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

# aurbot - Archlinux User Repository Builder Bot
# Copyright © 2015 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 email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.utils import formatdate
from json import load as jload, dump as jdump, loads as jloads
from logging import debug, warning, info, error
from logging import StreamHandler, getLogger, Formatter, DEBUG, INFO
from os import chdir, environ, getcwd, mkdir, makedirs
from os.path import exists, join
from signal import signal, SIGHUP
from subprocess import Popen, check_call, DEVNULL, PIPE
from systemd.daemon import notify
from tarfile import open as tar
from tempfile import TemporaryDirectory
from time import sleep, time, strftime, localtime
from urllib.request import urlopen, Request

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

DEFAULT_CHECK_INTERVAL = 86400
DEFAULT_CONFIG_FILE = "/etc/aurbot.conf"
DEFAULT_DATA_DIR = "/var/lib/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 (timeout: %s)" % (url, 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: %s" % d["version"])
		if len(d["results"]) == 0:
			raise Exception("No such package: %s" % name)
		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 LocalPackage(dict):
	'''Local package data abstraction'''

	def __init__(self, name):
		self.name = name
		self.path = join(environ.get("AURBOT_DATADIR", DEFAULT_DATA_DIR), name)
		debug("local path is: %s" % self.path)
		makedirs(self.path, exist_ok=True)

	@property
	def logdir(self):
		logdir = join(self.path, "log")
		if not exists(logdir):
			mkdir(logdir)
		return logdir

	def getlastX(self, X, cast=int, default=0):
		filepath = join(self.path, X)
		if not exists(filepath):
			return default
		try:
			return cast(open(filepath, "r").read())
		except Exception as exp:
			debug("Failed to load %s: %s" % (X, exp))
			return default

	def setlastX(self, X, value, cast=int):
		#try:
		open(join(self.path, X), "w").write("%s" % cast(value))
		#except Exception as exp:
		#	error("Failed to save %s: %s" % (X, exp))

	# store the moment where the build was done locally
	lastbuild = property(
		lambda x: LocalPackage.getlastX(x, "lastbuild"),
		lambda x, y: LocalPackage.setlastX(x, "lastbuild", y)
	)
	# store the aur lastmodified value of the last sucessful build
	lastsuccess = property(
		lambda x: LocalPackage.getlastX(x, "lastsuccess"),
		lambda x, y: LocalPackage.setlastX(x, "lastsuccess", y)
	)
	# store the aur lastmodified value of the last failed build
	lastfailed = property(
		lambda x: LocalPackage.getlastX(x, "lastfailed"),
		lambda x, y: LocalPackage.setlastX(x, "lastfailed", y)
	)
	# store the last time we check the aur
	lastchecked = property(
		lambda x: LocalPackage.getlastX(x, "lastchecked"),
		lambda x, y: LocalPackage.setlastX(x, "lastchecked", y)
	)
	# store the last maintainer for the package
	lastmaintainer = property(
		lambda x: LocalPackage.getlastX(x, "lastmaintainer", str, ""),
		lambda x, y: LocalPackage.setlastX(x, "lastmaintainer", y, str)
	)

def send_message(msg):
	proc = Popen(["sendmail", "-i", "-t"], stdin=PIPE, close_fds=True)
	proc.stdin.write(msg.as_bytes())
	proc.stdin.close()
	proc.wait()

def send_build_report(config, localpkg, aurpkg, status, logfile):
	'''Send build notification'''
	info("Send build report")
	# generate message
	msg = MIMEMultipart()
	msg["Subject"] = "Build %s for %s %s" % (
		"successful" if status else "failure", localpkg.name, aurpkg.version)
	msg["From"] = "Aurbot"
	msg["To"] = config["notify"]
	msg["Date"] = formatdate(localtime=True)
	# attach logfile
	with open(logfile, "r") as fd:
		mt = MIMEText(fd.read())
	msg.attach(mt)
	send_message(msg)

def send_maintainer_report(config, localpkg, aurpkg):
	'''Send email to notify invalid maintainer'''
	info("Send invalid maintainer report")
	# generate message
	msg = MIMEText(
		"Maintainer for package %s is invalid.\r\n" % localpkg.name +
		"He has probably changed. Check if the new one is trustworthy.\r\n"
		"\r\n"
		"Configured maintainer is %s.\r\n" % config.get("maintainer") +
		"AUR maintainer is %s.\r\n" % aurpkg.maintainer +
		"\r\n"
		"Your aurbot configuration need to be updated!\r\n")
	msg["Subject"] = "Invalid maintainer for %s" % localpkg.name
	msg["From"] = "Aurbot"
	msg["To"] = config["notify"]
	msg["Date"] = formatdate(localtime=True)
	send_message(msg)

def build(config, localpkg, aurpkg):
	'''
	Build and commit a package
	Notify if succeeded
	'''
	# register the build
	localpkg.lastbuild = time()
	# log files
	fp = join(localpkg.logdir, strftime("build-%Y-%m-%d-%H-%M-%S.log", localtime(time())))
	debug("Build log file path: %s" % fp)
	# 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)
	with open(fp, "w") as fd:
		try:
			cwd = getcwd()
			chdir("%s/%s" % (build_dir.name, aurpkg.name))

			# build
			info("Starting build command")
			debug(config["build_cmd"])
			fd.write("Build command: %s\n" % config["build_cmd"])
			fd.flush()
			start_time = time()
			try:
				check_call(config["build_cmd"], stdin=DEVNULL, stdout=fd,
					stderr=fd, shell=True, close_fds=True)
			except Exception as exp:
				error("Build command failure: %s" % exp)
				raise
			end_time = time()
			info("Build duration: %.2fs" % (end_time - start_time))
			fd.write("Build duration: %.2fs\n" % (end_time - start_time))

