Turn wifi off when exiting browser and wireless activities

# Conflicts:
#	src/CrossPointSettings.cpp
#	src/CrossPointSettings.h
#	src/activities/settings/SettingsActivity.cpp

README.md

@@ -25,7 +25,7 @@ This project is **not affiliated with Xteink**; it's built as a community projec
 
 ## Features & Usage
 
-- [x] EPUB parsing and rendering
+- [x] EPUB parsing and rendering (EPUB 2 and EPUB 3)
 - [ ] Image support within EPUB
 - [x] Saved reading position
 - [x] File explorer with file picker

lib/Epub/Epub.cpp

@@ -8,6 +8,7 @@
 
 #include "Epub/parsers/ContainerParser.h"
 #include "Epub/parsers/ContentOpfParser.h"
+#include "Epub/parsers/TocNavParser.h"
 #include "Epub/parsers/TocNcxParser.h"
 
 bool Epub::findContentOpfFile(std::string* contentOpfFile) const {
@@ -80,6 +81,10 @@ bool Epub::parseContentOpf(BookMetadataCache::BookMetadata& bookMetadata) {
     tocNcxItem = opfParser.tocNcxPath;
   }
 
+  if (!opfParser.tocNavPath.empty()) {
+    tocNavItem = opfParser.tocNavPath;
+  }
+
   Serial.printf("[%lu] [EBP] Successfully parsed content.opf\n", millis());
   return true;
 }
@@ -141,6 +146,60 @@ bool Epub::parseTocNcxFile() const {
   return true;
 }
 
+bool Epub::parseTocNavFile() const {
+  // the nav file should have been specified in the content.opf file (EPUB 3)
+  if (tocNavItem.empty()) {
+    Serial.printf("[%lu] [EBP] No nav file specified\n", millis());
+    return false;
+  }
+
+  Serial.printf("[%lu] [EBP] Parsing toc nav file: %s\n", millis(), tocNavItem.c_str());
+
+  const auto tmpNavPath = getCachePath() + "/toc.nav";
+  FsFile tempNavFile;
+  if (!SdMan.openFileForWrite("EBP", tmpNavPath, tempNavFile)) {
+    return false;
+  }
+  readItemContentsToStream(tocNavItem, tempNavFile, 1024);
+  tempNavFile.close();
+  if (!SdMan.openFileForRead("EBP", tmpNavPath, tempNavFile)) {
+    return false;
+  }
+  const auto navSize = tempNavFile.size();
+
+  TocNavParser navParser(contentBasePath, navSize, bookMetadataCache.get());
+
+  if (!navParser.setup()) {
+    Serial.printf("[%lu] [EBP] Could not setup toc nav parser\n", millis());
+    return false;
+  }
+
+  const auto navBuffer = static_cast<uint8_t*>(malloc(1024));
+  if (!navBuffer) {
+    Serial.printf("[%lu] [EBP] Could not allocate memory for toc nav parser\n", millis());
+    return false;
+  }
+
+  while (tempNavFile.available()) {
+    const auto readSize = tempNavFile.read(navBuffer, 1024);
+    const auto processedSize = navParser.write(navBuffer, readSize);
+
+    if (processedSize != readSize) {
+      Serial.printf("[%lu] [EBP] Could not process all toc nav data\n", millis());
+      free(navBuffer);
+      tempNavFile.close();
+      return false;
+    }
+  }
+
+  free(navBuffer);
+  tempNavFile.close();
+  SdMan.remove(tmpNavPath.c_str());
+
+  Serial.printf("[%lu] [EBP] Parsed TOC nav items\n", millis());
+  return true;
+}
+
 // load in the meta data for the epub file
 bool Epub::load(const bool buildIfMissing) {
   Serial.printf("[%lu] [EBP] Loading ePub: %s\n", millis(), filepath.c_str());
@@ -184,15 +243,31 @@ bool Epub::load(const bool buildIfMissing) {
     return false;
   }
 
-  // TOC Pass
+  // TOC Pass - try EPUB 3 nav first, fall back to NCX
   if (!bookMetadataCache->beginTocPass()) {
     Serial.printf("[%lu] [EBP] Could not begin writing toc pass\n", millis());
     return false;
   }
-  if (!parseTocNcxFile()) {
+
-    Serial.printf("[%lu] [EBP] Could not parse toc\n", millis());
+  bool tocParsed = false;
-    return false;
+
+  // Try EPUB 3 nav document first (preferred)
+  if (!tocNavItem.empty()) {
+    Serial.printf("[%lu] [EBP] Attempting to parse EPUB 3 nav document\n", millis());
+    tocParsed = parseTocNavFile();
   }
+
+  // Fall back to NCX if nav parsing failed or wasn't available
+  if (!tocParsed && !tocNcxItem.empty()) {
+    Serial.printf("[%lu] [EBP] Falling back to NCX TOC\n", millis());
+    tocParsed = parseTocNcxFile();
+  }
+
+  if (!tocParsed) {
+    Serial.printf("[%lu] [EBP] Warning: Could not parse any TOC format\n", millis());
+    // Continue anyway - book will work without TOC
+  }
+
   if (!bookMetadataCache->endTocPass()) {
     Serial.printf("[%lu] [EBP] Could not end writing toc pass\n", millis());
     return false;

lib/Epub/Epub.h

@@ -12,8 +12,10 @@
 class ZipFile;
 
 class Epub {
-  // the ncx file
+  // the ncx file (EPUB 2)
   std::string tocNcxItem;
+  // the nav file (EPUB 3)
+  std::string tocNavItem;
   // where is the EPUBfile?
   std::string filepath;
   // the base path for items in the EPUB file
@@ -26,6 +28,7 @@ class Epub {
   bool findContentOpfFile(std::string* contentOpfFile) const;
   bool parseContentOpf(BookMetadataCache::BookMetadata& bookMetadata);
   bool parseTocNcxFile() const;
+  bool parseTocNavFile() const;
 
  public:
   explicit Epub(std::string filepath, const std::string& cacheDir) : filepath(std::move(filepath)) {

lib/Epub/Epub/parsers/ContentOpfParser.cpp

@@ -161,6 +161,7 @@ void XMLCALL ContentOpfParser::startElement(void* userData, const XML_Char* name
     std::string itemId;
     std::string href;
     std::string mediaType;
+    std::string properties;
 
     for (int i = 0; atts[i]; i += 2) {
       if (strcmp(atts[i], "id") == 0) {
@@ -169,6 +170,8 @@ void XMLCALL ContentOpfParser::startElement(void* userData, const XML_Char* name
         href = self->baseContentPath + atts[i + 1];
       } else if (strcmp(atts[i], "media-type") == 0) {
         mediaType = atts[i + 1];
+      } else if (strcmp(atts[i], "properties") == 0) {
+        properties = atts[i + 1];
       }
     }
 
@@ -188,6 +191,15 @@ void XMLCALL ContentOpfParser::startElement(void* userData, const XML_Char* name
                       href.c_str());
       }
     }
+
+    // EPUB 3: Check for nav document (properties contains "nav")
+    if (!properties.empty() && self->tocNavPath.empty()) {
+      // Properties is space-separated, check if "nav" is present as a word
+      if (properties == "nav" || properties.find("nav ") == 0 || properties.find(" nav") != std::string::npos) {
+        self->tocNavPath = href;
+        Serial.printf("[%lu] [COF] Found EPUB 3 nav document: %s\n", millis(), href.c_str());
+      }
+    }
     return;
   }
 

lib/Epub/Epub/parsers/ContentOpfParser.h

@@ -35,6 +35,7 @@ class ContentOpfParser final : public Print {
   std::string title;
   std::string author;
   std::string tocNcxPath;
+  std::string tocNavPath;  // EPUB 3 nav document path
   std::string coverItemHref;
   std::string textReferenceHref;
 

