import typing as t

if t.TYPE_CHECKING:  # pragma: no cover
    from _typeshed.wsgi import WSGIApplication  # noqa: F401
    from werkzeug.datastructures import Headers  # noqa: F401
    from werkzeug.wrappers import Response  # noqa: F401

# The possible types that are directly convertible or are a Response object.
ResponseValue = t.Union[
    "Response",
    str,
    bytes,
    t.List[t.Any],
    # Only dict is actually accepted, but Mapping allows for TypedDict.
    t.Mapping[str, t.Any],
    t.Iterator[str],
    t.Iterator[bytes],
]

# the possible types for an individual HTTP header
# This should be a Union, but mypy doesn't pass unless it's a TypeVar.
HeaderValue = t.Union[str, t.List[str], t.Tuple[str, ...]]

# the possible types for HTTP headers
HeadersValue = t.Union[
    "Headers",
    t.Mapping[str, HeaderValue],
    t.Sequence[t.Tuple[str, HeaderValue]],
]

ResponseReturnValue = t.Union[
    ResponseValue,
    t.Tuple[ResponseValue, HeadersValue],
    t.Tuple[ResponseValue, int],
    t.Tuple[ResponseValue, int, HeadersValue],
    "WSGIApplication",
]