#!/usr/bin/python3
"""
Script to downloaded webpages, extract text and merge all of them
together to create one ebook.
"""

import errno
import os
import shutil
import subprocess


# Book name
name = "Name"
# Base url, this is used as url = mainUrl + <number of chapter>
mainUrl = "http://example.com/chapter-"
# Number of all chapter
chapters = 1
# Start from 0 or 1 ?
fromZero = False


# numerical representation of start for script
start = 0 if fromZero else 1


def runInShell(command):
  """Run giver string in shell"""
  process = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE)
  process.wait()
  process.communicate()


def download(mainUrl, name, number):
  """Download webpage, extract test, add some empty lines"""
  fileName = os.path.join('chapters', '%s-%d.txt' % (name, number))

  # download webpage
  command = 'wget -q -O- "%s%d" | unfluff | jq -r ".title, .text" > "%s"' %\
      (mainUrl, number, fileName)
  runInShell(command)

  # New line after title
  command = "sed -i '1 a\\\\' '%s'" % (fileName)
  runInShell(command)

  # New line at the end of the file
  command = "sed -i -e '$a\\' '%s'" % (fileName)
  runInShell(command)

  if number != start:
    # New lne at beginning of the file
    command = "sed -i '1i\\\\' '%s'" % (fileName)
    runInShell(command)


def main():
  """Start main downloader and converter"""
  try:
    os.makedirs("chapters")
  except OSError as e:
    if e.errno != errno.EEXIST:
      raise

  # Download all chapters one by one
  print("Downloading...")
  for i in range(start, chapters + 1, 1):
    print("Downloading: ", name, i)
    download(mainUrl, name, i)

  # merge all chapter to one file
  print("Merging...")
  command = 'cat "chapters/%s-"{%d..%d}.txt > "%s.txt"' % (name, start, chapters, name)
  runInShell(command)

  # convert to epub
  print("Converting...")
  command = 'ebook-convert "%s.txt" "%s.epub"' % (name, name)
  runInShell(command)

  # remove download directory
  print("Removing temporary data...")
  shutil.rmtree('chapters')
  os.remove("%s.txt" % (name))

  print("Done")


# if yused standalone start the script
if __name__ == '__main__':
  main()