+  ButtonNavigator buttonNavigator;
   bool updateRequired = false;
 
   BrowserState state = BrowserState::LOADING;

src/activities/home/HomeActivity.cpp

@@ -162,13 +162,18 @@ void HomeActivity::freeCoverBuffer() {
 }
 
 void HomeActivity::loop() {
-  const bool prevPressed = mappedInput.wasPressed(MappedInputManager::Button::Up) ||
-                           mappedInput.wasPressed(MappedInputManager::Button::Left);
-  const bool nextPressed = mappedInput.wasPressed(MappedInputManager::Button::Down) ||
-                           mappedInput.wasPressed(MappedInputManager::Button::Right);
-
   const int menuCount = getMenuItemCount();
 
+  buttonNavigator.onNext([this, menuCount] {
+    selectorIndex = ButtonNavigator::nextIndex(selectorIndex, menuCount);
+    updateRequired = true;
+  });
+
+  buttonNavigator.onPrevious([this, menuCount] {
+    selectorIndex = ButtonNavigator::previousIndex(selectorIndex, menuCount);
+    updateRequired = true;
+  });
+
   if (mappedInput.wasReleased(MappedInputManager::Button::Confirm)) {
     // Calculate dynamic indices based on which options are available
     int idx = 0;
@@ -189,12 +194,6 @@ void HomeActivity::loop() {
     } else if (selectorIndex == settingsIdx) {
       onSettingsOpen();
     }
-  } else if (prevPressed) {
-    selectorIndex = (selectorIndex + menuCount - 1) % menuCount;
-    updateRequired = true;
-  } else if (nextPressed) {
-    selectorIndex = (selectorIndex + 1) % menuCount;
-    updateRequired = true;
   }
 }
 

src/activities/home/HomeActivity.h

@@ -6,10 +6,12 @@
 #include <functional>
 
 #include "../Activity.h"
+#include "util/ButtonNavigator.h"
 
 class HomeActivity final : public Activity {
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
+  ButtonNavigator buttonNavigator;
   int selectorIndex = 0;
   bool updateRequired = false;
   bool hasContinueReading = false;

src/activities/home/MyLibraryActivity.cpp

@@ -21,7 +21,6 @@ constexpr int LEFT_MARGIN = 20;
 constexpr int RIGHT_MARGIN = 40;  // Extra space for scroll indicator
 
 // Timing thresholds
-constexpr int SKIP_PAGE_MS = 700;
 constexpr unsigned long GO_HOME_MS = 1000;
 
 void sortFileList(std::vector<std::string>& strs) {
@@ -178,13 +177,9 @@ void MyLibraryActivity::loop() {
     return;
   }
 
-  const bool upReleased = mappedInput.wasReleased(MappedInputManager::Button::Up);
-  const bool downReleased = mappedInput.wasReleased(MappedInputManager::Button::Down);
   const bool leftReleased = mappedInput.wasReleased(MappedInputManager::Button::Left);
   const bool rightReleased = mappedInput.wasReleased(MappedInputManager::Button::Right);
 
-  const bool skipPage = mappedInput.getHeldTime() > SKIP_PAGE_MS;
-
   // Confirm button - open selected item
   if (mappedInput.wasReleased(MappedInputManager::Button::Confirm)) {
     if (currentTab == Tab::Recent) {
@@ -249,24 +244,28 @@ void MyLibraryActivity::loop() {
   }
 
   // Navigation: Up/Down moves through items only
-  const bool prevReleased = upReleased;
-  const bool nextReleased = downReleased;
+  constexpr auto upButton = MappedInputManager::Button::Up;
+  constexpr auto downButton = MappedInputManager::Button::Down;
 
-  if (prevReleased && itemCount > 0) {
-    if (skipPage) {
-      selectorIndex = ((selectorIndex / pageItems - 1) * pageItems + itemCount) % itemCount;
-    } else {
-      selectorIndex = (selectorIndex + itemCount - 1) % itemCount;
-    }
+  buttonNavigator.onRelease({downButton}, [this, itemCount] {
+    selectorIndex = ButtonNavigator::nextIndex(selectorIndex, itemCount);
     updateRequired = true;
-  } else if (nextReleased && itemCount > 0) {
-    if (skipPage) {
-      selectorIndex = ((selectorIndex / pageItems + 1) * pageItems) % itemCount;
-    } else {
-      selectorIndex = (selectorIndex + 1) % itemCount;
-    }
+  });
+
+  buttonNavigator.onRelease({upButton}, [this, itemCount] {
+    selectorIndex = ButtonNavigator::previousIndex(selectorIndex, itemCount);
     updateRequired = true;
-  }
+  });
+
+  buttonNavigator.onContinuous({downButton}, [this, itemCount, pageItems] {
+    selectorIndex = ButtonNavigator::nextPageIndex(selectorIndex, itemCount, pageItems);
+    updateRequired = true;
+  });
+
+  buttonNavigator.onContinuous({upButton}, [this, itemCount, pageItems] {
+    selectorIndex = ButtonNavigator::previousPageIndex(selectorIndex, itemCount, pageItems);
+    updateRequired = true;
+  });
 }
 
