source-twilio: check for updated messages based on the lookback window

Twilio's API only allows us to query messages based on their creation
date, not their updated date. Previously, the connector was only getting
creates, with the option to use the lookback window to push back the
cursor value to re-emit all messages created in the past X minutes. The
`messages` stream now uses the lookback window to query Twilio for
messages created X minutes in the past, but it only emits messages that
have been created or updated after the current cursor value.

source-twilio/source_twilio/streams.py

@@ -547,6 +547,56 @@ class Messages(IncrementalTwilioStream, TwilioNestedStream):
     upper_boundary_filter_field = "DateSent<"
     cursor_field = "date_sent"
 
+    # This overwrites IncrementalTwilioStream's method. The only difference is that
+    # this method pushes back the start datetime based on the configured lookback window.
+    def generate_date_ranges(self) -> Iterable[Optional[MutableMapping[str, Any]]]:
+        def align_to_dt_format(dt: DateTime) -> DateTime:
+            return pendulum.parse(dt.format(self.time_filter_template))
+
+        end_datetime = pendulum.now("utc")
+        pushed_back_start_datetime = pendulum.parse(self.state.get(self.cursor_field, self._start_date)) - pendulum.duration(minutes=self._lookback_window)
+        start_datetime = min(end_datetime, pushed_back_start_datetime)
+        current_start = start_datetime
+        current_end = start_datetime
+        # Aligning to a datetime format is done to avoid the following scenario:
+        # start_dt = 2021-11-14T00:00:00, end_dt (now) = 2022-11-14T12:03:01, time_filter_template = "YYYY-MM-DD"
+        # First slice: (2021-11-14, 2022-11-14)
+        # (!) Second slice: (2022-11-15, 2022-11-14) - because 2022-11-14T00:00:00 (prev end) < 2022-11-14T12:03:01,
+        # so we have to compare dates, not date-times to avoid yielding that last slice
+        while align_to_dt_format(current_end) < align_to_dt_format(end_datetime):
+            current_end = min(end_datetime, current_start + self.slice_step)
+            slice_ = {
+                self.lower_boundary_filter_field: current_start.format(self.time_filter_template),
+                self.upper_boundary_filter_field: current_end.format(self.time_filter_template),
+            }
+            yield slice_
+            current_start = current_end + self.slice_granularity
+
+    def read_records(
+        self,
+        sync_mode: SyncMode,
+        cursor_field: List[str] = None,
+        stream_slice: Mapping[str, Any] = None,
+        stream_state: Mapping[str, Any] = None,
+    ) -> Iterable[Mapping[str, Any]]:
+        unsorted_records = []
+        initial_cursor = self.state.get(self.cursor_field, self._start_date)
+
+        # Skip the IncrementalTwilioStream's read_records method since it filters based on date_sent instead of date_updated.
+        for record in super(IncrementalTwilioStream, self).read_records(sync_mode, cursor_field, stream_slice, stream_state):
+            record[self.cursor_field] = pendulum.parse(record[self.cursor_field], strict=False).to_iso8601_string()
+            record["date_updated"] = pendulum.parse(record["date_updated"], strict=False).to_iso8601_string()
+            unsorted_records.append(record)
+        sorted_records = sorted(unsorted_records, key=lambda x: x[self.cursor_field])
+        for record in sorted_records:
+            # If this is a new record, yield it and update the cursor.
+            if record[self.cursor_field] >= initial_cursor:
+                self._cursor_value = record[self.cursor_field]
+                yield record
+            # Otherwise if it's an update to a record we've seen before, yield it.
+            elif record["date_updated"] >= initial_cursor:
+                yield record
+
 
 class MessageMedia(IncrementalTwilioStream, TwilioNestedStream):
     """https://www.twilio.com/docs/sms/api/media-resource#read-multiple-media-resources"""