Create rag_timeline.py

rag_timeline.py

@@ -0,0 +1,40 @@
+from datetime import datetime
+from rag_data import threads, messages
+
+
+def build_timeline(thread_id: str) -> str:
+    """
+    Build a simple markdown timeline for a thread:
+    - one line per message
+    - sorted by date
+    - with [msg: <id>] citations
+    """
+    msg_ids = threads.get(thread_id, [])
+    if not msg_ids:
+        return f"No messages found for thread {thread_id}."
+
+    entries = []
+    for mid in msg_ids:
+        m = messages.get(mid)
+        if not m:
+            continue
+        date_str = m.get("date") or ""
+        sender = m.get("from") or "(unknown)"
+        subject = m.get("subject") or "(no subject)"
+
+        # Try to format date nicely
+        try:
+            dt = datetime.fromisoformat(date_str.replace("Z", "+00:00"))
+            date_fmt = dt.strftime("%Y-%m-%d %H:%M")
+        except Exception:
+            date_fmt = date_str
+
+        line = f"- **{date_fmt}** — **{sender}** — _{subject}_ [msg: {mid}]"
+        entries.append((date_str, line))
+
+    # Sort by raw date string; not perfect but fine for this dataset
+    entries.sort(key=lambda x: x[0])
+    lines = [f"### Timeline for thread {thread_id}", ""]
+    lines.extend(line for _, line in entries)
+
+    return "\n".join(lines)