from . import base
import collections
import tuned.consts as consts
from .decorators import *
import os
import re
import tuned.logs
from tuned.utils.commands import commands

log = tuned.logs.get()
cmd = commands()

class Service():
	def __init__(self, start = None, enable = None, cfg_file = None, runlevel = None):
		self.enable = enable
		self.start = start
		self.cfg_file = cfg_file
		self.runlevel = runlevel

class InitHandler():
	def runlevel_get(self):
		(retcode, out) = cmd.execute(["runlevel"])
		return out.split()[-1] if retcode == 0 else None

	def daemon_reload(self):
		cmd.execute(["telinit", "q"])

	def cfg_install(self, name, cfg_file):
		pass

	def cfg_uninstall(self, name, cfg_file):
		pass

	def cfg_verify(self, name, cfg_file):
		return None

# no enable/disable
class SysVBasicHandler(InitHandler):
	def start(self, name):
		cmd.execute(["service", name, "start"])

	def stop(self, name):
		cmd.execute(["service", name, "stop"])

	def enable(self, name, runlevel):
		raise NotImplementedError()

	def disable(self, name, runlevel):
		raise NotImplementedError()

	def is_running(self, name):
		(retcode, out) = cmd.execute(["service", name, "status"], no_errors = [0])
		return retcode == 0

	def is_enabled(self, name, runlevel):
		raise NotImplementedError()

class SysVHandler(SysVBasicHandler):
	def enable(self, name, runlevel):
		cmd.execute(["chkconfig", "--level", runlevel, name, "on"])

	def disable(self, name, runlevel):
		cmd.execute(["chkconfig", "--level", runlevel, name, "off"])

	def is_enabled(self, name, runlevel):
		(retcode, out) = cmd.execute(["chkconfig", "--list", name])
		return out.split("%s:" % str(runlevel))[1][:2] == "on" if retcode == 0 else None

class SysVRCHandler(SysVBasicHandler):
	def enable(self, name, runlevel):
		cmd.execute(["sysv-rc-conf", "--level", runlevel, name, "on"])

	def disable(self, name, runlevel):
		cmd.execute(["sysv-rc-conf", "--level", runlevel, name, "off"])

	def is_enabled(self, name, runlevel):
		(retcode, out) = cmd.execute(["sysv-rc-conf", "--list", name])
		return out.split("%s:" % str(runlevel))[1][:2] == "on" if retcode == 0 else None

class OpenRCHandler(InitHandler):
	def runlevel_get(self):
		(retcode, out) = cmd.execute(["rc-status", "-r"])
		return out.strip() if retcode == 0 else None

	def start(self, name):
		cmd.execute(["rc-service", name, "start"])

	def stop(self, name):
		cmd.execute(["rc-service", name, "stop"])

	def enable(self, name, runlevel):
		cmd.execute(["rc-update", "add", name, runlevel])

	def disable(self, name, runlevel):
		cmd.execute(["rc-update", "del", name, runlevel])

	def is_running(self, name):
		(retcode, out) = cmd.execute(["rc-service", name, "status"], no_errors = [0])
		return retcode == 0

	def is_enabled(self, name, runlevel):
		(retcode, out) = cmd.execute(["rc-update", "show", runlevel])
		return bool(re.search(r"\b" + re.escape(name) + r"\b", out))

class SystemdHandler(InitHandler):
	# runlevel not used
	def runlevel_get(self):
		return ""

	def start(self, name):
		cmd.execute(["systemctl", "restart", name])

	def stop(self, name):
		cmd.execute(["systemctl", "stop", name])

	def enable(self, name, runlevel):
		cmd.execute(["systemctl", "enable", name])

	def disable(self, name, runlevel):
		cmd.execute(["systemctl", "disable", name])

	def is_running(self, name):
		(retcode, out) = cmd.execute(["systemctl", "is-active", name], no_errors = [0])
		return retcode == 0