 void MyLibraryActivity::displayTaskLoop() {

src/activities/home/MyLibraryActivity.h

@@ -9,6 +9,7 @@
 
 #include "../Activity.h"
 #include "RecentBooksStore.h"
+#include "util/ButtonNavigator.h"
 
 class MyLibraryActivity final : public Activity {
  public:
@@ -17,6 +18,7 @@ class MyLibraryActivity final : public Activity {
  private:
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
+  ButtonNavigator buttonNavigator;
 
   Tab currentTab = Tab::Recent;
   int selectorIndex = 0;

src/activities/network/NetworkModeSelectionActivity.cpp

@@ -72,18 +72,15 @@ void NetworkModeSelectionActivity::loop() {
   }
 
   // Handle navigation
-  const bool prevPressed = mappedInput.wasPressed(MappedInputManager::Button::Up) ||
-                           mappedInput.wasPressed(MappedInputManager::Button::Left);
-  const bool nextPressed = mappedInput.wasPressed(MappedInputManager::Button::Down) ||
-                           mappedInput.wasPressed(MappedInputManager::Button::Right);
+  buttonNavigator.onNext([this] {
+    selectedIndex = ButtonNavigator::nextIndex(selectedIndex, MENU_ITEM_COUNT);
+    updateRequired = true;
+  });
 
-  if (prevPressed) {
-    selectedIndex = (selectedIndex + MENU_ITEM_COUNT - 1) % MENU_ITEM_COUNT;
+  buttonNavigator.onPrevious([this] {
+    selectedIndex = ButtonNavigator::previousIndex(selectedIndex, MENU_ITEM_COUNT);
     updateRequired = true;
-  } else if (nextPressed) {
-    selectedIndex = (selectedIndex + 1) % MENU_ITEM_COUNT;
-    updateRequired = true;
-  }
+  });
 }
 
 void NetworkModeSelectionActivity::displayTaskLoop() {

src/activities/network/NetworkModeSelectionActivity.h

@@ -6,6 +6,7 @@
 #include <functional>
 
 #include "../Activity.h"
+#include "util/ButtonNavigator.h"
 
 // Enum for network mode selection
 enum class NetworkMode { JOIN_NETWORK, CONNECT_CALIBRE, CREATE_HOTSPOT };
@@ -22,6 +23,8 @@ enum class NetworkMode { JOIN_NETWORK, CONNECT_CALIBRE, CREATE_HOTSPOT };
 class NetworkModeSelectionActivity final : public Activity {
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
+  ButtonNavigator buttonNavigator;
+
   int selectedIndex = 0;
   bool updateRequired = false;
   const std::function<void(NetworkMode)> onModeSelected;

src/activities/network/WifiSelectionActivity.cpp

@@ -419,20 +419,16 @@ void WifiSelectionActivity::loop() {
       return;
     }
 
-    // Handle UP/DOWN navigation
-    if (mappedInput.wasPressed(MappedInputManager::Button::Up) ||
-        mappedInput.wasPressed(MappedInputManager::Button::Left)) {
-      if (selectedNetworkIndex > 0) {
-        selectedNetworkIndex--;
-        updateRequired = true;
-      }
-    } else if (mappedInput.wasPressed(MappedInputManager::Button::Down) ||
-               mappedInput.wasPressed(MappedInputManager::Button::Right)) {
-      if (!networks.empty() && selectedNetworkIndex < static_cast<int>(networks.size()) - 1) {
-        selectedNetworkIndex++;
-        updateRequired = true;
-      }
-    }
+    // Handle navigation
+    buttonNavigator.onNext([this] {
+      selectedNetworkIndex = ButtonNavigator::nextIndex(selectedNetworkIndex, networks.size());
+      updateRequired = true;
+    });
+
+    buttonNavigator.onPrevious([this] {
+      selectedNetworkIndex = ButtonNavigator::previousIndex(selectedNetworkIndex, networks.size());
+      updateRequired = true;
+    });
   }
 }
 

src/activities/network/WifiSelectionActivity.h

@@ -10,6 +10,7 @@
 #include <vector>
 
 #include "activities/ActivityWithSubactivity.h"
+#include "util/ButtonNavigator.h"
 