lib/Epub/Epub/parsers/TocNavParser.cpp

@@ -0,0 +1,184 @@
+#include "TocNavParser.h"
+
+#include <HardwareSerial.h>
+
+#include "../BookMetadataCache.h"
+
+bool TocNavParser::setup() {
+  parser = XML_ParserCreate(nullptr);
+  if (!parser) {
+    Serial.printf("[%lu] [NAV] Couldn't allocate memory for parser\n", millis());
+    return false;
+  }
+
+  XML_SetUserData(parser, this);
+  XML_SetElementHandler(parser, startElement, endElement);
+  XML_SetCharacterDataHandler(parser, characterData);
+  return true;
+}
+
+TocNavParser::~TocNavParser() {
+  if (parser) {
+    XML_StopParser(parser, XML_FALSE);
+    XML_SetElementHandler(parser, nullptr, nullptr);
+    XML_SetCharacterDataHandler(parser, nullptr);
+    XML_ParserFree(parser);
+    parser = nullptr;
+  }
+}
+
+size_t TocNavParser::write(const uint8_t data) { return write(&data, 1); }
+
+size_t TocNavParser::write(const uint8_t* buffer, const size_t size) {
+  if (!parser) return 0;
+
+  const uint8_t* currentBufferPos = buffer;
+  auto remainingInBuffer = size;
+
+  while (remainingInBuffer > 0) {
+    void* const buf = XML_GetBuffer(parser, 1024);
+    if (!buf) {
+      Serial.printf("[%lu] [NAV] Couldn't allocate memory for buffer\n", millis());
+      XML_StopParser(parser, XML_FALSE);
+      XML_SetElementHandler(parser, nullptr, nullptr);
+      XML_SetCharacterDataHandler(parser, nullptr);
+      XML_ParserFree(parser);
+      parser = nullptr;
+      return 0;
+    }
+
+    const auto toRead = remainingInBuffer < 1024 ? remainingInBuffer : 1024;
+    memcpy(buf, currentBufferPos, toRead);
+
+    if (XML_ParseBuffer(parser, static_cast<int>(toRead), remainingSize == toRead) == XML_STATUS_ERROR) {
+      Serial.printf("[%lu] [NAV] Parse error at line %lu: %s\n", millis(), XML_GetCurrentLineNumber(parser),
+                    XML_ErrorString(XML_GetErrorCode(parser)));
+      XML_StopParser(parser, XML_FALSE);
+      XML_SetElementHandler(parser, nullptr, nullptr);
+      XML_SetCharacterDataHandler(parser, nullptr);
+      XML_ParserFree(parser);
+      parser = nullptr;
+      return 0;
+    }
+
+    currentBufferPos += toRead;
+    remainingInBuffer -= toRead;
+    remainingSize -= toRead;
+  }
+  return size;
+}
+
+void XMLCALL TocNavParser::startElement(void* userData, const XML_Char* name, const XML_Char** atts) {
+  auto* self = static_cast<TocNavParser*>(userData);
+
+  // Track HTML structure loosely - we mainly care about finding <nav epub:type="toc">
+  if (strcmp(name, "html") == 0) {
+    self->state = IN_HTML;
+    return;
+  }
+
+  if (self->state == IN_HTML && strcmp(name, "body") == 0) {
+    self->state = IN_BODY;
+    return;
+  }
+
+  // Look for <nav epub:type="toc"> anywhere in body (or nested elements)
+  if (self->state >= IN_BODY && strcmp(name, "nav") == 0) {
+    for (int i = 0; atts[i]; i += 2) {
+      if ((strcmp(atts[i], "epub:type") == 0 || strcmp(atts[i], "type") == 0) && strcmp(atts[i + 1], "toc") == 0) {
+        self->state = IN_NAV_TOC;
+        Serial.printf("[%lu] [NAV] Found nav toc element\n", millis());
+        return;
+      }
+    }
+    return;
+  }
+
+  // Only process ol/li/a if we're inside the toc nav
+  if (self->state < IN_NAV_TOC) {
+    return;
+  }
+
+  if (strcmp(name, "ol") == 0) {
+    self->olDepth++;
+    self->state = IN_OL;
+    return;
+  }
+
+  if (self->state == IN_OL && strcmp(name, "li") == 0) {
+    self->state = IN_LI;
+    self->currentLabel.clear();
+    self->currentHref.clear();
+    return;
+  }
+
+  if (self->state == IN_LI && strcmp(name, "a") == 0) {
+    self->state = IN_ANCHOR;
+    // Get href attribute
+    for (int i = 0; atts[i]; i += 2) {
+      if (strcmp(atts[i], "href") == 0) {
+        self->currentHref = atts[i + 1];
+        break;
+      }
+    }
+    return;
+  }
+}
+
+void XMLCALL TocNavParser::characterData(void* userData, const XML_Char* s, const int len) {
+  auto* self = static_cast<TocNavParser*>(userData);
+
+  // Only collect text when inside an anchor within the TOC nav
+  if (self->state == IN_ANCHOR) {
+    self->currentLabel.append(s, len);
+  }
+}
+
+void XMLCALL TocNavParser::endElement(void* userData, const XML_Char* name) {
+  auto* self = static_cast<TocNavParser*>(userData);
+
+  if (strcmp(name, "a") == 0 && self->state == IN_ANCHOR) {
+    // Create TOC entry when closing anchor tag (we have all data now)
+    if (!self->currentLabel.empty() && !self->currentHref.empty()) {
+      std::string href = self->baseContentPath + self->currentHref;
+      std::string anchor;
+
+      const size_t pos = href.find('#');
+      if (pos != std::string::npos) {
+        anchor = href.substr(pos + 1);
+        href = href.substr(0, pos);
+      }
+
+      if (self->cache) {
+        // olDepth gives us the nesting level (1-based from the outer ol)
+        self->cache->createTocEntry(self->currentLabel, href, anchor, self->olDepth);
+      }
+
+      self->currentLabel.clear();
+      self->currentHref.clear();
+    }
+    self->state = IN_LI;
+    return;
+  }
+
+  if (strcmp(name, "li") == 0 && (self->state == IN_LI || self->state == IN_OL)) {
+    self->state = IN_OL;
+    return;
+  }
+
+  if (strcmp(name, "ol") == 0 && self->state >= IN_NAV_TOC) {
+    self->olDepth--;
+    if (self->olDepth == 0) {
+      self->state = IN_NAV_TOC;
+    } else {
+      self->state = IN_LI;  // Back to parent li
+    }
+    return;
+  }
+
+  if (strcmp(name, "nav") == 0 && self->state >= IN_NAV_TOC) {
+    self->state = IN_BODY;
+    Serial.printf("[%lu] [NAV] Finished parsing nav toc\n", millis());
+    return;
+  }
+}

lib/Epub/Epub/parsers/TocNavParser.h

@@ -0,0 +1,47 @@
+#pragma once
+#include <Print.h>
+#include <expat.h>
+
+#include <string>
+
+class BookMetadataCache;
+
+// Parser for EPUB 3 nav.xhtml navigation documents
+// Parses HTML5 nav elements with epub:type="toc" to extract table of contents
+class TocNavParser final : public Print {
+  enum ParserState {
+    START,
+    IN_HTML,
+    IN_BODY,
+    IN_NAV_TOC,  // Inside <nav epub:type="toc">
+    IN_OL,       // Inside <ol>
+    IN_LI,       // Inside <li>
+    IN_ANCHOR,   // Inside <a>
+  };
+
+  const std::string& baseContentPath;
+  size_t remainingSize;
+  XML_Parser parser = nullptr;
+  ParserState state = START;
+  BookMetadataCache* cache;
+
+  // Track nesting depth for <ol> elements to determine TOC depth
+  uint8_t olDepth = 0;
+  // Current entry data being collected
+  std::string currentLabel;
+  std::string currentHref;
+
+  static void startElement(void* userData, const XML_Char* name, const XML_Char** atts);
+  static void characterData(void* userData, const XML_Char* s, int len);
+  static void endElement(void* userData, const XML_Char* name);
+
+ public:
+  explicit TocNavParser(const std::string& baseContentPath, const size_t xmlSize, BookMetadataCache* cache)
+      : baseContentPath(baseContentPath), remainingSize(xmlSize), cache(cache) {}
+  ~TocNavParser() override;
+
+  bool setup();
+
+  size_t write(uint8_t) override;
+  size_t write(const uint8_t* buffer, size_t size) override;
+};

lib/GfxRenderer/GfxRenderer.cpp

@@ -327,6 +327,148 @@ void GfxRenderer::drawButtonHints(const int fontId, const char* btn1, const char
   }
 }
 
+void GfxRenderer::drawSideButtonHints(const int fontId, const char* topBtn, const char* bottomBtn) const {
+  const int screenWidth = getScreenWidth();
+  constexpr int buttonWidth = 40;   // Width on screen (height when rotated)
+  constexpr int buttonHeight = 80;  // Height on screen (width when rotated)
+  constexpr int buttonX = 5;        // Distance from right edge
+  // Position for the button group - buttons share a border so they're adjacent
+  constexpr int topButtonY = 345;  // Top button position
+
+  const char* labels[] = {topBtn, bottomBtn};
+
+  // Draw the shared border for both buttons as one unit
+  const int x = screenWidth - buttonX - buttonWidth;
+
+  // Draw top button outline (3 sides, bottom open)
+  if (topBtn != nullptr && topBtn[0] != '\0') {
+    drawLine(x, topButtonY, x + buttonWidth - 1, topButtonY);                                       // Top
+    drawLine(x, topButtonY, x, topButtonY + buttonHeight - 1);                                      // Left
+    drawLine(x + buttonWidth - 1, topButtonY, x + buttonWidth - 1, topButtonY + buttonHeight - 1);  // Right
+  }
+
+  // Draw shared middle border
+  if ((topBtn != nullptr && topBtn[0] != '\0') || (bottomBtn != nullptr && bottomBtn[0] != '\0')) {
+    drawLine(x, topButtonY + buttonHeight, x + buttonWidth - 1, topButtonY + buttonHeight);  // Shared border
+  }
+
+  // Draw bottom button outline (3 sides, top is shared)
+  if (bottomBtn != nullptr && bottomBtn[0] != '\0') {
+    drawLine(x, topButtonY + buttonHeight, x, topButtonY + 2 * buttonHeight - 1);  // Left
+    drawLine(x + buttonWidth - 1, topButtonY + buttonHeight, x + buttonWidth - 1,
+             topButtonY + 2 * buttonHeight - 1);                                                             // Right
+    drawLine(x, topButtonY + 2 * buttonHeight - 1, x + buttonWidth - 1, topButtonY + 2 * buttonHeight - 1);  // Bottom
+  }
+
+  // Draw text for each button
+  for (int i = 0; i < 2; i++) {
+    if (labels[i] != nullptr && labels[i][0] != '\0') {
+      const int y = topButtonY + i * buttonHeight;
+
+      // Draw rotated text centered in the button
+      const int textWidth = getTextWidth(fontId, labels[i]);
+      const int textHeight = getTextHeight(fontId);
+
+      // Center the rotated text in the button
+      const int textX = x + (buttonWidth - textHeight) / 2;
+      const int textY = y + (buttonHeight + textWidth) / 2;
+
+      drawTextRotated90CW(fontId, textX, textY, labels[i]);
+    }
+  }
+}
+
+int GfxRenderer::getTextHeight(const int fontId) const {
+  if (fontMap.count(fontId) == 0) {
+    Serial.printf("[%lu] [GFX] Font %d not found\n", millis(), fontId);
+    return 0;
+  }
+  return fontMap.at(fontId).getData(EpdFontFamily::REGULAR)->ascender;
+}
+
+void GfxRenderer::drawTextRotated90CW(const int fontId, const int x, const int y, const char* text, const bool black,
+                                      const EpdFontFamily::Style style) const {
+  // Cannot draw a NULL / empty string
+  if (text == nullptr || *text == '\0') {
+    return;
+  }
+
+  if (fontMap.count(fontId) == 0) {
+    Serial.printf("[%lu] [GFX] Font %d not found\n", millis(), fontId);
+    return;
+  }
+  const auto font = fontMap.at(fontId);
+
+  // No printable characters
+  if (!font.hasPrintableChars(text, style)) {
+    return;
+  }
+
+  // For 90° clockwise rotation:
+  // Original (glyphX, glyphY) -> Rotated (glyphY, -glyphX)
+  // Text reads from bottom to top
+
+  int yPos = y;  // Current Y position (decreases as we draw characters)
+
+  uint32_t cp;
+  while ((cp = utf8NextCodepoint(reinterpret_cast<const uint8_t**>(&text)))) {
+    const EpdGlyph* glyph = font.getGlyph(cp, style);
+    if (!glyph) {
+      glyph = font.getGlyph('?', style);
+    }
+    if (!glyph) {
+      continue;
+    }
+
+    const int is2Bit = font.getData(style)->is2Bit;
+    const uint32_t offset = glyph->dataOffset;
+    const uint8_t width = glyph->width;
+    const uint8_t height = glyph->height;
+    const int left = glyph->left;
+    const int top = glyph->top;
+
+    const uint8_t* bitmap = &font.getData(style)->bitmap[offset];
+
+    if (bitmap != nullptr) {
+      for (int glyphY = 0; glyphY < height; glyphY++) {
+        for (int glyphX = 0; glyphX < width; glyphX++) {
+          const int pixelPosition = glyphY * width + glyphX;
+
+          // 90° clockwise rotation transformation:
+          // screenX = x + (ascender - top + glyphY)
+          // screenY = yPos - (left + glyphX)
+          const int screenX = x + (font.getData(style)->ascender - top + glyphY);
+          const int screenY = yPos - left - glyphX;
+
+          if (is2Bit) {
+            const uint8_t byte = bitmap[pixelPosition / 4];
+            const uint8_t bit_index = (3 - pixelPosition % 4) * 2;
+            const uint8_t bmpVal = 3 - (byte >> bit_index) & 0x3;
+
+            if (renderMode == BW && bmpVal < 3) {
+              drawPixel(screenX, screenY, black);
+            } else if (renderMode == GRAYSCALE_MSB && (bmpVal == 1 || bmpVal == 2)) {
+              drawPixel(screenX, screenY, false);
+            } else if (renderMode == GRAYSCALE_LSB && bmpVal == 1) {
+              drawPixel(screenX, screenY, false);
+            }
+          } else {
+            const uint8_t byte = bitmap[pixelPosition / 8];
+            const uint8_t bit_index = 7 - (pixelPosition % 8);
+
+            if ((byte >> bit_index) & 1) {
+              drawPixel(screenX, screenY, black);
+            }
+          }
+        }
+      }
+    }
+
+    // Move to next character position (going up, so decrease Y)
+    yPos -= glyph->advanceX;
+  }
+}
+
 uint8_t* GfxRenderer::getFrameBuffer() const { return einkDisplay.getFrameBuffer(); }
 
