changes

backend/server/adventures/utils/weather.py

@@ -0,0 +1,172 @@
+import logging
+from datetime import date as date_cls
+
+import requests
+
+
+logger = logging.getLogger(__name__)
+
+OPEN_METEO_ARCHIVE_URL = "https://archive-api.open-meteo.com/v1/archive"
+OPEN_METEO_FORECAST_URL = "https://api.open-meteo.com/v1/forecast"
+
+HISTORICAL_YEARS_BACK = 5
+HISTORICAL_WINDOW_DAYS = 7
+
+
+def _base_payload(date: str) -> dict:
+    return {
+        "date": date,
+        "available": False,
+        "temperature_low_c": None,
+        "temperature_high_c": None,
+        "temperature_c": None,
+        "is_estimate": False,
+        "source": None,
+    }
+
+
+def _coerce_temperature(max_values, min_values):
+    if not max_values or not min_values:
+        return None
+
+    try:
+        low = float(min_values[0])
+        high = float(max_values[0])
+    except (TypeError, ValueError, IndexError):
+        return None
+
+    avg = (low + high) / 2
+    return {
+        "temperature_low_c": round(low, 1),
+        "temperature_high_c": round(high, 1),
+        "temperature_c": round(avg, 1),
+    }
+
+
+def _request_daily_range(
+    url: str, latitude: float, longitude: float, start_date: str, end_date: str
+):
+    try:
+        response = requests.get(
+            url,
+            params={
+                "latitude": latitude,
+                "longitude": longitude,
+                "start_date": start_date,
+                "end_date": end_date,
+                "daily": "temperature_2m_max,temperature_2m_min",
+                "timezone": "UTC",
+            },
+            timeout=8,
+        )
+        response.raise_for_status()
+        return response.json()
+    except requests.RequestException:
+        return None
+    except ValueError:
+        return None
+
+
+def _fetch_direct_temperature(date: str, latitude: float, longitude: float):
+    for source, url in (
+        ("archive", OPEN_METEO_ARCHIVE_URL),
+        ("forecast", OPEN_METEO_FORECAST_URL),
+    ):
+        data = _request_daily_range(url, latitude, longitude, date, date)
+        if not data:
+            continue
+
+        daily = data.get("daily") or {}
+        temperatures = _coerce_temperature(
+            daily.get("temperature_2m_max") or [],
+            daily.get("temperature_2m_min") or [],
+        )
+        if not temperatures:
+            continue
+
+        return {
+            **temperatures,
+            "available": True,
+            "is_estimate": False,
+            "source": source,
+        }
+
+    return None
+
+
+def _fetch_historical_estimate(date: str, latitude: float, longitude: float):
+    try:
+        target_date = date_cls.fromisoformat(date)
+    except ValueError:
+        return None
+
+    all_max: list[float] = []
+    all_min: list[float] = []
+
+    for years_back in range(1, HISTORICAL_YEARS_BACK + 1):
+        year = target_date.year - years_back
+        try:
+            same_day = target_date.replace(year=year)
+        except ValueError:
+            # Leap-day fallback: use Feb 28 for non-leap years
+            same_day = target_date.replace(year=year, day=28)
+
+        start = same_day.fromordinal(same_day.toordinal() - HISTORICAL_WINDOW_DAYS)
+        end = same_day.fromordinal(same_day.toordinal() + HISTORICAL_WINDOW_DAYS)
+        data = _request_daily_range(
+            OPEN_METEO_ARCHIVE_URL,
+            latitude,
+            longitude,
+            start.isoformat(),
+            end.isoformat(),
+        )
+        if not data:
+            continue
+
+        daily = data.get("daily") or {}
+        max_values = daily.get("temperature_2m_max") or []
+        min_values = daily.get("temperature_2m_min") or []
+        pair_count = min(len(max_values), len(min_values))
+
+        for index in range(pair_count):
+            try:
+                all_max.append(float(max_values[index]))
+                all_min.append(float(min_values[index]))
+            except (TypeError, ValueError):
+                continue
+
+    if not all_max or not all_min:
+        return None
+
+    avg_max = sum(all_max) / len(all_max)
+    avg_min = sum(all_min) / len(all_min)
+    avg = (avg_max + avg_min) / 2
+
+    return {
+        "available": True,
+        "temperature_low_c": round(avg_min, 1),
+        "temperature_high_c": round(avg_max, 1),
+        "temperature_c": round(avg, 1),
+        "is_estimate": True,
+        "source": "historical_estimate",
+    }
+
+
+def fetch_daily_temperature(date: str, latitude: float, longitude: float):
+    payload = _base_payload(date)
+
+    direct = _fetch_direct_temperature(date, latitude, longitude)
+    if direct:
+        return {**payload, **direct}
+
+    historical_estimate = _fetch_historical_estimate(date, latitude, longitude)
+    if historical_estimate:
+        return {**payload, **historical_estimate}
+
+    logger.info(
+        "No weather data available for date=%s lat=%s lon=%s",
+        date,
+        latitude,
+        longitude,
+    )
+    return payload