Add support for Notion Home Monitoring (#24634)

* Add support for Notion Home Monitoring

* Updated coverage

* Removed auto-generated translations

* Stale docstrings

* Corrected hardware version

* Fixed binary sensor representation

* Cleanup and update protection

* Updated log message

* Cleaned up is_on

* Updated docstring

* Modified which data is updated during async_update

* Added more checks during update

* More cleanup

* Fixed unhandled exception

* Owner-requested changes (round 1)

* Fixed incorrect scan interval retrieval

* Ugh

* Removed unnecessary import

* Simplified everything via dict lookups

* Ensure bridges are properly registered

* Fixed tests

* Added catch for invalid credentials

* Ensure bridge ID is updated as necessary

* Updated method name

* Simplified bridge update

* Add support for updating bridge via_device_id

* Device update guard clause

* Removed excess whitespace

* Whitespace

* Owner comments

* Member comments

homeassistant/components/notion/config_flow.py

@@ -0,0 +1,64 @@
+"""Config flow to configure the Notion integration."""
+import voluptuous as vol
+
+from homeassistant import config_entries
+from homeassistant.const import CONF_PASSWORD, CONF_USERNAME
+from homeassistant.core import callback
+from homeassistant.helpers import aiohttp_client
+
+from .const import DOMAIN
+
+
+@callback
+def configured_instances(hass):
+    """Return a set of configured Notion instances."""
+    return set(
+        entry.data[CONF_USERNAME]
+        for entry in hass.config_entries.async_entries(DOMAIN))
+
+
+@config_entries.HANDLERS.register(DOMAIN)
+class NotionFlowHandler(config_entries.ConfigFlow):
+    """Handle a Notion config flow."""
+
+    VERSION = 1
+    CONNECTION_CLASS = config_entries.CONN_CLASS_CLOUD_POLL
+
+    async def _show_form(self, errors=None):
+        """Show the form to the user."""
+        data_schema = vol.Schema({
+            vol.Required(CONF_USERNAME): str,
+            vol.Required(CONF_PASSWORD): str,
+        })
+
+        return self.async_show_form(
+            step_id='user',
+            data_schema=data_schema,
+            errors=errors or {},
+        )
+
+    async def async_step_import(self, import_config):
+        """Import a config entry from configuration.yaml."""
+        return await self.async_step_user(import_config)
+
+    async def async_step_user(self, user_input=None):
+        """Handle the start of the config flow."""
+        from aionotion import async_get_client
+        from aionotion.errors import NotionError
+
+        if not user_input:
+            return await self._show_form()
+
+        if user_input[CONF_USERNAME] in configured_instances(self.hass):
+            return await self._show_form({CONF_USERNAME: 'identifier_exists'})
+
+        session = aiohttp_client.async_get_clientsession(self.hass)
+
+        try:
+            await async_get_client(
+                user_input[CONF_USERNAME], user_input[CONF_PASSWORD], session)
+        except NotionError:
+            return await self._show_form({'base': 'invalid_credentials'})
+
+        return self.async_create_entry(
+            title=user_input[CONF_USERNAME], data=user_input)