 size_t GfxRenderer::getBufferSize() { return EInkDisplay::BUFFER_SIZE; }

lib/GfxRenderer/GfxRenderer.h

@@ -82,7 +82,15 @@ class GfxRenderer {
 
   // UI Components
   void drawButtonHints(int fontId, const char* btn1, const char* btn2, const char* btn3, const char* btn4) const;
+  void drawSideButtonHints(int fontId, const char* topBtn, const char* bottomBtn) const;
 
+ private:
+  // Helper for drawing rotated text (90 degrees clockwise, for side buttons)
+  void drawTextRotated90CW(int fontId, int x, int y, const char* text, bool black = true,
+                           EpdFontFamily::Style style = EpdFontFamily::REGULAR) const;
+  int getTextHeight(int fontId) const;
+
+ public:
   // Grayscale functions
   void setRenderMode(const RenderMode mode) { this->renderMode = mode; }
   void copyGrayscaleLsbBuffers() const;

platformio.ini

@@ -1,5 +1,5 @@
 [platformio]
-crosspoint_version = 0.11.2
+crosspoint_version = 0.12.0
 default_envs = default
 
 [base]

src/CrossPointSettings.cpp

@@ -40,9 +40,9 @@ bool CrossPointSettings::saveToFile() const {
   serialization::writePod(outputFile, fontSize);
   serialization::writePod(outputFile, lineSpacing);
   serialization::writePod(outputFile, paragraphAlignment);
-  serialization::writePod(outputFile, sideMargin);
+  serialization::writePod(outputFile, sleepTimeout);
+  serialization::writePod(outputFile, refreshFrequency);
   serialization::writeString(outputFile, std::string(opdsServerUrl));
-  serialization::writePod(outputFile, calibreWirelessEnabled);
   outputFile.close();
 
   Serial.printf("[%lu] [CPS] Settings saved to file\n", millis());
@@ -91,7 +91,9 @@ bool CrossPointSettings::loadFromFile() {
     if (++settingsRead >= fileSettingsCount) break;
     serialization::readPod(inputFile, paragraphAlignment);
     if (++settingsRead >= fileSettingsCount) break;
-    serialization::readPod(inputFile, sideMargin);
+    serialization::readPod(inputFile, sleepTimeout);
+    if (++settingsRead >= fileSettingsCount) break;
+    serialization::readPod(inputFile, refreshFrequency);
     if (++settingsRead >= fileSettingsCount) break;
     {
       std::string urlStr;
@@ -99,9 +101,6 @@ bool CrossPointSettings::loadFromFile() {
       strncpy(opdsServerUrl, urlStr.c_str(), sizeof(opdsServerUrl) - 1);
       opdsServerUrl[sizeof(opdsServerUrl) - 1] = '\0';
     }
-    if (++settingsRead >= fileSettingsCount) break;
-    serialization::readPod(inputFile, calibreWirelessEnabled);
-    if (++settingsRead >= fileSettingsCount) break;
   } while (false);
 
   inputFile.close();
@@ -145,6 +144,38 @@ float CrossPointSettings::getReaderLineCompression() const {
   }
 }
 
+unsigned long CrossPointSettings::getSleepTimeoutMs() const {
+  switch (sleepTimeout) {
+    case SLEEP_1_MIN:
+      return 1UL * 60 * 1000;
+    case SLEEP_5_MIN:
+      return 5UL * 60 * 1000;
+    case SLEEP_10_MIN:
+    default:
+      return 10UL * 60 * 1000;
+    case SLEEP_15_MIN:
+      return 15UL * 60 * 1000;
+    case SLEEP_30_MIN:
+      return 30UL * 60 * 1000;
+  }
+}
+
+int CrossPointSettings::getRefreshFrequency() const {
+  switch (refreshFrequency) {
+    case REFRESH_1:
+      return 1;
+    case REFRESH_5:
+      return 5;
+    case REFRESH_10:
+      return 10;
+    case REFRESH_15:
+    default:
+      return 15;
+    case REFRESH_30:
+      return 30;
+  }
+}
+
 int CrossPointSettings::getReaderFontId() const {
   switch (fontFamily) {
     case BOOKERLY:
@@ -186,17 +217,3 @@ int CrossPointSettings::getReaderFontId() const {
       }
   }
 }
-
-int CrossPointSettings::getReaderSideMargin() const {
-  switch (sideMargin) {
-    case MARGIN_NONE:
-      return 0;
-    case MARGIN_SMALL:
-    default:
-      return 5;
-    case MARGIN_MEDIUM:
-      return 20;
-    case MARGIN_LARGE:
-      return 30;
-  }
-}

src/CrossPointSettings.h

@@ -44,7 +44,12 @@ class CrossPointSettings {
   enum FONT_SIZE { SMALL = 0, MEDIUM = 1, LARGE = 2, EXTRA_LARGE = 3 };
   enum LINE_COMPRESSION { TIGHT = 0, NORMAL = 1, WIDE = 2 };
   enum PARAGRAPH_ALIGNMENT { JUSTIFIED = 0, LEFT_ALIGN = 1, CENTER_ALIGN = 2, RIGHT_ALIGN = 3 };
-  enum SIDE_MARGIN { MARGIN_NONE = 0, MARGIN_SMALL = 1, MARGIN_MEDIUM = 2, MARGIN_LARGE = 3 };
+
+  // Auto-sleep timeout options (in minutes)
+  enum SLEEP_TIMEOUT { SLEEP_1_MIN = 0, SLEEP_5_MIN = 1, SLEEP_10_MIN = 2, SLEEP_15_MIN = 3, SLEEP_30_MIN = 4 };
+
+  // E-ink refresh frequency (pages between full refreshes)
+  enum REFRESH_FREQUENCY { REFRESH_1 = 0, REFRESH_5 = 1, REFRESH_10 = 2, REFRESH_15 = 3, REFRESH_30 = 4 };
 
   // Sleep screen settings
   uint8_t sleepScreen = DARK;
@@ -65,11 +70,12 @@ class CrossPointSettings {
   uint8_t fontSize = MEDIUM;
   uint8_t lineSpacing = NORMAL;
   uint8_t paragraphAlignment = JUSTIFIED;
-  uint8_t sideMargin = MARGIN_SMALL;
+  // Auto-sleep timeout setting (default 10 minutes)
+  uint8_t sleepTimeout = SLEEP_10_MIN;
+  // E-ink refresh frequency (default 15 pages)
+  uint8_t refreshFrequency = REFRESH_15;
   // OPDS browser settings
   char opdsServerUrl[128] = "";
-  // Calibre wireless device settings
-  uint8_t calibreWirelessEnabled = 0;
 
   ~CrossPointSettings() = default;
 
@@ -83,7 +89,8 @@ class CrossPointSettings {
   bool loadFromFile();
 
   float getReaderLineCompression() const;
-  int getReaderSideMargin() const;
+  unsigned long getSleepTimeoutMs() const;
+  int getRefreshFrequency() const;
 };
 
 // Helper macro to access settings

src/ScreenComponents.cpp

@@ -2,6 +2,7 @@
 
 #include <GfxRenderer.h>
 
+#include <cstdint>
 #include <string>
 
 #include "Battery.h"
@@ -15,21 +16,21 @@ void ScreenComponents::drawBattery(const GfxRenderer& renderer, const int left,
 
   // 1 column on left, 2 columns on right, 5 columns of battery body
   constexpr int batteryWidth = 15;
-  constexpr int batteryHeight = 10;
+  constexpr int batteryHeight = 12;
   const int x = left;
-  const int y = top + 8;
+  const int y = top + 6;
 
