HexaWetter v1.3.0: Add precipitation map feature, update README, and enhance UI elements

api/app/services/wms.py

@@ -1,14 +1,18 @@
 from __future__ import annotations
 
+import logging
 import re
 from datetime import datetime, timedelta, timezone
 from xml.etree import ElementTree as ET
 
 from app.cache import cache_get, cache_set
-from app.http_client import get_client
 from app.config import CACHE_TTL_WMS_TIMES, DWD_WMS_URL
+from app.http_client import get_client
 
-NS = {"wms": "http://www.opengis.net/wms"}
+logger = logging.getLogger(__name__)
+
+WMS_NS = "http://www.opengis.net/wms"
+WMS_TAG = f"{{{WMS_NS}}}"
 
 
 def _parse_iso_duration_minutes(duration: str) -> int:
@@ -18,10 +22,18 @@ def _parse_iso_duration_minutes(duration: str) -> int:
     return int(match.group(1))
 
 
+def _parse_wms_datetime(value: str) -> datetime:
+    return datetime.fromisoformat(value.replace("Z", "+00:00"))
+
+
+def _format_wms_datetime(value: datetime) -> str:
+    return value.astimezone(timezone.utc).strftime("%Y-%m-%dT%H:%M:%S.000Z")
+
+
 def _parse_time_dimension(value: str) -> tuple[datetime, datetime, int]:
     start_raw, end_raw, step_raw = value.split("/")
-    start = datetime.fromisoformat(start_raw.replace("Z", "+00:00"))
-    end = datetime.fromisoformat(end_raw.replace("Z", "+00:00"))
+    start = _parse_wms_datetime(start_raw)
+    end = _parse_wms_datetime(end_raw)
     step_minutes = _parse_iso_duration_minutes(step_raw)
     return start, end, step_minutes
 
@@ -31,63 +43,155 @@ def _generate_time_steps(start: datetime, end: datetime, step_minutes: int) -> l
     current = start
     delta = timedelta(minutes=step_minutes)
     while current <= end:
-        steps.append(current.astimezone(timezone.utc).strftime("%Y-%m-%dT%H:%M:%S.000Z"))
+        steps.append(_format_wms_datetime(current))
         current += delta
     return steps
 
 
-def _find_layer_dimension(xml_text: str, layer_name: str) -> str | None:
+def _align_down(value: datetime, step_minutes: int) -> datetime:
+    aligned = value.replace(second=0, microsecond=0)
+    return aligned - timedelta(minutes=aligned.minute % step_minutes)
+
+
+def _layer_name_matches(requested: str, actual: str | None) -> bool:
+    if not actual:
+        return False
+    if requested == actual:
+        return True
+    return requested.split(":")[-1] == actual
+
+
+def _find_layer_times(xml_text: str, layer_name: str) -> tuple[str | None, int, datetime | None]:
     root = ET.fromstring(xml_text)
-    target = layer_name.split(":")[-1]
+    time_dimension: str | None = None
+    step_minutes = 5
+    latest_available: datetime | None = None
+
     for layer in root.iter():
         if not layer.tag.endswith("Layer"):
             continue
-        name_el = layer.find("wms:Name", NS) or layer.find("Name")
-        if name_el is None or name_el.text != target:
+        name_el = layer.find(f"{WMS_TAG}Name")
+        if not _layer_name_matches(layer_name, name_el.text if name_el is not None else None):
             continue
         for dim in layer:
-            if dim.tag.endswith("Dimension") and (dim.attrib.get("name") or "").lower() == "time":
-                return (dim.text or "").strip()
-    return None
+            if not dim.tag.endswith("Dimension"):
+                continue
+            dim_name = (dim.attrib.get("name") or "").lower()
+            if dim_name == "time":
+                time_dimension = (dim.text or "").strip() or None
+                if time_dimension and "/" in time_dimension:
+                    _, _, step_raw = time_dimension.split("/")
+                    step_minutes = _parse_iso_duration_minutes(step_raw)
+            elif dim_name == "reference_time":
+                default = (dim.attrib.get("default") or "").strip()
+                if default:
+                    try:
+                        latest_available = _parse_wms_datetime(default)
+                    except ValueError:
+                        pass
+        if time_dimension:
+            return time_dimension, step_minutes, latest_available
+    return None, step_minutes, latest_available
+
+
+def _filter_time_steps(
+    all_steps: list[str],
+    minutes: int,
+    latest_available: datetime | None = None,
+    step_minutes: int = 5,
+) -> list[str]:
+    now = _align_down(datetime.now(timezone.utc), step_minutes)
+    upper = latest_available or now
+    if upper > now:
+        upper = now
+    cutoff = now - timedelta(minutes=minutes)
+
+    filtered: list[str] = []
+    for step in all_steps:
+        try:
+            ts = _parse_wms_datetime(step)
+        except ValueError:
+            continue
+        if cutoff <= ts <= upper:
+            filtered.append(step)
+    return filtered
+
+
+def _fallback_time_steps(minutes: int, step_minutes: int = 5) -> list[str]:
+    now = _align_down(datetime.now(timezone.utc), step_minutes)
+    start = now - timedelta(minutes=minutes)
+    return _generate_time_steps(start, now, step_minutes)
+
+
+def _steps_from_dimension(dimension: str) -> list[str]:
+    if "/" in dimension:
+        start, end, step_minutes = _parse_time_dimension(dimension)
+        return _generate_time_steps(start, end, step_minutes)
+    return [item.strip() for item in dimension.split(",") if item.strip()]
+
+
+async def fetch_wms_time_steps_quick(layer: str, minutes: int = 120) -> dict:
+    step_minutes = 5
+    filtered = _fallback_time_steps(minutes, step_minutes)
+    return {
+        "layer": layer,
+        "minutes": minutes,
+        "step_minutes": step_minutes,
+        "count": len(filtered),
+        "times": filtered,
+        "latest": filtered[-1] if filtered else None,
+        "latest_available": filtered[-1] if filtered else None,
+        "source": "fallback",
+        "partial": True,
+    }
 
