fixed previous

src/DirectoryNode.cpp

@@ -262,39 +262,103 @@ DirectoryNode *DirectoryNode::advanceToMP3(const String *currentGlobal)
  */
 DirectoryNode *DirectoryNode::goToPreviousMP3(uint32_t thresholdSeconds)
 {
-    if (secondsPlayed > thresholdSeconds || currentPlaying == nullptr)
+    // Safety check for null pointer
+    if (currentPlaying == nullptr)
     {
-        // Restart the current song if it's been playing for more than thresholdSeconds
-        // Or if there is no current song (at the start of the list)
+        Serial.println("goToPreviousMP3: currentPlaying is null");
+        return nullptr;
+    }
+
+    // If we've been playing for more than threshold seconds, restart current song
+    if (secondsPlayed > thresholdSeconds)
+    {
+        Serial.println("goToPreviousMP3: Restarting current song (played > threshold)");
         return this;
     }
-    else
-    {
-        // Find the previous song
-        for (size_t i = 0; i < mp3Files.size(); i++)
-        {
-            if (currentPlaying != nullptr && *currentPlaying == mp3Files[i] && i > 0)
-            {
-                // Move to the previous song
-                setCurrentPlaying(&mp3Files[i - 1]);
-                return this;
-            }
-        }
 
-        // If the first song in the directory or no song was playing, move to the previous directory, if any
-        for (auto subdir : subdirectories)
+    // Find the current song index in this directory
+    int currentIndex = -1;
+    for (size_t i = 0; i < mp3Files.size(); i++)
+    {
+        if (*currentPlaying == mp3Files[i])
         {
-            DirectoryNode *previousNode = subdir->goToPreviousMP3(thresholdSeconds);
-            if (previousNode != nullptr)
-            {
-                return previousNode;
-            }
+            currentIndex = i;
+            break;
         }
     }
-    // No previous song available
+
+    // If current song found and not the first song, move to previous
+    if (currentIndex > 0)
+    {
+        Serial.print("goToPreviousMP3: Moving to previous song in same directory: ");
+        Serial.println(mp3Files[currentIndex - 1]);
+        setCurrentPlaying(&mp3Files[currentIndex - 1]);
+        return this;
+    }
+    
+    // If we're at the first song or song not found in current directory,
+    // we need to find the previous song globally
+    Serial.println("goToPreviousMP3: At first song or song not found, looking for previous globally");
+    return nullptr; // Let the caller handle global previous logic
+}
+
+DirectoryNode *DirectoryNode::findPreviousMP3Globally(const String *currentGlobal)
+{
+    if (currentGlobal == nullptr)
+    {
+        Serial.println("findPreviousMP3Globally: currentGlobal is null");
+        return nullptr;
+    }
+
+    // Build a flat list of all MP3 files in order
+    std::vector<std::pair<DirectoryNode*, int>> allMP3s;
+    buildFlatMP3List(allMP3s);
+
+    // Find current song in the flat list
+    int currentGlobalIndex = -1;
+    for (size_t i = 0; i < allMP3s.size(); i++)
+    {
+        DirectoryNode* node = allMP3s[i].first;
+        int fileIndex = allMP3s[i].second;
+        if (node->mp3Files[fileIndex] == *currentGlobal)
+        {
+            currentGlobalIndex = i;
+            break;
+        }
+    }
+
+    // If current song found and not the first globally, move to previous
+    if (currentGlobalIndex > 0)
+    {
+        DirectoryNode* prevNode = allMP3s[currentGlobalIndex - 1].first;
+        int prevFileIndex = allMP3s[currentGlobalIndex - 1].second;
+        
+        Serial.print("findPreviousMP3Globally: Moving to previous song globally: ");
+        Serial.println(prevNode->mp3Files[prevFileIndex]);
+        
+        prevNode->setCurrentPlaying(&prevNode->mp3Files[prevFileIndex]);
+        return prevNode;
+    }
+
+    Serial.println("findPreviousMP3Globally: No previous song found globally");
     return nullptr;
 }
 
+void DirectoryNode::buildFlatMP3List(std::vector<std::pair<DirectoryNode*, int>>& allMP3s)
+{
+    // Add all MP3 files from this directory
+    for (size_t i = 0; i < mp3Files.size(); i++)
+    {
+        allMP3s.push_back(std::make_pair(this, i));
+    }
+
+    // Recursively add MP3 files from subdirectories
+    for (DirectoryNode* subdir : subdirectories)
+    {
+        subdir->buildFlatMP3List(allMP3s);
+    }
+}
+
 DirectoryNode *DirectoryNode::advanceToNextMP3(const String *currentGlobal)
 {
     bool useFirst = false;