import logging
import time
from typing import Iterator
from .exceptions import SysCallError
from .general import SysCommand, SysCommandWorker, locate_binary
from .installer import Installer
from .output import log
from .storage import storage


class Ini:
	def __init__(self, *args :str, **kwargs :str):
		"""
		Limited INI handler for now.
		Supports multiple keywords through dictionary list items.
		"""
		self.kwargs = kwargs

	def __str__(self) -> str:
		result = ''
		first_row_done = False
		for top_level in self.kwargs:
			if first_row_done:
				result += f"\n[{top_level}]\n"
			else:
				result += f"[{top_level}]\n"
				first_row_done = True

			for key, val in self.kwargs[top_level].items():
				if type(val) == list:
					for item in val:
						result += f"{key}={item}\n"
				else:
					result += f"{key}={val}\n"

		return result


class Systemd(Ini):
	"""
	Placeholder class to do systemd specific setups.
	"""


class Networkd(Systemd):
	"""
	Placeholder class to do systemd-network specific setups.
	"""


class Boot:
	def __init__(self, installation: Installer):
		self.instance = installation
		self.container_name = 'archinstall'
		self.session = None
		self.ready = False

	def __enter__(self) -> 'Boot':
		if (existing_session := storage.get('active_boot', None)) and existing_session.instance != self.instance:
			raise KeyError("Archinstall only supports booting up one instance, and a active session is already active and it is not this one.")

		if existing_session:
			self.session = existing_session.session
			self.ready = existing_session.ready
		else:
			self.session = SysCommandWorker([
				'/usr/bin/systemd-nspawn',
				'-D', self.instance.target,
				'--timezone=off',
				'-b',
				'--no-pager',
				'--machine', self.container_name
			])
			# '-P' or --console=pipe  could help us not having to do a bunch of os.write() calls, but instead use pipes (stdin, stdout and stderr) as usual.

		if not self.ready:
			while self.session.is_alive():
				if b' login:' in self.session:
					self.ready = True
					break

		storage['active_boot'] = self
		return self

	def __exit__(self, *args :str, **kwargs :str) -> None:
		# b''.join(sys_command('sync')) # No need to, since the underlying fs() object will call sync.
		# TODO: https://stackoverflow.com/questions/28157929/how-to-safely-handle-an-exception-inside-a-context-manager

		if len(args) >= 2 and args[1]:
			log(args[1], level=logging.ERROR, fg='red')
			log(f"The error above occurred in a temporary boot-up of the installation {self.instance}", level=logging.ERROR, fg="red")

		shutdown = None
		shutdown_exit_code = -1

		try:
			shutdown = SysCommand(f'systemd-run --machine={self.container_name} --pty shutdown now')
		except SysCallError as error:
			shutdown_exit_code = error.exit_code

		while self.session.is_alive():
			time.sleep(0.25)

		if shutdown:
			shutdown_exit_code = shutdown.exit_code

		if self.session.exit_code == 0 or shutdown_exit_code == 0:
			storage['active_boot'] = None
		else:
			raise SysCallError(f"Could not shut down temporary boot of {self.instance}: {self.session.exit_code}/{shutdown_exit_code}", exit_code=next(filter(bool, [self.session.exit_code, shutdown_exit_code])))

	def __iter__(self) -> Iterator[str]:
		if self.session:
			for value in self.session:
				yield value

	def __contains__(self, key: bytes) -> bool:
		if self.session is None:
			return False

		return key in self.session

	def is_alive(self) -> bool:
		if self.session is None:
			return False

		return self.session.is_alive()

	def SysCommand(self, cmd: list, *args, **kwargs) -> SysCommand:
		if cmd[0][0] != '/' and cmd[0][:2] != './':
			# This check is also done in SysCommand & SysCommandWorker.
			# However, that check is done for `machinectl` and not for our chroot command.
			# So this wrapper for SysCommand will do this additionally.

			cmd[0] = locate_binary(cmd[0])

		return SysCommand(["systemd-run", f"--machine={self.container_name}", "--pty", *cmd], *args, **kwargs)

	def SysCommandWorker(self, cmd: list, *args, **kwargs) -> SysCommandWorker:
		if cmd[0][0] != '/' and cmd[0][:2] != './':
			cmd[0] = locate_binary(cmd[0])

		return SysCommandWorker(["systemd-run", f"--machine={self.container_name}", "--pty", *cmd], *args, **kwargs)