Implement performance improvements for memory caching, HTTP client reuse, and regex optimization

Co-authored-by: Kenearos <86194771+Kenearos@users.noreply.github.com>

memory.py

@@ -27,6 +27,8 @@ class ConversationMemory:
         self.max_messages = max_messages
         self.retention_hours = retention_hours
         self.logger = logger or logging.getLogger(__name__)
+        # In-memory cache to reduce file I/O for frequently accessed users
+        self._cache: Dict[str, List[Dict]] = {}
 
     def _get_user_file(self, username):
         """Get the file path for a user's conversation history"""
@@ -34,6 +36,59 @@ class ConversationMemory:
         safe_username = "".join(c for c in username.lower() if c.isalnum() or c in "._-")
         return self.data_dir / f"{safe_username}.json"
 
+    def _load_user_history(self, username):
+        """
+        Load user history from cache or file
+
+        Args:
+            username (str): Twitch username
+
+        Returns:
+            list: List of message dicts or empty list
+        """
+        safe_username = username.lower()
+
+        # Check cache first
+        if safe_username in self._cache:
+            return self._cache[safe_username]
+
+        file_path = self._get_user_file(username)
+
+        if not file_path.exists():
+            self._cache[safe_username] = []
+            return []
+
+        try:
+            with open(file_path, 'r', encoding='utf-8') as f:
+                history = json.load(f)
+                self._cache[safe_username] = history
+                return history
+        except Exception as e:
+            self.logger.error(f"Error loading history for {username}: {e}")
+            self._cache[safe_username] = []
+            return []
+
+    def _save_user_history(self, username, history):
+        """
+        Save user history to file and update cache
+
+        Args:
+            username (str): Twitch username
+            history (list): List of message dicts
+        """
+        safe_username = username.lower()
+        file_path = self._get_user_file(username)
+
+        # Update cache
+        self._cache[safe_username] = history
+
+        # Save to file
+        try:
+            with open(file_path, 'w', encoding='utf-8') as f:
+                json.dump(history, f, ensure_ascii=False, indent=2)
+        except Exception as e:
+            self.logger.error(f"Error saving history for {username}: {e}")
+
     def get_user_history(self, username, limit=5):
         """
         Load recent chat history for a user
@@ -45,29 +100,22 @@ class ConversationMemory:
         Returns:
             list: List of message dicts with role, content, timestamp
         """
-        file_path = self._get_user_file(username)
+        history = self._load_user_history(username)
 
-        if not file_path.exists():
+        if not history:
             return []
 
-        try:
-            with open(file_path, 'r', encoding='utf-8') as f:
-                history = json.load(f)
-        except Exception as e:
-            self.logger.error(f"Error loading history for {username}: {e}")
-            return []
-
-        # Filter by retention time
+        # Filter by retention time using list comprehension for better performance
         cutoff_time = datetime.now() - timedelta(hours=self.retention_hours)
-        recent = []
 
-        for msg in history:
+        def is_recent(msg):
             try:
                 msg_time = datetime.fromisoformat(msg['timestamp'])
-                if msg_time > cutoff_time:
-                    recent.append(msg)
+                return msg_time > cutoff_time
             except (KeyError, ValueError):
-                continue
+                return False
+
+        recent = [msg for msg in history if is_recent(msg)]
 
         # Return only the most recent messages up to limit
         return recent[-limit:] if recent else []
@@ -81,17 +129,8 @@ class ConversationMemory:
             role (str): 'user' or 'assistant'
             content (str): Message content
         """
-        file_path = self._get_user_file(username)
-
-        # Load existing history
-        history = []
-        if file_path.exists():
-            try:
-                with open(file_path, 'r', encoding='utf-8') as f:
-                    history = json.load(f)
-            except Exception as e:
-                self.logger.error(f"Error loading history for {username}: {e}")
-                history = []
+        # Load existing history (uses cache if available)
+        history = self._load_user_history(username)
 
         # Add new message
         history.append({
@@ -104,12 +143,8 @@ class ConversationMemory:
         if len(history) > self.max_messages:
             history = history[-self.max_messages:]
 
-        # Save back to file
-        try:
-            with open(file_path, 'w', encoding='utf-8') as f:
-                json.dump(history, f, ensure_ascii=False, indent=2)
-        except Exception as e:
-            self.logger.error(f"Error saving history for {username}: {e}")
+        # Save back to file and update cache
+        self._save_user_history(username, history)
 
     def format_for_prompt(self, history):
         """
@@ -136,6 +171,13 @@ class ConversationMemory:
         Args:
             username (str): Twitch username
         """
+        safe_username = username.lower()
+
+        # Clear from cache
+        if safe_username in self._cache:
+            del self._cache[safe_username]
+
+        # Clear from disk
         file_path = self._get_user_file(username)
         if file_path.exists():
             try: