handle errors better

database.py

@@ -74,7 +74,8 @@ class Database:
 
     def load_reference_data(self):
         """Load projects and workspaces into memory for fast lookups."""
-        assert self.conn is not None
+        if self.conn is None:
+            raise RuntimeError("Database is not connected. Call connect() first.")
         cursor = self.conn.cursor()
 
         # Load projects
@@ -125,7 +126,8 @@ class Database:
         Returns:
             List of Session objects with computed counts
         """
-        assert self.conn is not None, "Database not connected"
+        if self.conn is None:
+            raise RuntimeError("Database is not connected. Call connect() first.")
         cursor = self.conn.cursor()
 
         query = """
@@ -205,7 +207,8 @@ class Database:
 
     def get_session_counts_by_project(self) -> dict:
         """Return a dict of project_id -> active session count."""
-        assert self.conn is not None
+        if self.conn is None:
+            raise RuntimeError("Database is not connected. Call connect() first.")
         cursor = self.conn.cursor()
         cursor.execute(
             "SELECT project_id, COUNT(*) FROM session WHERE time_archived IS NULL GROUP BY project_id"
@@ -228,7 +231,8 @@ class Database:
         Returns:
             (success, list of SQL statements executed)
         """
-        assert self.conn is not None, "Database not connected"
+        if self.conn is None:
+            raise RuntimeError("Database is not connected. Call connect() first.")
         cursor = self.conn.cursor()
 
         # Verify target project exists
@@ -265,7 +269,8 @@ class Database:
         Returns:
             (success, list of SQL statements, list of new session IDs)
         """
-        assert self.conn is not None, "Database not connected"
+        if self.conn is None:
+            raise RuntimeError("Database is not connected. Call connect() first.")
         import uuid
 
         cursor = self.conn.cursor()
@@ -355,7 +360,8 @@ class Database:
         Returns:
             (success, error_message)
         """
-        assert self.conn is not None, "Database not connected"
+        if self.conn is None:
+            raise RuntimeError("Database is not connected. Call connect() first.")
         cursor = self.conn.cursor()
 
         try: