"""
Code dealing with the configuration of the program.

Windows uses the Registry to store values in a flat manner.
Linux uses a file, but for commonality it's still a flat data structure.
macOS uses a 'defaults' object.
"""

# spell-checker: words HKEY FOLDERID wchar wstring edcdhkey

import abc
import contextlib
import functools
import logging
import os
import pathlib
import re
import subprocess
import sys
import traceback
import warnings
from abc import abstractmethod
from sys import platform
from typing import TYPE_CHECKING, Any, Callable, Dict, List, Optional, Type, TypeVar, Union

import semantic_version

from constants import GITVERSION_FILE, applongname, appname

# Any of these may be imported by plugins
appcmdname = 'EDMC'
# appversion **MUST** follow Semantic Versioning rules:
# <https://semver.org/#semantic-versioning-specification-semver>
# Major.Minor.Patch(-prerelease)(+buildmetadata)
# NB: Do *not* import this, use the functions appversion() and appversion_nobuild()
_static_appversion = '5.1.1-beta0'
copyright = '© 2015-2019 Jonathan Harris, 2020-2021 EDCD'

update_feed = 'https://raw.githubusercontent.com/EDCD/EDMarketConnector/releases/edmarketconnector.xml'
update_interval = 8*60*60

# This must be done here in order to avoid an import cycle with EDMCLogging.
# Other code should use EDMCLogging.get_main_logger
if os.getenv("EDMC_NO_UI"):
    logger = logging.getLogger(appcmdname)

else:
    logger = logging.getLogger(appname)

if platform == 'darwin':
    from Foundation import (  # type: ignore
        NSApplicationSupportDirectory, NSBundle, NSDocumentDirectory, NSSearchPathForDirectoriesInDomains,
        NSUserDefaults, NSUserDomainMask
    )

elif platform == 'win32':
    import ctypes
    import uuid
    import winreg
    from ctypes.wintypes import DWORD, HANDLE
    if TYPE_CHECKING:
        import ctypes.windll  # type: ignore

    REG_RESERVED_ALWAYS_ZERO = 0

    # This is the only way to do this from python without external deps (which do this anyway).
    FOLDERID_Documents = uuid.UUID('{FDD39AD0-238F-46AF-ADB4-6C85480369C7}')
    FOLDERID_LocalAppData = uuid.UUID('{F1B32785-6FBA-4FCF-9D55-7B8E7F157091}')
    FOLDERID_Profile = uuid.UUID('{5E6C858F-0E22-4760-9AFE-EA3317B67173}')
    FOLDERID_SavedGames = uuid.UUID('{4C5C32FF-BB9D-43b0-B5B4-2D72E54EAAA4}')

    SHGetKnownFolderPath = ctypes.windll.shell32.SHGetKnownFolderPath
    SHGetKnownFolderPath.argtypes = [ctypes.c_char_p, DWORD, HANDLE, ctypes.POINTER(ctypes.c_wchar_p)]

    CoTaskMemFree = ctypes.windll.ole32.CoTaskMemFree
    CoTaskMemFree.argtypes = [ctypes.c_void_p]

    def known_folder_path(guid: uuid.UUID) -> Optional[str]:
        """Look up a Windows GUID to actual folder path name."""
        buf = ctypes.c_wchar_p()
        if SHGetKnownFolderPath(ctypes.create_string_buffer(guid.bytes_le), 0, 0, ctypes.byref(buf)):
            return None
        retval = buf.value  # copy data
        CoTaskMemFree(buf)  # and free original
        return retval

elif platform == 'linux':
    from configparser import ConfigParser


_T = TypeVar('_T')


###########################################################################
def git_shorthash_from_head() -> str:
    """
    Determine short hash for current git HEAD.

    Includes `.DIRTY` if any changes have been made from HEAD

    :return: str - None if we couldn't determine the short hash.
    """
    shorthash: str = None  # type: ignore

    try:
        git_cmd = subprocess.Popen('git rev-parse --short HEAD'.split(),
                                   stdout=subprocess.PIPE,
                                   stderr=subprocess.STDOUT
                                   )
        out, err = git_cmd.communicate()

    except Exception as e:
        logger.error(f"Couldn't run git command for short hash: {e!r}")

    else:
        shorthash = out.decode().rstrip('\n')
        if re.match(r'^[0-9a-f]{7,}$', shorthash) is None:
            logger.error(f"'{shorthash}' doesn't look like a valid git short hash, forcing to None")
            shorthash = None  # type: ignore

    if shorthash is not None:
        with contextlib.suppress(Exception):
            result = subprocess.run('git diff --stat HEAD'.split(), capture_output=True)
            if len(result.stdout) > 0:
                shorthash += '.DIRTY'

            if len(result.stderr) > 0:
                logger.warning(f'Data from git on stderr:\n{str(result.stderr)}')

    return shorthash


def appversion() -> semantic_version.Version:
    """
    Determine app version including git short hash if possible.

