From 1826139cc81bbdb0b9fdd616b16fa92b07654f6b Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sat, 15 Jul 2023 11:50:07 -1000
Subject: [PATCH] feat: add ability to set the bind key after init (#83)

BREAKING CHANGE: the bindkey should no longer be set directly on the object, call `set_bindkey` instead
---
 src/bthome_ble/parser.py | 14 ++++++----
 tests/test_parser_v2.py  | 56 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+), 5 deletions(-)

diff --git a/src/bthome_ble/parser.py b/src/bthome_ble/parser.py
index 13f3e07..aef9138 100644
--- a/src/bthome_ble/parser.py
+++ b/src/bthome_ble/parser.py
@@ -117,11 +117,7 @@ class BTHomeBluetoothDeviceData(BluetoothData):
 
     def __init__(self, bindkey: bytes | None = None) -> None:
         super().__init__()
-        self.bindkey = bindkey
-        if bindkey:
-            self.cipher: AESCCM | None = AESCCM(bindkey, tag_length=4)
-        else:
-            self.cipher = None
+        self.set_bindkey(bindkey)
 
         # Data that we know how to parse but don't yet map to the SensorData model.
         self.unhandled: dict[str, Any] = {}
@@ -152,6 +148,14 @@ def __init__(self, bindkey: bytes | None = None) -> None:
         # If this is True, the device is not sending advertisements in a regular interval
         self.sleepy_device = False
 
+    def set_bindkey(self, bindkey: bytes | None) -> None:
+        """Set the bindkey."""
+        self.bindkey = bindkey
+        if bindkey:
+            self.cipher: AESCCM | None = AESCCM(bindkey, tag_length=4)
+        else:
+            self.cipher = None
+
     def supported(self, data: BluetoothServiceInfo) -> bool:
         if not super().supported(data):
             return False
diff --git a/tests/test_parser_v2.py b/tests/test_parser_v2.py
index 879d395..f14f75a 100644
--- a/tests/test_parser_v2.py
+++ b/tests/test_parser_v2.py
@@ -313,6 +313,62 @@ def test_bindkey_correct():
     )
 
 
+def test_bindkey_set_late():
+    """Test BTHome parser with correct encryption key set after the device is created."""
+    bindkey = "231d39c1d7cc1ab1aee224cd096db932"
+    data_string = b"\x41\xa4\x72\x66\xc9\x5f\x73\x00\x11\x22\x33\x78\x23\x72\x14"
+    advertisement = bytes_to_service_info(
+        data_string,
+        local_name="TEST DEVICE",
+        address="54:48:E6:8F:80:A5",
+    )
+
+    device = BTHomeBluetoothDeviceData()
+    device.set_bindkey(bytes.fromhex(bindkey))
+    assert device.supported(advertisement)
+    assert device.bindkey_verified
+    assert device.update(advertisement) == SensorUpdate(
+        title="TEST DEVICE 80A5",
+        devices={
+            None: SensorDeviceInfo(
+                name="TEST DEVICE 80A5",
+                manufacturer=None,
+                model="BTHome sensor",
+                sw_version="BTHome BLE v2 (encrypted)",
+                hw_version=None,
+            )
+        },
+        entity_descriptions={
+            KEY_TEMPERATURE: SensorDescription(
+                device_key=KEY_TEMPERATURE,
+                device_class=SensorDeviceClass.TEMPERATURE,
+                native_unit_of_measurement=Units.TEMP_CELSIUS,
+            ),
+            KEY_HUMIDITY: SensorDescription(
+                device_key=KEY_HUMIDITY,
+                device_class=SensorDeviceClass.HUMIDITY,
+                native_unit_of_measurement=Units.PERCENTAGE,
+            ),
+            KEY_SIGNAL_STRENGTH: SensorDescription(
+                device_key=KEY_SIGNAL_STRENGTH,
+                device_class=SensorDeviceClass.SIGNAL_STRENGTH,
+                native_unit_of_measurement=Units.SIGNAL_STRENGTH_DECIBELS_MILLIWATT,
+            ),
+        },
+        entity_values={
+            KEY_TEMPERATURE: SensorValue(
+                device_key=KEY_TEMPERATURE, name="Temperature", native_value=25.06
+            ),
+            KEY_HUMIDITY: SensorValue(
+                device_key=KEY_HUMIDITY, name="Humidity", native_value=50.55
+            ),
+            KEY_SIGNAL_STRENGTH: SensorValue(
+                device_key=KEY_SIGNAL_STRENGTH, name="Signal Strength", native_value=-60
+            ),
+        },
+    )
+
+
 def test_bindkey_verified_can_be_unset():
     """Test BTHome parser with wrong encryption key."""
     bindkey = "814aac74c4f17b6c1581e1ab87816b99"