 // Structure to hold WiFi network information
 struct WifiNetworkInfo {
@@ -45,6 +46,7 @@ enum class WifiSelectionState {
 class WifiSelectionActivity final : public ActivityWithSubactivity {
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
+  ButtonNavigator buttonNavigator;
   bool updateRequired = false;
   WifiSelectionState state = WifiSelectionState::SCANNING;
   int selectedNetworkIndex = 0;

src/activities/reader/EpubReaderChapterSelectionActivity.cpp

@@ -7,11 +7,6 @@
 #include "MappedInputManager.h"
 #include "fontIds.h"
 
-namespace {
-// Time threshold for treating a long press as a page-up/page-down
-constexpr int SKIP_PAGE_MS = 700;
-}  // namespace
-
 bool EpubReaderChapterSelectionActivity::hasSyncOption() const { return KOREADER_STORE.hasCredentials(); }
 
 int EpubReaderChapterSelectionActivity::getTotalItems() const {
@@ -119,12 +114,6 @@ void EpubReaderChapterSelectionActivity::loop() {
     return;
   }
 
-  const bool prevReleased = mappedInput.wasReleased(MappedInputManager::Button::Up) ||
-                            mappedInput.wasReleased(MappedInputManager::Button::Left);
-  const bool nextReleased = mappedInput.wasReleased(MappedInputManager::Button::Down) ||
-                            mappedInput.wasReleased(MappedInputManager::Button::Right);
-
-  const bool skipPage = mappedInput.getHeldTime() > SKIP_PAGE_MS;
   const int pageItems = getPageItems();
   const int totalItems = getTotalItems();
 
@@ -145,21 +134,27 @@ void EpubReaderChapterSelectionActivity::loop() {
     }
   } else if (mappedInput.wasReleased(MappedInputManager::Button::Back)) {
     onGoBack();
-  } else if (prevReleased) {
-    if (skipPage) {
-      selectorIndex = ((selectorIndex / pageItems - 1) * pageItems + totalItems) % totalItems;
-    } else {
-      selectorIndex = (selectorIndex + totalItems - 1) % totalItems;
-    }
-    updateRequired = true;
-  } else if (nextReleased) {
-    if (skipPage) {
-      selectorIndex = ((selectorIndex / pageItems + 1) * pageItems) % totalItems;
-    } else {
-      selectorIndex = (selectorIndex + 1) % totalItems;
-    }
-    updateRequired = true;
   }
+
+  buttonNavigator.onNextRelease([this, totalItems] {
+    selectorIndex = ButtonNavigator::nextIndex(selectorIndex, totalItems);
+    updateRequired = true;
+  });
+
+  buttonNavigator.onPreviousRelease([this, totalItems] {
+    selectorIndex = ButtonNavigator::previousIndex(selectorIndex, totalItems);
+    updateRequired = true;
+  });
+
+  buttonNavigator.onNextContinuous([this, totalItems, pageItems] {
+    selectorIndex = ButtonNavigator::nextPageIndex(selectorIndex, totalItems, pageItems);
+    updateRequired = true;
+  });
+
+  buttonNavigator.onPreviousContinuous([this, totalItems, pageItems] {
+    selectorIndex = ButtonNavigator::previousPageIndex(selectorIndex, totalItems, pageItems);
+    updateRequired = true;
+  });
 }
 
 void EpubReaderChapterSelectionActivity::displayTaskLoop() {

src/activities/reader/EpubReaderChapterSelectionActivity.h

@@ -7,12 +7,14 @@
 #include <memory>
 
 #include "../ActivityWithSubactivity.h"
+#include "util/ButtonNavigator.h"
 
 class EpubReaderChapterSelectionActivity final : public ActivityWithSubactivity {
   std::shared_ptr<Epub> epub;
   std::string epubPath;
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
+  ButtonNavigator buttonNavigator;
   int currentSpineIndex = 0;
   int currentPage = 0;
   int totalPagesInSpine = 0;

src/activities/reader/XtcReaderChapterSelectionActivity.cpp

@@ -5,10 +5,6 @@
 #include "MappedInputManager.h"
 #include "fontIds.h"
 
