from .haystack import haystack


# class haystackmapper:
    
#     """
#     haystackmapper is a class responsible for map process, 
#     it emits key-value pair if a needle can be found in the haystack
#     (key: haystack name, value: 1 represents a match)
#     """
    
#     emission = []
#     def __init__ (self, haystacks):
#         self.haystacks = haystacks
def mapper (stack, needle):
    len_needle = len(needle)
    emission = []
    for haystack in stack:
        len_haystack = haystack.get_length()
        data = haystack.get_data()
        for i in range(len_haystack):
                
            #get subsequence length
            len_sub = min(len_needle, (len_haystack - i)) 
            
            subsequence = data[i:i + len_needle]
            nomatch = 0
            """ 
            Uncomment this for debugging:                 
            #difference = []
            """
            
            if len_sub <= 1:
                nomatch = 1
                break
            for i in range(len_sub): # len_sub <= len_needle
                """ 
                Uncomment this for debugging: 
                if abs(needle[i]) > 100 :
                    difference.append(abs(subsequence[i] - needle[i])/needle[i] )
                else:
                    difference.append(0)
                """
                if abs(needle[i]) > 100 and abs(subsequence[i] - needle[i]) > abs(0.05*needle[i]): 
                    # allow slight variation
                    nomatch = 1
                    break
            
            if nomatch == 0:
                
                """ 
                Uncomment this section for deubgging to show comparison
                print(needle)
                print(subsequence)
                print(difference)
                print(haystack.get_name(),nomatch)
                """
                
                emission.append([haystack.get_name(), 1])
                break
            else:
                pass
    
    return emission