   // Top line
-  renderer.drawLine(x, y, x + batteryWidth - 4, y);
+  renderer.drawLine(x + 1, y, x + batteryWidth - 3, y);
   // Bottom line
-  renderer.drawLine(x, y + batteryHeight - 1, x + batteryWidth - 4, y + batteryHeight - 1);
+  renderer.drawLine(x + 1, y + batteryHeight - 1, x + batteryWidth - 3, y + batteryHeight - 1);
   // Left line
-  renderer.drawLine(x, y, x, y + batteryHeight - 1);
+  renderer.drawLine(x, y + 1, x, y + batteryHeight - 2);
   // Battery end
-  renderer.drawLine(x + batteryWidth - 4, y, x + batteryWidth - 4, y + batteryHeight - 1);
+  renderer.drawLine(x + batteryWidth - 2, y + 1, x + batteryWidth - 2, y + batteryHeight - 2);
-  renderer.drawLine(x + batteryWidth - 3, y + 2, x + batteryWidth - 1, y + 2);
+  renderer.drawPixel(x + batteryWidth - 1, y + 3);
-  renderer.drawLine(x + batteryWidth - 3, y + batteryHeight - 3, x + batteryWidth - 1, y + batteryHeight - 3);
+  renderer.drawPixel(x + batteryWidth - 1, y + batteryHeight - 4);
-  renderer.drawLine(x + batteryWidth - 1, y + 2, x + batteryWidth - 1, y + batteryHeight - 3);
+  renderer.drawLine(x + batteryWidth - 0, y + 4, x + batteryWidth - 0, y + batteryHeight - 5);
 
   // The +1 is to round up, so that we always fill at least one pixel
   int filledWidth = percentage * (batteryWidth - 5) / 100 + 1;
@@ -37,5 +38,28 @@ void ScreenComponents::drawBattery(const GfxRenderer& renderer, const int left,
     filledWidth = batteryWidth - 5;  // Ensure we don't overflow
   }
 
-  renderer.fillRect(x + 1, y + 1, filledWidth, batteryHeight - 2);
+  renderer.fillRect(x + 2, y + 2, filledWidth, batteryHeight - 4);
+}
+
+void ScreenComponents::drawProgressBar(const GfxRenderer& renderer, const int x, const int y, const int width,
+                                        const int height, const size_t current, const size_t total) {
+  if (total == 0) {
+    return;
+  }
+
+  // Use 64-bit arithmetic to avoid overflow for large files
+  const int percent = static_cast<int>((static_cast<uint64_t>(current) * 100) / total);
+
+  // Draw outline
+  renderer.drawRect(x, y, width, height);
+
+  // Draw filled portion
+  const int fillWidth = (width - 4) * percent / 100;
+  if (fillWidth > 0) {
+    renderer.fillRect(x + 2, y + 2, fillWidth, height - 4);
+  }
+
+  // Draw percentage text centered below bar
+  const std::string percentText = std::to_string(percent) + "%";
+  renderer.drawCenteredText(UI_10_FONT_ID, y + height + 15, percentText.c_str());
 }

src/ScreenComponents.h

@@ -1,8 +1,24 @@
 #pragma once
 
+#include <cstddef>
+#include <cstdint>
+
 class GfxRenderer;
 
 class ScreenComponents {
  public:
   static void drawBattery(const GfxRenderer& renderer, int left, int top);
+
+  /**
+   * Draw a progress bar with percentage text.
+   * @param renderer The graphics renderer
+   * @param x Left position of the bar
+   * @param y Top position of the bar
+   * @param width Width of the bar
+   * @param height Height of the bar
+   * @param current Current progress value
+   * @param total Total value for 100% progress
+   */
+  static void drawProgressBar(const GfxRenderer& renderer, int x, int y, int width, int height, size_t current,
+                              size_t total);
 };

src/activities/browser/OpdsBookBrowserActivity.cpp

@@ -2,57 +2,21 @@
 
 #include <GfxRenderer.h>
 #include <HardwareSerial.h>
+#include <WiFi.h>
 
 #include "CrossPointSettings.h"
 #include "MappedInputManager.h"
+#include "ScreenComponents.h"
+#include "WifiCredentialStore.h"
 #include "fontIds.h"
 #include "network/HttpDownloader.h"
+#include "util/StringUtils.h"
+#include "util/UrlUtils.h"
 
 namespace {
 constexpr int PAGE_ITEMS = 23;
 constexpr int SKIP_PAGE_MS = 700;
 constexpr char OPDS_ROOT_PATH[] = "opds";  // No leading slash - relative to server URL
-
-// Prepend http:// if no protocol specified (server will redirect to https if needed)
-std::string ensureProtocol(const std::string& url) {
-  if (url.find("://") == std::string::npos) {
-    return "http://" + url;
-  }
-  return url;
-}
-
-// Extract host with protocol from URL (e.g., "http://example.com" from "http://example.com/path")
-std::string extractHost(const std::string& url) {
-  const size_t protocolEnd = url.find("://");
-  if (protocolEnd == std::string::npos) {
-    // No protocol, find first slash
-    const size_t firstSlash = url.find('/');
-    return firstSlash == std::string::npos ? url : url.substr(0, firstSlash);
-  }
-  // Find the first slash after the protocol
-  const size_t hostStart = protocolEnd + 3;
-  const size_t pathStart = url.find('/', hostStart);
-  return pathStart == std::string::npos ? url : url.substr(0, pathStart);
-}
-
-// Build full URL from server URL and path
-// If path starts with /, it's an absolute path from the host root
-// Otherwise, it's relative to the server URL
-std::string buildUrl(const std::string& serverUrl, const std::string& path) {
-  const std::string urlWithProtocol = ensureProtocol(serverUrl);
-  if (path.empty()) {
-    return urlWithProtocol;
-  }
-  if (path[0] == '/') {
-    // Absolute path - use just the host
-    return extractHost(urlWithProtocol) + path;
-  }
-  // Relative path - append to server URL
-  if (urlWithProtocol.back() == '/') {
-    return urlWithProtocol + path;
-  }
-  return urlWithProtocol + "/" + path;
-}
 }  // namespace
 
 void OpdsBookBrowserActivity::taskTrampoline(void* param) {
@@ -64,13 +28,13 @@ void OpdsBookBrowserActivity::onEnter() {
   Activity::onEnter();
 
   renderingMutex = xSemaphoreCreateMutex();
-  state = BrowserState::LOADING;
+  state = BrowserState::CHECK_WIFI;
   entries.clear();
   navigationHistory.clear();
   currentPath = OPDS_ROOT_PATH;
   selectorIndex = 0;
   errorMessage.clear();
-  statusMessage = "Loading...";
+  statusMessage = "Checking WiFi...";
   updateRequired = true;
 
   xTaskCreate(&OpdsBookBrowserActivity::taskTrampoline, "OpdsBookBrowserTask",
@@ -80,13 +44,16 @@ void OpdsBookBrowserActivity::onEnter() {
               &displayTaskHandle  // Task handle
   );
 
-  // Fetch feed after setting up the display task
+  // Check WiFi and connect if needed, then fetch feed
-  fetchFeed(currentPath);
+  checkAndConnectWifi();
 }
 
 void OpdsBookBrowserActivity::onExit() {
   Activity::onExit();
 
+  // Turn off WiFi when exiting
+  WiFi.mode(WIFI_OFF);
+
   xSemaphoreTake(renderingMutex, portMAX_DELAY);
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
@@ -112,6 +79,14 @@ void OpdsBookBrowserActivity::loop() {
     return;
   }
 
+  // Handle WiFi check state - only Back works
+  if (state == BrowserState::CHECK_WIFI) {
+    if (mappedInput.wasReleased(MappedInputManager::Button::Back)) {
+      onGoHome();
+    }
+    return;
+  }
+
   // Handle loading state - only Back works
   if (state == BrowserState::LOADING) {
     if (mappedInput.wasReleased(MappedInputManager::Button::Back)) {
@@ -182,6 +157,14 @@ void OpdsBookBrowserActivity::render() const {
 
   renderer.drawCenteredText(UI_12_FONT_ID, 15, "Calibre Library", true, EpdFontFamily::BOLD);
 
+  if (state == BrowserState::CHECK_WIFI) {
+    renderer.drawCenteredText(UI_10_FONT_ID, pageHeight / 2, statusMessage.c_str());
+    const auto labels = mappedInput.mapLabels("« Back", "", "", "");
+    renderer.drawButtonHints(UI_10_FONT_ID, labels.btn1, labels.btn2, labels.btn3, labels.btn4);
+    renderer.displayBuffer();
+    return;
+  }
+
   if (state == BrowserState::LOADING) {
     renderer.drawCenteredText(UI_10_FONT_ID, pageHeight / 2, statusMessage.c_str());
     const auto labels = mappedInput.mapLabels("« Back", "", "", "");
@@ -200,13 +183,14 @@ void OpdsBookBrowserActivity::render() const {
   }
 
   if (state == BrowserState::DOWNLOADING) {
-    renderer.drawCenteredText(UI_10_FONT_ID, pageHeight / 2 - 20, "Downloading...");
+    renderer.drawCenteredText(UI_10_FONT_ID, pageHeight / 2 - 40, "Downloading...");
-    renderer.drawCenteredText(UI_10_FONT_ID, pageHeight / 2 + 10, statusMessage.c_str());
+    renderer.drawCenteredText(UI_10_FONT_ID, pageHeight / 2 - 10, statusMessage.c_str());
     if (downloadTotal > 0) {
-      const int percent = (downloadProgress * 100) / downloadTotal;
+      const int barWidth = pageWidth - 100;
-      char progressText[32];
+      constexpr int barHeight = 20;
-      snprintf(progressText, sizeof(progressText), "%d%%", percent);
+      constexpr int barX = 50;
-      renderer.drawCenteredText(UI_10_FONT_ID, pageHeight / 2 + 40, progressText);
+      const int barY = pageHeight / 2 + 20;
+      ScreenComponents::drawProgressBar(renderer, barX, barY, barWidth, barHeight, downloadProgress, downloadTotal);
     }
     renderer.displayBuffer();
     return;
@@ -262,7 +246,7 @@ void OpdsBookBrowserActivity::fetchFeed(const std::string& path) {
     return;
   }
 
