#!/usr/bin/env python3

# Copyright 2016 Google Inc.
#
# Licensed 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
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import apache_beam as beam
import csv


def addtimezone(lat, lon):
    try:
        import timezonefinder
        tf = timezonefinder.TimezoneFinder()
        tz = tf.timezone_at(lng=float(lon), lat=float(lat))
        if tz is None:
            tz = 'UTC'
        return lat, lon, tz
    except ValueError:
        return lat, lon, 'TIMEZONE'  # header


if __name__ == '__main__':
    with beam.Pipeline('DirectRunner') as pipeline:
        airports = (pipeline
                    | beam.io.ReadFromText('airports.csv.gz')
                    | beam.Filter(lambda line: "United States" in line)
                    | beam.Map(lambda line: next(csv.reader([line])))
                    | beam.Map(lambda fields: (fields[0], addtimezone(fields[21], fields[26])))
                    )

        airports | beam.Map(lambda f: '{},{}'.format(f[0], ','.join(f[1]))) | beam.io.textio.WriteToText(
            'airports_with_tz')