	def is_enabled(self, name, runlevel):
		(retcode, out) = cmd.execute(["systemctl", "is-enabled", name], no_errors = [0])
		status = out.strip()
		return True if status == "enabled" else False if status =="disabled" else None

	def cfg_install(self, name, cfg_file):
		log.info("installing service configuration overlay file '%s' for service '%s'" % (cfg_file, name))
		if not os.path.exists(cfg_file):
			log.error("Unable to find service configuration '%s'" % cfg_file)
			return
		dirpath = consts.SERVICE_SYSTEMD_CFG_PATH % name
		try:
			os.makedirs(dirpath, consts.DEF_SERVICE_CFG_DIR_MODE)
		except OSError as e:
			log.error("Unable to create directory '%s': %s" % (dirpath, e))
			return
		cmd.copy(cfg_file, dirpath)
		self.daemon_reload()

	def cfg_uninstall(self, name, cfg_file):
		log.info("uninstalling service configuration overlay file '%s' for service '%s'" % (cfg_file, name))
		dirpath = consts.SERVICE_SYSTEMD_CFG_PATH % name
		path = "%s/%s" % (dirpath, os.path.basename(cfg_file))
		cmd.unlink(path)
		self.daemon_reload()
		# remove the service dir if empty, do not check for errors
		try:
			os.rmdir(dirpath)
		except (FileNotFoundError, OSError):
			pass

	def cfg_verify(self, name, cfg_file):
		if cfg_file is None:
			return None
		path = "%s/%s" % (consts.SERVICE_SYSTEMD_CFG_PATH % name, os.path.basename(cfg_file))
		if not os.path.exists(cfg_file):
			log.error("Unable to find service '%s' configuration '%s'" % (name, cfg_file))
			return False
		if not os.path.exists(path):
			log.error("Service '%s' configuration not installed in '%s'" % (name, path))
			return False
		sha256sum1 = cmd.sha256sum(cfg_file)
		sha256sum2 = cmd.sha256sum(path)
		return sha256sum1 == sha256sum2

class ServicePlugin(base.Plugin):
	"""
	`service`::
	
	Plug-in for handling sysvinit, sysv-rc, openrc and systemd services.
	+
	The syntax is as follows:
	+
	[subs="+quotes,+macros"]
	----
	[service]
	service.__service_name__=__commands__[,file:__file__]
	----
	+
	Supported service-handling `_commands_` are `start`, `stop`, `enable`
	and `disable`. The optional `file:__file__` directive installs an overlay
	configuration file `__file__`. Multiple commands must be comma (`,`)
	or semicolon (`;`) separated. If the directives conflict, the last
	one is used.
	+
	The service plugin supports configuration overlays only for systemd.
	In other init systems, this directive is ignored. The configuration
	overlay files are copied to `/etc/systemd/system/__service_name__.service.d/`
	directories. Upon profile unloading, the directory is removed if it is empty.
	+
	With systemd, the `start` command is implemented by `restart` in order
	to allow loading of the service configuration file overlay.
	+
	NOTE: With non-systemd init systems, the plug-in operates on the
	current runlevel only.
	+
	.Start and enable the `sendmail` service with an overlay file
	====
	----
	[service]
	service.sendmail=start,enable,file:${i:PROFILE_DIR}/tuned-sendmail.conf
	----
	The internal variable `${i:PROFILE_DIR}` points to the directory
	from which the profile is loaded.
	====
	"""

	def __init__(self, *args, **kwargs):
		super(ServicePlugin, self).__init__(*args, **kwargs)
		self._has_dynamic_options = True
		self._init_handler = self._detect_init_system()

	def _check_cmd(self, command):
		(retcode, out) = cmd.execute(command, no_errors = [0])
		return retcode == 0

	def _detect_init_system(self):
		if self._check_cmd(["systemctl", "status"]):
			log.debug("detected systemd")
			return SystemdHandler()
		elif self._check_cmd(["chkconfig"]):
			log.debug("detected generic sysvinit")
			return SysVHandler()
		elif self._check_cmd(["update-rc.d", "-h"]):
			log.debug("detected sysv-rc")
			return SysVRCHandler()
		elif self._check_cmd(["rc-update", "-h"]):
			log.debug("detected openrc")
			return OpenRCHandler()
		else:
			raise exceptions.NotSupportedPluginException("Unable to detect your init system, disabling the plugin.")