-  std::string url = buildUrl(serverUrl, path);
+  std::string url = UrlUtils::buildUrl(serverUrl, path);
   Serial.printf("[%lu] [OPDS] Fetching: %s\n", millis(), url.c_str());
 
   std::string content;
@@ -336,10 +320,14 @@ void OpdsBookBrowserActivity::downloadBook(const OpdsEntry& book) {
   updateRequired = true;
 
   // Build full download URL
-  std::string downloadUrl = buildUrl(SETTINGS.opdsServerUrl, book.href);
+  std::string downloadUrl = UrlUtils::buildUrl(SETTINGS.opdsServerUrl, book.href);
 
-  // Create sanitized filename
+  // Create sanitized filename: "Title - Author.epub" or just "Title.epub" if no author
-  std::string filename = "/" + sanitizeFilename(book.title) + ".epub";
+  std::string baseName = book.title;
+  if (!book.author.empty()) {
+    baseName += " - " + book.author;
+  }
+  std::string filename = "/" + StringUtils::sanitizeFilename(baseName) + ".epub";
 
   Serial.printf("[%lu] [OPDS] Downloading: %s -> %s\n", millis(), downloadUrl.c_str(), filename.c_str());
 
@@ -361,33 +349,51 @@ void OpdsBookBrowserActivity::downloadBook(const OpdsEntry& book) {
   }
 }
 
-std::string OpdsBookBrowserActivity::sanitizeFilename(const std::string& title) const {
+void OpdsBookBrowserActivity::checkAndConnectWifi() {
-  std::string result;
+  // Already connected?
-  result.reserve(title.size());
+  if (WiFi.status() == WL_CONNECTED) {
-
+    state = BrowserState::LOADING;
-  for (char c : title) {
+    statusMessage = "Loading...";
-    // Replace invalid filename characters with underscore
+    updateRequired = true;
-    if (c == '/' || c == '\\' || c == ':' || c == '*' || c == '?' || c == '"' || c == '<' || c == '>' || c == '|') {
+    fetchFeed(currentPath);
-      result += '_';
+    return;
-    } else if (c >= 32 && c < 127) {
-      // Keep printable ASCII characters
-      result += c;
-    }
-    // Skip non-printable characters
   }
 
-  // Trim leading/trailing spaces and dots
+  // Try to connect using saved credentials
-  size_t start = result.find_first_not_of(" .");
+  statusMessage = "Connecting to WiFi...";
-  if (start == std::string::npos) {
+  updateRequired = true;
-    return "book";  // Fallback if title is all invalid characters
-  }
-  size_t end = result.find_last_not_of(" .");
-  result = result.substr(start, end - start + 1);
 
-  // Limit filename length (SD card FAT32 has 255 char limit, but let's be safe)
+  WIFI_STORE.loadFromFile();
-  if (result.length() > 100) {
+  const auto& credentials = WIFI_STORE.getCredentials();
-    result.resize(100);
+  if (credentials.empty()) {
+    state = BrowserState::ERROR;
+    errorMessage = "No WiFi credentials saved";
+    updateRequired = true;
+    return;
   }
 
-  return result.empty() ? "book" : result;
+  // Use the first saved credential
+  const auto& cred = credentials[0];
+  WiFi.mode(WIFI_STA);
+  WiFi.begin(cred.ssid.c_str(), cred.password.c_str());
+
+  // Wait for connection with timeout
+  constexpr int WIFI_TIMEOUT_MS = 10000;
+  const unsigned long startTime = millis();
+  while (WiFi.status() != WL_CONNECTED && millis() - startTime < WIFI_TIMEOUT_MS) {
+    vTaskDelay(100 / portTICK_PERIOD_MS);
+  }
+
+  if (WiFi.status() == WL_CONNECTED) {
+    Serial.printf("[%lu] [OPDS] WiFi connected: %s\n", millis(), WiFi.localIP().toString().c_str());
+    state = BrowserState::LOADING;
+    statusMessage = "Loading...";
+    updateRequired = true;
+    fetchFeed(currentPath);
+  } else {
+    state = BrowserState::ERROR;
+    errorMessage = "WiFi connection failed";
+    updateRequired = true;
+  }
 }
+

src/activities/browser/OpdsBookBrowserActivity.h

@@ -17,6 +17,7 @@
 class OpdsBookBrowserActivity final : public Activity {
  public:
   enum class BrowserState {
+    CHECK_WIFI,   // Checking WiFi connection
     LOADING,      // Fetching OPDS feed
     BROWSING,     // Displaying entries (navigation or books)
     DOWNLOADING,  // Downloading selected EPUB
@@ -52,9 +53,9 @@ class OpdsBookBrowserActivity final : public Activity {
   [[noreturn]] void displayTaskLoop();
   void render() const;
 
+  void checkAndConnectWifi();
   void fetchFeed(const std::string& path);
   void navigateToEntry(const OpdsEntry& entry);
   void navigateBack();
   void downloadBook(const OpdsEntry& book);
-  std::string sanitizeFilename(const std::string& title) const;
 };

src/activities/home/HomeActivity.cpp

@@ -21,7 +21,7 @@ void HomeActivity::taskTrampoline(void* param) {
 int HomeActivity::getMenuItemCount() const {
   int count = 3;  // Browse files, File transfer, Settings
   if (hasContinueReading) count++;
-  if (hasBrowserUrl) count++;
+  if (hasOpdsUrl) count++;
   return count;
 }
 
@@ -33,8 +33,8 @@ void HomeActivity::onEnter() {
   // Check if we have a book to continue reading
   hasContinueReading = !APP_STATE.openEpubPath.empty() && SdMan.exists(APP_STATE.openEpubPath.c_str());
 
-  // Check if browser URL is configured
+  // Check if OPDS browser URL is configured
-  hasBrowserUrl = strlen(SETTINGS.opdsServerUrl) > 0;
+  hasOpdsUrl = strlen(SETTINGS.opdsServerUrl) > 0;
 
   if (hasContinueReading) {
     // Extract filename from path for display
@@ -102,7 +102,7 @@ void HomeActivity::loop() {
     int idx = 0;
     const int continueIdx = hasContinueReading ? idx++ : -1;
     const int browseFilesIdx = idx++;
-    const int browseBookIdx = hasBrowserUrl ? idx++ : -1;
+    const int opdsLibraryIdx = hasOpdsUrl ? idx++ : -1;
     const int fileTransferIdx = idx++;
     const int settingsIdx = idx;
 
@@ -110,8 +110,8 @@ void HomeActivity::loop() {
       onContinueReading();
     } else if (selectorIndex == browseFilesIdx) {
       onReaderOpen();
-    } else if (selectorIndex == browseBookIdx) {
+    } else if (selectorIndex == opdsLibraryIdx) {
-      onBrowserOpen();
+      onOpdsBrowserOpen();
     } else if (selectorIndex == fileTransferIdx) {
       onFileTransferOpen();
     } else if (selectorIndex == settingsIdx) {
@@ -289,13 +289,11 @@ void HomeActivity::render() const {
 
   // --- Bottom menu tiles ---
   // Build menu items dynamically
-  std::vector<const char*> menuItems;
+  std::vector<const char*> menuItems = {"Browse Files", "File Transfer", "Settings"};
-  menuItems.push_back("Browse Files");
+  if (hasOpdsUrl) {
-  if (hasBrowserUrl) {
+    // Insert Calibre Library after Browse Files
-    menuItems.push_back("Calibre Library");
+    menuItems.insert(menuItems.begin() + 1, "Calibre Library");
   }
-  menuItems.push_back("File Transfer");
-  menuItems.push_back("Settings");
 
   const int menuTileWidth = pageWidth - 2 * margin;
   constexpr int menuTileHeight = 45;

src/activities/home/HomeActivity.h

@@ -13,14 +13,14 @@ class HomeActivity final : public Activity {
   int selectorIndex = 0;
   bool updateRequired = false;
   bool hasContinueReading = false;
-  bool hasBrowserUrl = false;
+  bool hasOpdsUrl = false;
   std::string lastBookTitle;
   std::string lastBookAuthor;
   const std::function<void()> onContinueReading;
   const std::function<void()> onReaderOpen;
   const std::function<void()> onSettingsOpen;
   const std::function<void()> onFileTransferOpen;
-  const std::function<void()> onBrowserOpen;
+  const std::function<void()> onOpdsBrowserOpen;
 
   static void taskTrampoline(void* param);
   [[noreturn]] void displayTaskLoop();
@@ -31,13 +31,13 @@ class HomeActivity final : public Activity {
   explicit HomeActivity(GfxRenderer& renderer, MappedInputManager& mappedInput,
                         const std::function<void()>& onContinueReading, const std::function<void()>& onReaderOpen,
                         const std::function<void()>& onSettingsOpen, const std::function<void()>& onFileTransferOpen,
-                        const std::function<void()>& onBrowserOpen)
+                        const std::function<void()>& onOpdsBrowserOpen)
       : Activity("Home", renderer, mappedInput),
         onContinueReading(onContinueReading),
         onReaderOpen(onReaderOpen),
         onSettingsOpen(onSettingsOpen),
         onFileTransferOpen(onFileTransferOpen),
-        onBrowserOpen(onBrowserOpen) {}
+        onOpdsBrowserOpen(onOpdsBrowserOpen) {}
   void onEnter() override;
   void onExit() override;
   void loop() override;

src/activities/network/CalibreWirelessActivity.cpp

@@ -1,17 +1,21 @@
 #include "CalibreWirelessActivity.h"
 
 #include <GfxRenderer.h>
+#include <HardwareSerial.h>
 #include <SDCardManager.h>
 #include <WiFi.h>
 
 #include <cstring>
 
-#include "CrossPointSettings.h"
 #include "MappedInputManager.h"
+#include "ScreenComponents.h"
 #include "fontIds.h"
+#include "util/StringUtils.h"
 