-namespace {
-constexpr int SKIP_PAGE_MS = 700;
-}  // namespace
-
 int XtcReaderChapterSelectionActivity::getPageItems() const {
   constexpr int startY = 60;
   constexpr int lineHeight = 30;
@@ -75,13 +71,8 @@ void XtcReaderChapterSelectionActivity::onExit() {
 }
 
 void XtcReaderChapterSelectionActivity::loop() {
-  const bool prevReleased = mappedInput.wasReleased(MappedInputManager::Button::Up) ||
-                            mappedInput.wasReleased(MappedInputManager::Button::Left);
-  const bool nextReleased = mappedInput.wasReleased(MappedInputManager::Button::Down) ||
-                            mappedInput.wasReleased(MappedInputManager::Button::Right);
-
-  const bool skipPage = mappedInput.getHeldTime() > SKIP_PAGE_MS;
   const int pageItems = getPageItems();
+  const int totalItems = static_cast<int>(xtc->getChapters().size());
 
   if (mappedInput.wasReleased(MappedInputManager::Button::Confirm)) {
     const auto& chapters = xtc->getChapters();
@@ -90,29 +81,27 @@ void XtcReaderChapterSelectionActivity::loop() {
     }
   } else if (mappedInput.wasReleased(MappedInputManager::Button::Back)) {
     onGoBack();
-  } else if (prevReleased) {
-    const int total = static_cast<int>(xtc->getChapters().size());
-    if (total == 0) {
-      return;
-    }
-    if (skipPage) {
-      selectorIndex = ((selectorIndex / pageItems - 1) * pageItems + total) % total;
-    } else {
-      selectorIndex = (selectorIndex + total - 1) % total;
-    }
-    updateRequired = true;
-  } else if (nextReleased) {
-    const int total = static_cast<int>(xtc->getChapters().size());
-    if (total == 0) {
-      return;
-    }
-    if (skipPage) {
-      selectorIndex = ((selectorIndex / pageItems + 1) * pageItems) % total;
-    } else {
-      selectorIndex = (selectorIndex + 1) % total;
-    }
-    updateRequired = true;
   }
+
+  buttonNavigator.onNextRelease([this, totalItems] {
+    selectorIndex = ButtonNavigator::nextIndex(selectorIndex, totalItems);
+    updateRequired = true;
+  });
+
+  buttonNavigator.onPreviousRelease([this, totalItems] {
+    selectorIndex = ButtonNavigator::previousIndex(selectorIndex, totalItems);
+    updateRequired = true;
+  });
+
+  buttonNavigator.onNextContinuous([this, totalItems, pageItems] {
+    selectorIndex = ButtonNavigator::nextPageIndex(selectorIndex, totalItems, pageItems);
+    updateRequired = true;
+  });
+
+  buttonNavigator.onPreviousContinuous([this, totalItems, pageItems] {
+    selectorIndex = ButtonNavigator::previousPageIndex(selectorIndex, totalItems, pageItems);
+    updateRequired = true;
+  });
 }
 
 void XtcReaderChapterSelectionActivity::displayTaskLoop() {

src/activities/reader/XtcReaderChapterSelectionActivity.h

@@ -7,11 +7,13 @@
 #include <memory>
 
 #include "../Activity.h"
+#include "util/ButtonNavigator.h"
 
 class XtcReaderChapterSelectionActivity final : public Activity {
   std::shared_ptr<Xtc> xtc;
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
+  ButtonNavigator buttonNavigator;
   uint32_t currentPage = 0;
   int selectorIndex = 0;
   bool updateRequired = false;

src/activities/settings/CalibreSettingsActivity.cpp

@@ -62,15 +62,16 @@ void CalibreSettingsActivity::loop() {
     return;
   }
 
-  if (mappedInput.wasPressed(MappedInputManager::Button::Up) ||
-      mappedInput.wasPressed(MappedInputManager::Button::Left)) {
-    selectedIndex = (selectedIndex + MENU_ITEMS - 1) % MENU_ITEMS;
-    updateRequired = true;
-  } else if (mappedInput.wasPressed(MappedInputManager::Button::Down) ||
-             mappedInput.wasPressed(MappedInputManager::Button::Right)) {
+  // Handle navigation
+  buttonNavigator.onNext([this] {
     selectedIndex = (selectedIndex + 1) % MENU_ITEMS;
     updateRequired = true;
-  }
+  });
+
+  buttonNavigator.onPrevious([this] {
+    selectedIndex = (selectedIndex + MENU_ITEMS - 1) % MENU_ITEMS;
+    updateRequired = true;
+  });
 }
 
 void CalibreSettingsActivity::handleSelection() {

src/activities/settings/CalibreSettingsActivity.h

@@ -6,6 +6,7 @@
 #include <functional>
 
 #include "activities/ActivityWithSubactivity.h"
+#include "util/ButtonNavigator.h"
 
