Merge 3b9a37e075 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/home/MyLibraryActivity.cpp

@@ -20,9 +20,10 @@ constexpr int RECENTS_LINE_HEIGHT = 65;  // Increased for two-line items
 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;
+// Timing thresholds for button behavior
+constexpr int LONG_PRESS_MS = 450;          // Long press: change tab
+constexpr int DOUBLE_PRESS_MS = 120;        // Double press: skip page
+constexpr unsigned long GO_HOME_MS = 1000;  // Long press back: go to root
 
 void sortFileList(std::vector<std::string>& strs) {
   std::sort(begin(strs), end(strs), [](const std::string& str1, const std::string& str2) {
@@ -126,6 +127,51 @@ void MyLibraryActivity::taskTrampoline(void* param) {
   self->displayTaskLoop();
 }
 
+// Action execution: Move one item (short press timeout)
+void MyLibraryActivity::executeMoveItem(bool isPrevButton) {
+  const int itemCount = getCurrentItemCount();
+  if (itemCount > 0) {
+    if (isPrevButton) {
+      selectorIndex = (selectorIndex + itemCount - 1) % itemCount;
+    } else {
+      selectorIndex = (selectorIndex + 1) % itemCount;
+    }
+  }
+}
+
+// Action execution: Skip page (double press)
+void MyLibraryActivity::executeSkipPage(bool isPrevButton) {
+  const int itemCount = getCurrentItemCount();
+  const int pageItems = getPageItems();
+  if (itemCount > 0) {
+    if (isPrevButton) {
+      int targetPage = (selectorIndex / pageItems) - 1;
+      if (targetPage < 0) {
+        targetPage = ((itemCount - 1) / pageItems);
+      }
+      selectorIndex = targetPage * pageItems;
+    } else {
+      int targetPage = (selectorIndex / pageItems) + 1;
+      int maxPage = (itemCount - 1) / pageItems;
+      if (targetPage > maxPage) {
+        targetPage = 0;
+      }
+      selectorIndex = targetPage * pageItems;
+    }
+  }
+}
+
+// Action execution: Switch tab (long press)
+void MyLibraryActivity::executeSwitchTab(bool isPrevButton) {
+  if (isPrevButton && currentTab == Tab::Files) {
+    currentTab = Tab::Recent;
+    selectorIndex = 0;
+  } else if (!isPrevButton && currentTab == Tab::Recent) {
+    currentTab = Tab::Files;
+    selectorIndex = 0;
+  }
+}
+
 void MyLibraryActivity::onEnter() {
   Activity::onEnter();
 
@@ -163,8 +209,8 @@ void MyLibraryActivity::onExit() {
 }
 
 void MyLibraryActivity::loop() {
-  const int itemCount = getCurrentItemCount();
-  const int pageItems = getPageItems();
+  // Get current time for all timing operations
+  unsigned long currentTime = millis();
 
   // Long press BACK (1s+) in Files tab goes to root folder
   if (currentTab == Tab::Files && mappedInput.isPressed(MappedInputManager::Button::Back) &&
@@ -178,13 +224,6 @@ 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) {
@@ -234,38 +273,84 @@ void MyLibraryActivity::loop() {
     return;
   }
 
-  // Tab switching: Left/Right always control tabs
-  if (leftReleased && currentTab == Tab::Files) {
-    currentTab = Tab::Recent;
-    selectorIndex = 0;
-    updateRequired = true;
-    return;
-  }
-  if (rightReleased && currentTab == Tab::Recent) {
-    currentTab = Tab::Files;
-    selectorIndex = 0;
-    updateRequired = true;
-    return;
-  }
+  // Navigation buttons (UP/LEFT and DOWN/RIGHT have same behavior)
+  const bool upPressed = mappedInput.isPressed(MappedInputManager::Button::Up);
+  const bool leftPressed = mappedInput.isPressed(MappedInputManager::Button::Left);
+  const bool downPressed = mappedInput.isPressed(MappedInputManager::Button::Down);
+  const bool rightPressed = mappedInput.isPressed(MappedInputManager::Button::Right);
+  const bool upReleased = mappedInput.wasReleased(MappedInputManager::Button::Up);
+  const bool leftReleased = mappedInput.wasReleased(MappedInputManager::Button::Left);
+  const bool downReleased = mappedInput.wasReleased(MappedInputManager::Button::Down);
+  const bool rightReleased = mappedInput.wasReleased(MappedInputManager::Button::Right);
 