-// Define static constexpr members
+namespace {
-constexpr uint16_t CalibreWirelessActivity::UDP_PORTS[];
+constexpr uint16_t UDP_PORTS[] = {54982, 48123, 39001, 44044, 59678};
+constexpr uint16_t LOCAL_UDP_PORT = 8134;  // Port to receive responses
+}  // namespace
 
 void CalibreWirelessActivity::displayTaskTrampoline(void* param) {
   auto* self = static_cast<CalibreWirelessActivity*>(param);
@@ -57,9 +61,8 @@ void CalibreWirelessActivity::onEnter() {
 void CalibreWirelessActivity::onExit() {
   Activity::onExit();
 
-  // Always turn off the setting when exiting so it shows OFF in settings
+  // Turn off WiFi when exiting
-  SETTINGS.calibreWirelessEnabled = 0;
+  WiFi.mode(WIFI_OFF);
-  SETTINGS.saveToFile();
 
   // Stop UDP listening
   udp.stop();
@@ -74,13 +77,15 @@ void CalibreWirelessActivity::onExit() {
     currentFile.close();
   }
 
-  // Delete network task first (it may be blocked on network operations)
+  // Acquire stateMutex before deleting network task to avoid race condition
+  xSemaphoreTake(stateMutex, portMAX_DELAY);
   if (networkTaskHandle) {
     vTaskDelete(networkTaskHandle);
     networkTaskHandle = nullptr;
   }
+  xSemaphoreGive(stateMutex);
 
-  // Acquire mutex before deleting display task
+  // Acquire renderingMutex before deleting display task
   xSemaphoreTake(renderingMutex, portMAX_DELAY);
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
@@ -143,8 +148,8 @@ void CalibreWirelessActivity::networkTaskLoop() {
 
 void CalibreWirelessActivity::listenForDiscovery() {
   // Broadcast "hello" on all UDP discovery ports to find Calibre
-  for (size_t i = 0; i < UDP_PORT_COUNT; i++) {
+  for (const uint16_t port : UDP_PORTS) {
-    udp.beginPacket("255.255.255.255", UDP_PORTS[i]);
+    udp.beginPacket("255.255.255.255", port);
     udp.write(reinterpret_cast<const uint8_t*>("hello"), 5);
     udp.endPacket();
   }
@@ -384,9 +389,10 @@ bool CalibreWirelessActivity::readJsonMessage(std::string& message) {
 void CalibreWirelessActivity::sendJsonResponse(int opcode, const std::string& data) {
   // Format: length + [opcode, {data}]
   std::string json = "[" + std::to_string(opcode) + "," + data + "]";
-  std::string packet = std::to_string(json.length()) + json;
+  const std::string lengthPrefix = std::to_string(json.length());
+  json.insert(0, lengthPrefix);
 
-  tcpClient.write(reinterpret_cast<const uint8_t*>(packet.c_str()), packet.length());
+  tcpClient.write(reinterpret_cast<const uint8_t*>(json.c_str()), json.length());
   tcpClient.flush();
 }
 
@@ -418,17 +424,24 @@ void CalibreWirelessActivity::handleCommand(int opcode, const std::string& data)
       break;
     case OP_SET_CALIBRE_DEVICE_INFO:
     case OP_SET_CALIBRE_DEVICE_NAME:
-      // Just acknowledge
+      // These set metadata about the connected Calibre instance.
+      // We don't need this info, just acknowledge receipt.
       sendJsonResponse(OP_OK, "{}");
       break;
     case OP_SET_LIBRARY_INFO:
+      // Library metadata (name, UUID) - not needed for receiving books
+      sendJsonResponse(OP_OK, "{}");
+      break;
     case OP_SEND_BOOKLISTS:
+      // Calibre asking us to send our book list. We report 0 books in
+      // handleGetBookCount, so this is effectively a no-op.
       sendJsonResponse(OP_OK, "{}");
       break;
     case OP_TOTAL_SPACE:
       handleFreeSpace();
       break;
     default:
+      Serial.printf("[%lu] [CAL] Unknown opcode: %d\n", millis(), opcode);
       sendJsonResponse(OP_OK, "{}");
       break;
   }
@@ -453,8 +466,11 @@ void CalibreWirelessActivity::handleGetInitializationInfo(const std::string& dat
   response += "\"canStreamBooks\":true,";
   response += "\"canStreamMetadata\":true,";
   response += "\"canUseCachedMetadata\":true,";
-  response += "\"ccVersionNumber\":212,";  // Match a known CC version
+  // ccVersionNumber: Calibre Companion protocol version. 212 matches CC 5.4.20+.
-  response += "\"coverHeight\":240,";
+  // Using a known version ensures compatibility with Calibre's feature detection.
+  response += "\"ccVersionNumber\":212,";
+  // coverHeight: Max cover image height. We don't process covers, so this is informational only.
+  response += "\"coverHeight\":800,";
   response += "\"deviceKind\":\"CrossPoint\",";
   response += "\"deviceName\":\"CrossPoint\",";
   response += "\"extensionPathLengths\":{\"epub\":37},";
@@ -472,17 +488,18 @@ void CalibreWirelessActivity::handleGetDeviceInformation() {
   response += "\"device_info\":{";
   response += "\"device_store_uuid\":\"" + getDeviceUuid() + "\",";
   response += "\"device_name\":\"CrossPoint Reader\",";
-  response += "\"device_version\":\"1.0\"";
+  response += "\"device_version\":\"" CROSSPOINT_VERSION "\"";
   response += "},";
   response += "\"version\":1,";
-  response += "\"device_version\":\"1.0\"";
+  response += "\"device_version\":\"" CROSSPOINT_VERSION "\"";
   response += "}";
 
   sendJsonResponse(OP_OK, response);
 }
 
 void CalibreWirelessActivity::handleFreeSpace() {
-  // Report 10GB free space
+  // TODO: Report actual SD card free space instead of hardcoded value
+  // Report 10GB free space for now
   sendJsonResponse(OP_OK, "{\"free_space_on_device\":10737418240}");
 }
 
@@ -558,7 +575,7 @@ void CalibreWirelessActivity::handleSendBook(const std::string& data) {
   }
 
   // Sanitize and create full path
-  currentFilename = "/" + sanitizeFilename(filename);
+  currentFilename = "/" + StringUtils::sanitizeFilename(filename);
   if (currentFilename.find(".epub") == std::string::npos) {
     currentFilename += ".epub";
   }
@@ -684,20 +701,11 @@ void CalibreWirelessActivity::render() const {
 
   // Draw progress if receiving
   if (state == CalibreWirelessState::RECEIVING && currentFileSize > 0) {
-    const int percent = static_cast<int>((bytesReceived * 100) / currentFileSize);
-
-    // Progress bar
     const int barWidth = pageWidth - 100;
-    const int barHeight = 20;
+    constexpr int barHeight = 20;
-    const int barX = 50;
+    constexpr int barX = 50;
     const int barY = statusY + 20;
-
+    ScreenComponents::drawProgressBar(renderer, barX, barY, barWidth, barHeight, bytesReceived, currentFileSize);
-    renderer.drawRect(barX, barY, barWidth, barHeight);
-    renderer.fillRect(barX + 2, barY + 2, (barWidth - 4) * percent / 100, barHeight - 4);
-
-    // Percentage text
-    const std::string percentText = std::to_string(percent) + "%";
-    renderer.drawCenteredText(UI_10_FONT_ID, barY + barHeight + 15, percentText.c_str());
   }
 
   // Draw error if present
@@ -712,31 +720,6 @@ void CalibreWirelessActivity::render() const {
   renderer.displayBuffer();
 }
 
-std::string CalibreWirelessActivity::sanitizeFilename(const std::string& name) const {
-  std::string result;
-  result.reserve(name.size());
-
-  for (char c : name) {
-    if (c == '/' || c == '\\' || c == ':' || c == '*' || c == '?' || c == '"' || c == '<' || c == '>' || c == '|') {
-      result += '_';
-    } else if (c >= 32 && c < 127) {
-      result += c;
-    }
-  }
-
-  // Trim leading/trailing spaces and dots
-  size_t start = 0;
-  while (start < result.size() && (result[start] == ' ' || result[start] == '.')) {
-    start++;
-  }
-  size_t end = result.size();
-  while (end > start && (result[end - 1] == ' ' || result[end - 1] == '.')) {
-    end--;
-  }
-
-  return result.substr(start, end - start);
-}
-
 std::string CalibreWirelessActivity::getDeviceUuid() const {
   // Generate a consistent UUID based on MAC address
   uint8_t mac[6];

src/activities/network/CalibreWirelessActivity.h

@@ -28,11 +28,14 @@ enum class CalibreWirelessState {
  * CalibreWirelessActivity implements Calibre's "wireless device" protocol.
  * This allows Calibre desktop to send books directly to the device over WiFi.
  *
- * Protocol:
+ * Protocol specification sourced from Calibre's smart device driver:
- * 1. Device listens on UDP ports 54982, 48123, 39001, 44044, 59678
+ * https://github.com/kovidgoyal/calibre/blob/master/src/calibre/devices/smart_device_app/driver.py
- * 2. Calibre broadcasts discovery messages
+ *
- * 3. Device responds with its TCP server address
+ * Protocol overview:
- * 4. Calibre connects via TCP and sends JSON commands
+ * 1. Device broadcasts "hello" on UDP ports 54982, 48123, 39001, 44044, 59678
+ * 2. Calibre responds with its TCP server address
+ * 3. Device connects to Calibre's TCP server
+ * 4. Calibre sends JSON commands with length-prefixed messages
  * 5. Books are transferred as binary data after SEND_BOOK command
  */
 class CalibreWirelessActivity final : public Activity {
@@ -47,9 +50,6 @@ class CalibreWirelessActivity final : public Activity {
 
   // UDP discovery
   WiFiUDP udp;
-  static constexpr uint16_t UDP_PORTS[] = {54982, 48123, 39001, 44044, 59678};
-  static constexpr size_t UDP_PORT_COUNT = 5;
-  static constexpr uint16_t LOCAL_UDP_PORT = 8134;  // Port to receive responses
 
   // TCP connection (we connect to Calibre)
   WiFiClient tcpClient;
@@ -118,7 +118,6 @@ class CalibreWirelessActivity final : public Activity {
   void handleNoop(const std::string& data);
 
