# -*- coding: utf-8 -*-

# pylint: disable=too-few-public-methods

"""Collection of application detection utilities."""

__all__ = [
    'join',
    'Linux', 'Mac', 'Win',
    'DetectedApplication', 'Group',
    'CheckConfiguredRoots', 'CheckKnownRoots', 'check_known_mac_roots', 'AppendExecutable',
]

import inspect
import itertools
import os
import typing
from anaconda_navigator import config as navigator_config

if typing.TYPE_CHECKING:
    import typing_extensions
    from anaconda_navigator.config import user as user_config

    class Source(typing_extensions.Protocol):
        """
        Initial source of application details.

        It is not required for application details to be complete - they still might be extended with filters.
        """

        def __call__(self) -> typing.Iterator['DetectedApplication']:
            """Iterate through detected applications."""

    class Filter(typing_extensions.Protocol):
        """
        Filters for application details.

        Filters are allowed to generate new application details, as well as modify existing ones before forwarding them
        further.
        """

        def __call__(self, parent: typing.Iterator['DetectedApplication']) -> typing.Iterator['DetectedApplication']:
            """Iterate through detected applications."""


def is_source(
        instance: typing.Callable[..., typing.Iterator['DetectedApplication']],
) -> 'typing_extensions.TypeGuard[Source]':
    """
    Check if `instance` is :class:`~Source` instance.

    This check is a rough one, as we don't have a strict type limitations.
    """
    signature: inspect.Signature = inspect.signature(instance)
    return len(signature.parameters) == 0


def is_filter(
        instance: typing.Callable[..., typing.Iterator['DetectedApplication']],
) -> 'typing_extensions.TypeGuard[Filter]':
    """
    Check if `instance` is :class:`~Filter` instance.

    This check is a rough one, as we don't have a strict type limitations.
    """
    signature: inspect.Signature = inspect.signature(instance)
    if len(signature.parameters) != 1:
        return False
    parent: typing.Optional[inspect.Parameter] = signature.parameters.get('parent', None)
    return (parent is not None) and (parent.kind == inspect.Parameter.POSITIONAL_OR_KEYWORD)


def join(root: typing.Optional[str], *args: typing.Optional[str]) -> typing.Optional[str]:
    """Join path parts, if all of them are not :code:`None`."""
    if root is None:
        return None

    if any(arg is None for arg in args):
        return None
    args = typing.cast(typing.Tuple[str, ...], args)

    return os.path.abspath(os.path.join(root, *args))


class Linux:
    """Collection of Linux locations."""

    def __init__(self) -> None:
        """Initialize new :class:`~Linux` instance."""
        raise NotImplementedError()

    root: typing.ClassVar[typing.Optional[str]] = None
    home: typing.ClassVar[typing.Optional[str]] = None

    if navigator_config.LINUX:
        root = '/'
        home = os.path.expanduser('~')


class Mac:
    """Collection of OS X locations."""

    def __init__(self) -> None:
        """Initialize new :class:`~Mac` instance."""
        raise NotImplementedError()

    root: typing.ClassVar[typing.Optional[str]] = None
    home: typing.ClassVar[typing.Optional[str]] = None

    applications: typing.ClassVar[typing.Optional[str]] = None
    user_applications: typing.ClassVar[typing.Optional[str]] = None

    if navigator_config.MAC:
        root = '/'
        home = os.path.expanduser('~')

        applications = os.path.join(root, 'Applications')
        user_applications = os.path.join(home, 'Applications')


class Win:
    """Collection of Windows locations."""

    def __init__(self) -> None:
        """Initialize new :class:`~Win` instance."""
        raise NotImplementedError()

    home: typing.ClassVar[typing.Optional[str]] = None

    program_files_x86: typing.ClassVar[typing.Optional[str]] = None
    program_files_x64: typing.ClassVar[typing.Optional[str]] = None

    program_data: typing.ClassVar[typing.Optional[str]] = None

    local_app_data: typing.ClassVar[typing.Optional[str]] = None
    local_app_data_low: typing.ClassVar[typing.Optional[str]] = None
    roaming_app_data: typing.ClassVar[typing.Optional[str]] = None

    if navigator_config.WIN:
        from anaconda_navigator.external import knownfolders  # pylint: disable=import-outside-toplevel

        home = os.path.expanduser('~')

        program_files_x86 = knownfolders.get_folder_path(knownfolders.FOLDERID.ProgramFilesX86)[0]  # type: ignore
        program_files_x64 = knownfolders.get_folder_path(knownfolders.FOLDERID.ProgramFilesX64)[0]  # type: ignore

        program_data = knownfolders.get_folder_path(knownfolders.FOLDERID.ProgramData)[0]  # type: ignore

        local_app_data = knownfolders.get_folder_path(knownfolders.FOLDERID.LocalAppData)[0]  # type: ignore
        local_app_data_low = knownfolders.get_folder_path(knownfolders.FOLDERID.LocalAppDataLow)[0]  # type: ignore
        roaming_app_data = knownfolders.get_folder_path(knownfolders.FOLDERID.RoamingAppData)[0]  # type: ignore


KEEP: typing.Any = object()


class DetectedApplication:
    """Description of the detected application."""

