accessory: Integrate .plist reading into library

examples/real_airtag.py

@@ -3,13 +3,11 @@ Example showing how to fetch locations of an AirTag, or any other FindMy accesso
 """
 from __future__ import annotations
 
-import plistlib
-from datetime import datetime, timedelta, timezone
 from pathlib import Path
 
 from _login import get_account_sync
 
-from findmy import FindMyAccessory, KeyPair
+from findmy import FindMyAccessory
 from findmy.reports import RemoteAnisetteProvider
 
 # URL to (public or local) anisette server
@@ -18,37 +16,11 @@ ANISETTE_SERVER = "http://localhost:6969"
 # Path to a .plist dumped from the Find My app.
 PLIST_PATH = Path("airtag.plist")
 
-# == The variables below are auto-filled from the plist!! ==
-
-with PLIST_PATH.open("rb") as f:
-    device_data = plistlib.load(f)
-
-# PRIVATE master key. 28 (?) bytes.
-MASTER_KEY = device_data["privateKey"]["key"]["data"][-28:]
-
-# "Primary" shared secret. 32 bytes.
-SKN = device_data["sharedSecret"]["key"]["data"]
-
-# "Secondary" shared secret. 32 bytes.
-SKS = device_data["secondarySharedSecret"]["key"]["data"]
-
-# "Paired at" timestamp (UTC)
-PAIRED_AT = device_data["pairingDate"].replace(tzinfo=timezone.utc)
-
-
-def _gen_keys(airtag: FindMyAccessory, _from: datetime, to: datetime) -> set[KeyPair]:
-    keys = set()
-    while _from < to:
-        keys.update(airtag.keys_at(_from))
-
-        _from += timedelta(minutes=15)
-
-    return keys
-
 
 def main() -> None:
     # Step 0: create an accessory key generator
-    airtag = FindMyAccessory(MASTER_KEY, SKN, SKS, PAIRED_AT)
+    with PLIST_PATH.open("rb") as f:
+        airtag = FindMyAccessory.from_plist(f)
 
     # Step 1: log into an Apple account
     print("Logging into account")