from mrjob.job import MRJob
from mrjob.step import MRStep
from collections import Counter

class MR_Ex3(MRJob):

    def mapper_get_words(self, _, line):
        # split line into array
        (event_time,event_type,product_id,category_id,category_code,brand,price,user_id,user_session) = line.split(',')

        # check if brand has a value and if so yield user_id and brand
        # also check if event_type is purchase
        if brand and event_type == "purchase":
            yield user_id, brand


    def reducer_count_words(self, user, brands):
        yield  user,Counter(brands).most_common(1)[0][0]


    def steps(self):
        return [
            MRStep(mapper  = self.mapper_get_words,
                   reducer = self.reducer_count)
        ]

if __name__ == '__main__':
    MR_Ex3.run()