import json
import logging
import os
import pathlib
import shlex
import time

from .disk import Partition
from .general import SysCommand
from .output import log
from .exceptions import SysCallError, DiskError

class luks2:
	def __init__(self, partition, mountpoint, password, key_file=None, auto_unmount=False, *args, **kwargs):
		self.password = password
		self.partition = partition
		self.mountpoint = mountpoint
		self.args = args
		self.kwargs = kwargs
		self.key_file = key_file
		self.auto_unmount = auto_unmount
		self.filesystem = 'crypto_LUKS'
		self.mapdev = None

	def __enter__(self):
		if not self.key_file:
			self.key_file = f"/tmp/{os.path.basename(self.partition.path)}.disk_pw"  # TODO: Make disk-pw-file randomly unique?

		if type(self.password) != bytes:
			self.password = bytes(self.password, 'UTF-8')

		with open(self.key_file, 'wb') as fh:
			fh.write(self.password)

		return self.unlock(self.partition, self.mountpoint, self.key_file)

	def __exit__(self, *args, **kwargs):
		# TODO: https://stackoverflow.com/questions/28157929/how-to-safely-handle-an-exception-inside-a-context-manager
		if self.auto_unmount:
			self.close()

		if len(args) >= 2 and args[1]:
			raise args[1]
		return True

	def encrypt(self, partition, password=None, key_size=512, hash_type='sha512', iter_time=10000, key_file=None):
		log(f'Encrypting {partition} (This might take a while)', level=logging.INFO)

		if not key_file:
			if self.key_file:
				key_file = self.key_file
			else:
				key_file = f"/tmp/{os.path.basename(self.partition.path)}.disk_pw"  # TODO: Make disk-pw-file randomly unique?

		if not password:
			password = self.password

		if type(password) != bytes:
			password = bytes(password, 'UTF-8')

		with open(key_file, 'wb') as fh:
			fh.write(password)

		cryptsetup_args = shlex.join([
			'/usr/bin/cryptsetup',
			'--batch-mode',
			'--verbose',
			'--type', 'luks2',
			'--pbkdf', 'argon2id',
			'--hash', hash_type,
			'--key-size', str(key_size),
			'--iter-time', str(iter_time),
			'--key-file', os.path.abspath(key_file),
			'--use-urandom',
			'luksFormat', partition.path,
		])

		try:
			# Try to setup the crypt-device
			cmd_handle = SysCommand(cryptsetup_args)
		except SysCallError as err:
			if err.exit_code == 256:
				log(f'{partition} is being used, trying to unmount and crypt-close the device and running one more attempt at encrypting the device.', level=logging.DEBUG)
				# Partition was in use, unmount it and try again
				partition.unmount()

				# Get crypt-information about the device by doing a reverse lookup starting with the partition path
				# For instance: /dev/sda
				devinfo = json.loads(b''.join(SysCommand(f"lsblk --fs -J {partition.path}")).decode('UTF-8'))['blockdevices'][0]

				# For each child (sub-partition/sub-device)
				if len(children := devinfo.get('children', [])):
					for child in children:
						# Unmount the child location
						if child_mountpoint := child.get('mountpoint', None):
							log(f'Unmounting {child_mountpoint}', level=logging.DEBUG)
							SysCommand(f"umount -R {child_mountpoint}")

						# And close it if possible.
						log(f"Closing crypt device {child['name']}", level=logging.DEBUG)
						SysCommand(f"cryptsetup close {child['name']}")

				# Then try again to set up the crypt-device
				cmd_handle = SysCommand(cryptsetup_args)
			else:
				raise err

		if cmd_handle.exit_code != 0:
			raise DiskError(f'Could not encrypt volume "{partition.path}": {b"".join(cmd_handle)}')

		return key_file

	def unlock(self, partition, mountpoint, key_file):
		"""
		Mounts a luks2 compatible partition to a certain mountpoint.
		Keyfile must be specified as there's no way to interact with the pw-prompt atm.

		:param mountpoint: The name without absolute path, for instance "luksdev" will point to /dev/mapper/luksdev
		:type mountpoint: str
		"""
		from .disk import get_filesystem_type

		if '/' in mountpoint:
			os.path.basename(mountpoint)  # TODO: Raise exception instead?

		wait_timer = time.time()
		while pathlib.Path(partition.path).exists() is False and time.time() - wait_timer < 10:
			time.sleep(0.025)

		SysCommand(f'/usr/bin/cryptsetup open {partition.path} {mountpoint} --key-file {os.path.abspath(key_file)} --type luks2')
		if os.path.islink(f'/dev/mapper/{mountpoint}'):
			self.mapdev = f'/dev/mapper/{mountpoint}'
			unlocked_partition = Partition(self.mapdev, None, encrypted=True, filesystem=get_filesystem_type(self.mapdev), autodetect_filesystem=False)
			return unlocked_partition

	def close(self, mountpoint=None):
		if not mountpoint:
			mountpoint = self.mapdev

		SysCommand(f'/usr/bin/cryptsetup close {self.mapdev}')
		return os.path.islink(self.mapdev) is False

	def format(self, path):
		if (handle := SysCommand(f"/usr/bin/cryptsetup -q -v luksErase {path}")).exit_code != 0:
			raise DiskError(f'Could not format {path} with {self.filesystem} because: {b"".join(handle)}')