# Utility types for typeshed
#
# See the README.md file in this directory for more information.

import sys
from collections.abc import Awaitable, Callable, Iterable, Sequence, Set as AbstractSet, Sized
from dataclasses import Field
from os import PathLike
from types import FrameType, TracebackType
from typing import (
    Any,
    AnyStr,
    ClassVar,
    Final,
    Generic,
    Literal,
    Protocol,
    SupportsFloat,
    SupportsIndex,
    SupportsInt,
    TypeVar,
    final,
    overload,
)
from typing_extensions import Buffer, LiteralString, TypeAlias

_KT = TypeVar("_KT")
_KT_co = TypeVar("_KT_co", covariant=True)
_KT_contra = TypeVar("_KT_contra", contravariant=True)
_VT = TypeVar("_VT")
_VT_co = TypeVar("_VT_co", covariant=True)
_T = TypeVar("_T")
_T_co = TypeVar("_T_co", covariant=True)
_T_contra = TypeVar("_T_contra", contravariant=True)

# Alternative to `typing_extensions.Self`, exclusively for use with `__new__`
# in metaclasses:
#     def __new__(cls: type[Self], ...) -> Self: ...
# In other cases, use `typing_extensions.Self`.
Self = TypeVar("Self")  # noqa: Y001

# covariant version of typing.AnyStr, useful for protocols
AnyStr_co = TypeVar("AnyStr_co", str, bytes, covariant=True)  # noqa: Y001

# For partially known annotations. Usually, fields where type annotations
# haven't been added are left unannotated, but in some situations this
# isn't possible or a type is already partially known. In cases like these,
# use Incomplete instead of Any as a marker. For example, use
# "Incomplete | None" instead of "Any | None".
Incomplete: TypeAlias = Any  # stable

# To describe a function parameter that is unused and will work with anything.
Unused: TypeAlias = object  # stable

# Marker for return types that include None, but where forcing the user to
# check for None can be detrimental. Sometimes called "the Any trick". See
# CONTRIBUTING.md for more information.
MaybeNone: TypeAlias = Any  # stable

# Used to mark arguments that default to a sentinel value. This prevents
# stubtest from complaining about the default value not matching.
#
# def foo(x: int | None = sentinel) -> None: ...
#
# In cases where the sentinel object is exported and can be used by user code,
# a construct like this is better:
#
# _SentinelType = NewType("_SentinelType", object)
# sentinel: _SentinelType
# def foo(x: int | None | _SentinelType = ...) -> None: ...
sentinel: Any

# stable
class IdentityFunction(Protocol):
    def __call__(self, x: _T, /) -> _T: ...

# stable
class SupportsNext(Protocol[_T_co]):
    def __next__(self) -> _T_co: ...

# stable
class SupportsAnext(Protocol[_T_co]):
    def __anext__(self) -> Awaitable[_T_co]: ...

# Comparison protocols

class SupportsDunderLT(Protocol[_T_contra]):
    def __lt__(self, other: _T_contra, /) -> bool: ...

class SupportsDunderGT(Protocol[_T_contra]):
    def __gt__(self, other: _T_contra, /) -> bool: ...

class SupportsDunderLE(Protocol[_T_contra]):
    def __le__(self, other: _T_contra, /) -> bool: ...

class SupportsDunderGE(Protocol[_T_contra]):
    def __ge__(self, other: _T_contra, /) -> bool: ...

class SupportsAllComparisons(
    SupportsDunderLT[Any], SupportsDunderGT[Any], SupportsDunderLE[Any], SupportsDunderGE[Any], Protocol
): ...

SupportsRichComparison: TypeAlias = SupportsDunderLT[Any] | SupportsDunderGT[Any]
SupportsRichComparisonT = TypeVar("SupportsRichComparisonT", bound=SupportsRichComparison)  # noqa: Y001

# Dunder protocols

class SupportsAdd(Protocol[_T_contra, _T_co]):
    def __add__(self, x: _T_contra, /) -> _T_co: ...

class SupportsRAdd(Protocol[_T_contra, _T_co]):
    def __radd__(self, x: _T_contra, /) -> _T_co: ...

class SupportsSub(Protocol[_T_contra, _T_co]):
    def __sub__(self, x: _T_contra, /) -> _T_co: ...

class SupportsRSub(Protocol[_T_contra, _T_co]):
    def __rsub__(self, x: _T_contra, /) -> _T_co: ...

class SupportsDivMod(Protocol[_T_contra, _T_co]):
    def __divmod__(self, other: _T_contra, /) -> _T_co: ...

class SupportsRDivMod(Protocol[_T_contra, _T_co]):
    def __rdivmod__(self, other: _T_contra, /) -> _T_co: ...

