# Copyright 2009-2010 Yelp
#
# 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.

"""An implementation of wc as an MRJob.

This is meant as an example of why mapper_final is useful."""
from mrjob.job import MRJob


class MRWordCountUtility(MRJob):

    def __init__(self, *args, **kwargs):
        super(MRWordCountUtility, self).__init__(*args, **kwargs)
        self.chars = 0
        self.words = 0
        self.lines = 0

    def mapper(self, _, line):
        # Don't actually yield anything for each line. Instead, collect them
        # and yield the sums when all lines have been processed. The results
        # will be collected by the reducer.
        self.chars += len(line) + 1  # +1 for newline
        self.words += sum(1 for word in line.split() if word.strip())
        self.lines += 1

    def mapper_final(self):
        yield('chars', self.chars)
        yield('words', self.words)
        yield('lines', self.lines)

    def reducer(self, key, values):
        yield(key, sum(values))


if __name__ == '__main__':
    MRWordCountUtility.run()