#!/usr/bin/env python

"""
Authors: Anthony Gargiulo (anthony@agargiulo.com)
         Steffen Vogel (post@steffenvogel.de)

Created: Fri Jun 15 2012
"""

from pygithub3 import Github
from argparse import ArgumentParser
import os


def main():
	parser = init_parser()
	args = parser.parse_args()

	# Process args
	if args.cron:
		args.git += "--quiet"

	# Make the connection to Github here.
	config = { 'user': args.username }

	if (args.password):
		config['password'] = args.password
		config['login'] = args.username

	gh = Github(**config)

	# Get all of the given user's repos
	user_repos = gh.repos.list().all()
	for repo in user_repos:
		repo.user = gh.users.get(repo.owner.login)
		process_repo(repo, args)


def init_parser():
	"""
	set up the argument parser
	"""

	parser = ArgumentParser(description="makes a backup of all of a github user's repositories")

	parser.add_argument("username", help="A Github username")
	parser.add_argument("backupdir", help="The folder where you want your backups to go")
	parser.add_argument("-c","--cron", help="Use this when running from a cron job", action="store_true")
	parser.add_argument("-m","--mirror", help="Create a bare mirror", action="store_true")
	parser.add_argument("-g","--git", help="Pass extra arguments to git", default="", metavar="ARGS")
	parser.add_argument("-s", "--suffix", help="Add suffix to repository directory names", default="")
	parser.add_argument("-p", "--password", help="Authenticate with Github API")

	return parser

def process_repo(repo, args):
	if not args.cron:
		print("Processing repo: %s"%(repo.full_name))

	dir = "%s/%s"%(args.backupdir, repo.name + args.suffix)
	config = "%s/%s"%(dir, "config" if args.mirror else ".git/config")

	if not os.access(config, os.F_OK):
		if not args.cron: print("Repo doesn't exists, lets clone it")
		clone_repo(repo, dir, args)
	else:
		if not args.cron: print("Repo already exists, let's try to update it instead")

	update_repo(repo, dir, args)


def clone_repo(repo, dir, args):
	if args.mirror:
		options = args.git + " --mirror"
	else:
		options = args.git

	os.system('git clone %s %s %s'%(options, repo.git_url, dir))


def update_repo(repo, dir, args):
	savedPath = os.getcwd()
	os.chdir(dir)

	# GitHub => Local
	# TODO: use subprocess package and fork git into background (major performance boost expected)
	if args.mirror:
		os.system("git fetch %s"%(args.git + " --prune",))
	else:
		os.system("git pull %s"%(args.git,))

	# Fetch description and owner (useful for gitweb, cgit etc.)
	# TODO: can we combine that in a single call to 'git config'
	os.system("git config --local gitweb.description %s"%(shell_escape(repo.description),))
	os.system("git config --local gitweb.owner %s"%(shell_escape("%s <%s>"%(repo.user.name, repo.user.email.encode("utf-8"))),))

	os.system("git config --local cgit.name %s"%(shell_escape(repo.name),))
	os.system("git config --local cgit.defbranch %s"%(shell_escape(repo.master_branch),))
	os.system("git config --local cgit.clone-url %s"%(shell_escape(repo.clone_url),))
      
	os.chdir(savedPath)

def shell_escape(str):
	return "'" + unicode(str.replace("'", "\\'")).encode("utf-8") + "'"

if __name__ == "__main__":
	main()