   // Utility
-  std::string sanitizeFilename(const std::string& title) const;
   std::string getDeviceUuid() const;
   void setState(CalibreWirelessState newState);
   void setStatus(const std::string& message);

src/activities/reader/EpubReaderActivity.cpp

@@ -13,10 +13,11 @@
 #include "fontIds.h"
 
 namespace {
-constexpr int pagesPerRefresh = 15;
+// pagesPerRefresh now comes from SETTINGS.getRefreshFrequency()
 constexpr unsigned long skipChapterMs = 700;
 constexpr unsigned long goHomeMs = 1000;
 constexpr int topPadding = 5;
+constexpr int horizontalPadding = 5;
 constexpr int statusBarMargin = 19;
 }  // namespace
 
@@ -253,8 +254,8 @@ void EpubReaderActivity::renderScreen() {
   renderer.getOrientedViewableTRBL(&orientedMarginTop, &orientedMarginRight, &orientedMarginBottom,
                                    &orientedMarginLeft);
   orientedMarginTop += topPadding;
-  orientedMarginLeft += SETTINGS.getReaderSideMargin();
+  orientedMarginLeft += horizontalPadding;
-  orientedMarginRight += SETTINGS.getReaderSideMargin();
+  orientedMarginRight += horizontalPadding;
   orientedMarginBottom += statusBarMargin;
 
   if (!section) {
@@ -378,7 +379,7 @@ void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int or
   renderStatusBar(orientedMarginRight, orientedMarginBottom, orientedMarginLeft);
   if (pagesUntilFullRefresh <= 1) {
     renderer.displayBuffer(EInkDisplay::HALF_REFRESH);
-    pagesUntilFullRefresh = pagesPerRefresh;
+    pagesUntilFullRefresh = SETTINGS.getRefreshFrequency();
   } else {
     renderer.displayBuffer();
     pagesUntilFullRefresh--;

src/activities/reader/XtcReaderActivity.cpp

@@ -11,13 +11,13 @@
 #include <GfxRenderer.h>
 #include <SDCardManager.h>
 
+#include "CrossPointSettings.h"
 #include "CrossPointState.h"
 #include "MappedInputManager.h"
 #include "XtcReaderChapterSelectionActivity.h"
 #include "fontIds.h"
 
 namespace {
-constexpr int pagesPerRefresh = 15;
 constexpr unsigned long skipPageMs = 700;
 constexpr unsigned long goHomeMs = 1000;
 }  // namespace
@@ -266,7 +266,7 @@ void XtcReaderActivity::renderPage() {
     // Display BW with conditional refresh based on pagesUntilFullRefresh
     if (pagesUntilFullRefresh <= 1) {
       renderer.displayBuffer(EInkDisplay::HALF_REFRESH);
-      pagesUntilFullRefresh = pagesPerRefresh;
+      pagesUntilFullRefresh = SETTINGS.getRefreshFrequency();
     } else {
       renderer.displayBuffer();
       pagesUntilFullRefresh--;
@@ -346,7 +346,7 @@ void XtcReaderActivity::renderPage() {
   // Display with appropriate refresh
   if (pagesUntilFullRefresh <= 1) {
     renderer.displayBuffer(EInkDisplay::HALF_REFRESH);
-    pagesUntilFullRefresh = pagesPerRefresh;
+    pagesUntilFullRefresh = SETTINGS.getRefreshFrequency();
   } else {
     renderer.displayBuffer();
     pagesUntilFullRefresh--;

src/activities/settings/CalibreSettingsActivity.cpp

@@ -98,13 +98,7 @@ void CalibreSettingsActivity::handleSelection() {
           updateRequired = true;
         }));
   } else if (selectedIndex == 1) {
-    // Wireless Device - toggle and launch activity if enabling
+    // Wireless Device - launch the activity (handles WiFi connection internally)
-    const bool wasEnabled = SETTINGS.calibreWirelessEnabled;
-    SETTINGS.calibreWirelessEnabled = !wasEnabled;
-    SETTINGS.saveToFile();
-
-    if (!wasEnabled) {
-      // Just enabled - launch the wireless activity
     exitActivity();
     if (WiFi.status() != WL_CONNECTED) {
       enterNewActivity(new WifiSelectionActivity(renderer, mappedInput, [this](bool connected) {
@@ -115,9 +109,6 @@ void CalibreSettingsActivity::handleSelection() {
             updateRequired = true;
           }));
         } else {
-            // WiFi connection failed/cancelled, turn off the setting
-            SETTINGS.calibreWirelessEnabled = 0;
-            SETTINGS.saveToFile();
           updateRequired = true;
         }
       }));
@@ -127,10 +118,6 @@ void CalibreSettingsActivity::handleSelection() {
         updateRequired = true;
       }));
     }
-    } else {
-      // Just disabled - just update the display
-      updateRequired = true;
-    }
   }
 
   xSemaphoreGive(renderingMutex);
@@ -166,19 +153,13 @@ void CalibreSettingsActivity::render() {
 
     renderer.drawText(UI_10_FONT_ID, 20, settingY, menuNames[i], !isSelected);
 
-    // Draw status
+    // Draw status for URL setting
-    const char* status = "";
     if (i == 0) {
-      // Calibre Web URL
+      const char* status = (strlen(SETTINGS.opdsServerUrl) > 0) ? "[Set]" : "[Not Set]";
-      status = (strlen(SETTINGS.opdsServerUrl) > 0) ? "[Set]" : "[Not Set]";
-    } else if (i == 1) {
-      // Wireless Device
-      status = SETTINGS.calibreWirelessEnabled ? "ON" : "OFF";
-    }
-
       const auto width = renderer.getTextWidth(UI_10_FONT_ID, status);
       renderer.drawText(UI_10_FONT_ID, pageWidth - 20 - width, settingY, status, !isSelected);
     }
+  }
 
   // Draw button hints
   const auto labels = mappedInput.mapLabels("« Back", "Select", "", "");

src/activities/settings/SettingsActivity.cpp

@@ -12,7 +12,7 @@
 
 // Define the static settings list
 namespace {
-constexpr int settingsCount = 14;
+constexpr int settingsCount = 15;
 const SettingInfo settingsList[settingsCount] = {
     // Should match with SLEEP_SCREEN_MODE
     {"Sleep Screen", SettingType::ENUM, &CrossPointSettings::sleepScreen, {"Dark", "Light", "Custom", "Cover"}},
@@ -41,7 +41,14 @@ const SettingInfo settingsList[settingsCount] = {
      SettingType::ENUM,
      &CrossPointSettings::paragraphAlignment,
      {"Justify", "Left", "Center", "Right"}},
-    {"Reader Side Margin", SettingType::ENUM, &CrossPointSettings::sideMargin, {"None", "Small", "Medium", "Large"}},
+    {"Time to Sleep",
+     SettingType::ENUM,
+     &CrossPointSettings::sleepTimeout,
+     {"1 min", "5 min", "10 min", "15 min", "30 min"}},
+    {"Refresh Frequency",
+     SettingType::ENUM,
+     &CrossPointSettings::refreshFrequency,
+     {"1 page", "5 pages", "10 pages", "15 pages", "30 pages"}},
     {"Calibre Settings", SettingType::ACTION, nullptr, {}},
     {"Check for updates", SettingType::ACTION, nullptr, {}},
 };

src/activities/util/KeyboardEntryActivity.cpp

@@ -329,9 +329,13 @@ void KeyboardEntryActivity::render() const {
     }
   }
 
-  // Draw help text at absolute bottom of screen (consistent with other screens)
+  // Draw help text
-  const auto pageHeight = renderer.getScreenHeight();
+  const auto labels = mappedInput.mapLabels("« Back", "Select", "Left", "Right");
-  renderer.drawText(SMALL_FONT_ID, 10, pageHeight - 30, "Navigate: D-pad | Select: OK | Cancel: BACK");
+  renderer.drawButtonHints(UI_10_FONT_ID, labels.btn1, labels.btn2, labels.btn3, labels.btn4);
+
+  // Draw side button hints for Up/Down navigation
+  renderer.drawSideButtonHints(UI_10_FONT_ID, "Up", "Down");
+
   renderer.displayBuffer();
 }
 

src/main.cpp

@@ -5,7 +5,6 @@
 #include <InputManager.h>
 #include <SDCardManager.h>
 #include <SPI.h>
-#include <WiFi.h>
 #include <builtinFonts/all.h>
 
 #include <cstring>
@@ -23,7 +22,6 @@
 #include "activities/reader/ReaderActivity.h"
 #include "activities/settings/SettingsActivity.h"
 #include "activities/util/FullScreenMessageActivity.h"
-#include "activities/util/KeyboardEntryActivity.h"
 #include "fontIds.h"
 
 #define SPI_FQ 40000000
@@ -132,8 +130,6 @@ EpdFont ui12RegularFont(&ubuntu_12_regular);
 EpdFont ui12BoldFont(&ubuntu_12_bold);
 EpdFontFamily ui12FontFamily(&ui12RegularFont, &ui12BoldFont);
 
-// Auto-sleep timeout (10 minutes of inactivity)
-constexpr unsigned long AUTO_SLEEP_TIMEOUT_MS = 10 * 60 * 1000;
 // measurement of power button press duration calibration value
 unsigned long t1 = 0;
 unsigned long t2 = 0;
@@ -156,8 +152,10 @@ void verifyWakeupLongPress() {
   // Give the user up to 1000ms to start holding the power button, and must hold for SETTINGS.getPowerButtonDuration()
   const auto start = millis();
   bool abort = false;
-  // It takes us some time to wake up from deep sleep, so we need to subtract that from the duration
+  // Subtract the current time, because inputManager only starts counting the HeldTime from the first update()
-  constexpr uint16_t calibration = 29;
+  // This way, we remove the time we already took to reach here from the duration,
+  // assuming the button was held until now from millis()==0 (i.e. device start time).
+  const uint16_t calibration = start;
   const uint16_t calibratedPressDuration =
       (calibration < SETTINGS.getPowerButtonDuration()) ? SETTINGS.getPowerButtonDuration() - calibration : 1;
 