-  // Navigation: Up/Down moves through items only
-  const bool prevReleased = upReleased;
-  const bool nextReleased = downReleased;
+  // Navigation: UP/LEFT move backward, DOWN/RIGHT move forward
+  const bool prevPressed = upPressed || leftPressed;
+  const bool nextPressed = downPressed || rightPressed;
+  const bool prevReleased = upReleased || leftReleased;
+  const bool nextReleased = downReleased || rightReleased;
 
-  if (prevReleased && itemCount > 0) {
-    if (skipPage) {
-      selectorIndex = ((selectorIndex / pageItems - 1) * pageItems + itemCount) % itemCount;
-    } else {
-      selectorIndex = (selectorIndex + itemCount - 1) % itemCount;
+  // State machine for button press detection
+  // ==========================================
+
+  // IDLE: Wait for first press
+  if (buttonState == ButtonState::Idle) {
+    if (prevPressed || nextPressed) {
+      buttonState = ButtonState::FirstPress;
+      firstPressTime = currentTime;
+      isPrevButtonPressed = prevPressed;
     }
-    updateRequired = true;
-  } else if (nextReleased && itemCount > 0) {
-    if (skipPage) {
-      selectorIndex = ((selectorIndex / pageItems + 1) * pageItems) % itemCount;
-    } else {
-      selectorIndex = (selectorIndex + 1) % itemCount;
+  }
+  // FIRST_PRESS: Button is held, check for long press or release
+  else if (buttonState == ButtonState::FirstPress) {
+    const unsigned long holdDuration = currentTime - firstPressTime;
+
+    // Check for long press (>=450ms) - switch tab
+    if (holdDuration >= LONG_PRESS_MS) {
+      executeSwitchTab(isPrevButtonPressed);
+      buttonState = ButtonState::WaitingForReleaseAfterLongPress;
+      updateRequired = true;
+      return;
+    }
+
+    // Check for release (<450ms) - transition to waiting for second press
+    if ((isPrevButtonPressed && prevReleased) || (!isPrevButtonPressed && nextReleased)) {
+      buttonState = ButtonState::WaitingForSecondPress;
+      firstReleaseTime = currentTime;
+    }
+  }
+  // WAITING_FOR_SECOND_PRESS: First button released, waiting for second press
+  else if (buttonState == ButtonState::WaitingForSecondPress) {
+    const unsigned long waitDuration = currentTime - firstReleaseTime;
+
+    // Timeout (>=120ms without second press) - execute move_item
+    if (waitDuration >= DOUBLE_PRESS_MS) {
+      executeMoveItem(isPrevButtonPressed);
+      buttonState = ButtonState::Idle;
+      updateRequired = true;
+      return;
+    }
+
+    // Second press detected (<120ms) - double press
+    if (prevPressed || nextPressed) {
+      buttonState = ButtonState::DoublePressDetected;
+    }
+  }
+  // DOUBLE_PRESS_DETECTED: Second press detected, wait for release
+  else if (buttonState == ButtonState::DoublePressDetected) {
+    // Wait for second button release
+    if (prevReleased || nextReleased) {
+      executeSkipPage(isPrevButtonPressed);
+      buttonState = ButtonState::Idle;
+      updateRequired = true;
+      return;
+    }
+  }
+  // WAITING_FOR_RELEASE_AFTER_LONG_PRESS: Ignore release after long press
+  else if (buttonState == ButtonState::WaitingForReleaseAfterLongPress) {
+    // Wait for button to be released, then go back to idle
+    if ((isPrevButtonPressed && prevReleased) || (!isPrevButtonPressed && nextReleased)) {
+      buttonState = ButtonState::Idle;
     }
-    updateRequired = true;
   }
 }
 

src/activities/home/MyLibraryActivity.h

@@ -22,6 +22,25 @@ class MyLibraryActivity final : public Activity {
   int selectorIndex = 0;
   bool updateRequired = false;
 
+  // State machine for button press detection
+  enum class ButtonState {
+    Idle,
+    FirstPress,
+    WaitingForSecondPress,
+    DoublePressDetected,
+    WaitingForReleaseAfterLongPress
+  };
+
+  ButtonState buttonState = ButtonState::Idle;
+  unsigned long firstPressTime = 0;    // Time of first PRESS
+  unsigned long firstReleaseTime = 0;  // Time of first RELEASE
+  bool isPrevButtonPressed = false;    // Which button was pressed first
+
+  // Action execution functions
+  void executeMoveItem(bool isPrevButton);
+  void executeSkipPage(bool isPrevButton);
+  void executeSwitchTab(bool isPrevButton);
+
   // Recent tab state
   std::vector<RecentBook> recentBooks;
 

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;
     }