    :return: The augmented app version.
    """
    if getattr(sys, 'frozen', False):
        # Running frozen, so we should have a .gitversion file
        # Yes, .parent because if frozen we're inside library.zip
        with open(pathlib.Path(sys.path[0]).parent / GITVERSION_FILE, 'r', encoding='utf-8') as gitv:
            shorthash = gitv.read()

    else:
        # Running from source
        shorthash = git_shorthash_from_head()
        if shorthash is None:
            shorthash = 'UNKNOWN'

    return semantic_version.Version(f'{_static_appversion}+{shorthash}')


def appversion_nobuild() -> semantic_version.Version:
    """
    Determine app version without *any* build meta data.

    This will not only strip any added git short hash, but also any trailing
    '+<string>' in _static_appversion.

    :return: App version without any build meta data.
    """
    return appversion().truncate('prerelease')
###########################################################################


class AbstractConfig(abc.ABC):
    """Abstract root class of all platform specific Config implementations."""

    OUT_MKT_EDDN = 1
    # OUT_MKT_BPC = 2	# No longer supported
    OUT_MKT_TD = 4
    OUT_MKT_CSV = 8
    OUT_SHIP = 16
    # OUT_SHIP_EDS = 16	# Replaced by OUT_SHIP
    # OUT_SYS_FILE = 32	# No longer supported
    # OUT_STAT = 64	# No longer available
    # OUT_SHIP_CORIOLIS = 128	# Replaced by OUT_SHIP
    OUT_STATION_ANY = OUT_MKT_EDDN | OUT_MKT_TD | OUT_MKT_CSV
    # OUT_SYS_EDSM = 256  # Now a plugin
    # OUT_SYS_AUTO = 512  # Now always automatic
    OUT_MKT_MANUAL = 1024
    OUT_SYS_EDDN = 2048
    OUT_SYS_DELAY = 4096

    app_dir_path: pathlib.Path
    plugin_dir_path: pathlib.Path
    internal_plugin_dir_path: pathlib.Path
    respath_path: pathlib.Path
    home_path: pathlib.Path
    default_journal_dir_path: pathlib.Path

    identifier: str

    __in_shutdown = False  # Is the application currently shutting down ?
    __auth_force_localserver = False  # Should we use localhost for auth callback ?
    __auth_force_edmc_protocol = False  # Should we force edmc:// protocol ?

    def __init__(self) -> None:
        self.home_path = pathlib.Path.home()

    def set_shutdown(self):
        """Set flag denoting we're in the shutdown sequence."""
        self.__in_shutdown = True

    @property
    def shutting_down(self) -> bool:
        """
        Determine if we're in the shutdown sequence.

        :return: bool - True if in shutdown sequence.
        """
        return self.__in_shutdown

    def set_auth_force_localserver(self):
        """Set flag to force use of localhost web server for Frontier Auth callback."""
        self.__auth_force_localserver = True

    @property
    def auth_force_localserver(self) -> bool:
        """
        Determine if use of localhost is forced for Frontier Auth callback.

        :return: bool - True if we should use localhost web server.
        """
        return self.__auth_force_localserver

    def set_auth_force_edmc_protocol(self):
        """Set flag to force use of localhost web server for Frontier Auth callback."""
        self.__auth_force_edmc_protocol = True

    @property
    def auth_force_edmc_protocol(self) -> bool:
        """
        Determine if use of localhost is forced for Frontier Auth callback.

        :return: bool - True if we should use localhost web server.
        """
        return self.__auth_force_edmc_protocol

    @property
    def app_dir(self) -> str:
        """Return a string version of app_dir."""
        return str(self.app_dir_path)

    @property
    def plugin_dir(self) -> str:
        """Return a string version of plugin_dir."""
        return str(self.plugin_dir_path)

    @property
    def internal_plugin_dir(self) -> str:
        """Return a string version of internal_plugin_dir."""
        return str(self.internal_plugin_dir_path)

    @property
    def respath(self) -> str:
        """Return a string version of respath."""
        return str(self.respath_path)

    @property
    def home(self) -> str:
        """Return a string version of home."""
        return str(self.home_path)

    @property
    def default_journal_dir(self) -> str:
        """Return a string version of default_journal_dir."""
        return str(self.default_journal_dir_path)

    @staticmethod
    def _suppress_call(
        func: Callable[..., _T], exceptions: Union[Type[BaseException], List[Type[BaseException]]] = Exception,
        *args: Any, **kwargs: Any
    ) -> Optional[_T]:
        if exceptions is None:
            exceptions = [Exception]

        if not isinstance(exceptions, list):
            exceptions = [exceptions]

        with contextlib.suppress(*exceptions):  # type: ignore # it works fine, mypy
            return func(*args, **kwargs)

        return None

    def get(self, key: str, default: Union[list, str, bool, int] = None) -> Union[list, str, bool, int]:
        """
        Return the data for the requested key, or a default.

        :param key: The key data is being requested for.
        :param default: The default to return if the key does not exist, defaults to None.
        :raises OSError: On Windows, if a Registry error occurs.
        :return: The data or the default.
        """
        warnings.warn(DeprecationWarning('get is Deprecated. use the specific getter for your type'))
        logger.debug('Attempt to use Deprecated get() method\n' + ''.join(traceback.format_stack()))

        if (l := self._suppress_call(self.get_list, ValueError, key, default=None)) is not None:
            return l

        elif (s := self._suppress_call(self.get_str, ValueError, key, default=None)) is not None:
            return s

        elif (b := self._suppress_call(self.get_bool, ValueError, key, default=None)) is not None:
            return b

        elif (i := self._suppress_call(self.get_int, ValueError, key, default=None)) is not None:
            return i

        return default  # type: ignore

    @abstractmethod
    def get_list(self, key: str, *, default: list = None) -> list:
        """
        Return the list referred to by the given key if it exists, or the default.

        Implements :meth:`AbstractConfig.get_list`.
        """
        raise NotImplementedError

    @abstractmethod
    def get_str(self, key: str, *, default: str = None) -> str:
        """
        Return the string referred to by the given key if it exists, or the default.

        :param key: The key data is being requested for.
        :param default: Default to return if the key does not exist, defaults to None.
        :raises ValueError: If an internal error occurs getting or converting a value.
        :raises OSError: On Windows, if a Registry error occurs.
        :return: The requested data or the default.
        """
        raise NotImplementedError

    @abstractmethod
    def get_bool(self, key: str, *, default: bool = None) -> bool:
        """
        Return the bool referred to by the given key if it exists, or the default.

        :param key: The key data is being requested for.
        :param default: Default to return if the key does not exist, defaults to None
        :raises ValueError: If an internal error occurs getting or converting a value
        :raises OSError: On Windows, if a Registry error occurs.
        :return: The requested data or the default
        """
        raise NotImplementedError

    def getint(self, key: str, *, default: int = 0) -> int:
        """
        Getint is a Deprecated getter method.

        See get_int for its replacement.
        :raises OSError: On Windows, if a Registry error occurs.
        """
        warnings.warn(DeprecationWarning('getint is Deprecated. Use get_int instead'))
        logger.debug('Attempt to use Deprecated getint() method\n' + ''.join(traceback.format_stack()))

        return self.get_int(key, default=default)

    @abstractmethod
    def get_int(self, key: str, *, default: int = 0) -> int:
        """
        Return the int referred to by key if it exists in the config.

        For legacy reasons, the default is 0 and not None.

        :param key: The key data is being requested for.
        :param default: Default to return if the key does not exist, defaults to 0.
        :raises ValueError: If the internal representation of this key cannot be converted to an int.
        :raises OSError: On Windows, if a Registry error occurs.
        :return: The requested data or the default.
        """
        raise NotImplementedError

    @abstractmethod
    def set(self, key: str, val: Union[int, str, List[str], bool]) -> None:
        """
        Set the given key's data to the given value.

