import download_file
from PIL import Image
def main():
url = "http://www.pythonchallenge.com/pc/ring/bell.png"
file_path = "ring/bell.png"
username = "repeat"
password = "switch"
# first_step(url, file_path, username, password)
second_step(file_path)
def first_step(url, file_path, username, password):
download_file.download_with_auth(url, file_path, username, password)
def second_step(file_path):
im = Image.open(file_path)
green_channel = 1
green_data = im.getdata(green_channel)
datas = list(green_data)
datas_len = len(datas)
assert datas_len % 2 == 0
message = ""
for i in range(int(datas_len / 2)):
index = 2 * i
left = datas[index]
right = datas[index + 1]
abs_left_min_right = abs(left - right)
if abs_left_min_right != 42:
message += chr(abs_left_min_right)
print(message)
if __name__ == "__main__":
main()