Allow serializing and passing of credentials_hashes in DeviceConfig (#607)

* Allow passing of credentials_hashes in DeviceConfig

* Update following review

kasa/aestransport.py

@@ -16,6 +16,7 @@ from cryptography.hazmat.primitives.asymmetric import padding as asymmetric_padd
 from cryptography.hazmat.primitives.asymmetric import rsa
 from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
 
+from .credentials import Credentials
 from .deviceconfig import DeviceConfig
 from .exceptions import (
     SMART_AUTHENTICATION_ERRORS,
@@ -62,6 +63,16 @@ class AesTransport(BaseTransport):
     ) -> None:
         super().__init__(config=config)
 
+        self._login_version = config.connection_type.login_version
+        if not self._credentials and not self._credentials_hash:
+            self._credentials = Credentials()
+        if self._credentials:
+            self._login_params = self._get_login_params()
+        else:
+            self._login_params = json_loads(
+                base64.b64decode(self._credentials_hash.encode()).decode()  # type: ignore[union-attr]
+            )
+
         self._default_http_client: Optional[httpx.AsyncClient] = None
 
         self._handshake_done = False
@@ -80,6 +91,11 @@ class AesTransport(BaseTransport):
         """Default port for the transport."""
         return self.DEFAULT_PORT
 
+    @property
+    def credentials_hash(self) -> str:
+        """The hashed credentials used by the transport."""
+        return base64.b64encode(json_dumps(self._login_params).encode()).decode()
+
     @property
     def _http_client(self) -> httpx.AsyncClient:
         if self._config.http_client:
@@ -88,6 +104,12 @@ class AesTransport(BaseTransport):
             self._default_http_client = httpx.AsyncClient()
         return self._default_http_client
 
+    def _get_login_params(self):
+        """Get the login parameters based on the login_version."""
+        un, pw = self.hash_credentials(self._login_version == 2)
+        password_field_name = "password2" if self._login_version == 2 else "password"
+        return {password_field_name: pw, "username": un}
+
     def hash_credentials(self, login_v2):
         """Hash the credentials."""
         if login_v2:
@@ -171,14 +193,12 @@ class AesTransport(BaseTransport):
         resp_dict = json_loads(response)
         return resp_dict
 
-    async def _perform_login_for_version(self, *, login_version: int = 1):
+    async def perform_login(self):
         """Login to the device."""
         self._login_token = None
-        un, pw = self.hash_credentials(login_version == 2)
-        password_field_name = "password2" if login_version == 2 else "password"
         login_request = {
             "method": "login_device",
-            "params": {password_field_name: pw, "username": un},
+            "params": self._login_params,
             "request_time_milis": round(time.time() * 1000),
         }
         request = json_dumps(login_request)
@@ -187,15 +207,6 @@ class AesTransport(BaseTransport):
         self._handle_response_error_code(resp_dict, "Error logging in")
         self._login_token = resp_dict["result"]["token"]
 
-    async def perform_login(self) -> None:
-        """Login to the device."""
-        try:
-            await self._perform_login_for_version(login_version=2)
-        except AuthenticationException:
-            _LOGGER.warning("Login version 2 failed, trying version 1")
-            await self.perform_handshake()
-            await self._perform_login_for_version(login_version=1)
-
     async def perform_handshake(self):
         """Perform the handshake."""
         _LOGGER.debug("Will perform handshaking...")