        :param key: The key to set the value on.
        :param val: The value to set the key's data to.
        :raises ValueError: On an invalid type.
        :raises OSError: On Windows, if a Registry error occurs.
        """
        raise NotImplementedError

    @abstractmethod
    def delete(self, key: str, *, suppress=False) -> None:
        """
        Delete the given key from the config.

        :param key: The key to delete.
        :param suppress: bool - Whether to suppress any errors.  Useful in case
          code to migrate settings is blindly removing an old key.
        :raises OSError: On Windows, if a registry error occurs.
        """
        raise NotImplementedError

    @abstractmethod
    def save(self) -> None:
        """
        Save the current configuration.

        :raises OSError: On Windows, if a Registry error occurs.
        """
        raise NotImplementedError

    @abstractmethod
    def close(self) -> None:
        """Close this config and release any associated resources."""
        raise NotImplementedError

    def get_password(self, account: str) -> None:
        """Legacy password retrieval."""
        warnings.warn("password subsystem is no longer supported", DeprecationWarning)

    def set_password(self, account: str, password: str) -> None:
        """Legacy password setting."""
        warnings.warn("password subsystem is no longer supported", DeprecationWarning)

    def delete_password(self, account: str) -> None:
        """Legacy password deletion."""
        warnings.warn("password subsystem is no longer supported", DeprecationWarning)


class WinConfig(AbstractConfig):
    """Implementation of AbstractConfig for Windows."""

    def __init__(self, do_winsparkle=True) -> None:
        self.app_dir_path = pathlib.Path(str(known_folder_path(FOLDERID_LocalAppData))) / appname
        self.app_dir_path.mkdir(exist_ok=True)

        self.plugin_dir_path = self.app_dir_path / 'plugins'
        self.plugin_dir_path.mkdir(exist_ok=True)

        if getattr(sys, 'frozen', False):
            self.respath_path = pathlib.Path(sys.executable).parent
            self.internal_plugin_dir_path = self.respath_path / 'plugins'

        else:
            self.respath_path = pathlib.Path(__file__).parent
            self.internal_plugin_dir_path = self.respath_path / 'plugins'

        self.home_path = pathlib.Path.home()

        journal_dir_str = known_folder_path(FOLDERID_SavedGames)
        journaldir = pathlib.Path(journal_dir_str) if journal_dir_str is not None else None
        self.default_journal_dir_path = None  # type: ignore
        if journaldir is not None:
            self.default_journal_dir_path = journaldir / 'Frontier Developments' / 'Elite Dangerous'

        create_key_defaults = functools.partial(
            winreg.CreateKeyEx,
            key=winreg.HKEY_CURRENT_USER,
            access=winreg.KEY_ALL_ACCESS | winreg.KEY_WOW64_64KEY,
        )

        try:
            self.__reg_handle: winreg.HKEYType = create_key_defaults(
                sub_key=r'Software\Marginal\EDMarketConnector'
            )
            if do_winsparkle:
                self.__setup_winsparkle()

        except OSError:
            logger.exception('could not create required registry keys')
            raise

        self.identifier = applongname
        if (outdir_str := self.get_str('outdir')) is None or not pathlib.Path(outdir_str).is_dir():
            docs = known_folder_path(FOLDERID_Documents)
            self.set('outdir',  docs if docs is not None else self.home)

    def __setup_winsparkle(self):
        """Ensure the necessary Registry keys for WinSparkle are present."""
        create_key_defaults = functools.partial(
            winreg.CreateKeyEx,
            key=winreg.HKEY_CURRENT_USER,
            access=winreg.KEY_ALL_ACCESS | winreg.KEY_WOW64_64KEY,
        )
        try:
            edcd_handle: winreg.HKEYType = create_key_defaults(sub_key=r'Software\EDCD\EDMarketConnector')
            winsparkle_reg: winreg.HKEYType = winreg.CreateKeyEx(
                edcd_handle, sub_key='WinSparkle', access=winreg.KEY_ALL_ACCESS | winreg.KEY_WOW64_64KEY
            )

        except OSError:
            logger.exception('could not open WinSparkle handle')
            raise

