[ai] memory optimizations, wifi reset, battery

src/DirectoryNode.cpp

@@ -234,9 +234,24 @@ void DirectoryNode::buildDirectoryTree(const char *currentPath)
     mp3Files.reserve(fileNames.size());
     ids.reserve(fileNames.size());
 
-    // Create subdirectories in alphabetical order
-    for (const String &dirName : dirNames)
+    // Add MP3 files in alphabetical order first to free fileNames memory before recursing
+    for (const String &fileName : fileNames)
     {
+        mp3Files.push_back(fileName);
+        ids.push_back(getNextId());
+    }
+    // Free memory used by fileNames vector
+    {
+        std::vector<String> empty;
+        fileNames.swap(empty);
+    }
+
+    // Create subdirectories in alphabetical order
+    // Use index loop and std::move to free strings in dirNames as we go, reducing stack memory usage during recursion
+    for (size_t i = 0; i < dirNames.size(); ++i)
+    {
+        String dirName = std::move(dirNames[i]); // Move string content out of vector
+        
         DirectoryNode *newNode = new DirectoryNode(dirName);
         if (!newNode)
         {
@@ -261,13 +276,6 @@ void DirectoryNode::buildDirectoryTree(const char *currentPath)
 
         newNode->buildDirectoryTree(childPath.c_str());
     }
-
-    // Add MP3 files in alphabetical order (store only filenames; build full paths on demand)
-    for (const String &fileName : fileNames)
-    {
-        mp3Files.push_back(fileName);
-        ids.push_back(getNextId());
-    }
 }
 
 void DirectoryNode::printDirectoryTree(int level) const
@@ -648,50 +656,3 @@ DirectoryNode *DirectoryNode::advanceToNextMP3(const String &currentGlobal)
     Serial.println(F("no more nodes found"));
     return this;
 }
-
-/**
- * @brief Not used anymore due to new 
- * backpressure-safe, low-heap HTML streaming solution to prevent AsyncTCP cbuf resize OOM during /directory.
- * 
- * @param out 
- */
-void DirectoryNode::streamDirectoryHTML(Print &out) const {
-#ifdef DEBUG 
-    Serial.printf("StreamDirectoryHTML name=%s numOfFiles=%i\n", name, mp3Files.size());
-#endif
-    
-    if (name == "/") {
-        out.println(F("<ul>"));
-    }
-
-    if (name != "/") {
-        out.print(F("<li data-id=\""));
-        out.print(id);
-        out.print(F("\"><b>"));
-        out.print(name);
-        out.println(F("</b></li>"));
-        yield();  // Yield to allow network stack to send buffered data
-    }
-
-    for (size_t i = 0; i < mp3Files.size(); i++) {
-        out.print(F("<li data-id=\""));
-        out.print(ids[i]);
-        out.print(F("\">"));
-        out.print(mp3Files[i].c_str());
-        out.println(F("</li>"));
-  
-        // Yield every few items to allow the async web server to send buffered data
-        if (i % 5 == 4) {
-            yield();
-        }
-    }
-
-    for (DirectoryNode* child : subdirectories) {
-        child->streamDirectoryHTML(out);
-    }
-
-    if (name == "/") {
-        out.println(F("</ul>"));
-        yield();  // Final yield before completing
-    }
-}