text: # coding: utf-8
  from __future__ import unicode_literals, print_function
  
  import sys
  import re
  import os
  import string
  import zipfile
  import shutil
  import requests
  
  from nhentai import constant
  from nhentai.logger import logger
  
  
  def request(method, url, **kwargs):
      session = requests.Session()
      session.headers.update({
          'Referer': constant.LOGIN_URL,
          'User-Agent': 'nhentai command line client (https://github.com/RicterZ/nhentai)',
          'Cookie': constant.COOKIE
      })
      return getattr(session, method)(url, proxies=constant.PROXY, verify=False, **kwargs)
  
  
  def check_cookie():
      response = request('get', constant.BASE_URL).text
      username = re.findall('"/users/\d+/(.*?)"', response)
      if not username:
          logger.error('Cannot get your username, please check your cookie or use `nhentai --cookie` to set your cookie')
      else:
          logger.info('Login successfully! Your username: {}'.format(username[0]))
  
  
  class _Singleton(type):
      """ A metaclass that creates a Singleton base class when called. """
      _instances = {}
  
      def __call__(cls, *args, **kwargs):
          if cls not in cls._instances:
              cls._instances[cls] = super(_Singleton, cls).__call__(*args, **kwargs)
          return cls._instances[cls]
  
  
  class Singleton(_Singleton(str('SingletonMeta'), (object,), {})):
      pass
  
  
  def urlparse(url):
      try:
          from urlparse import urlparse
      except ImportError:
          from urllib.parse import urlparse
  
      return urlparse(url)
  
  
  def readfile(path):
      loc = os.path.dirname(__file__)
  
      with open(os.path.join(loc, path), 'r') as file:
          return file.read()
  
  
  def generate_html(output_dir='.', doujinshi_obj=None):
      image_html = ''
  
      if doujinshi_obj is not None:
          doujinshi_dir = os.path.join(output_dir, doujinshi_obj.filename)
      else:
          doujinshi_dir = '.'
  
      file_list = os.listdir(doujinshi_dir)
      file_list.sort()
  
      for image in file_list:
          if not os.path.splitext(image)[1] in ('.jpg', '.png'):
              continue
  
          image_html += '<img src="{0}" class="image-item"/>\n'\
              .format(image)
  
      html = readfile('viewer/index.html')
      css = readfile('viewer/styles.css')
      js = readfile('viewer/scripts.js')
  
      if doujinshi_obj is not None:
          title = doujinshi_obj.name
          if sys.version_info < (3, 0):
              title = title.encode('utf-8')
      else:
          title = 'nHentai HTML Viewer'
  
      data = html.format(TITLE=title, IMAGES=image_html, SCRIPTS=js, STYLES=css)
      try:
          if sys.version_info < (3, 0):
              with open(os.path.join(doujinshi_dir, 'index.html'), 'w') as f:
                  f.write(data)
          else:
              with open(os.path.join(doujinshi_dir, 'index.html'), 'wb') as f:
                  f.write(data.encode('utf-8'))
  
          logger.log(15, 'HTML Viewer has been write to \'{0}\''.format(os.path.join(doujinshi_dir, 'index.html')))
      except Exception as e:
          logger.warning('Writen HTML Viewer failed ({})'.format(str(e)))
  
  
  def generate_main_html(output_dir='./'):
      """
      Generate a main html to show all the contain doujinshi.
      With a link to their `index.html`.
      Default output folder will be the CLI path.
      """
  
      count = 0
      image_html = ''
      main = readfile('viewer/main.html')
      css = readfile('viewer/main.css')
      element = '\n\
              <div class="gallery-favorite">\n\
                  <div class="gallery">\n\
                      <a href="./{FOLDER}/index.html" class="cover" style="padding:0 0 141.6% 0"><img\n\
                              src="./{FOLDER}/{IMAGE}" />\n\
                          <div class="caption">{TITLE}</div>\n\
                      </a>\n\
                  </div>\n\
              </div>\n'
  
      os.chdir(output_dir)
      doujinshi_dirs = next(os.walk('.'))[1]
  
      for folder in doujinshi_dirs:
  
          files = os.listdir(folder)
          files.sort()
  
          if 'index.html' in files:
              count += 1
              logger.info('Add doujinshi \'{}\''.format(folder))
          else:
              continue
  
          image = files[0]  # 001.jpg or 001.png
          if folder is not None:
              title = folder.replace('_', ' ')
          else:
              title = 'nHentai HTML Viewer'
  
          image_html += element.format(FOLDER=folder, IMAGE=image, TITLE=title)
  
      if image_html == '':
          logger.warning('None index.html found, --gen-main paused.')
          return
      try:
          data = main.format(STYLES=css, COUNT=count, PICTURE=image_html)
          if sys.version_info < (3, 0):
              with open('./main.html', 'w') as f:
                  f.write(data)
          else:
              with open('./main.html', 'wb') as f:
                  f.write(data.encode('utf-8'))
          logger.log(
              15, 'Main Viewer has been write to \'{0}main.html\''.format(output_dir))
      except Exception as e:
          logger.warning('Writen Main Viewer failed ({})'.format(str(e)))
  
  
  def generate_cbz(output_dir='.', doujinshi_obj=None, rm_origin_dir=False):
      if doujinshi_obj is not None:
          doujinshi_dir = os.path.join(output_dir, doujinshi_obj.filename)
          cbz_filename = os.path.join(os.path.join(doujinshi_dir, '..'), '%s.cbz' % doujinshi_obj.id)
      else:
          cbz_filename = './doujinshi.cbz'
          doujinshi_dir = '.'
  
      file_list = os.listdir(doujinshi_dir)
      file_list.sort()
  
      logger.info('Writing CBZ file to path: {}'.format(cbz_filename))
      with zipfile.ZipFile(cbz_filename, 'w') as cbz_pf:
          for image in file_list:
              image_path = os.path.join(doujinshi_dir, image)
              cbz_pf.write(image_path, image)
  
      if rm_origin_dir:
          shutil.rmtree(doujinshi_dir, ignore_errors=True)
  
      logger.log(15, 'Comic Book CBZ file has been write to \'{0}\''.format(doujinshi_dir))
  
  
  def format_filename(s):
      """Take a string and return a valid filename constructed from the string.
  Uses a whitelist approach: any characters not present in valid_chars are
  removed. Also spaces are replaced with underscores.
  
  Note: this method may produce invalid filenames such as ``, `.` or `..`
  When I use this method I prepend a date string like '2009_01_15_19_46_32_'
  and append a file extension like '.txt', so I avoid the potential of using
  an invalid filename.
  
  """
      valid_chars = "-_.()[] %s%s" % (string.ascii_letters, string.digits)
      filename = ''.join(c for c in s if c in valid_chars)
      if len(filename) > 100:
          filename = filename[:100] + '...]'
  
      # Remove [] from filename
      filename = filename.replace('[]', '')
      return filename
  