Add Google Mail integration (#82637)

* Add Google Mail integration

* oops

* prettier

* Add email service

* adjustments

* update

* move email to notify

* break out services

* tweaks

* Add CC and BCC support

* drop scope check, breakout tests

* use abstract auth

* tweak

* bump dependency

* dependency bump

* remove oauth2client

homeassistant/components/google_mail/api.py

@@ -0,0 +1,41 @@
+"""API for Google Mail bound to Home Assistant OAuth."""
+from aiohttp import ClientSession
+from google.auth.exceptions import RefreshError
+from google.oauth2.credentials import Credentials
+from google.oauth2.utils import OAuthClientAuthHandler
+from googleapiclient.discovery import Resource, build
+
+from homeassistant.const import CONF_ACCESS_TOKEN
+from homeassistant.helpers import config_entry_oauth2_flow
+
+
+class AsyncConfigEntryAuth(OAuthClientAuthHandler):
+    """Provide Google Mail authentication tied to an OAuth2 based config entry."""
+
+    def __init__(
+        self,
+        websession: ClientSession,
+        oauth2Session: config_entry_oauth2_flow.OAuth2Session,
+    ) -> None:
+        """Initialize Google Mail Auth."""
+        self.oauth_session = oauth2Session
+        super().__init__(websession)
+
+    @property
+    def access_token(self) -> str:
+        """Return the access token."""
+        return self.oauth_session.token[CONF_ACCESS_TOKEN]
+
+    async def check_and_refresh_token(self) -> str:
+        """Check the token."""
+        await self.oauth_session.async_ensure_token_valid()
+        return self.access_token
+
+    async def get_resource(self) -> Resource:
+        """Get current resource."""
+        try:
+            credentials = Credentials(await self.check_and_refresh_token())
+        except RefreshError as ex:
+            self.oauth_session.config_entry.async_start_reauth(self.oauth_session.hass)
+            raise ex
+        return build("gmail", "v1", credentials=credentials)