@@ -228,43 +226,9 @@ void onGoToSettings() {
   enterNewActivity(new SettingsActivity(renderer, mappedInputManager, onGoHome));
 }
 
-// Helper to launch browser after WiFi is connected
-void launchBrowserWithUrlCheck() {
-  // If no server URL configured, prompt for one first
-  if (strlen(SETTINGS.opdsServerUrl) == 0) {
-    enterNewActivity(new KeyboardEntryActivity(
-        renderer, mappedInputManager, "Calibre Web URL", "", 10, 127, false,
-        [](const std::string& url) {
-          strncpy(SETTINGS.opdsServerUrl, url.c_str(), sizeof(SETTINGS.opdsServerUrl) - 1);
-          SETTINGS.opdsServerUrl[sizeof(SETTINGS.opdsServerUrl) - 1] = '\0';
-          SETTINGS.saveToFile();
-          exitActivity();
-          enterNewActivity(new OpdsBookBrowserActivity(renderer, mappedInputManager, onGoHome));
-        },
-        [] {
-          exitActivity();
-          onGoHome();
-        }));
-  } else {
-    enterNewActivity(new OpdsBookBrowserActivity(renderer, mappedInputManager, onGoHome));
-  }
-}
-
 void onGoToBrowser() {
   exitActivity();
-  // Check WiFi connectivity first
+  enterNewActivity(new OpdsBookBrowserActivity(renderer, mappedInputManager, onGoHome));
-  if (WiFi.status() != WL_CONNECTED) {
-    enterNewActivity(new WifiSelectionActivity(renderer, mappedInputManager, [](bool connected) {
-      exitActivity();
-      if (connected) {
-        launchBrowserWithUrlCheck();
-      } else {
-        onGoHome();
-      }
-    }));
-  } else {
-    launchBrowserWithUrlCheck();
-  }
 }
 
 void onGoHome() {
@@ -368,8 +332,9 @@ void loop() {
     lastActivityTime = millis();  // Reset inactivity timer
   }
 
-  if (millis() - lastActivityTime >= AUTO_SLEEP_TIMEOUT_MS) {
+  const unsigned long sleepTimeoutMs = SETTINGS.getSleepTimeoutMs();
-    Serial.printf("[%lu] [SLP] Auto-sleep triggered after %lu ms of inactivity\n", millis(), AUTO_SLEEP_TIMEOUT_MS);
+  if (millis() - lastActivityTime >= sleepTimeoutMs) {
+    Serial.printf("[%lu] [SLP] Auto-sleep triggered after %lu ms of inactivity\n", millis(), sleepTimeoutMs);
     enterDeepSleep();
     // This should never be hit as `enterDeepSleep` calls esp_deep_sleep_start
     return;

src/network/OtaUpdater.cpp

@@ -3,7 +3,6 @@
 #include <ArduinoJson.h>
 #include <HTTPClient.h>
 #include <Update.h>
-#include <WiFiClientSecure.h>
 
 namespace {
 constexpr char latestReleaseUrl[] = "https://api.github.com/repos/daveallie/crosspoint-reader/releases/latest";
@@ -69,44 +68,41 @@ OtaUpdater::OtaUpdaterError OtaUpdater::checkForUpdate() {
   return OK;
 }
 
-bool OtaUpdater::isUpdateNewer() {
+bool OtaUpdater::isUpdateNewer() const {
   if (!updateAvailable || latestVersion.empty() || latestVersion == CROSSPOINT_VERSION) {
     return false;
   }
 
+  int currentMajor, currentMinor, currentPatch;
+  int latestMajor, latestMinor, latestPatch;
+
+  const auto currentVersion = CROSSPOINT_VERSION;
+
   // semantic version check (only match on 3 segments)
-  const auto updateMajor = stoi(latestVersion.substr(0, latestVersion.find('.')));
+  sscanf(latestVersion.c_str(), "%d.%d.%d", &latestMajor, &latestMinor, &latestPatch);
-  const auto updateMinor = stoi(
+  sscanf(currentVersion, "%d.%d.%d", &currentMajor, &currentMinor, &currentPatch);
-      latestVersion.substr(latestVersion.find('.') + 1, latestVersion.find_last_of('.') - latestVersion.find('.') - 1));
-  const auto updatePatch = stoi(latestVersion.substr(latestVersion.find_last_of('.') + 1));
 
-  std::string currentVersion = CROSSPOINT_VERSION;
+  /*
-  const auto currentMajor = stoi(currentVersion.substr(0, currentVersion.find('.')));
+   * Compare major versions.
-  const auto currentMinor = stoi(currentVersion.substr(
+   * If they differ, return true if latest major version greater than current major version
-      currentVersion.find('.') + 1, currentVersion.find_last_of('.') - currentVersion.find('.') - 1));
+   * otherwise return false.
-  const auto currentPatch = stoi(currentVersion.substr(currentVersion.find_last_of('.') + 1));
+   */
+  if (latestMajor != currentMajor) return latestMajor > currentMajor;
 
-  if (updateMajor > currentMajor) {
+  /*
-    return true;
+   * Compare minor versions.
-  }
+   * If they differ, return true if latest minor version greater than current minor version
-  if (updateMajor < currentMajor) {
+   * otherwise return false.
-    return false;
+   */
-  }
+  if (latestMinor != currentMinor) return latestMinor > currentMinor;
 
-  if (updateMinor > currentMinor) {
+  /*
-    return true;
+   * Check patch versions.
-  }
+   */
-  if (updateMinor < currentMinor) {
+  return latestPatch > currentPatch;
-    return false;
-  }
-
-  if (updatePatch > currentPatch) {
-    return true;
-  }
-  return false;
 }
 
-const std::string& OtaUpdater::getLatestVersion() { return latestVersion; }
+const std::string& OtaUpdater::getLatestVersion() const { return latestVersion; }
 
 OtaUpdater::OtaUpdaterError OtaUpdater::installUpdate(const std::function<void(size_t, size_t)>& onProgress) {
   if (!isUpdateNewer()) {

src/network/OtaUpdater.h

@@ -23,8 +23,8 @@ class OtaUpdater {
   size_t totalSize = 0;
 
   OtaUpdater() = default;
-  bool isUpdateNewer();
+  bool isUpdateNewer() const;
-  const std::string& getLatestVersion();
+  const std::string& getLatestVersion() const;
   OtaUpdaterError checkForUpdate();
   OtaUpdaterError installUpdate(const std::function<void(size_t, size_t)>& onProgress);
 };

src/util/StringUtils.cpp

@@ -0,0 +1,36 @@
+#include "StringUtils.h"
+
+namespace StringUtils {
+
+std::string sanitizeFilename(const std::string& name, size_t maxLength) {
+  std::string result;
+  result.reserve(name.size());
+
+  for (char c : name) {
+    // Replace invalid filename characters with underscore
+    if (c == '/' || c == '\\' || c == ':' || c == '*' || c == '?' || c == '"' || c == '<' || c == '>' || c == '|') {
+      result += '_';
+    } else if (c >= 32 && c < 127) {
+      // Keep printable ASCII characters
+      result += c;
+    }
+    // Skip non-printable characters
+  }
+
+  // Trim leading/trailing spaces and dots
+  size_t start = result.find_first_not_of(" .");
+  if (start == std::string::npos) {
+    return "book";  // Fallback if name is all invalid characters
+  }
+  size_t end = result.find_last_not_of(" .");
+  result = result.substr(start, end - start + 1);
+
+  // Limit filename length
+  if (result.length() > maxLength) {
+    result.resize(maxLength);
+  }
+
+  return result.empty() ? "book" : result;
+}
+
+}  // namespace StringUtils

src/util/StringUtils.h

@@ -0,0 +1,13 @@
+#pragma once
+#include <string>
+
+namespace StringUtils {
+
+/**
+ * Sanitize a string for use as a filename.
+ * Replaces invalid characters with underscores, trims spaces/dots,
+ * and limits length to maxLength characters.
+ */
+std::string sanitizeFilename(const std::string& name, size_t maxLength = 100);
+
+}  // namespace StringUtils

src/util/UrlUtils.cpp

@@ -0,0 +1,41 @@
+#include "UrlUtils.h"
+
+namespace UrlUtils {
+
+std::string ensureProtocol(const std::string& url) {
+  if (url.find("://") == std::string::npos) {
+    return "http://" + url;
+  }
+  return url;
+}
+
+std::string extractHost(const std::string& url) {
+  const size_t protocolEnd = url.find("://");
+  if (protocolEnd == std::string::npos) {
+    // No protocol, find first slash
+    const size_t firstSlash = url.find('/');
+    return firstSlash == std::string::npos ? url : url.substr(0, firstSlash);
+  }
+  // Find the first slash after the protocol
+  const size_t hostStart = protocolEnd + 3;
+  const size_t pathStart = url.find('/', hostStart);
+  return pathStart == std::string::npos ? url : url.substr(0, pathStart);
+}
+
+std::string buildUrl(const std::string& serverUrl, const std::string& path) {
+  const std::string urlWithProtocol = ensureProtocol(serverUrl);
+  if (path.empty()) {
+    return urlWithProtocol;
+  }
+  if (path[0] == '/') {
+    // Absolute path - use just the host
+    return extractHost(urlWithProtocol) + path;
+  }
+  // Relative path - append to server URL
+  if (urlWithProtocol.back() == '/') {
+    return urlWithProtocol + path;
+  }
+  return urlWithProtocol + "/" + path;
+}
+
+}  // namespace UrlUtils

src/util/UrlUtils.h

@@ -0,0 +1,23 @@
+#pragma once
+#include <string>
+
+namespace UrlUtils {
+
+/**
+ * Prepend http:// if no protocol specified (server will redirect to https if needed)
+ */
+std::string ensureProtocol(const std::string& url);
+
+/**
+ * Extract host with protocol from URL (e.g., "http://example.com" from "http://example.com/path")
+ */
+std::string extractHost(const std::string& url);
+
+/**
+ * Build full URL from server URL and path.
+ * If path starts with /, it's an absolute path from the host root.
+ * Otherwise, it's relative to the server URL.
+ */
+std::string buildUrl(const std::string& serverUrl, const std::string& path);
+
+}  // namespace UrlUtils