perf: connection pooling, query consolidation, inline chart data, batch milestones

app/utils.py

@@ -4,7 +4,7 @@ Shared business-logic helpers.
 Keep route handlers thin — calculation logic lives here.
 """
 
-from app.db import query, execute
+from app.db import query, execute_many
 from app.config import SYDNEY_TZ
 from datetime import datetime, timedelta
 
@@ -66,19 +66,11 @@ def calculate_weight_change(start_w, current_w):
 # Streaks
 # ---------------------------------------------------------------------------
 
-def calculate_streak(user_id):
-    """Calculate current and best consecutive-day check-in streaks."""
-    rows = query(
-        """SELECT DISTINCT (checked_in_at AT TIME ZONE 'UTC' AT TIME ZONE 'Australia/Sydney')::date AS d
-           FROM checkins WHERE user_id = %s ORDER BY d DESC""",
-        (user_id,),
-    )
-    if not rows:
+def _compute_streak_from_dates(days, today):
+    """Compute current and best streak from a sorted-desc list of dates."""
+    if not days:
         return {"current": 0, "best": 0}
 
-    days = [r["d"] for r in rows]
-    today = datetime.now(SYDNEY_TZ).date()
-
     # Current streak: must include today or yesterday to count
     current = 0
     expected = today
@@ -105,6 +97,50 @@ def calculate_streak(user_id):
     return {"current": current, "best": best}
 
 
+def calculate_streak(user_id):
+    """Calculate current and best consecutive-day check-in streaks."""
+    rows = query(
+        """SELECT DISTINCT (checked_in_at AT TIME ZONE 'UTC' AT TIME ZONE 'Australia/Sydney')::date AS d
+           FROM checkins WHERE user_id = %s ORDER BY d DESC""",
+        (user_id,),
+    )
+    days = [r["d"] for r in rows]
+    today = datetime.now(SYDNEY_TZ).date()
+    return _compute_streak_from_dates(days, today)
+
+
+def calculate_streaks_bulk(user_ids):
+    """Calculate streaks for multiple users in a single query.
+
+    Returns a dict: {user_id: {"current": int, "best": int}}.
+    """
+    if not user_ids:
+        return {}
+
+    placeholders = ",".join(["%s"] * len(user_ids))
+    rows = query(
+        f"""SELECT user_id,
+                   (checked_in_at AT TIME ZONE 'UTC' AT TIME ZONE 'Australia/Sydney')::date AS d
+            FROM checkins
+            WHERE user_id IN ({placeholders})
+            GROUP BY user_id, d
+            ORDER BY user_id, d DESC""",
+        tuple(user_ids),
+    )
+
+    # Group by user
+    from collections import defaultdict
+    user_days = defaultdict(list)
+    for r in rows:
+        user_days[r["user_id"]].append(r["d"])
+
+    today = datetime.now(SYDNEY_TZ).date()
+    result = {}
+    for uid in user_ids:
+        result[uid] = _compute_streak_from_dates(user_days.get(uid, []), today)
+    return result
+
+
 # ---------------------------------------------------------------------------
 # Milestone checker
 # ---------------------------------------------------------------------------
@@ -136,15 +172,12 @@ def check_milestones(user_id, user):
         ("lost_20kg",     total_lost >= 20),
     ]
 
-    for key, achieved in milestone_checks:
-        if achieved:
-            try:
-                execute(
-                    "INSERT INTO milestones (user_id, milestone_key) VALUES (%s, %s) ON CONFLICT DO NOTHING",
-                    (user_id, key),
-                )
-            except Exception:
-                pass
+    achieved = [(user_id, key) for key, ok in milestone_checks if ok]
+    if achieved:
+        execute_many(
+            "INSERT INTO milestones (user_id, milestone_key) VALUES (%s, %s) ON CONFLICT DO NOTHING",
+            achieved,
+        )
 
 
 # ---------------------------------------------------------------------------