From 510527c4007a7b109b49e38325404aec4f629fb6 Mon Sep 17 00:00:00 2001
From: Ed_ <edwardgz@gmail.com>
Date: Thu, 19 Mar 2026 19:53:09 -0400
Subject: [PATCH] feat(backend): Implement multi-take sequence differencing and
 text formatting utility

---
 src/app_controller.py             |  3 +-
 src/gui_2.py                      |  3 +-
 src/synthesis_formatter.py        | 42 ++++++++++++++++++++++
 tests/test_synthesis_formatter.py | 59 +++++++++++++++++++++++++++++++
 4 files changed, 105 insertions(+), 2 deletions(-)
 create mode 100644 src/synthesis_formatter.py
 create mode 100644 tests/test_synthesis_formatter.py

diff --git a/src/app_controller.py b/src/app_controller.py
index cafd84f..0e8a4cd 100644
--- a/src/app_controller.py
+++ b/src/app_controller.py
@@ -2206,7 +2206,8 @@ class AppController:
   project_manager.branch_discussion(self.project, self.active_discussion, new_name, index)
   self._switch_discussion(new_name)
 
- def _rename_discussion(self, old_name: str, new_name: str) -> None:  disc_sec = self.project.get("discussion", {})
+ def _rename_discussion(self, old_name: str, new_name: str) -> None:
+  disc_sec = self.project.get("discussion", {})
   discussions = disc_sec.get("discussions", {})
   if old_name not in discussions:
    return
diff --git a/src/gui_2.py b/src/gui_2.py
index e5365da..1c3c754 100644
--- a/src/gui_2.py
+++ b/src/gui_2.py
@@ -2493,7 +2493,8 @@ def hello():
        break # Break from inner loop, clipper will re-step
       imgui.same_line()
       if imgui.button("Branch"):
-       self._branch_discussion(i)      imgui.same_line()
+       self._branch_discussion(i)
+      imgui.same_line()
       preview = entry["content"].replace("\\n", " ")[:60]
       if len(entry["content"]) > 60: preview += "..."
       if not preview.strip() and entry.get("thinking_segments"):
diff --git a/src/synthesis_formatter.py b/src/synthesis_formatter.py
new file mode 100644
index 0000000..34a3578
--- /dev/null
+++ b/src/synthesis_formatter.py
@@ -0,0 +1,42 @@
+def format_takes_diff(takes: dict[str, list[dict]]) -> str:
+ if not takes:
+  return ""
+ 
+ histories = list(takes.values())
+ if not histories:
+  return ""
+
+ min_len = min(len(h) for h in histories)
+ common_prefix_len = 0
+ for i in range(min_len):
+  first_msg = histories[0][i]
+  if all(h[i] == first_msg for h in histories):
+   common_prefix_len += 1
+  else:
+   break
+
+ shared_lines = []
+ for i in range(common_prefix_len):
+  msg = histories[0][i]
+  shared_lines.append(f"{msg.get('role', 'unknown')}: {msg.get('content', '')}")
+ 
+ shared_text = "=== Shared History ==="
+ if shared_lines:
+  shared_text += "\n" + "\n".join(shared_lines)
+
+ variation_lines = []
+ if len(takes) > 1:
+  for take_name, history in takes.items():
+   if len(history) > common_prefix_len:
+    variation_lines.append(f"[{take_name}]")
+    for i in range(common_prefix_len, len(history)):
+     msg = history[i]
+     variation_lines.append(f"{msg.get('role', 'unknown')}: {msg.get('content', '')}")
+    variation_lines.append("")
+ else:
+  # Single take case
+  pass
+
+ variations_text = "=== Variations ===\n" + "\n".join(variation_lines)
+
+ return shared_text + "\n\n" + variations_text
diff --git a/tests/test_synthesis_formatter.py b/tests/test_synthesis_formatter.py
new file mode 100644
index 0000000..a42b281
--- /dev/null
+++ b/tests/test_synthesis_formatter.py
@@ -0,0 +1,59 @@
+import pytest
+from src.synthesis_formatter import format_takes_diff
+
+def test_format_takes_diff_empty():
+ assert format_takes_diff({}) == ""
+
+def test_format_takes_diff_single_take():
+ takes = {
+  "take1": [
+   {"role": "user", "content": "hello"},
+   {"role": "assistant", "content": "hi"}
+  ]
+ }
+ expected = "=== Shared History ===\nuser: hello\nassistant: hi\n\n=== Variations ===\n"
+ assert format_takes_diff(takes) == expected
+
+def test_format_takes_diff_common_prefix():
+ takes = {
+  "take1": [
+   {"role": "user", "content": "hello"},
+   {"role": "assistant", "content": "hi"},
+   {"role": "user", "content": "how are you?"},
+   {"role": "assistant", "content": "I am fine."}
+  ],
+  "take2": [
+   {"role": "user", "content": "hello"},
+   {"role": "assistant", "content": "hi"},
+   {"role": "user", "content": "what is the time?"},
+   {"role": "assistant", "content": "It is noon."}
+  ]
+ }
+ expected = (
+  "=== Shared History ===\n"
+  "user: hello\n"
+  "assistant: hi\n\n"
+  "=== Variations ===\n"
+  "[take1]\n"
+  "user: how are you?\n"
+  "assistant: I am fine.\n\n"
+  "[take2]\n"
+  "user: what is the time?\n"
+  "assistant: It is noon.\n"
+ )
+ assert format_takes_diff(takes) == expected
+
+def test_format_takes_diff_no_common_prefix():
+ takes = {
+  "take1": [{"role": "user", "content": "a"}],
+  "take2": [{"role": "user", "content": "b"}]
+ }
+ expected = (
+  "=== Shared History ===\n\n"
+  "=== Variations ===\n"
+  "[take1]\n"
+  "user: a\n\n"
+  "[take2]\n"
+  "user: b\n"
+ )
+ assert format_takes_diff(takes) == expected