        # set WinSparkle defaults - https://github.com/vslavik/winsparkle/wiki/Registry-Settings
        winreg.SetValueEx(
            winsparkle_reg, 'UpdateInterval', REG_RESERVED_ALWAYS_ZERO, winreg.REG_SZ, str(update_interval)
        )

        try:
            winreg.QueryValueEx(winsparkle_reg, 'CheckForUpdates')

        except FileNotFoundError:
            # Key doesn't exist, set it to a default
            winreg.SetValueEx(winsparkle_reg, 'CheckForUpdates', REG_RESERVED_ALWAYS_ZERO, winreg.REG_SZ, '1')

        winsparkle_reg.Close()
        edcd_handle.Close()

    def __get_regentry(self, key: str) -> Union[None, list, str, int]:
        """Access the Registry for the raw entry."""
        try:
            value, _type = winreg.QueryValueEx(self.__reg_handle, key)
        except FileNotFoundError:
            # Key doesn't exist
            return None

        # The type returned is actually as we'd expect for each of these. The casts are here for type checkers and
        # For programmers who want to actually know what is going on
        if _type == winreg.REG_SZ:
            return str(value)

        elif _type == winreg.REG_DWORD:
            return int(value)

        elif _type == winreg.REG_MULTI_SZ:
            return list(value)

        else:
            logger.warning(f'registry key {key=} returned unknown type {_type=} {value=}')
            return None

    def get_str(self, key: str, *, default: str = None) -> str:
        """
        Return the string referred to by the given key if it exists, or the default.

        Implements :meth:`AbstractConfig.get_str`.
        """
        res = self.__get_regentry(key)
        if res is None:
            return default  # type: ignore # Yes it could be None, but we're _assuming_ that people gave us a default

        elif not isinstance(res, str):
            raise ValueError(f'Data from registry is not a string: {type(res)=} {res=}')

        return res

    def get_list(self, key: str, *, default: list = None) -> list:
        """
        Return the list referred to by the given key if it exists, or the default.

        Implements :meth:`AbstractConfig.get_list`.
        """
        res = self.__get_regentry(key)
        if res is None:
            return default  # type: ignore # Yes it could be None, but we're _assuming_ that people gave us a default

        elif not isinstance(res, list):
            raise ValueError(f'Data from registry is not a list: {type(res)=} {res}')

        return res

    def get_int(self, key: str, *, default: int = 0) -> int:
        """
        Return the int referred to by key if it exists in the config.

        Implements :meth:`AbstractConfig.get_int`.
        """
        res = self.__get_regentry(key)
        if res is None:
            return default

        if not isinstance(res, int):
            raise ValueError(f'Data from registry is not an int: {type(res)=} {res}')

        return res

    def get_bool(self, key: str, *, default: bool = None) -> bool:
        """
        Return the bool referred to by the given key if it exists, or the default.

        Implements :meth:`AbstractConfig.get_bool`.
        """
        res = self.get_int(key)
        if res is None:
            return default  # type: ignore # Yes it could be None, but we're _assuming_ that people gave us a default

        return bool(res)

    def set(self, key: str, val: Union[int, str, List[str], bool]) -> None:
        """
        Set the given key's data to the given value.

        Implements :meth:`AbstractConfig.set`.
        """
        reg_type = None
        if isinstance(val, str):
            reg_type = winreg.REG_SZ
            winreg.SetValueEx(self.__reg_handle, key, REG_RESERVED_ALWAYS_ZERO, winreg.REG_SZ, val)

        elif isinstance(val, int):  # The original code checked for numbers.Integral, I dont think that is needed.
            reg_type = winreg.REG_DWORD

        elif isinstance(val, list):
            reg_type = winreg.REG_MULTI_SZ

        elif isinstance(val, bool):
            reg_type = winreg.REG_DWORD
            val = int(val)

        else:
            raise ValueError(f'Unexpected type for value {type(val)=}')

        # Its complaining about the list, it works, tested on windows, ignored.
        winreg.SetValueEx(self.__reg_handle, key, REG_RESERVED_ALWAYS_ZERO, reg_type, val)  # type: ignore

    def delete(self, key: str, *, suppress=False) -> None:
        """
        Delete the given key from the config.

        'key' is relative to the base Registry path we use.

        Implements :meth:`AbstractConfig.delete`.
        """
        try:
            winreg.DeleteValue(self.__reg_handle, key)
        except OSError:
            if suppress:
                return

            raise

    def save(self) -> None:
        """
        Save the configuration.

        Not required for WinConfig as Registry keys are flushed on write.
        """
        pass

    def close(self):
        """
        Close this config and release any associated resources.