			# commit
			if "commit_cmd" in config:
				info("Starting commit command")
				debug(config["commit_cmd"])
				fd.write("Commit command: %s\n" % config["commit_cmd"])
				fd.flush()
				start_time = time()
				try:
					check_call(config["commit_cmd"], stdin=DEVNULL, stdout=fd,
						stderr=fd, shell=True, close_fds=True)
				except Exception as exp:
					error("Commit command failure: %s" % exp)
					raise
				end_time = time()
				info("Commit duration: %.2fs" % (end_time - start_time))
				fd.write("Commit duration: %.2fs\n" % (end_time - start_time))
			status = True
		except Exception as exp:
			status = False
		finally:
			chdir(cwd)
	# we have to register after chdir in the original directory
	if status:
		localpkg.lastsuccess = aurpkg.lastmodified
	else:
		localpkg.lastfailed = aurpkg.lastmodified
	# notify
	if "notify" in config:
		send_build_report(config, localpkg, aurpkg, status, fp)

def event_loop(config_path):
	'''
	program roundabout
	'''
	while True:
		# parse package list
		packages = ConfigParser()
		packages.read(config_path)
		next_checks = set()
		for name, config in packages.items():
			if name == "DEFAULT":
				continue
			info("[%s]" % name)
			if "build_cmd" not in config:
				error("build_cmd is missing in config file")
				continue
			local = LocalPackage(name)
			check_interval = config.getint("check_interval", DEFAULT_CHECK_INTERVAL)
			debug("Check interval is %ss" % check_interval)
			check_delta = int(local.lastchecked - time() + check_interval)
			debug("Check delta is %ss" % check_delta)
			if check_delta > 0:
				# next check is in the future
				next_checks.add(check_delta)
				info("Nothing to check. Next is planned in %ss" % check_delta)
				continue
			next_checks.add(check_interval)
			# get remote data
			try:
				aur = AURPackage(name, config.getint("timeout"))
				local.lastchecked = int(time())
			except Exception as exp:
				error("Unable to get AUR package info: %s" % exp)
				continue
			# For security, if the maintainer has changed we pass
			maintainer = config.get("maintainer")
			if maintainer != aur.maintainer:
				debug("Configured maintainer: %s" % maintainer)
				debug("AUR maintainer: %s" % aur.maintainer)
				debug("Last maintainer: %s" % local.lastmaintainer)
				# we notify by mail if the aur has changed
				if local.lastmaintainer != aur.maintainer:
					send_maintainer_report(config, local, aur)
				local.lastmaintainer = aur.maintainer
				error("Invalid maintainer for package %s" % name)
				continue
			local.lastmaintainer = aur.maintainer
			# checks update
			debug("AUR last modified: %s" % aur.lastmodified)
			debug("Local last success lastmodified: %s" % local.lastbuild)
			debug("Local last failed lastmodified: %s" % local.lastfailed)
			debug("Local last build time: %s" % local.lastbuild)
			# build new aur version
			if local.lastsuccess >= aur.lastmodified :
				if "force" in config:
					info("Up to date, but force value is present.")
					if config["force"].isdigit() is False:
						warning("Invalid force value, ignore it")
						continue
					# if lastbuild not exists, it will be equal to 0
					# too small to be > to time() even with big force time
					now = int(time())
					force = int(config["force"])
					debug("Force is: %ss" % force)
					force_delta = local.lastbuild - now + force
					debug("Force Delta is: %ss" % force_delta)
					if force_delta < 0:
						info("Forced update")
						build(config, local, aur)
					else:
						info("Next forced update in %ss" % force_delta)
				else:
					info("Up to date, nothing to do.")
			elif local.lastfailed >= aur.lastmodified:
				info("Last build has failed. We skip.")
			else:
				info("New version available: %s" % aur.version)
				build(config, local, aur)
		# sleep until next check
		# len(next_checks) is 0 when there is no package configured
		timeout = min(next_checks) if len(next_checks) > 0 else DEFAULT_CHECK_INTERVAL
		debug("waiting for %ds" % timeout)
		sleep(timeout)

def parse_argv():
	'''Parse command line arguments'''
	# load parser
	parser = ArgumentParser()
	parser.add_argument("-c", "--config", help="config file path",
		default=environ.get("AURBOT_CONFIG", DEFAULT_CONFIG_FILE))
	parser.add_argument("-d", "--debug", action="store_true", help="debug mode")
	parser.epilog = "You could set $XDG_DATA_HOME to change the path of the local package cache."
	# parse it!
	args = parser.parse_args()
	# set global debug mode
	if args.debug:
		getLogger().setLevel(DEBUG)
	return args

def main():
	'''Program entry point'''
	try:
		# set logger config
		hdlr = StreamHandler()
		hdlr.setFormatter(ABFormatter())
		getLogger().addHandler(hdlr)
		# Early debugging mode
		getLogger().setLevel(DEBUG if "AURBOT_DEBUG" in environ else INFO)
		# use sighup to unblock sleep syscall
		signal(SIGHUP, lambda signum, frame: info("SIGHUP received"))
		# parse command line
		args = parse_argv()
		# tell to systemd we are ready
		notify("READY=1\n")
		# while 42
		event_loop(args.config)
	except KeyboardInterrupt:
		exit(ERR_ABORT)
	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()