	def _parse_service_options(self, name,  val):
		l = re.split(r"\s*[,;]\s*", val)
		service = Service()
		for i in l:
			if i == "enable":
				service.enable = True
			elif i == "disable":
				service.enable = False
			elif i == "start":
				service.start = True
			elif i == "stop":
				service.start = False
			elif i[:5] == "file:":
				service.cfg_file = i[5:]
			else:
				log.error("service '%s': invalid service option: '%s'" % (name, i))
		return service

	def _instance_init(self, instance):
		instance._has_dynamic_tuning = False
		instance._has_static_tuning = True

		self._services = collections.OrderedDict([(option[8:], self._parse_service_options(option[8:], 
			self._variables.expand(value))) for option, value in instance.options.items()
			if option[:8] == "service." and len(option) > 8])
		instance._services_original = {}

	def _instance_cleanup(self, instance):
		pass

	def _process_service(self, name, start, enable, runlevel):
		if start:
			self._init_handler.start(name)
		elif start is not None:
			self._init_handler.stop(name)
		if enable:
			self._init_handler.enable(name, runlevel)
		elif enable is not None:
			self._init_handler.disable(name, runlevel)

	def _instance_apply_static(self, instance):
		runlevel = self._init_handler.runlevel_get()
		if runlevel is None:
			log.error("Cannot detect runlevel")
			return
		
		for service in self._services.items():
			is_enabled = self._init_handler.is_enabled(service[0], runlevel)
			is_running = self._init_handler.is_running(service[0])
			instance._services_original[service[0]] = Service(is_running, is_enabled, service[1].cfg_file, runlevel)
			if service[1].cfg_file:
				self._init_handler.cfg_install(service[0], service[1].cfg_file)
			self._process_service(service[0], service[1].start, service[1].enable, runlevel)

	def _instance_verify_static(self, instance, ignore_missing, devices):
		runlevel = self._init_handler.runlevel_get()
		if runlevel is None:
			log.error(consts.STR_VERIFY_PROFILE_FAIL % "cannot detect runlevel")
			return False

		ret = True
		for service in self._services.items():
			ret_cfg_verify = self._init_handler.cfg_verify(service[0], service[1].cfg_file)
			if ret_cfg_verify:
				log.info(consts.STR_VERIFY_PROFILE_OK % "service '%s' configuration '%s' matches" % (service[0], service[1].cfg_file))
			elif ret_cfg_verify is not None:
				log.error(consts.STR_VERIFY_PROFILE_FAIL % "service '%s' configuration '%s' differs" % (service[0], service[1].cfg_file))
				ret = False
			else:
				log.info(consts.STR_VERIFY_PROFILE_VALUE_MISSING % "service '%s' configuration '%s'" % (service[0], service[1].cfg_file))
			is_enabled = self._init_handler.is_enabled(service[0], runlevel)
			is_running = self._init_handler.is_running(service[0])
			if self._verify_value("%s running" % service[0], service[1].start, is_running, ignore_missing) is False:
				ret = False
			if self._verify_value("%s enabled" % service[0], service[1].enable, is_enabled, ignore_missing) is False:
				ret = False
		return ret

	def _instance_unapply_static(self, instance, rollback = consts.ROLLBACK_SOFT):
		for name, value in list(instance._services_original.items()):
			if value.cfg_file:
				self._init_handler.cfg_uninstall(name, value.cfg_file)
			self._process_service(name, value.start, value.enable, value.runlevel)
