'''
Extracting code
'''

StegoFile = open('Stego.txt', 'r')
StegoLength = StegoFile.read()
StegoFile.close()

print("# Character after hiding (Stego Length) = ", len(StegoLength))

StegoList = []
StegoTemp = []
ReadChar = 0


StegoFile = open('Stego.txt', 'r')

#Read Stego text and convert it to hex strings
while ReadChar < len(StegoLength):
    StegoChar = StegoFile.read(1)
    StegoTemp.append(''.join([f'\\u{ord(StegoChar):0>4x}']))
    StegoList.append(StegoTemp[ReadChar].replace('\\u','0x'))
    ReadChar += 1
StegoFile.close()

StegoText = []
StegoXor = []
Extracted = []

#Extract the Xor bits corresponding to secret bits
i = 0
W_Count = 0
C_Count = 0
while (StegoList[i] != '0xfe00') and (StegoList[i] != '0xfe01'): # check for the end of secret bits
    if (StegoList[i]) == '0x061c':
        StegoXor.append(0)
        StegoXor.append(0)
        W_Count += 1
    elif (StegoList[i]) == '0x200f':
        StegoXor.append(0)
        StegoXor.append(1)
        W_Count += 1
    elif (StegoList[i]) == '0x200c':
        StegoXor.append(1)
        StegoXor.append(0)
        W_Count += 1
    elif (StegoList[i]) == '0x034f':
        StegoXor.append(1)
        StegoXor.append(1)
        W_Count += 1
    elif (StegoList[i]) == '0x0020':
        if W_Count != C_Count:
            print("Text may be altered.")
        else:
            # print(W_Count, '=', C_Count)
            None
        C_Count = 0
        W_Count = 0
    else:
        StegoText.append(chr(int(StegoList[i], base = 16)))
        C_Count += 1
    i += 1



LastChar = StegoList[i]  

#Extract secret bits by Xoring the corresponding letters    
j= 0
i = 0
while j < len(StegoXor):
    if StegoText[i] in ["ب" ,"ت" ,"ث","ج","خ","ذ","ز", "ش","ض","ظ","غ", "ف","ق", "ن","ي","ة"]:
        D = 1     # The letter is dotted
    else:
        D = 0     # The letter is undotted
    if StegoText[i] in ["أ" ,"ا" ,"آ","إ","د","ذ","ر", "ز","و","ؤ","ى","ة","ء"]:
        C = 0       # The letter is disconnected
    else:
        C = 1       # The letter is connected

    Extracted.append(D ^ StegoXor[j])
    Extracted.append(C ^ StegoXor[j+1])
    j += 2
    i += 1

#Check if Extarced bits are the same as Secret bits
if (Secret == Extracted):
    print("Successful Extraction")
else:
    print("False Extarction")

#Remove last bit if the number of secret bits is odd
if LastChar == '0xfe00':
    k = len(Extracted)-1
    Extracted.pop(k)



print(Extracted)

StegoFile.close()