Update backend/api/routes/biology.py

backend/api/routes/biology.py

@@ -5,7 +5,7 @@ from __future__ import annotations
 import logging
 from datetime import date
 
-from fastapi import APIRouter, Depends, HTTPException
+from fastapi import APIRouter, Depends, HTTPException, Query
 
 from backend.api.deps import get_datahub
 from src.data.data_providers import DataHub
@@ -41,3 +41,53 @@ async def biology_rules(hub: DataHub = Depends(get_datahub)):
 async def biology_rule_detail(rule_name: str, hub: DataHub = Depends(get_datahub)):
     """Explain a specific biology rule."""
     return hub.biology.explain_rule(rule_name)
+
+
+@router.get("/chill-units")
+async def biology_chill_units(
+    season_start: str = Query("2025-11-01", description="Season start (YYYY-MM-DD)"),
+    hub: DataHub = Depends(get_datahub),
+):
+    """Accumulated chill units from IMS hourly temperature.
+
+    Model: T<=7 → +1 CU/h, 7<T<=10 → +0.5, 10<T<=18 → 0, T>18 → -1.
+    Daily totals clipped at 0.
+    """
+    import numpy as np
+    import pandas as pd
+
+    try:
+        df = hub.weather._load_df()
+        if df.empty:
+            return {"error": "No IMS data available"}
+        if "timestamp_utc" in df.columns:
+            df = df.set_index(pd.to_datetime(df["timestamp_utc"], utc=True))
+
+        start = pd.Timestamp(season_start, tz="UTC")
+        subset = df.loc[start:]
+        if subset.empty or "air_temperature_c" not in subset.columns:
+            return {"error": "No temperature data in season range"}
+
+        hourly = subset["air_temperature_c"].resample("1h").mean().dropna()
+        temps = hourly.values
+        chill_h = np.select(
+            [temps <= 7, (temps > 7) & (temps <= 10), (temps > 10) & (temps <= 18), temps > 18],
+            [1.0, 0.5, 0.0, -1.0],
+        )
+        daily = pd.Series(chill_h, index=hourly.index).resample("D").sum().clip(lower=0)
+        cumulative = daily.cumsum()
+
+        return {
+            "season_start": season_start,
+            "total_chill_units": round(float(cumulative.iloc[-1]), 1) if len(cumulative) else 0,
+            "days_counted": len(daily),
+            "daily": [
+                {"date": ts.strftime("%Y-%m-%d"),
+                 "cumulative_cu": round(float(cumulative.loc[ts]), 1),
+                 "daily_cu": round(float(daily.loc[ts]), 1)}
+                for ts in daily.index
+            ],
+        }
+    except Exception as exc:
+        log.error("Chill units failed: %s", exc)
+        return {"error": f"Chill units failed: {exc}"}