Add Config flow to august (#32133)

* Add battery sensors for August devices

* Additional tests and cleanup in prep for config flow
  and device registry

* pylint

* update name for new style guidelines - https://developers.home-assistant.io/docs/development_guidelines/#use-new-style-string-formatting

* Config Flow for august push

* Update homeassistant/components/august/__init__.py

Co-Authored-By: Paulus Schoutsen <paulus@home-assistant.io>

* Address review items

* Update tests

Co-authored-by: Paulus Schoutsen <paulus@home-assistant.io>

homeassistant/components/august/gateway.py

@@ -0,0 +1,143 @@
+"""Handle August connection setup and authentication."""
+
+import asyncio
+import logging
+
+from august.api import Api
+from august.authenticator import AuthenticationState, Authenticator
+from requests import RequestException, Session
+
+from homeassistant.const import CONF_PASSWORD, CONF_TIMEOUT, CONF_USERNAME
+from homeassistant.core import callback
+
+from .const import (
+    CONF_ACCESS_TOKEN_CACHE_FILE,
+    CONF_INSTALL_ID,
+    CONF_LOGIN_METHOD,
+    DEFAULT_AUGUST_CONFIG_FILE,
+    VERIFICATION_CODE_KEY,
+)
+from .exceptions import CannotConnect, InvalidAuth, RequireValidation
+
+_LOGGER = logging.getLogger(__name__)
+
+
+class AugustGateway:
+    """Handle the connection to August."""
+
+    def __init__(self, hass):
+        """Init the connection."""
+        self._api_http_session = Session()
+        self._token_refresh_lock = asyncio.Lock()
+        self._hass = hass
+        self._config = None
+        self._api = None
+        self._authenticator = None
+        self._authentication = None
+
+    @property
+    def authenticator(self):
+        """August authentication object from py-august."""
+        return self._authenticator
+
+    @property
+    def authentication(self):
+        """August authentication object from py-august."""
+        return self._authentication
+
+    @property
+    def access_token(self):
+        """Access token for the api."""
+        return self._authentication.access_token
+
+    @property
+    def api(self):
+        """August api object from py-august."""
+        return self._api
+
+    def config_entry(self):
+        """Config entry."""
+        return {
+            CONF_LOGIN_METHOD: self._config[CONF_LOGIN_METHOD],
+            CONF_USERNAME: self._config[CONF_USERNAME],
+            CONF_PASSWORD: self._config[CONF_PASSWORD],
+            CONF_INSTALL_ID: self._config.get(CONF_INSTALL_ID),
+            CONF_TIMEOUT: self._config.get(CONF_TIMEOUT),
+            CONF_ACCESS_TOKEN_CACHE_FILE: self._config[CONF_ACCESS_TOKEN_CACHE_FILE],
+        }
+
+    @callback
+    def async_setup(self, conf):
+        """Create the api and authenticator objects."""
+        if conf.get(VERIFICATION_CODE_KEY):
+            return
+        if conf.get(CONF_ACCESS_TOKEN_CACHE_FILE) is None:
+            conf[
+                CONF_ACCESS_TOKEN_CACHE_FILE
+            ] = f".{conf[CONF_USERNAME]}{DEFAULT_AUGUST_CONFIG_FILE}"
+        self._config = conf
+
+        self._api = Api(
+            timeout=self._config.get(CONF_TIMEOUT), http_session=self._api_http_session,
+        )
+
+        self._authenticator = Authenticator(
+            self._api,
+            self._config[CONF_LOGIN_METHOD],
+            self._config[CONF_USERNAME],
+            self._config[CONF_PASSWORD],
+            install_id=self._config.get(CONF_INSTALL_ID),
+            access_token_cache_file=self._hass.config.path(
+                self._config[CONF_ACCESS_TOKEN_CACHE_FILE]
+            ),
+        )
+
+    def authenticate(self):
+        """Authenticate with the details provided to setup."""
+        self._authentication = None
+        try:
+            self._authentication = self.authenticator.authenticate()
+        except RequestException as ex:
+            _LOGGER.error("Unable to connect to August service: %s", str(ex))
+            raise CannotConnect
+
+        if self._authentication.state == AuthenticationState.BAD_PASSWORD:
+            raise InvalidAuth
+
+        if self._authentication.state == AuthenticationState.REQUIRES_VALIDATION:
+            raise RequireValidation
+
+        if self._authentication.state != AuthenticationState.AUTHENTICATED:
+            _LOGGER.error(
+                "Unknown authentication state: %s", self._authentication.state
+            )
+            raise InvalidAuth
+
+        return self._authentication
+
+    async def async_refresh_access_token_if_needed(self):
+        """Refresh the august access token if needed."""
+        if self.authenticator.should_refresh():
+            async with self._token_refresh_lock:
+                await self._hass.async_add_executor_job(self._refresh_access_token)
+
+    def _refresh_access_token(self):
+        refreshed_authentication = self.authenticator.refresh_access_token(force=False)
+        _LOGGER.info(
+            "Refreshed august access token. The old token expired at %s, and the new token expires at %s",
+            self.authentication.access_token_expires,
+            refreshed_authentication.access_token_expires,
+        )
+        self._authentication = refreshed_authentication
+
+    def _close_http_session(self):
+        """Close API sessions used to connect to August."""
+        if self._api_http_session:
+            try:
+                self._api_http_session.close()
+            except RequestException:
+                pass
+
+    def __del__(self):
+        """Close out the http session on destroy."""
+        self._close_http_session()