 /**
  * Submenu for OPDS Browser settings.
@@ -24,6 +25,7 @@ class CalibreSettingsActivity final : public ActivityWithSubactivity {
  private:
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
+  ButtonNavigator buttonNavigator;
   bool updateRequired = false;
 
   int selectedIndex = 0;

src/activities/settings/CategorySettingsActivity.cpp

@@ -62,15 +62,15 @@ void CategorySettingsActivity::loop() {
   }
 
   // Handle navigation
-  if (mappedInput.wasPressed(MappedInputManager::Button::Up) ||
-      mappedInput.wasPressed(MappedInputManager::Button::Left)) {
-    selectedSettingIndex = (selectedSettingIndex > 0) ? (selectedSettingIndex - 1) : (settingsCount - 1);
+  buttonNavigator.onNext([this] {
+    selectedSettingIndex = (selectedSettingIndex + 1) % settingsCount;
     updateRequired = true;
-  } else if (mappedInput.wasPressed(MappedInputManager::Button::Down) ||
-             mappedInput.wasPressed(MappedInputManager::Button::Right)) {
-    selectedSettingIndex = (selectedSettingIndex < settingsCount - 1) ? (selectedSettingIndex + 1) : 0;
+  });
+
+  buttonNavigator.onPrevious([this] {
+    selectedSettingIndex = (selectedSettingIndex + settingsCount - 1) % settingsCount;
     updateRequired = true;
-  }
+  });
 }
 
 void CategorySettingsActivity::toggleCurrentSetting() {

src/activities/settings/CategorySettingsActivity.h

@@ -8,6 +8,7 @@
 #include <vector>
 
 #include "activities/ActivityWithSubactivity.h"
+#include "util/ButtonNavigator.h"
 
 class CrossPointSettings;
 
@@ -44,6 +45,7 @@ struct SettingInfo {
 class CategorySettingsActivity final : public ActivityWithSubactivity {
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
+  ButtonNavigator buttonNavigator;
   bool updateRequired = false;
   int selectedSettingIndex = 0;
   const char* categoryName;

src/activities/settings/KOReaderSettingsActivity.cpp

@@ -63,15 +63,16 @@ void KOReaderSettingsActivity::loop() {
     return;
   }
 
-  if (mappedInput.wasPressed(MappedInputManager::Button::Up) ||
-      mappedInput.wasPressed(MappedInputManager::Button::Left)) {
-    selectedIndex = (selectedIndex + MENU_ITEMS - 1) % MENU_ITEMS;
-    updateRequired = true;
-  } else if (mappedInput.wasPressed(MappedInputManager::Button::Down) ||
-             mappedInput.wasPressed(MappedInputManager::Button::Right)) {
+  // Handle navigation
+  buttonNavigator.onNext([this] {
     selectedIndex = (selectedIndex + 1) % MENU_ITEMS;
     updateRequired = true;
-  }
+  });
+
+  buttonNavigator.onPrevious([this] {
+    selectedIndex = (selectedIndex + MENU_ITEMS - 1) % MENU_ITEMS;
+    updateRequired = true;
+  });
 }
 
 void KOReaderSettingsActivity::handleSelection() {

src/activities/settings/KOReaderSettingsActivity.h

@@ -6,6 +6,7 @@
 #include <functional>
 
 #include "activities/ActivityWithSubactivity.h"
+#include "util/ButtonNavigator.h"
 
 /**
  * Submenu for KOReader Sync settings.
@@ -24,6 +25,7 @@ class KOReaderSettingsActivity final : public ActivityWithSubactivity {
  private:
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
+  ButtonNavigator buttonNavigator;
   bool updateRequired = false;
 
   int selectedIndex = 0;

src/activities/settings/SettingsActivity.cpp

@@ -111,17 +111,15 @@ void SettingsActivity::loop() {
   }
 
   // Handle navigation
-  if (mappedInput.wasPressed(MappedInputManager::Button::Up) ||
-      mappedInput.wasPressed(MappedInputManager::Button::Left)) {
-    // Move selection up (with wrap-around)
-    selectedCategoryIndex = (selectedCategoryIndex > 0) ? (selectedCategoryIndex - 1) : (categoryCount - 1);
+  buttonNavigator.onNext([this] {
+    selectedCategoryIndex = (selectedCategoryIndex + 1) % categoryCount;
     updateRequired = true;
-  } else if (mappedInput.wasPressed(MappedInputManager::Button::Down) ||
-             mappedInput.wasPressed(MappedInputManager::Button::Right)) {
-    // Move selection down (with wrap around)
-    selectedCategoryIndex = (selectedCategoryIndex < categoryCount - 1) ? (selectedCategoryIndex + 1) : 0;
+  });
+
+  buttonNavigator.onPrevious([this] {
+    selectedCategoryIndex = (selectedCategoryIndex + categoryCount - 1) % categoryCount;
     updateRequired = true;
-  }
+  });
 }
 