# This protocol is generic over the iterator type, while Iterable is
# generic over the type that is iterated over.
class SupportsIter(Protocol[_T_co]):
    def __iter__(self) -> _T_co: ...

# This protocol is generic over the iterator type, while AsyncIterable is
# generic over the type that is iterated over.
class SupportsAiter(Protocol[_T_co]):
    def __aiter__(self) -> _T_co: ...

class SupportsLenAndGetItem(Protocol[_T_co]):
    def __len__(self) -> int: ...
    def __getitem__(self, k: int, /) -> _T_co: ...

class SupportsTrunc(Protocol):
    def __trunc__(self) -> int: ...

# Mapping-like protocols

# stable
class SupportsItems(Protocol[_KT_co, _VT_co]):
    def items(self) -> AbstractSet[tuple[_KT_co, _VT_co]]: ...

# stable
class SupportsKeysAndGetItem(Protocol[_KT, _VT_co]):
    def keys(self) -> Iterable[_KT]: ...
    def __getitem__(self, key: _KT, /) -> _VT_co: ...

# This protocol is currently under discussion. Use SupportsContainsAndGetItem
# instead, if you require the __contains__ method.
# See https://github.com/python/typeshed/issues/11822.
class SupportsGetItem(Protocol[_KT_contra, _VT_co]):
    def __contains__(self, x: Any, /) -> bool: ...
    def __getitem__(self, key: _KT_contra, /) -> _VT_co: ...

# stable
class SupportsContainsAndGetItem(Protocol[_KT_contra, _VT_co]):
    def __contains__(self, x: Any, /) -> bool: ...
    def __getitem__(self, key: _KT_contra, /) -> _VT_co: ...

# stable
class SupportsItemAccess(Protocol[_KT_contra, _VT]):
    def __contains__(self, x: Any, /) -> bool: ...
    def __getitem__(self, key: _KT_contra, /) -> _VT: ...
    def __setitem__(self, key: _KT_contra, value: _VT, /) -> None: ...
    def __delitem__(self, key: _KT_contra, /) -> None: ...

StrPath: TypeAlias = str | PathLike[str]  # stable
BytesPath: TypeAlias = bytes | PathLike[bytes]  # stable
GenericPath: TypeAlias = AnyStr | PathLike[AnyStr]
StrOrBytesPath: TypeAlias = str | bytes | PathLike[str] | PathLike[bytes]  # stable

OpenTextModeUpdating: TypeAlias = Literal[
    "r+",
    "+r",
    "rt+",
    "r+t",
    "+rt",
    "tr+",
    "t+r",
    "+tr",
    "w+",
    "+w",
    "wt+",
    "w+t",
    "+wt",
    "tw+",
    "t+w",
    "+tw",
    "a+",
    "+a",
    "at+",
    "a+t",
    "+at",
    "ta+",
    "t+a",
    "+ta",
    "x+",
    "+x",
    "xt+",
    "x+t",
    "+xt",
    "tx+",
    "t+x",
    "+tx",
]
OpenTextModeWriting: TypeAlias = Literal["w", "wt", "tw", "a", "at", "ta", "x", "xt", "tx"]
OpenTextModeReading: TypeAlias = Literal["r", "rt", "tr", "U", "rU", "Ur", "rtU", "rUt", "Urt", "trU", "tUr", "Utr"]
OpenTextMode: TypeAlias = OpenTextModeUpdating | OpenTextModeWriting | OpenTextModeReading
OpenBinaryModeUpdating: TypeAlias = Literal[
    "rb+",
    "r+b",
    "+rb",
    "br+",
    "b+r",
    "+br",
    "wb+",
    "w+b",
    "+wb",
    "bw+",
    "b+w",
    "+bw",
    "ab+",
    "a+b",
    "+ab",
    "ba+",
    "b+a",
    "+ba",
    "xb+",
    "x+b",
    "+xb",
    "bx+",
    "b+x",
    "+bx",
]
OpenBinaryModeWriting: TypeAlias = Literal["wb", "bw", "ab", "ba", "xb", "bx"]
OpenBinaryModeReading: TypeAlias = Literal["rb", "br", "rbU", "rUb", "Urb", "brU", "bUr", "Ubr"]
OpenBinaryMode: TypeAlias = OpenBinaryModeUpdating | OpenBinaryModeReading | OpenBinaryModeWriting

# stable
class HasFileno(Protocol):
    def fileno(self) -> int: ...

FileDescriptor: TypeAlias = int  # stable
FileDescriptorLike: TypeAlias = int | HasFileno  # stable
FileDescriptorOrPath: TypeAlias = int | StrOrBytesPath

