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# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#  http://www.apache.org/licenses/LICENSE-2.0
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# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
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# KIND, either express or implied.  See the License for the
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# beam-playground:
#   name: EventTimeTriggers
#   description: Task from katas to count events with event time triggers
#   multifile: true
#   context_line: 46
#   categories:
#     - Streaming
#   complexity: MEDIUM
#   tags:
#     - windowing
#     - triggers
#     - count
#     - event

import apache_beam as beam
from generate_event import GenerateEvent
from apache_beam.transforms.window import FixedWindows
from apache_beam.transforms.trigger import AccumulationMode
from apache_beam.transforms.trigger import AfterWatermark
from apache_beam.utils.timestamp import Duration
from log_elements import LogElements


class CountEvents(beam.PTransform):
    def expand(self, events):
      return (events
              | beam.WindowInto(FixedWindows(5),
                                trigger=AfterWatermark(),
                                accumulation_mode=AccumulationMode.DISCARDING,
                                allowed_lateness=Duration(seconds=0))
              | beam.CombineGlobally(beam.combiners.CountCombineFn()).without_defaults())

with beam.Pipeline() as p:
    (p | GenerateEvent.sample_data()
     | CountEvents()
     | LogElements(with_window=True))
