HA-008 HA-009: add discovery and history pipeline

Closes #17

Closes #18

app/ha/client.py

@@ -2,6 +2,9 @@ from __future__ import annotations
 
 import logging
 from dataclasses import dataclass
+from datetime import datetime
+import re
+from urllib.parse import quote
 
 import requests
 
@@ -14,6 +17,9 @@ from app.ha.exceptions import (
 
 logger = logging.getLogger(__name__)
 
+_ENTITY_ID_PATTERN = re.compile(r"^[a-z0-9_]+\.[a-z0-9_]+$")
+_MAX_HISTORY_SECONDS = 31 * 24 * 60 * 60
+
 
 @dataclass(frozen=True)
 class HaClientSettings:
@@ -35,9 +41,58 @@ class HaClient:
         self._session.close()
 
     def list_entities(self) -> list[dict[str, object]]:
+        payload = self._get_json("/api/states")
+        if not isinstance(payload, list):
+            raise HaUnexpectedPayloadError(
+                "Antwort von Home Assistant hat unerwartetes Format."
+            )
+        return payload
+
+    def get_history(
+        self,
+        entity_ids: list[str],
+        start_time: datetime,
+        end_time: datetime,
+    ) -> list[object]:
+        if not entity_ids:
+            raise ValueError("Mindestens eine entity_id ist erforderlich.")
+        if len(entity_ids) > 100:
+            raise ValueError("Es können höchstens 100 Entities abgefragt werden.")
+        if any(not _ENTITY_ID_PATTERN.fullmatch(entity_id) for entity_id in entity_ids):
+            raise ValueError("entity_id enthält ein ungültiges Format.")
+        if start_time.tzinfo is None or end_time.tzinfo is None:
+            raise ValueError("start_time und end_time müssen eine Zeitzone enthalten.")
+        if end_time <= start_time:
+            raise ValueError("end_time muss nach start_time liegen.")
+        if (end_time - start_time).total_seconds() > _MAX_HISTORY_SECONDS:
+            raise ValueError("History-Abfragen sind auf 31 Tage begrenzt.")
+
+        start = quote(start_time.isoformat(), safe=":+")
+        payload = self._get_json(
+            f"/api/history/period/{start}",
+            params={
+                "filter_entity_id": ",".join(entity_ids),
+                "end_time": end_time.isoformat(),
+                "minimal_response": "1",
+                "no_attributes": "1",
+            },
+        )
+        if not isinstance(payload, list):
+            raise HaUnexpectedPayloadError(
+                "History-Antwort von Home Assistant hat unerwartetes Format."
+            )
+        return payload
+
+    def _get_json(
+        self,
+        path: str,
+        *,
+        params: dict[str, str] | None = None,
+    ) -> object:
         try:
             response = self._session.get(
-                f"{self._settings.url.rstrip('/')}/api/states",
+                f"{self._settings.url.rstrip('/')}{path}",
+                params=params,
                 timeout=self._settings.timeout_seconds,
             )
         except requests.Timeout as exc:
@@ -69,9 +124,4 @@ class HaClient:
                 "Antwort von Home Assistant ist kein gültiges JSON."
             ) from exc
 
-        if not isinstance(payload, list):
-            raise HaUnexpectedPayloadError(
-                "Antwort von Home Assistant hat unerwartetes Format."
-            )
-
         return payload