import requests
import tarfile
from lxml.html import parse
from sys import exit
import codecs
import os


def process_downloads():
        url = "http://www.net-security.org/insecure-archive.php"
        html_tree = parse(url)
        pdf_links = html_tree.xpath("//h2[@class='style12']/a/@href")

        print("\nNumber of Mags to be downloaded : " + str(len(pdf_links)))

        dir_save_name = "netsec-mags"
        dir_save_path = os.path.join(os.getcwd(), dir_save_name)
        print("\nMags Will be saved at : " + dir_save_path)

        if not os.path.exists(dir_save_path):
                os.mkdir(dir_save_path)

        os.chdir(dir_save_path)

        for link in iter(pdf_links):
                filename = link.rpartition('/')[2]
                if os.path.exists(os.path.join(dir_save_path, filename)):
                        print(filename + " already exists and therefore skipping.")
                else:
                        print("\nCurrently downloading " + filename)
                        req = requests.get(link)
                        with codecs.open(filename, "wb") as f:
                            f.write(req.content)
        print("\nAll mags have been downloaded.")

        print("\nNow adding all the files to an Archive")
        archive_loc = create_targz(dir_save_path, dir_save_name + ".tar.gz")
        if archive_loc is not None:
            print("\nArchive created successfully. Location :- " + archive_loc)
        else:
            print("Unable to create .tar.gz file. Report to Developer.")


def create_targz(dirpath, archivename):
        """
        Create a .tar.gz Archive of a directory

        :param dirpath: Directory location to save the the book archive.
        :param archivename: Name of the archive.
        """
        try:
            with tarfile.open(archivename, "w:gz") as tar:
                tar.add(dirpath, arcname=os.path.basename(dirpath))
            return os.path.join(dirpath, archivename)
        except tarfile.TarError:
            return None

if __name__ == "__main__":
    exit(process_downloads())