From 3723edf9a9e35e9880c74f84fcdeda84182f3c2f Mon Sep 17 00:00:00 2001
From: "Samuele E. Locatelli" <samuele.locatelli@egalware.com>
Date: Wed, 3 Sep 2025 07:04:33 +0000
Subject: [PATCH] inizio modifiche backend x TTL sessioni

---
 backend/api/v1/sessions.py        | 10 ++++++++++
 backend/services/redis_service.py | 30 ++++++++++++++++++++++--------
 2 files changed, 32 insertions(+), 8 deletions(-)

diff --git a/backend/api/v1/sessions.py b/backend/api/v1/sessions.py
index 367e8db..62c88e8 100644
--- a/backend/api/v1/sessions.py
+++ b/backend/api/v1/sessions.py
@@ -61,3 +61,13 @@ async def delete_session_endpoint(
     redis_service.delete_session(user_id, session_id)
     return {"status": "deleted"}
 
+# estensione TTL sessioni
+@router.post("/sessions/{session_id}/extend_ttl", response_model=dict)
+async def extend_ttl_endpoint(
+    user_id: str = Query(..., description="User ID"),
+    session_id: str = Path(..., description="Session ID")
+    extra_seconds: int = Body(..., embed=True)
+):
+    redis_service.extend_session_ttl(user_id, session_id, extra_seconds)
+    return {"status": "ttl_extended"}
+
diff --git a/backend/services/redis_service.py b/backend/services/redis_service.py
index 149af0d..cb7e17e 100644
--- a/backend/services/redis_service.py
+++ b/backend/services/redis_service.py
@@ -13,6 +13,9 @@ r = redis.Redis(
     decode_responses=True
 )
 
+# setup defaults
+DEFAULT_TTL_SECONDS = 30 * 24 * 3600 # 30 gg
+
 # -------------------------
 # Chat message operations
 # -------------------------
@@ -28,11 +31,11 @@ def save_chat(user_id: str, session_id: str, message: dict):
         "timestamp": datetime.utcnow().isoformat() + "Z"
     }
     r.rpush(key, json.dumps(enriched))
+    r.expire(key, DEFAULT_TTL_SECONDS)  # TTL anche per la history
 
     # Update metadata after adding
     _update_session_stats(user_id, session_id)
 
-
 def get_chat(user_id: str, session_id: str, limit: Optional[int] = None):
     """
     Retrieve messages for a user/session, sorted by timestamp.
@@ -68,7 +71,6 @@ def create_session(user_id: str, first_message: str) -> dict:
     session_id = str(uuid.uuid4())
     created_at = datetime.utcnow().isoformat() + "Z"
     session_name = (first_message.strip()[:50] or "New Chat")
-
     meta = {
         "session_id": session_id,
         "created_at": created_at,
@@ -76,16 +78,15 @@ def create_session(user_id: str, first_message: str) -> dict:
         "message_count": 0,
         "history_size_bytes": 0
     }
+    meta_key = f"chatSession:{user_id}:{session_id}"
+    index_key = f"chatSessionsIndex:{user_id}"
 
-    # Save metadata
-    r.set(f"chatSession:{user_id}:{session_id}", json.dumps(meta))
-
-    # Add to per-user index (sorted set with score = timestamp)
-    r.zadd(f"chatSessionsIndex:{user_id}", {session_id: datetime.utcnow().timestamp()})
+    r.set(meta_key, json.dumps(meta), ex=DEFAULT_TTL_SECONDS)
+    r.zadd(index_key, {session_id: datetime.utcnow().timestamp()})
+    r.expire(index_key, DEFAULT_TTL_SECONDS)  # TTL anche per l’indice utente
 
     return meta
 
-
 def get_sessions(user_id: str) -> List[dict]:
     """
     Return all sessions for a user, newest first.
@@ -124,6 +125,19 @@ def delete_session(user_id: str, session_id: str):
     r.delete(f"chatHistory:{user_id}:{session_id}")
     r.zrem(f"chatSessionsIndex:{user_id}", session_id)
 
+def extend_session_ttl(user_id: str, session_id: str, extra_seconds: int):
+    meta_key = f"chatSession:{user_id}:{session_id}"
+    history_key = f"chatHistory:{user_id}:{session_id}"
+    index_key = f"chatSessionsIndex:{user_id}"
+
+    for key in [meta_key, history_key, index_key]:
+        if r.exists(key):
+            current_ttl = r.ttl(key)
+            if current_ttl > 0:
+                r.expire(key, current_ttl + extra_seconds)
+            else:
+                r.expire(key, extra_seconds)
+
 
 # -------------------------
 # Internal helpers