Add in-memory metrics + /stats, /get_history and include router

app/metrics.py

@@ -0,0 +1,42 @@
+from collections import deque, defaultdict
+from datetime import datetime, timedelta, timezone
+
+class StatsTracker:
+    def __init__(self, max_recent=200):
+        self.questions_answered = 0
+        self.total_chunks = 0
+        self._latencies_ms = deque(maxlen=max_recent)
+        self._recent_questions = deque(maxlen=max_recent)
+        self._by_day = defaultdict(int)
+
+    def record_upload(self, chunks_added:int):
+        self.total_chunks += int(chunks_added)
+
+    def record_question(self, question:str, latency_ms:float, top_k:int):
+        self.questions_answered += 1
+        self._latencies_ms.append(float(latency_ms))
+        now = datetime.now(timezone.utc)
+        self._recent_questions.append({
+            "timestamp": now.isoformat(),
+            "question": question,
+            "latency_ms": round(latency_ms, 2),
+            "top_k": top_k
+        })
+        self._by_day[now.date()] += 1
+
+    def get_stats(self):
+        avg_ms = round(sum(self._latencies_ms)/len(self._latencies_ms), 2) if self._latencies_ms else 0.0
+        today = datetime.now(timezone.utc).date()
+        last7 = []
+        for i in range(6, -1, -1):
+            d = today - timedelta(days=i)
+            last7.append({ "date": d.isoformat(), "questions": int(self._by_day.get(d, 0)) })
+        return {
+            "total_chunks": int(self.total_chunks),
+            "questions_answered": int(self.questions_answered),
+            "avg_ms": avg_ms,
+            "last7": last7,
+            "lastN_questions": list(self._recent_questions)[-20:],
+        }
+
+tracker = StatsTracker()

app/routes_stats.py

@@ -0,0 +1,13 @@
+from fastapi import APIRouter
+from .metrics import tracker
+
+router = APIRouter()
+
+@router.get("/stats")
+def get_stats():
+    return tracker.get_stats()
+
+@router.get("/get_history")
+def get_history():
+    s = tracker.get_stats()
+    return {"history": s["lastN_questions"], "total_chunks": s["total_chunks"]}