Implemented tplink_lte components and notify service via SMS (#17111)

* Implemented tplink_lte components and notify service

* Device discovery for the notify component

* Improved the config schema. Small fixes

* Improved login retry mechanism

* Log successful connection only on retries

* Removed CancelledError handlers and small fixes

homeassistant/components/notify/tplink_lte.py

@@ -0,0 +1,50 @@
+"""TP-Link LTE platform for notify component.
+
+For more details about this platform, please refer to the documentation at
+https://home-assistant.io/components/notify.tplink_lte/
+"""
+
+import logging
+
+import attr
+
+from homeassistant.components.notify import (
+    ATTR_TARGET, BaseNotificationService)
+
+from ..tplink_lte import DATA_KEY
+
+DEPENDENCIES = ['tplink_lte']
+
+_LOGGER = logging.getLogger(__name__)
+
+
+async def async_get_service(hass, config, discovery_info=None):
+    """Get the notification service."""
+    if discovery_info is None:
+        return
+    return TplinkNotifyService(hass, discovery_info)
+
+
+@attr.s
+class TplinkNotifyService(BaseNotificationService):
+    """Implementation of a notification service."""
+
+    hass = attr.ib()
+    config = attr.ib()
+
+    async def async_send_message(self, message="", **kwargs):
+        """Send a message to a user."""
+        import tp_connected
+        modem_data = self.hass.data[DATA_KEY].get_modem_data(self.config)
+        if not modem_data:
+            _LOGGER.error("No modem available")
+            return
+
+        phone = self.config[ATTR_TARGET]
+        targets = kwargs.get(ATTR_TARGET, phone)
+        if targets and message:
+            for target in targets:
+                try:
+                    await modem_data.modem.sms(target, message)
+                except tp_connected.Error:
+                    _LOGGER.error("Unable to send to %s", target)