#Assignment 2 solutions
import conversions
import rc4
import javarandom
import os
import importlib

#grading script for Assignment 2

#Test code specific to this assignment.


def solve_6a(module):
    ciphertext=conversions.b64_to_as(open('HW2_6a_ciphertext.txt','r').read())
    key=conversions.hex_to_as('7f65a580cb')
    return module.rc4_iv_decrypt(key,ciphertext)
    



def solve_6b(module):
    #get the ciphertext
    ciphertext=conversions.b64_to_as(open('HW2_6b_ciphertext.txt','r').read())
    seed=module.find_key6(ciphertext)
    initstate=rc4.rc4_initialize(seed)
    keystream=rc4.rc4_genbytes(initstate,len(ciphertext))
    return conversions.xor(ciphertext,keystream)



def solve_7(module):
    ct=conversions.b64_to_as(open('HW2_7_ciphertext.txt','r').read())
    start_four=conversions.xor(ct[:4],'FROM')
    key=start_four+conversions.hex_to_as(module.find_key7(ct))
    return 'FROM'+javarandom.encdec(key,ct[4:])


#Run the test code for this assignment.

def grade_hw2(student_name,module):
    print module
    print 'Problem 6a\n\n'
    try:
        print 'Attempting to run student code.'
        print repr(solve_6a(module))
        raw_input('\n\nhit return to continue')
        print '\n\n'
        
    except AttributeError:
        print student_name+' did not supply or misnamed the function solve_6a\n\n'

    except Exception as e:
        print e.message
        
    
    
    print 'Problem 6b\n'
    try:
        print 'Attempting to run student code.'
        print repr(solve_6b(module))
        print '\n\n\n'
    except AttributeError:
        print student_name+' did not supply or misnamed the function find_key6\n\n\n'
    except Exception as e:
        print e.message
    raw_input('\n\nhit return to continue')
    
    print 'Problem 7\n'
    
    try:
        print repr(solve_7(module))
    except AttributeError:
        print student_name+' did not supply or misnamed the function find_key7\n\n'
    except Exception as e:
        print e.message
    raw_input('\n\nhit return to continue')
    



#first step, extract all files from zip archives, and
#remove the zipped files
def extract_from_zip():
    filelist=os.listdir(os.curdir)
    for s in filelist:
        if s[-7:]=='HW2.zip':
            os.system('unzip '+s)
            os.system('rm '+s)
            print 'unzipping '+s

#Now go through the directory, and run each
#of the required functions
        
def grade_all_submissions():
    filelist=os.listdir(os.curdir)
    for s in filelist:
        if s[-3:]=='HW2':
            print 'grading code for '+s[:-3]
            sublist=os.listdir(os.curdir+'/'+s)
        #Now this is weird.  The directory has to
        #contain a file called '__init__.py
            f=open(os.curdir+'/'+s+'/__init__.py','w')
            f.close()
    
            for t in sublist:
            
                if t[-6:]=='HW2.py':
##                    cleanse(t[:-6])
                    module=importlib.import_module(s+'.'+s)
                    #print 'imported '+ s
                    grade_hw2(t[:-6],module)
                
                    print 'Done testing code for '+t[:-6]+'.\n\n'
                
                    raw_input('hit return to continue\n\n')

def do_it():
    extract_from_zip()
    grade_all_submissions()