        Implements :meth:`AbstractConfig.close`.
        """
        self.__reg_handle.Close()


class MacConfig(AbstractConfig):
    """MacConfig is the implementation of AbstractConfig for Darwin based OSes."""

    def __init__(self) -> None:
        super().__init__()
        support_path = pathlib.Path(
            NSSearchPathForDirectoriesInDomains(
                NSApplicationSupportDirectory, NSUserDomainMask, True
            )[0]
        )

        self.app_dir_path = support_path / appname
        self.app_dir_path.mkdir(exist_ok=True)

        self.plugin_dir_path = self.app_dir_path / 'plugins'
        self.plugin_dir_path.mkdir(exist_ok=True)

        # Bundle IDs identify a singled app though out a system

        if getattr(sys, 'frozen', False):
            exe_dir = pathlib.Path(sys.executable).parent
            self.internal_plugin_dir_path = exe_dir.parent / 'Library' / 'plugins'
            self.respath_path = exe_dir.parent / 'Resources'
            self.identifier = NSBundle.mainBundle().bundleIdentifier()

        else:
            file_dir = pathlib.Path(__file__).parent
            self.internal_plugin_dir_path = file_dir / 'plugins'
            self.respath_path = file_dir

            self.identifier = f'uk.org.marginal.{appname.lower()}'
            NSBundle.mainBundle().infoDictionary()['CFBundleIdentifier'] = self.identifier

        self.default_journal_dir_path = support_path / 'Frontier Developments' / 'Elite Dangerous'
        self._defaults = NSUserDefaults.standardUserDefaults()
        self._settings: Dict[str, Union[int, str, list]] = dict(
            self._defaults.persistentDomainForName_(self.identifier) or {}
        )  # make writeable

        if (out_dir := self.get_str('out_dir')) is None or not pathlib.Path(out_dir).exists():
            self.set('outdir', NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, True)[0])

    def __raw_get(self, key: str) -> Union[None, list, str, int]:
        """
        Retrieve the raw data for the given key.

        :param str: str - The key data is being requested for.
        :return: The requested data.
        """
        res = self._settings.get(key)
        # On MacOS Catalina, with python.org python 3.9.2 any 'list'
        # has type __NSCFArray so a simple `isinstance(res, list)` is
        # False.  So, check it's not-None, and not the other types.
        #
        # If we can find where to import the definition of NSCFArray
        # then we could possibly test against that.
        if res is not None and not isinstance(res, str) and not isinstance(res, int):
            return list(res)

        return res

    def get_str(self, key: str, *, default: str = None) -> str:
        """
        Return the string referred to by the given key if it exists, or the default.

        Implements :meth:`AbstractConfig.get_str`.
        """
        res = self.__raw_get(key)
        if res is None:
            return default  # type: ignore # Yes it could be None, but we're _assuming_ that people gave us a default

        if not isinstance(res, str):
            raise ValueError(f'unexpected data returned from __raw_get: {type(res)=} {res}')

        return res

    def get_list(self, key: str, *, default: list = None) -> list:
        """
        Return the list referred to by the given key if it exists, or the default.

        Implements :meth:`AbstractConfig.get_list`.
        """
        res = self.__raw_get(key)
        if res is None:
            return default  # type: ignore # Yes it could be None, but we're _assuming_ that people gave us a default

        elif not isinstance(res, list):
            raise ValueError(f'__raw_get returned unexpected type {type(res)=} {res!r}')

        return res

    def get_int(self, key: str, *, default: int = 0) -> int:
        """
        Return the int referred to by key if it exists in the config.

        Implements :meth:`AbstractConfig.get_int`.
        """
        res = self.__raw_get(key)
        if res is None:
            return default

        elif not isinstance(res, (str, int)):
            raise ValueError(f'__raw_get returned unexpected type {type(res)=} {res!r}')

        try:
            return int(res)

        except ValueError as e:
            logger.error(f'__raw_get returned {res!r} which cannot be parsed to an int: {e}')
            return default  # type: ignore # Yes it could be None, but we're _assuming_ that people gave us a default

    def get_bool(self, key: str, *, default: bool = None) -> bool:
        """
        Return the bool referred to by the given key if it exists, or the default.