    __slots__ = ('__root', '__executable', '__version')

    def __init__(
            self,
            *,
            root: typing.Optional[str] = None,
            executable: typing.Optional[str] = None,
            version: typing.Optional[str] = None,
    ) -> None:
        """Initialize new :class:`~DetectedApplication`."""
        self.__root: 'typing_extensions.Final[typing.Optional[str]]' = root
        self.__executable: 'typing_extensions.Final[typing.Optional[str]]' = executable
        self.__version: 'typing_extensions.Final[typing.Optional[str]]' = version

    @property
    def complete(self) -> bool:  # noqa: D401
        """All required values are provided."""
        return all(
            item is not None
            for item in (self.__root, self.__executable, self.__version)
        )

    @property
    def root(self) -> str:  # noqa: D401
        """Root directory of the detected application."""
        if self.__root is None:
            raise AttributeError('Incomplete detected application description')
        return self.__root

    @property
    def executable(self) -> str:  # noqa: D401
        """Path to the executable of the detected application."""
        if self.__executable is None:
            raise AttributeError('Incomplete detected application description')
        return self.__executable

    @property
    def version(self) -> str:  # noqa: D401
        """Version of the detected application."""
        if self.__version is None:
            raise AttributeError('Incomplete detected application description')
        return self.__version

    def replace(
            self,
            *,
            root: typing.Optional[str] = KEEP,
            executable: typing.Optional[str] = KEEP,
            version: typing.Optional[str] = KEEP,
    ) -> 'DetectedApplication':
        """Prepare a copy of current instance with some additional replacements."""
        if root is KEEP:
            root = self.__root
        if executable is KEEP:
            executable = self.__executable
        if version is KEEP:
            version = self.__version
        return DetectedApplication(root=root, executable=executable, version=version)


class Group:
    """
    Group of application detecting sources and filters.

    Order in which you provide sources and filters matters. Output of each source is chained with all previously
    detected applications (if such). Filters are applied to all previously detected applications.
    """

    __slots__ = ('__content',)

    def __init__(self, *args: typing.Union['Source', 'Filter']) -> None:
        """Initialize new :class:`~Group` instance."""
        if len(args) <= 0:
            raise TypeError('at least one source must be provided')

        if not is_source(args[0]):
            raise TypeError('first argument must be a Source')

        arg: typing.Union['Source', 'Filter']
        for arg in args:
            if (not is_source(arg)) and (not is_filter(arg)):
                raise TypeError(f'each argument must be source- of filter-compatible, not {type(arg).__name__}')

        self.__content: 'typing_extensions.Final[typing.Tuple[typing.Union[Source, Filter], ...]]' = args

    def __call__(self) -> typing.Iterator[DetectedApplication]:
        """Iterate through detected applications."""
        result: typing.Iterator[DetectedApplication] = typing.cast('Source', self.__content[0])()

        arg: typing.Union['Source', 'Filter']
        for arg in itertools.islice(self.__content, 1, len(self.__content), 1):
            if is_source(arg):
                result = itertools.chain(result, arg())
            else:
                arg = typing.cast('Filter', arg)
                result = arg(result)

        return result


def collect_str(source: typing.Union[None, str, typing.Iterable[typing.Any]]) -> typing.Iterator[str]:
    """Collect string values from the recursive collections/iterables of :class:`~str` or :code:`None` instances."""
    stack: typing.List[typing.Union[None, str, typing.Iterable[typing.Any]]] = [source]
    while stack:
        current: typing.Union[None, str, typing.Iterable[typing.Any]] = stack.pop()

        if current is None:
            continue

        if isinstance(current, str):
            yield current

        else:
            offset: int = len(stack)
            child: typing.Union[None, str, typing.Iterable[typing.Any]]
            for child in current:
                stack.insert(offset, child)


class CheckConfiguredRoots:
    """
    Get application root from the configuration.

    Multiple configuration keys might be provided as `args`.

    Configuration, from which value should be retrieved, must be provided as a keyword argument.

    If configuration section is not provided - "main" will be used by default.
    """

    __slots__ = ('__content', '__configuration', '__section')

    def __init__(
            self,
            *args: typing.Union[None, str, typing.Iterable[typing.Optional[str]]],
            configuration: 'user_config.UserConfig',
            section: str = 'main',
    ) -> None:
        """Initialize new :class:`~CheckKnownRoots` instance."""
        self.__content: 'typing_extensions.Final[typing.Tuple[str, ...]]' = tuple(collect_str(args))
        self.__configuration: 'typing_extensions.Final[user_config.UserConfig]' = configuration
        self.__section: 'typing_extensions.Final[str]' = section

    def __call__(self) -> typing.Iterator[DetectedApplication]:
        """Iterate through detected applications."""
        setting: str
        for setting in self.__content:
            root: str = self.__configuration.get(self.__section, setting, '')
            if not root:
                continue

            root = os.path.abspath(root)
            if os.path.exists(root):
                yield DetectedApplication(root=root)


class CheckKnownRoots:
    """
    Iterate through known roots, selecting only existing ones.

