add my.location.home, use it as location/timezone fallback

my/location/home.py

@@ -0,0 +1,61 @@
+'''
+Simple location provider, serving as a fallback when more detailed data isn't available
+'''
+from dataclasses import dataclass
+from datetime import datetime, date
+from functools import lru_cache
+from typing import Optional, Sequence, Tuple, Union
+
+from ..core.common import fromisoformat
+
+from my.config import location as L
+user_config = L.home
+
+
+DateIsh = Union[datetime, str]
+
+# todo hopefully reasonable? might be nice to add name or something too
+LatLon = Tuple[float, float]
+
+@dataclass
+class home(user_config):
+    # TODO could make current Optional and somehow determine from system settings?
+    # todo possibly also could be core config.. but not sure
+    current: LatLon
+
+    '''
+    First element is location, the second is the date when you left it (datetime/ISO string)
+    '''
+    past: Sequence[Tuple[LatLon, DateIsh]] = ()
+    # todo test for proper localized/not localized handling as well
+    # todo make sure they are increasing
+
+
+    @property
+    def _past(self) -> Sequence[Tuple[LatLon, datetime]]:
+        # todo cache?
+        res = []
+        for loc, x in self.past:
+            dt: datetime
+            if isinstance(x, str):
+                dt = fromisoformat(x)
+            else:
+                dt = x
+            res.append((loc, dt))
+        return res
+
+        
+
+from ..core.cfg import make_config
+config = make_config(home)
+
+
+@lru_cache(maxsize=None)
+def get_location(dt: datetime) -> LatLon:
+    '''
+    Interpolates the location at dt
+    '''
+    for loc, pdt in config._past:
+        if dt <= pdt:
+            return loc
+    return config.current