        Implements :meth:`AbstractConfig.get_bool`.
        """
        res = self.__raw_get(key)
        if res is None:
            return default  # type: ignore # Yes it could be None, but we're _assuming_ that people gave us a default

        elif not isinstance(res, bool):
            raise ValueError(f'__raw_get returned unexpected type {type(res)=} {res!r}')

        return res

    def set(self, key: str, val: Union[int, str, List[str], bool]) -> None:
        """
        Set the given key's data to the given value.

        Implements :meth:`AbstractConfig.set`.
        """
        if self._settings is None:
            raise ValueError('attempt to use a closed _settings')

        if not isinstance(val, (bool, str, int, list)):
            raise ValueError(f'Unexpected type for value {type(val)=}')

        self._settings[key] = val

    def delete(self, key: str, *, suppress=False) -> None:
        """
        Delete the given key from the config.

        Implements :meth:`AbstractConfig.delete`.
        """
        try:
            del self._settings[key]

        except Exception:
            if suppress:
                pass

    def save(self) -> None:
        """
        Save the current configuration.

        Implements :meth:`AbstractConfig.save`.
        """
        self._defaults.setPersistentDomain_forName_(self._settings, self.identifier)
        self._defaults.synchronize()

    def close(self) -> None:
        """
        Close this config and release any associated resources.

        Implements :meth:`AbstractConfig.close`.
        """
        self.save()
        self._defaults = None


class LinuxConfig(AbstractConfig):
    """Linux implementation of AbstractConfig."""

    SECTION = 'config'
    # TODO: I dislike this, would rather use a sane config file format. But here we are.
    __unescape_lut = {'\\': '\\', 'n': '\n', ';': ';', 'r': '\r', '#': '#'}
    __escape_lut = {'\\': '\\', '\n': 'n', ';': ';', '\r': 'r'}

    def __init__(self, filename: Optional[str] = None) -> None:
        super().__init__()
        # http://standards.freedesktop.org/basedir-spec/latest/ar01s03.html
        xdg_data_home = pathlib.Path(os.getenv('XDG_DATA_HOME', default='~/.local/share')).expanduser()
        self.app_dir_path = xdg_data_home / appname
        self.app_dir_path.mkdir(exist_ok=True, parents=True)

        self.plugin_dir_path = self.app_dir_path / 'plugins'
        self.plugin_dir_path.mkdir(exist_ok=True)

        self.respath_path = pathlib.Path(__file__).parent

        self.internal_plugin_dir_path = self.respath_path / 'plugins'
        self.default_journal_dir_path = None  # type: ignore
        self.identifier = f'uk.org.marginal.{appname.lower()}'  # TODO: Unused?

        config_home = pathlib.Path(os.getenv('XDG_CONFIG_HOME', default='~/.config')).expanduser()

        self.filename = config_home / appname / f'{appname}.ini'
        if filename is not None:
            self.filename = pathlib.Path(filename)

        self.filename.parent.mkdir(exist_ok=True, parents=True)

        self.config: Optional[ConfigParser] = ConfigParser(comment_prefixes=('#',), interpolation=None)
        self.config.read(self.filename)  # read() ignores files that dont exist

        # Ensure that our section exists. This is here because configparser will happily create files for us, but it
        # does not magically create sections
        try:
            self.config[self.SECTION].get("this_does_not_exist", fallback=None)
        except KeyError:
            logger.info("Config section not found. Backing up existing file (if any) and readding a section header")
            if self.filename.exists():
                (self.filename.parent / f'{appname}.ini.backup').write_bytes(self.filename.read_bytes())

            self.config.add_section(self.SECTION)

        if (outdir := self.get_str('outdir')) is None or not pathlib.Path(outdir).is_dir():
            self.set('outdir', self.home)

    def __escape(self, s: str) -> str:
        """
        Escape a string using self.__escape_lut.

        This does NOT support multi-character escapes.

        :param s: str - String to be escaped.
        :return: str - The escaped string.
        """
        out = ""
        for c in s:
            if c not in self.__escape_lut:
                out += c
                continue

            out += '\\' + self.__escape_lut[c]

        return out

    def __unescape(self, s: str) -> str:
        """
        Unescape a string.

        :param s: str - The string to unescape.
        :return: str - The unescaped string.
        """
        out: List[str] = []
        i = 0
        while i < len(s):
            c = s[i]
            if c != '\\':
                out.append(c)
                i += 1
                continue

            # We have a backslash, check what its escaping
            if i == len(s)-1:
                raise ValueError('Escaped string has unescaped trailer')

            unescaped = self.__unescape_lut.get(s[i+1])
            if unescaped is None:
                raise ValueError(f'Unknown escape: \\ {s[i+1]}')

            out.append(unescaped)
            i += 2

        return "".join(out)

    def __raw_get(self, key: str) -> Optional[str]:
        """
        Get a raw data value from the config file.