# stable
class SupportsRead(Protocol[_T_co]):
    def read(self, length: int = ..., /) -> _T_co: ...

# stable
class SupportsReadline(Protocol[_T_co]):
    def readline(self, length: int = ..., /) -> _T_co: ...

# stable
class SupportsNoArgReadline(Protocol[_T_co]):
    def readline(self) -> _T_co: ...

# stable
class SupportsWrite(Protocol[_T_contra]):
    def write(self, s: _T_contra, /) -> object: ...

# stable
class SupportsFlush(Protocol):
    def flush(self) -> object: ...

# Unfortunately PEP 688 does not allow us to distinguish read-only
# from writable buffers. We use these aliases for readability for now.
# Perhaps a future extension of the buffer protocol will allow us to
# distinguish these cases in the type system.
ReadOnlyBuffer: TypeAlias = Buffer  # stable
# Anything that implements the read-write buffer interface.
WriteableBuffer: TypeAlias = Buffer
# Same as WriteableBuffer, but also includes read-only buffer types (like bytes).
ReadableBuffer: TypeAlias = Buffer  # stable

class SliceableBuffer(Buffer, Protocol):
    def __getitem__(self, slice: slice, /) -> Sequence[int]: ...

class IndexableBuffer(Buffer, Protocol):
    def __getitem__(self, i: int, /) -> int: ...

class SupportsGetItemBuffer(SliceableBuffer, IndexableBuffer, Protocol):
    def __contains__(self, x: Any, /) -> bool: ...
    @overload
    def __getitem__(self, slice: slice, /) -> Sequence[int]: ...
    @overload
    def __getitem__(self, i: int, /) -> int: ...

class SizedBuffer(Sized, Buffer, Protocol): ...

# for compatibility with third-party stubs that may use this
_BufferWithLen: TypeAlias = SizedBuffer  # not stable  # noqa: Y047

ExcInfo: TypeAlias = tuple[type[BaseException], BaseException, TracebackType]
OptExcInfo: TypeAlias = ExcInfo | tuple[None, None, None]

# stable
if sys.version_info >= (3, 10):
    from types import NoneType as NoneType
else:
    # Used by type checkers for checks involving None (does not exist at runtime)
    @final
    class NoneType:
        def __bool__(self) -> Literal[False]: ...

# This is an internal CPython type that is like, but subtly different from, a NamedTuple
# Subclasses of this type are found in multiple modules.
# In typeshed, `structseq` is only ever used as a mixin in combination with a fixed-length `Tuple`
# See discussion at #6546 & #6560
# `structseq` classes are unsubclassable, so are all decorated with `@final`.
class structseq(Generic[_T_co]):
    n_fields: Final[int]
    n_unnamed_fields: Final[int]
    n_sequence_fields: Final[int]
    # The first parameter will generally only take an iterable of a specific length.
    # E.g. `os.uname_result` takes any iterable of length exactly 5.
    #
    # The second parameter will accept a dict of any kind without raising an exception,
    # but only has any meaning if you supply it a dict where the keys are strings.
    # https://github.com/python/typeshed/pull/6560#discussion_r767149830
    def __new__(cls: type[Self], sequence: Iterable[_T_co], dict: dict[str, Any] = ...) -> Self: ...

# Superset of typing.AnyStr that also includes LiteralString
AnyOrLiteralStr = TypeVar("AnyOrLiteralStr", str, bytes, LiteralString)  # noqa: Y001

# Represents when str or LiteralStr is acceptable. Useful for string processing
# APIs where literalness of return value depends on literalness of inputs
StrOrLiteralStr = TypeVar("StrOrLiteralStr", LiteralString, str)  # noqa: Y001

# Objects suitable to be passed to sys.setprofile, threading.setprofile, and similar
ProfileFunction: TypeAlias = Callable[[FrameType, str, Any], object]

# Objects suitable to be passed to sys.settrace, threading.settrace, and similar
TraceFunction: TypeAlias = Callable[[FrameType, str, Any], TraceFunction | None]

# experimental
# Might not work as expected for pyright, see
#   https://github.com/python/typeshed/pull/9362
#   https://github.com/microsoft/pyright/issues/4339
class DataclassInstance(Protocol):
    __dataclass_fields__: ClassVar[dict[str, Field[Any]]]

# Anything that can be passed to the int/float constructors
ConvertibleToInt: TypeAlias = str | ReadableBuffer | SupportsInt | SupportsIndex | SupportsTrunc
ConvertibleToFloat: TypeAlias = str | ReadableBuffer | SupportsFloat | SupportsIndex

# A few classes updated from Foo(str, Enum) to Foo(StrEnum). This is a convenience so these
# can be accurate on all python versions without getting too wordy
if sys.version_info >= (3, 11):
    from enum import StrEnum as StrEnum
else:
    from enum import Enum

    class StrEnum(str, Enum): ...
