from C1 import encodeHexStrToRawBytes
from C3 import decryptMessage, decryptWithChiSquare

def readnThFile(fileName, pos):
    '''
    read the nth line of a file,
    removes the '\n' characters
    and return the newer line
    '''
    i = 0
    with open(fileName, "r") as text:   
        for line in text:
            line = line.replace('\n', '')
            if i == pos:
                return line
            i += 1
    return line

rawBytesStr = list()
results = list()

# read the file with the strings given to the challenge
# encode it to rawBytes, decrypt it with Chi Square function
#and save the result to results list

bestIndex = 0
bestKey = 0
minimumResult = 0
i = 0

with open("C4_strings.txt", "r") as text:   
    for line in text:
        line = line.replace('\n', '')
        rawBytesStr = encodeHexStrToRawBytes(line)
        results = decryptWithChiSquare(rawBytesStr)        
        if i == 0:
            minimumResult = min(results[0], key=results[0].get)
            bestKey = results[1]
            bestIndex = i
        else:
            if minimumResult  > min(results[0], key=results[0].get):
                minimumResult = min(results[0], key=results[0].get)
                bestKey = results[1]
                bestIndex = i
        i += 1

#decryptMessage(rawBytesStr, decryptWithChiSquare(rawBytesStr)[1])        
        
string = readnThFile("C4_strings.txt", bestIndex)
rawBytesStr = encodeHexStrToRawBytes(string)
print(decryptMessage(rawBytesStr, bestKey))