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 to get needed values
        (event_time,event_type,product_id,category_id,category_code,brand,price,user_id,user_session) = line.split(',')

        month = event_time[5:7]

        # if brand is available and type is purchase yield
        if brand and event_type == "purchase":
            yield (user_id,brand), month

    def reducer_sum(self, key, values):
        # variables to save the sums for both months
        sum_nov = 0
        sum_oct = 0

        # create sums for both months
        for v in values:
            if v=="10":
                sum_oct+=1
            elif v=="11":
                sum_nov+=1

        # only if both sums are larger than 1 create output tupel
        if sum_oct > 0 and sum_nov > 0 :
            yield key[0],(key[1],(sum_oct+sum_nov))


    def mapper_noAction(self, key, value):
        yield key, value

    # this step may be done with counter but i did not figure out how
    def reducer_maxBrand(self, key, brandAndSum):
        # variables to save max value and brand
        maxSum = 0
        maxBrand = ""
        for v in brandAndSum:
            if v[1] > maxSum:
                maxBrand = v[0]
                maxSum = v[1]

        yield maxBrand,1


    # create sum and output
    def reducer_finalSum(self,brand,values):
        yield brand,sum(values)


    def steps(self):
        return [
            MRStep(mapper=self.mapper_get_words, reducer=self.reducer_sum),
            MRStep(mapper=self.mapper_noAction, reducer=self.reducer_maxBrand),
            MRStep(mapper=self.mapper_noAction, reducer=self.reducer_finalSum)
        ]


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