from __future__ import print_function
from __future__ import absolute_import

from os import link, remove
from os.path import isdir, realpath, join as pathJoin, splitext
from tempfile import NamedTemporaryFile

from Components.config import config
from Screens.LocationBox import TimeshiftLocationBox
from Screens.MessageBox import MessageBox
from Screens.Setup import Setup
from Tools.Directories import fileExists
import Components.Harddisk


class TimeshiftSettings(Setup):
	def __init__(self, session):
		self.buildChoices("TimeshiftPath", config.usage.timeshift_path, None)
		Setup.__init__(self, session=session, setup="timeshift")
		self.greenText = self["key_green"].text
		self.errorItem = -1
		if self.getCurrentItem() is config.usage.timeshift_path:
			self.pathStatus(self.getCurrentValue())

	def buildChoices(self, item, configEntry, path):
		configList = config.usage.allowed_timeshift_paths.value[:]
		if configEntry.saved_value and configEntry.saved_value not in configList:
			configList.append(configEntry.saved_value)
			configEntry.value = configEntry.saved_value
		if path is None:
			path = configEntry.value
		if path and path not in configList:
			configList.append(path)
		pathList = [(x, x) for x in configList]
		configEntry.value = path
		configEntry.setChoices(pathList, default=configEntry.default)
		print("[Timeshift] %s: Current='%s', Default='%s', Choices='%s'" % (item, configEntry.value, configEntry.default, configList))

	def pathSelect(self, path):
		if path is not None:
			path = pathJoin(path, "")
			self.buildChoices("TimeshiftPath", config.usage.timeshift_path, path)
		self["config"].invalidateCurrent()
		self.changedEntry()

	def pathStatus(self, path):
		if not isdir(path):
			self.errorItem = self["config"].getCurrentIndex()
			footnote = _("Directory '%s' does not exist!") % path
			green = ""
		elif not self.isValidPartition(path):
			self.errorItem = self["config"].getCurrentIndex()
			footnote = _("Directory '%s' not valid. Partition must be ext or nfs") % path
			green = ""
		elif not fileExists(path, "w"):
			self.errorItem = self["config"].getCurrentIndex()
			footnote = _("Directory '%s' not writeable!") % path
			green = ""
		elif not self.hasHardLinks(path): # Timeshift requires a hardlinks
			self.errorItem = self["config"].getCurrentIndex()
			footnote = _("Directory '%s' is not hard links capable!") % path
			green = ""
		else:
			self.errorItem = -1
			footnote = ""
			green = self.greenText
		self.setFootnote(footnote)
		self["key_green"].text = green

	def isValidPartition(self, path):
		if path is not None:
			supported_filesystems = ('ext4', 'ext3', 'ext2', 'nfs', 'cifs', 'ntfs')
			valid_partitions = []
			for partition in Components.Harddisk.harddiskmanager.getMountedPartitions():
				if partition.filesystem() in supported_filesystems:
					valid_partitions.append(partition.mountpoint)
			print("[" + self.__class__.__name__ + "] valid partitions", valid_partitions)
			if valid_partitions:
				return Components.Harddisk.findMountPoint(realpath(path))+'/' in valid_partitions or Components.Harddisk.findMountPoint(realpath(path)) in valid_partitions
		return False

	def hasHardLinks(self, path):
		try:
			tmpfile = NamedTemporaryFile(suffix='.file', prefix='tmp', dir=path, delete=False)
		except (IOError, OSError) as err:
			print("[Timeshift] DEBUG: Create temp file - I/O Error %d: %s!" % (err.errno, err.strerror))
			return False
		srcname = tmpfile.name
		tmpfile.close()
		dstname = "%s.link" % splitext(srcname)[0]
		try:
			link(srcname, dstname)
			result = True
		except (IOError, OSError) as err:
			print("[Timeshift] DEBUG: Create link - I/O Error %d: %s!" % (err.errno, err.strerror))
			result = False
		try:
			remove(srcname)
		except (IOError, OSError) as err:
			print("[Timeshift] DEBUG: Remove source - I/O Error %d: %s!" % (err.errno, err.strerror))
			pass
		try:
			remove(dstname)
		except (IOError, OSError) as err:
			print("[Timeshift] DEBUG: Remove target - I/O Error %d: %s!" % (err.errno, err.strerror))
			pass
		return result

	def selectionChanged(self):
		if self.errorItem == -1:
			Setup.selectionChanged(self)
		else:
			self["config"].setCurrentIndex(self.errorItem)

	def changedEntry(self):
		if self.getCurrentItem() is config.usage.timeshift_path:
			self.pathStatus(self.getCurrentValue())
		Setup.changedEntry(self)

	def keySelect(self):
		if self.getCurrentItem() is config.usage.timeshift_path:
			self.session.openWithCallback(self.pathSelect, TimeshiftLocationBox)
		else:
			Setup.keySelect(self)

	def keySave(self):
		if self.errorItem == -1:
			Setup.keySave(self)
		else:
			self.session.open(MessageBox, "%s\n\n%s" % (self.getFootnote(), _("Please select an acceptable directory.")), type=MessageBox.TYPE_ERROR)