feat(backend): Implement discussion branching and take promotion

src/project_manager.py

@@ -424,3 +424,36 @@ def calculate_track_progress(tickets: list) -> dict:
   "todo": todo
  }
 
+
+def branch_discussion(project_dict: dict, source_id: str, new_id: str, message_index: int) -> None:
+ """
+ Creates a new discussion in project_dict['discussion']['discussions'] by copying 
+ the history from source_id up to (and including) message_index, and sets active to new_id.
+ """
+ if "discussion" not in project_dict or "discussions" not in project_dict["discussion"]:
+  return
+ if source_id not in project_dict["discussion"]["discussions"]:
+  return
+ 
+ source_disc = project_dict["discussion"]["discussions"][source_id]
+ new_disc = default_discussion()
+ new_disc["git_commit"] = source_disc.get("git_commit", "")
+ # Copy history up to and including message_index
+ new_disc["history"] = source_disc["history"][:message_index + 1]
+ 
+ project_dict["discussion"]["discussions"][new_id] = new_disc
+ project_dict["discussion"]["active"] = new_id
+
+def promote_take(project_dict: dict, take_id: str, new_id: str) -> None:
+ """Renames a take_id to new_id in the discussions dict."""
+ if "discussion" not in project_dict or "discussions" not in project_dict["discussion"]:
+  return
+ if take_id not in project_dict["discussion"]["discussions"]:
+  return
+ 
+ disc = project_dict["discussion"]["discussions"].pop(take_id)
+ project_dict["discussion"]["discussions"][new_id] = disc
+ 
+ # If the take was active, update the active pointer
+ if project_dict["discussion"].get("active") == take_id:
+  project_dict["discussion"]["active"] = new_id

tests/test_discussion_takes.py

@@ -0,0 +1,50 @@
+import unittest
+from src import project_manager
+
+class TestDiscussionTakes(unittest.TestCase):
+ def setUp(self):
+  self.project_dict = project_manager.default_project("test_branching")
+  # Populate initial history in 'main'
+  self.project_dict["discussion"]["discussions"]["main"]["history"] = [
+   "User: Message 0",
+   "AI: Response 0",
+   "User: Message 1",
+   "AI: Response 1",
+   "User: Message 2"
+  ]
+
+ def test_branch_discussion_creates_new_take(self):
+  """Verify that branch_discussion copies history up to index and sets active."""
+  source_id = "main"
+  new_id = "take_1"
+  message_index = 1
+  
+  # This will fail with AttributeError until implemented in project_manager.py
+  project_manager.branch_discussion(self.project_dict, source_id, new_id, message_index)
+  
+  # Asserts
+  self.assertIn(new_id, self.project_dict["discussion"]["discussions"])
+  new_history = self.project_dict["discussion"]["discussions"][new_id]["history"]
+  self.assertEqual(len(new_history), 2)
+  self.assertEqual(new_history[0], "User: Message 0")
+  self.assertEqual(new_history[1], "AI: Response 0")
+  self.assertEqual(self.project_dict["discussion"]["active"], new_id)
+
+ def test_promote_take_renames_discussion(self):
+  """Verify that promote_take renames a discussion key."""
+  take_id = "take_experimental"
+  self.project_dict["discussion"]["discussions"][take_id] = project_manager.default_discussion()
+  self.project_dict["discussion"]["discussions"][take_id]["history"] = ["User: Experimental"]
+  
+  new_id = "feature_refined"
+  
+  # This will fail with AttributeError until implemented in project_manager.py
+  project_manager.promote_take(self.project_dict, take_id, new_id)
+  
+  # Asserts
+  self.assertNotIn(take_id, self.project_dict["discussion"]["discussions"])
+  self.assertIn(new_id, self.project_dict["discussion"]["discussions"])
+  self.assertEqual(self.project_dict["discussion"]["discussions"][new_id]["history"], ["User: Experimental"])
+
+if __name__ == "__main__":
+ unittest.main()