 void SettingsActivity::enterCategory(int categoryIndex) {

src/activities/settings/SettingsActivity.h

@@ -8,6 +8,7 @@
 #include <vector>
 
 #include "activities/ActivityWithSubactivity.h"
+#include "util/ButtonNavigator.h"
 
 class CrossPointSettings;
 struct SettingInfo;
@@ -15,6 +16,7 @@ struct SettingInfo;
 class SettingsActivity final : public ActivityWithSubactivity {
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
+  ButtonNavigator buttonNavigator;
   bool updateRequired = false;
   int selectedCategoryIndex = 0;  // Currently selected category
   const std::function<void()> onGoHome;

src/activities/util/KeyboardEntryActivity.cpp

@@ -138,37 +138,24 @@ void KeyboardEntryActivity::handleKeyPress() {
 }
 
 void KeyboardEntryActivity::loop() {
-  // Navigation
-  if (mappedInput.wasPressed(MappedInputManager::Button::Up)) {
-    if (selectedRow > 0) {
-      selectedRow--;
-      // Clamp column to valid range for new row
-      const int maxCol = getRowLength(selectedRow) - 1;
-      if (selectedCol > maxCol) selectedCol = maxCol;
-    } else {
-      // Wrap to bottom row
-      selectedRow = NUM_ROWS - 1;
-      const int maxCol = getRowLength(selectedRow) - 1;
-      if (selectedCol > maxCol) selectedCol = maxCol;
-    }
-    updateRequired = true;
-  }
+  // Handle navigation
+  buttonNavigator.onPressAndContinuous({MappedInputManager::Button::Up}, [this] {
+    selectedRow = ButtonNavigator::previousIndex(selectedRow, NUM_ROWS);
 
-  if (mappedInput.wasPressed(MappedInputManager::Button::Down)) {
-    if (selectedRow < NUM_ROWS - 1) {
-      selectedRow++;
-      const int maxCol = getRowLength(selectedRow) - 1;
-      if (selectedCol > maxCol) selectedCol = maxCol;
-    } else {
-      // Wrap to top row
-      selectedRow = 0;
-      const int maxCol = getRowLength(selectedRow) - 1;
-      if (selectedCol > maxCol) selectedCol = maxCol;
-    }
+    const int maxCol = getRowLength(selectedRow) - 1;
+    if (selectedCol > maxCol) selectedCol = maxCol;
     updateRequired = true;
-  }
+  });
 
-  if (mappedInput.wasPressed(MappedInputManager::Button::Left)) {
+  buttonNavigator.onPressAndContinuous({MappedInputManager::Button::Down}, [this] {
+    selectedRow = ButtonNavigator::nextIndex(selectedRow, NUM_ROWS);
+
+    const int maxCol = getRowLength(selectedRow) - 1;
+    if (selectedCol > maxCol) selectedCol = maxCol;
+    updateRequired = true;
+  });
+
+  buttonNavigator.onPressAndContinuous({MappedInputManager::Button::Left}, [this] {
     const int maxCol = getRowLength(selectedRow) - 1;
 
     // Special bottom row case
@@ -187,20 +174,14 @@ void KeyboardEntryActivity::loop() {
         // At done button, move to backspace
         selectedCol = BACKSPACE_COL;
       }
-      updateRequired = true;
-      return;
-    }
-
-    if (selectedCol > 0) {
-      selectedCol--;
     } else {
-      // Wrap to end of current row
-      selectedCol = maxCol;
+      selectedCol = ButtonNavigator::previousIndex(selectedCol, maxCol + 1);
     }
-    updateRequired = true;
-  }
 
-  if (mappedInput.wasPressed(MappedInputManager::Button::Right)) {
+    updateRequired = true;
+  });
+
+  buttonNavigator.onPressAndContinuous({MappedInputManager::Button::Right}, [this] {
     const int maxCol = getRowLength(selectedRow) - 1;
 
     // Special bottom row case
@@ -219,18 +200,11 @@ void KeyboardEntryActivity::loop() {
         // At done button, wrap to beginning of row
         selectedCol = SHIFT_COL;
       }
-      updateRequired = true;
-      return;
-    }
-
-    if (selectedCol < maxCol) {
-      selectedCol++;
     } else {
-      // Wrap to beginning of current row
-      selectedCol = 0;
+      selectedCol = ButtonNavigator::nextIndex(selectedCol, maxCol + 1);
     }
     updateRequired = true;
-  }
+  });
 
   // Selection
   if (mappedInput.wasPressed(MappedInputManager::Button::Confirm)) {

src/activities/util/KeyboardEntryActivity.h

@@ -9,6 +9,7 @@
 #include <utility>
 
 #include "../Activity.h"
+#include "util/ButtonNavigator.h"
 
 /**
  * Reusable keyboard entry activity for text input.
@@ -65,6 +66,7 @@ class KeyboardEntryActivity : public Activity {
   bool isPassword;
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
+  ButtonNavigator buttonNavigator;
   bool updateRequired = false;
 
   // Keyboard state

src/main.cpp

@@ -25,6 +25,7 @@
 #include "activities/settings/SettingsActivity.h"
 #include "activities/util/FullScreenMessageActivity.h"
 #include "fontIds.h"
+#include "util/ButtonNavigator.h"
 
 HalDisplay display;
 HalGPIO gpio;
@@ -293,6 +294,7 @@ void setup() {
 
   SETTINGS.loadFromFile();
   KOREADER_STORE.loadFromFile();
+  ButtonNavigator::setMappedInputManager(mappedInputManager);
 
   switch (gpio.getWakeupReason()) {
     case HalGPIO::WakeupReason::PowerButton:

src/network/html/FilesPage.html

@@ -1146,10 +1146,10 @@ function retryAllFailedUploads() {
       return;
     }
 
-    // Validate folder name (no special characters except underscore and hyphen)
-    const validName = /^[a-zA-Z0-9_\-]+$/.test(folderName);
+    // Validate folder name
+    const validName = /^(?!\.{1,2}$)[^"*:<>?\/\\|]+$/.test(folderName);
     if (!validName) {
-      alert('Folder name can only contain letters, numbers, underscores, and hyphens.');
+      alert('Folder name cannot contain \" * : < > ? / \\ | and must not be . or ..');
       return;
     }
 

src/util/ButtonNavigator.cpp

@@ -0,0 +1,124 @@
+#include "ButtonNavigator.h"
+
+const MappedInputManager* ButtonNavigator::mappedInput = nullptr;
+
+void ButtonNavigator::onNext(const Callback& callback) {
+  onNextPress(callback);
+  onNextContinuous(callback);
+}
+
+void ButtonNavigator::onPrevious(const Callback& callback) {
+  onPreviousPress(callback);
+  onPreviousContinuous(callback);
+}
+
+void ButtonNavigator::onPressAndContinuous(const Buttons& buttons, const Callback& callback) {
+  onPress(buttons, callback);
+  onContinuous(buttons, callback);
+}
+
+void ButtonNavigator::onNextPress(const Callback& callback) { onPress(getNextButtons(), callback); }
+
+void ButtonNavigator::onPreviousPress(const Callback& callback) { onPress(getPreviousButtons(), callback); }
+
+void ButtonNavigator::onNextRelease(const Callback& callback) { onRelease(getNextButtons(), callback); }
+
+void ButtonNavigator::onPreviousRelease(const Callback& callback) { onRelease(getPreviousButtons(), callback); }
+
+void ButtonNavigator::onNextContinuous(const Callback& callback) { onContinuous(getNextButtons(), callback); }
+
+void ButtonNavigator::onPreviousContinuous(const Callback& callback) { onContinuous(getPreviousButtons(), callback); }
+
+void ButtonNavigator::onPress(const Buttons& buttons, const Callback& callback) {
+  const bool wasPressed = std::any_of(buttons.begin(), buttons.end(), [](const MappedInputManager::Button button) {
+    return mappedInput != nullptr && mappedInput->wasPressed(button);
+  });
+
+  if (wasPressed) {
+    callback();
+  }
+}
+
+void ButtonNavigator::onRelease(const Buttons& buttons, const Callback& callback) {
+  const bool wasReleased = std::any_of(buttons.begin(), buttons.end(), [](const MappedInputManager::Button button) {
+    return mappedInput != nullptr && mappedInput->wasReleased(button);
+  });
+
+  if (wasReleased) {
+    if (lastContinuousNavTime == 0) {
+      callback();
+    }
+
+    lastContinuousNavTime = 0;
+  }
+}
+
+void ButtonNavigator::onContinuous(const Buttons& buttons, const Callback& callback) {
+  const bool isPressed = std::any_of(buttons.begin(), buttons.end(), [this](const MappedInputManager::Button button) {
+    return mappedInput != nullptr && mappedInput->isPressed(button) && shouldNavigateContinuously();
+  });
+
+  if (isPressed) {
+    callback();
+    lastContinuousNavTime = millis();
+  }
+}
+
+bool ButtonNavigator::shouldNavigateContinuously() const {
+  if (!mappedInput) return false;
+
+  const bool buttonHeldLongEnough = mappedInput->getHeldTime() > continuousStartMs;
+  const bool navigationIntervalElapsed = (millis() - lastContinuousNavTime) > continuousIntervalMs;
+
+  return buttonHeldLongEnough && navigationIntervalElapsed;
+}
+
+int ButtonNavigator::nextIndex(const int currentIndex, const int totalItems) {
+  if (totalItems <= 0) return 0;
+
+  // Calculate the next index with wrap-around
+  return (currentIndex + 1) % totalItems;
+}
+
+int ButtonNavigator::previousIndex(const int currentIndex, const int totalItems) {
+  if (totalItems <= 0) return 0;
+
+  // Calculate the previous index with wrap-around
+  return (currentIndex + totalItems - 1) % totalItems;
+}
+
+int ButtonNavigator::nextPageIndex(const int currentIndex, const int totalItems, const int itemsPerPage) {
+  if (totalItems <= 0 || itemsPerPage <= 0) return 0;
+
+  // When items fit on one page, use index navigation instead
+  if (totalItems <= itemsPerPage) {
+    return nextIndex(currentIndex, totalItems);
+  }
+
+  const int lastPageIndex = (totalItems - 1) / itemsPerPage;
+  const int currentPageIndex = currentIndex / itemsPerPage;
+
+  if (currentPageIndex < lastPageIndex) {
+    return (currentPageIndex + 1) * itemsPerPage;
+  }
+
+  return 0;
+}
+
+int ButtonNavigator::previousPageIndex(const int currentIndex, const int totalItems, const int itemsPerPage) {
+  if (totalItems <= 0 || itemsPerPage <= 0) return 0;
+
+  // When items fit on one page, use index navigation instead
+  if (totalItems <= itemsPerPage) {
+    return previousIndex(currentIndex, totalItems);
+  }
+
+  const int lastPageIndex = (totalItems - 1) / itemsPerPage;
+  const int currentPageIndex = currentIndex / itemsPerPage;
+
+  if (currentPageIndex > 0) {
+    return (currentPageIndex - 1) * itemsPerPage;
+  }
+
+  return lastPageIndex * itemsPerPage;
+}

src/util/ButtonNavigator.h

@@ -0,0 +1,53 @@
+#pragma once
+
+#include <functional>
+#include <vector>
+
+#include "MappedInputManager.h"
+
+class ButtonNavigator final {
+  using Callback = std::function<void()>;
+  using Buttons = std::vector<MappedInputManager::Button>;
+
+  const uint16_t continuousStartMs;
+  const uint16_t continuousIntervalMs;
+  uint32_t lastContinuousNavTime = 0;
+  static const MappedInputManager* mappedInput;
+
+  [[nodiscard]] bool shouldNavigateContinuously() const;
+
+ public:
+  explicit ButtonNavigator(const uint16_t continuousIntervalMs = 500, const uint16_t continuousStartMs = 500)
+      : continuousStartMs(continuousStartMs), continuousIntervalMs(continuousIntervalMs) {}
+
+  static void setMappedInputManager(const MappedInputManager& mappedInputManager) { mappedInput = &mappedInputManager; }
+
+  void onNext(const Callback& callback);
+  void onPrevious(const Callback& callback);
+  void onPressAndContinuous(const Buttons& buttons, const Callback& callback);
+
+  void onNextPress(const Callback& callback);
+  void onPreviousPress(const Callback& callback);
+  void onPress(const Buttons& buttons, const Callback& callback);
+
+  void onNextRelease(const Callback& callback);
+  void onPreviousRelease(const Callback& callback);
+  void onRelease(const Buttons& buttons, const Callback& callback);
+
+  void onNextContinuous(const Callback& callback);
+  void onPreviousContinuous(const Callback& callback);
+  void onContinuous(const Buttons& buttons, const Callback& callback);
+
+  [[nodiscard]] static int nextIndex(int currentIndex, int totalItems);
+  [[nodiscard]] static int previousIndex(int currentIndex, int totalItems);
+
+  [[nodiscard]] static int nextPageIndex(int currentIndex, int totalItems, int itemsPerPage);
+  [[nodiscard]] static int previousPageIndex(int currentIndex, int totalItems, int itemsPerPage);
+
+  [[nodiscard]] static Buttons getNextButtons() {
+    return {MappedInputManager::Button::Down, MappedInputManager::Button::Right};
+  }
+  [[nodiscard]] static Buttons getPreviousButtons() {
+    return {MappedInputManager::Button::Up, MappedInputManager::Button::Left};
+  }
+};