#!/usr/bin/python3
# coding: utf-8

# aurbot - Archlinux User Repository Builder Bot
# Copyright © 2014 Sébastien Luttringer
#
# Started, October 30th 2011
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

from argparse import ArgumentParser
from configparser import ConfigParser
from json import load as jload, dump as jdump, loads as jloads
from logging import StreamHandler, getLogger, Formatter, DEBUG, INFO
from logging import debug, warning, info, error
from os import chdir, environ, getcwd
from os.path import join
from subprocess import check_call
from tarfile import open as tar
from tempfile import TemporaryDirectory
from time import sleep
from urllib.request import urlopen, Request
from xdg.BaseDirectory import save_config_path, save_cache_path
from systemd.daemon import notify

AUR_URL = 'https://aur.archlinux.org'
USER_AGENT = "aurbot"
XDG_DIRECTORY = "aurbot"

ERR_USAGE = 1
ERR_FATAL = 2
ERR_ABORT = 3
ERR_UNKNOWN = 4

class ABFormatter(Formatter):
	'''
	Customer logging formater
	'''
	def __init__(self, fmt="[%(levelname)s] %(msg)s"):
		Formatter.__init__(self, fmt)

	def format(self, record):
		format_orig = self._style._fmt
		if record.levelno == INFO and getLogger(record.name).getEffectiveLevel() != DEBUG:
			self._style._fmt =  "%(msg)s"
		result = Formatter.format(self, record)
		self._style._fmt = format_orig
		return result


class AURPackage(dict):
	'''
	Abstract AUR package action
	'''

	def __init__(self, name, timeout=None):
		self.name = name
		debug("getting %s aur infos" % self.name)
		url = "%s/rpc.php?type=info&arg=%s" % (AUR_URL, name)
		url_req = Request(url, headers={"User-Agent": USER_AGENT})
		debug("Requesting url: %s" % url)
		debug("Timeout is %s" % timeout)
		url_fd = urlopen(url_req, timeout=timeout)
		d = jloads(url_fd.read().decode("utf-8"))
		if d["version"] != 1:
			raise Exception("Unknown AUR Backend version")
		self._info = d["results"]

	def __getattr__(self, name):
		for k, v in self._info.items():
			if name == k.lower():
				return v
		raise AttributeError()

	def __repr__(self):
		return "%s %s" % (self.name, self.version)

	def extract(self, path):
		'''
		Extract aur source tarball inside a directory path
		'''
		fo = urlopen('%s/%s' % (AUR_URL, self.urlpath))
		tarball = tar(mode='r|*', fileobj=fo)
		tarball.extractall(path)
		fo.close()


class JsonDictFile(dict):
	'''Json serialized dict'''

	def __init__(self, path):
		'''Load json file'''
		assert(path is not None)
		try:
			self._fileobj = open(path, "a+")
		except (IOError, OSError) as exp:
			error("Unable to access to json file %s: %s" % (path, exp))
			raise
		if self._fileobj.seek(0, 1) == 0:
			debug("Json file is empty")
		else:
			debug("Loading json file %s" % path)
			try:
				self._fileobj.seek(0, 0)
				dico = jload(self._fileobj)
				self.update(dico)
			except Exception as exp:
				error("Unable to load json file %s: %s" % (path, exp))
				raise

	def save(self):
		'''Save current dict into a json file'''
		if len(self) == 0:
			debug("Not saved. Dict is empty")
			return
		if self._fileobj is not None:
			debug("Saving dict into json file")
			try:
				self._fileobj.truncate(0)
				self._fileobj.seek(0, 0)
				jdump(self, self._fileobj)
				self._fileobj.flush()
			except Exception as exp:
				error("Unable to save json file: %s" % exp)
				raise

def build(localpkg, aurpkg):
	info("Getting last AUR version")
	# find build dir
	build_dir = TemporaryDirectory()
	debug("Build dir is %s" % build_dir.name)
	# extract tarball
	debug("Extracting aur tarball")
	aurpkg.extract(build_dir.name)
	cwd = getcwd()
	try:
		chdir("%s/%s" % (build_dir.name, aurpkg.name))

		info("Starting build command")
		check_call(localpkg["build_cmd"], shell=True, close_fds=True)

		if localpkg.get("commit_cmd", None) is not None:
			info("Starting commit command")
			check_call(localpkg["commit_cmd"], shell=True, close_fds=True)
	finally:
		chdir(cwd)

def event_loop(packages, cache, timeout):
	'''
	program roundabout
	'''
	while True:
		for name, config in packages.items():
			if name == "DEFAULT":
				continue
			info("[%s]" % name)
			if config.get("build_cmd", None) is None:
				error("Build_cmd is missing in config file")
				continue
			pkg = AURPackage(name)
			# For security, if the maintainer has changed we pass
			maintainer = config.get("maintainer", None)
			if maintainer != pkg.maintainer:
				error("Invalid maintainer for package %s" % name)
				debug("registered maintainer: %s" % maintainer)
				debug("AUR maintainer: %s" % pkg.maintainer)
				continue
			# checks update
			debug("Cache lastmodified: %s" % cache.get(name, 0))
			debug("AUR lastmodified: %s" % pkg.lastmodified)
			if pkg.lastmodified <= cache.get(name, 0):
				info("No new version available")
				continue
			# package needs to be built and commited
			try:
				info("New version available: %s" % pkg.version)
				build(config, pkg)
			except Exception as exp:
				error(exp)
				continue
			# we save last successful build in cache
			cache[name] = pkg.lastmodified
			cache.save()
		# night is coming, save cache
		debug("waiting for %ds" % timeout)
		sleep(timeout)

def parse_argv():
	'''Parse command line arguments'''
	# load parser
	parser = ArgumentParser()
	parser.add_argument("-p", "--packages-path", help="packages config file path")
	parser.add_argument("-c", "--cache-path", help="cache file path")
	parser.add_argument("-s", "--sleep", type=int, default=86400, help="sleep interval between checks")
	parser.add_argument("-d", "--debug", action="store_true", help="debug mode")
	# parse it!
	args = parser.parse_args()
	# set global debug mode
	if args.debug:
		getLogger().setLevel(DEBUG)
	# set default paths
	if args.packages_path is None:
		args.packages_path = join(save_config_path(XDG_DIRECTORY), "packages.conf")
	if args.cache_path is None:
		args.cache_path = join(save_cache_path(XDG_DIRECTORY), "packages.cache")
	return args

def main():
	'''Program entry point'''
	try:
		# set logger config
		hdlr = StreamHandler()
		hdlr.setFormatter(ABFormatter())
		getLogger().addHandler(hdlr)
		getLogger().setLevel(DEBUG if "AURBOT_DEBUG" in environ else INFO)
		# parse command line
		args = parse_argv()
		# parse package list
		packages = ConfigParser()
		packages.read(args.packages_path)
		# load cache
		cache = JsonDictFile(args.cache_path)
		# tell to systemd we are ready
		notify("READY=1\n")
		# while 42
		event_loop(packages, cache, args.sleep)
	except KeyboardInterrupt:
		exit(ERR_ABORT)
	# except BaseError as exp:
	#     error(exp)
	#     exit(ERR_FATAL)
	except Exception as exp:
		error(exp)
		if getLogger().getEffectiveLevel() != DEBUG:
			error("Unknown error. Please report it with --debug.")
		else:
			raise
		exit(ERR_UNKNOWN)

if __name__ == '__main__':
	main()