    Some of root options might be :code:`None` - they will be skipped.
    """

    __slots__ = ('__content',)

    def __init__(self, *args: typing.Union[None, str, typing.Iterable[typing.Optional[str]]]) -> None:
        """Initialize new :class:`~CheckKnownRoots` instance."""
        self.__content: 'typing_extensions.Final[typing.Tuple[str, ...]]' = tuple(collect_str(args))

    def __call__(self) -> typing.Iterator[DetectedApplication]:
        """Iterate through detected applications."""
        root: str
        for root in self.__content:
            root = os.path.abspath(root)
            if os.path.exists(root):
                yield DetectedApplication(root=root)


def check_known_mac_roots(*args: typing.Union[None, str, typing.Iterable[typing.Optional[str]]]) -> CheckKnownRoots:
    """
    Shortcut for checking application roots of OS X applications.

    Unlike :class:`~CheckKnownRoots` - you need to provide application names instead of directory paths.
    """
    return CheckKnownRoots(*(
        join(root, arg)
        for root in (Mac.user_applications, Mac.applications)
        for arg in collect_str(args)
    ))


class StepIntoRoot:
    """
    Iterate through children of application root.

    Each child might be checked that it `starts_with`, `ends_with` or `equals` to one or multiple values.

    Iteration results are sorted. If you want descending order of the results - set `reverse` to :code:`True`.
    """

    __slots__ = ('__equals', '__starts_with', '__ends_with', '__reverse')

    def __init__(
            self,
            *,
            equals: typing.Union[str, typing.Iterable[str]] = (),
            starts_with: typing.Union[str, typing.Iterable[str]] = (),
            ends_with: typing.Union[str, typing.Iterable[str]] = (),
            reverse: bool = False,
    ) -> None:
        """Initialize new :class:`~StepIntoRoot` instance."""
        if isinstance(equals, str):
            equals = {equals}
        else:
            equals = set(equals)

        if isinstance(starts_with, str):
            starts_with = (starts_with,)
        else:
            starts_with = tuple(starts_with)

        if isinstance(ends_with, str):
            ends_with = (ends_with,)
        else:
            ends_with = tuple(ends_with)

        self.__equals: 'typing_extensions.Final[typing.Set[str]]' = equals
        self.__starts_with: 'typing_extensions.Final[typing.Tuple[str, ...]]' = starts_with
        self.__ends_with: 'typing_extensions.Final[typing.Tuple[str, ...]]' = ends_with
        self.__reverse: 'typing_extensions.Final[bool]' = reverse

    def __call__(self, parent: typing.Iterator[DetectedApplication]) -> typing.Iterator[DetectedApplication]:
        """Iterate through detected applications."""
        application: DetectedApplication
        for application in parent:
            if not application.root:
                continue

            children: typing.List[str]
            try:
                children = sorted(os.listdir(application.root), reverse=self.__reverse)
            except OSError:
                continue

            child: str
            for child in children:
                if self.__equals and (child not in self.__equals):
                    continue
                if self.__starts_with and not any(child.startswith(item) for item in self.__starts_with):
                    continue
                if self.__ends_with and not any(child.endswith(item) for item in self.__ends_with):
                    continue
                yield application.replace(root=os.path.join(application.root, child))


class AppendExecutable:
    """
    Check multiple options of executables and iterate through existing ones.

    Each option of the executable must be a path relative to the application root.
    """

    __slots__ = ('__content',)

    def __init__(self, *args: typing.Union[None, str, typing.Iterable[typing.Optional[str]]]) -> None:
        """Initialize new :class:`~AppendExecutable` instance."""
        self.__content: 'typing_extensions.Final[typing.Tuple[str, ...]]' = tuple(collect_str(args))

    def __call__(self, parent: typing.Iterator[DetectedApplication]) -> typing.Iterator[DetectedApplication]:
        """Iterate through detected applications."""
        application: DetectedApplication
        executable: str
        for application in parent:
            for executable in self.__content:
                executable = os.path.abspath(os.path.join(application.root, executable))
                if os.path.exists(executable):
                    yield application.replace(executable=executable)


class If:
    """Iterate through application only if a `condition` is met."""

    __slots__ = ('__condition',)

    def __init__(self, condition: bool) -> None:
        """Initialize new :class:`~If` instance."""
        self.__condition: 'typing_extensions.Final[bool]' = condition

    def __call__(self, parent: typing.Iterator[DetectedApplication]) -> typing.Iterator[DetectedApplication]:
        """Iterate through detected applications."""
        if self.__condition:
            return parent

        return iter(())


def linux_only() -> If:
    """Iterate through applications only if on a linux machine."""
    return If(navigator_config.LINUX)


def mac_only() -> If:
    """Iterate through applications only if on an os x machine."""
    return If(navigator_config.MAC)


def win_only() -> If:
    """Iterate through applications only if on a windows machine."""
    return If(navigator_config.WIN)