fix

backend/app/services/fitness.py

@@ -0,0 +1,107 @@
+"""CTL / ATL / TSB (Fitness / Fatigue / Form) calculation service."""
+
+from datetime import date, timedelta
+
+from sqlalchemy import select, func
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from backend.app.models.activity import Activity, ActivityMetrics
+from backend.app.models.fitness import FitnessHistory
+
+CTL_DAYS = 42  # Chronic Training Load time constant
+ATL_DAYS = 7   # Acute Training Load time constant
+
+
+async def rebuild_fitness_history(
+    rider_id,
+    session: AsyncSession,
+    days_back: int = 365,
+) -> list[FitnessHistory]:
+    """Rebuild CTL/ATL/TSB for a rider from scratch using exponential moving averages."""
+
+    end_date = date.today()
+    start_date = end_date - timedelta(days=days_back)
+
+    # Get all activities with TSS in the date range
+    query = (
+        select(
+            func.date(Activity.date).label("activity_date"),
+            func.sum(ActivityMetrics.tss).label("daily_tss"),
+        )
+        .join(ActivityMetrics, ActivityMetrics.activity_id == Activity.id)
+        .where(Activity.rider_id == rider_id)
+        .where(Activity.date >= start_date)
+        .where(ActivityMetrics.tss.isnot(None))
+        .group_by(func.date(Activity.date))
+        .order_by(func.date(Activity.date))
+    )
+
+    result = await session.execute(query)
+    tss_by_date: dict[date, float] = {}
+    for row in result:
+        tss_by_date[row.activity_date] = float(row.daily_tss)
+
+    # Delete existing history for this rider
+    existing = await session.execute(
+        select(FitnessHistory).where(FitnessHistory.rider_id == rider_id)
+    )
+    for entry in existing.scalars().all():
+        await session.delete(entry)
+
+    # Calculate EMA-based CTL/ATL/TSB
+    ctl = 0.0
+    atl = 0.0
+    prev_ctl = 0.0
+    entries: list[FitnessHistory] = []
+
+    current = start_date
+    while current <= end_date:
+        daily_tss = tss_by_date.get(current, 0.0)
+
+        ctl = ctl + (daily_tss - ctl) / CTL_DAYS
+        atl = atl + (daily_tss - atl) / ATL_DAYS
+        tsb = ctl - atl
+        ramp_rate = ctl - prev_ctl
+
+        entry = FitnessHistory(
+            rider_id=rider_id,
+            date=current,
+            ctl=round(ctl, 1),
+            atl=round(atl, 1),
+            tsb=round(tsb, 1),
+            ramp_rate=round(ramp_rate, 2),
+        )
+        entries.append(entry)
+
+        prev_ctl = ctl
+        current += timedelta(days=1)
+
+    session.add_all(entries)
+    await session.flush()
+    return entries
+
+
+async def get_fitness_history(
+    rider_id,
+    session: AsyncSession,
+    days: int = 90,
+) -> list[FitnessHistory]:
+    """Get fitness history for a rider, rebuilding if needed."""
+
+    cutoff = date.today() - timedelta(days=days)
+
+    query = (
+        select(FitnessHistory)
+        .where(FitnessHistory.rider_id == rider_id)
+        .where(FitnessHistory.date >= cutoff)
+        .order_by(FitnessHistory.date)
+    )
+    result = await session.execute(query)
+    entries = list(result.scalars().all())
+
+    # If no data or stale, rebuild
+    if not entries or entries[-1].date < date.today() - timedelta(days=1):
+        all_entries = await rebuild_fitness_history(rider_id, session)
+        entries = [e for e in all_entries if e.date >= cutoff]
+
+    return entries