 
 async def fetch_wms_time_steps(layer: str, minutes: int = 120) -> dict:
-    cache_key = f"wms:times:{layer}:{minutes}"
+    cache_key = f"wms:times:v2:{layer}:{minutes}"
     cached = await cache_get(cache_key)
     if cached:
         return cached
 
-    params = {"service": "WMS", "version": "1.3.0", "request": "GetCapabilities"}
-    client = get_client()
-    response = await client.get(DWD_WMS_URL, params=params, timeout=15.0)
-    response.raise_for_status()
-    dimension = _find_layer_dimension(response.text, layer)
-    if not dimension:
-        raise ValueError(f"No TIME dimension found for layer {layer}")
+    step_minutes = 5
+    latest_available: datetime | None = None
+    all_steps: list[str] = []
+    source = "capabilities"
 
-    if "/" in dimension:
-        start, end, step_minutes = _parse_time_dimension(dimension)
-        all_steps = _generate_time_steps(start, end, step_minutes)
-    else:
-        all_steps = [item.strip() for item in dimension.split(",") if item.strip()]
+    try:
+        params = {"service": "WMS", "version": "1.3.0", "request": "GetCapabilities"}
+        client = get_client()
+        response = await client.get(DWD_WMS_URL, params=params, timeout=20.0)
+        response.raise_for_status()
+        dimension, step_minutes, latest_available = _find_layer_times(response.text, layer)
+        if dimension:
+            all_steps = _steps_from_dimension(dimension)
+        else:
+            source = "fallback"
+            logger.warning("No TIME dimension in WMS capabilities for layer %s", layer)
+    except Exception as exc:
+        source = "fallback"
+        logger.warning("WMS GetCapabilities failed for layer %s: %s", layer, exc)
 
-    cutoff = datetime.now(timezone.utc) - timedelta(minutes=minutes)
-    filtered = []
-    for step in all_steps:
-        try:
-            ts = datetime.fromisoformat(step.replace("Z", "+00:00"))
-        except ValueError:
-            continue
-        if ts >= cutoff:
-            filtered.append(step)
+    if not all_steps:
+        all_steps = _fallback_time_steps(minutes, step_minutes)
+        source = "fallback"
+
+    filtered = _filter_time_steps(all_steps, minutes, latest_available, step_minutes)
+    if not filtered:
+        filtered = _fallback_time_steps(minutes, step_minutes)
+        source = "fallback"
 
     payload = {
         "layer": layer,
         "minutes": minutes,
-        "step_minutes": _parse_iso_duration_minutes("PT5M") if "/" in dimension else 5,
+        "step_minutes": step_minutes,
         "count": len(filtered),
         "times": filtered,
         "latest": filtered[-1] if filtered else None,
+        "latest_available": _format_wms_datetime(latest_available) if latest_available else None,
+        "source": source,
+        "partial": False,
+        "note": "Niederschlagsradar zeigt vergangene Messungen, keine Vorhersage in die Zukunft.",
     }
     await cache_set(cache_key, payload, CACHE_TTL_WMS_TIMES)
     return payload