        :param key: str - The key data is being requested for.
        :return: str - The raw data, if found.
        """
        if self.config is None:
            raise ValueError('Attempt to use a closed config')

        return self.config[self.SECTION].get(key)

    def get_str(self, key: str, *, default: str = None) -> str:
        """
        Return the string referred to by the given key if it exists, or the default.

        Implements :meth:`AbstractConfig.get_str`.
        """
        data = self.__raw_get(key)
        if data is None:
            return default  # type: ignore # Yes it could be None, but we're _assuming_ that people gave us a default

        if '\n' in data:
            raise ValueError('asked for string, got list')

        return self.__unescape(data)

    def get_list(self, key: str, *, default: list = None) -> list:
        """
        Return the list referred to by the given key if it exists, or the default.

        Implements :meth:`AbstractConfig.get_list`.
        """
        data = self.__raw_get(key)

        if data is None:
            return default  # type: ignore # Yes it could be None, but we're _assuming_ that people gave us a default

        split = data.split('\n')
        if split[-1] != ';':
            raise ValueError('Encoded list does not have trailer sentinel')

        return list(map(self.__unescape, split[:-1]))

    def get_int(self, key: str, *, default: int = 0) -> int:
        """
        Return the int referred to by key if it exists in the config.

        Implements :meth:`AbstractConfig.get_int`.
        """
        data = self.__raw_get(key)

        if data is None:
            return default

        try:
            return int(data)

        except ValueError as e:
            raise ValueError(f'requested {key=} as int cannot be converted to int') from e

    def get_bool(self, key: str, *, default: bool = None) -> bool:
        """
        Return the bool referred to by the given key if it exists, or the default.

        Implements :meth:`AbstractConfig.get_bool`.
        """
        if self.config is None:
            raise ValueError('attempt to use a closed config')

        data = self.__raw_get(key)
        if data is None:
            return default  # type: ignore # Yes it could be None, but we're _assuming_ that people gave us a default

        return bool(int(data))

    def set(self, key: str, val: Union[int, str, List[str]]) -> None:
        """
        Set the given key's data to the given value.

        Implements :meth:`AbstractConfig.set`.
        """
        if self.config is None:
            raise ValueError('attempt to use a closed config')

        to_set: Optional[str] = None
        if isinstance(val, bool):
            to_set = str(int(val))

        elif isinstance(val, str):
            to_set = self.__escape(val)

        elif isinstance(val, int):
            to_set = str(val)

        elif isinstance(val, list):
            to_set = '\n'.join([self.__escape(s) for s in val] + [';'])

        else:
            raise ValueError(f'Unexpected type for value {type(val)=}')

        self.config.set(self.SECTION, key, to_set)
        self.save()

    def delete(self, key: str, *, suppress=False) -> None:
        """
        Delete the given key from the config.

        Implements :meth:`AbstractConfig.delete`.
        """
        if self.config is None:
            raise ValueError('attempt to use a closed config')

        self.config.remove_option(self.SECTION, key)
        self.save()

    def save(self) -> None:
        """
        Save the current configuration.

        Implements :meth:`AbstractConfig.save`.
        """
        if self.config is None:
            raise ValueError('attempt to use a closed config')

        with open(self.filename, 'w', encoding='utf-8') as f:
            self.config.write(f)

    def close(self) -> None:
        """
        Close this config and release any associated resources.

        Implements :meth:`AbstractConfig.close`.
        """
        self.save()
        self.config = None


def get_config(*args, **kwargs) -> AbstractConfig:
    """
    Get the appropriate config class for the current platform.

    :param args: Args to be passed through to implementation.
    :param kwargs: Args to be passed through to implementation.
    :return: Instance of the implementation.
    """
    if sys.platform == "darwin":
        return MacConfig(*args, **kwargs)
    elif sys.platform == "win32":
        return WinConfig(*args, **kwargs)
    elif sys.platform == "linux":
        return LinuxConfig(*args, **kwargs)
    else:
        raise ValueError(f'Unknown platform: {sys.platform=}')


config = get_config()