#################################################
# 15-112-n18 hw4
# Your Name:
# Your Andrew ID:
# Your Section:
#################################################

import math
import string

#################################################
# Helper functions
#################################################

def almostEqual(d1, d2, epsilon=10**-7):
    return (abs(d2 - d1) < epsilon)

import decimal
def roundHalfUp(d):
    # Round to nearest with ties going away from zero.
    rounding = decimal.ROUND_HALF_UP
    # See other rounding options here:
    # https://docs.python.org/3/library/decimal.html#rounding-modes
    return int(decimal.Decimal(d).to_integral_value(rounding=rounding))


#################################################
# hw4 problems
#################################################

def longestCommonSubstring(s1, s2):
    return 42

def bestStudentAndAvg(gradebook):
    return 42

def encodeColumnShuffleCipher(message, key):
    return 42

#These two are bonus questions. 
def decodeColumnShuffleCipher(message):
    return 42

def mostFrequentLetters(s):
    return 42

#################################################
# hw4 Test Functions
################################################

def testLongestCommonSubstring():
    print("Testing longestCommonSubstring()...", end="")
    assert(longestCommonSubstring("abcdef", "abqrcdest") == "cde")
    assert(longestCommonSubstring("abcdef", "ghi") == "")
    assert(longestCommonSubstring("", "abqrcdest") == "")
    assert(longestCommonSubstring("abcdef", "") == "")
    assert(longestCommonSubstring("abcABC", "zzabZZAB") == "AB")
    print("Passed!")

def testBestStudentAndAvg():
    print("Testing bestStudentAndAvg()...", end="")
    gradebook = """
# ignore  blank lines and lines starting  with  #'s
wilma,91,93
fred,80,85,90,95,100
betty,88
"""
    assert(bestStudentAndAvg(gradebook) ==  "wilma:92")
    gradebook   =   """
#   ignore  blank   lines   and lines   starting    with    #'s
wilma,93,95

fred,80,85,90,95,100
betty,88
"""
    assert(bestStudentAndAvg(gradebook) ==  "wilma:94")
    gradebook = "fred,0"
    assert(bestStudentAndAvg(gradebook) ==  "fred:0")
    gradebook = "fred,-1\nwilma,-2"
    assert(bestStudentAndAvg(gradebook) ==  "fred:-1")
    gradebook = "fred,100"
    assert(bestStudentAndAvg(gradebook) ==  "fred:100")
    gradebook = "fred,100,110"
    assert(bestStudentAndAvg(gradebook) ==  "fred:105")
    gradebook = "fred,49\nwilma" + ",50"*50
    assert(bestStudentAndAvg(gradebook) ==  "wilma:50")
    print("Passed!")


def testEncodeColumnShuffleCipher():
    print("Testing encodeColumnShuffleCipher()...", end="")

    msg = "ILOVECMUSOMUCH"
    result = "021IVMOCOCSU-LEUMH"
    assert(encodeColumnShuffleCipher(msg, "021") == result)
    
    msg = "WEATTACKATDAWN"
    result = "0213WTAWACD-EATNTKA-"
    assert(encodeColumnShuffleCipher(msg, "0213") == result)
    
    msg = "SUDDENLYAWHITERABBITWITHPINKEYESRANCLOSEBYHER"
    result = "210DNAIRBWHNYRCSYRUEYHEBTTIESNOBESDLWTAIIPKEALEH"
    assert(encodeColumnShuffleCipher(msg,"210") == result)

    print("Passed!")
    
def testDecodeColumnShuffleCipher():
    print("Testing decodeColumnShuffleCipher()...", end="")
    msg = "0213WTAWACD-EATNTKA-"
    result = "WEATTACKATDAWN"
    assert(decodeColumnShuffleCipher(msg) == result)

    msg = "210DNAIRBWHNYRCSYR-UEYHEBTTIESNOBE-SDLWTAIIPKEALEH-"
    result = "SUDDENLYAWHITERABBITWITHPINKEYESRANCLOSEBYHER"
    assert(decodeColumnShuffleCipher(msg) == result)

    print("Passed!")

def testMostFrequentLetters():
    print("Testing mostFrequentLetters()...", end="")

    s = "We attack at Dawn"
    result = "atwcdekn"
    assert(mostFrequentLetters(s) == result)

    s = "Note that digits, punctuation, and whitespace are not letters!"
    result = "teanioscdhpruglw"
    assert(mostFrequentLetters(s) == result)

    s = ""
    result = ""
    assert(mostFrequentLetters(s) == result)

    print("Passed!")


#################################################
# hw4 Main
################################################

def testAll():
    testLongestCommonSubstring()
    testBestStudentAndAvg()
    testEncodeColumnShuffleCipher()

    #Comment these in if you want to test the bonus functions
    # testDecodeColumnShuffleCipher()
    # testMostFrequentLetters()


def main():
    testAll()

if __name__ == '__main__':
    main()