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# Source code for astropy.utils.misc

    # Licensed under a 3-clause BSD style license - see LICENSE.rst
    """
    A "grab bag" of relatively small general-purpose utilities that don't have
    a clear module/package to live in.
    """

    import contextlib
    import difflib
    import inspect
    import json
    import locale
    import os
    import re
    import sys
    import threading
    import traceback
    import unicodedata
    from collections import defaultdict
    from collections.abc import Callable, Iterable
    from contextlib import contextmanager
    from itertools import chain

    from astropy.utils import deprecated

    __all__ = [
        "JsonCustomEncoder",
        "NumpyRNGContext",
        "dtype_bytes_or_chars",
        "find_api_page",
        "format_exception",
        "indent",
        "is_path_hidden",
        "isiterable",
        "silence",
        "walk_skip_hidden",
    ]

    NOT_OVERWRITING_MSG = (
        "File {} already exists. If you mean to replace it "
        'then use the argument "overwrite=True".'
    )
    # A useful regex for tests.
    _NOT_OVERWRITING_MSG_MATCH = (
        r"File .* already exists\. If you mean to "
        r"replace it then use the argument "
        r'"overwrite=True"\.'
    )

    def isiterable(obj):
        """Returns `True` if the given object is iterable."""
        try:
            iter(obj)
            return True
        except TypeError:
            return False

    @deprecated(since="6.1", alternative="textwrap.indent()")
    def indent(s, shift=1, width=4):
        """Indent a block of text.  The indentation is applied to each line."""
        indented = "\n".join(" " * (width * shift) + l if l else "" for l in s.splitlines())
        if s[-1] == "\n":
            indented += "\n"

        return indented

    class _DummyFile:
        """A noop writeable object."""

        def write(self, s):
            pass

    @contextlib.contextmanager
    def silence():
        """A context manager that silences sys.stdout and sys.stderr."""
        old_stdout = sys.stdout
        old_stderr = sys.stderr
        sys.stdout = _DummyFile()
        sys.stderr = _DummyFile()
        yield
        sys.stdout = old_stdout
        sys.stderr = old_stderr

    @deprecated(since="7.0")
    def format_exception(msg, *args, **kwargs):
        """Fill in information about the exception that occurred.

        Given an exception message string, uses new-style formatting arguments
        ``{filename}``, ``{lineno}``, ``{func}`` and/or ``{text}`` to fill in
        information about the exception that occurred.  For example:

            try:
                1/0
            except:
                raise ZeroDivisionError(
                    format_except('A divide by zero occurred in {filename} at '
                                  'line {lineno} of function {func}.'))

        Any additional positional or keyword arguments passed to this function are
        also used to format the message.

        .. note::
            This uses `sys.exc_info` to gather up the information needed to fill
            in the formatting arguments. Since `sys.exc_info` is not carried
            outside a handled exception, it's not wise to use this
            outside of an ``except`` clause - if it is, this will substitute
            '<unknown>' for the 4 formatting arguments.
        """
        tb = traceback.extract_tb(sys.exc_info()[2], limit=1)
        if len(tb) > 0:
            filename, lineno, func, text = tb[0]
        else:
            filename = lineno = func = text = "<unknown>"

        return msg.format(
            *args, filename=filename, lineno=lineno, func=func, text=text, **kwargs
        )

    class NumpyRNGContext:
        """
        A context manager (for use with the ``with`` statement) that will seed the
        numpy random number generator (RNG) to a specific value, and then restore
        the RNG state back to whatever it was before.

        This is primarily intended for use in the astropy testing suit, but it
        may be useful in ensuring reproducibility of Monte Carlo simulations in a
        science context.

        Parameters
        ----------
        seed : int
            The value to use to seed the numpy RNG

        Examples
        --------
        A typical use case might be::

            with NumpyRNGContext(<some seed value you pick>):
                from numpy import random

                randarr = random.randn(100)
                ... run your test using `randarr` ...

            #Any code using numpy.random at this indent level will act just as it
            #would have if it had been before the with statement - e.g. whatever
            #the default seed is.

        """

        def __init__(self, seed):
            self.seed = seed

        def __enter__(self):
            from numpy import random

            self.startstate = random.get_state()
            random.seed(self.seed)

        def __exit__(self, exc_type, exc_value, traceback):
            from numpy import random

            random.set_state(self.startstate)

    def find_api_page(obj, version=None, openinbrowser=True, timeout=None):
        """
        Determines the URL of the API page for the specified object, and
        optionally open that page in a web browser.

        .. note::
            You must be connected to the internet for this to function even if
            ``openinbrowser`` is `False`, unless you provide a local version of
            the documentation to ``version`` (e.g., ``file:///path/to/docs``).

        Parameters
        ----------
        obj
            The object to open the docs for or its fully-qualified name
            (as a str).
        version : str
            The doc version - either a version number like '0.1', 'dev' for
            the development/latest docs, or a URL to point to a specific
            location that should be the *base* of the documentation. Defaults to
            latest if you are on aren't on a release, otherwise, the version you
            are on.
        openinbrowser : bool
            If `True`, the `webbrowser` package will be used to open the doc
            page in a new web browser window.
        timeout : number, optional
            The number of seconds to wait before timing-out the query to
            the astropy documentation.  If not given, the default python
            stdlib timeout will be used.

        Returns
        -------
        url : str
            The loaded URL

        Raises
        ------
        ValueError
            If the documentation can't be found

        """
        import webbrowser
        from zlib import decompress

        from astropy.utils.data import get_readable_fileobj

        if (
            not isinstance(obj, str)
            and hasattr(obj, "__module__")
            and hasattr(obj, "__name__")
        ):
            obj = obj.__module__ + "." + obj.__name__
        elif inspect.ismodule(obj):
            obj = obj.__name__

        if version is None:
            from astropy import version

            if version.release:
                version = "v" + version.version
            else:
                version = "dev"

        if "://" in version:
            if version.endswith("index.html"):
                baseurl = version[:-10]
            elif version.endswith("/"):
                baseurl = version
            else:
                baseurl = version + "/"
        elif version == "dev" or version == "latest":
            baseurl = "http://devdocs.astropy.org/"
        else:
            baseurl = f"https://docs.astropy.org/en/{version}/"

        # Custom request headers; see
        # https://github.com/astropy/astropy/issues/8990
        url = baseurl + "objects.inv"
        headers = {"User-Agent": f"Astropy/{version}"}
        with get_readable_fileobj(
            url, encoding="binary", remote_timeout=timeout, http_headers=headers
        ) as uf:
            oiread = uf.read()

            # need to first read/remove the first four lines, which have info before
            # the compressed section with the actual object inventory
            idx = -1
            headerlines = []
            for _ in range(4):
                oldidx = idx
                idx = oiread.index(b"\n", oldidx + 1)
                headerlines.append(oiread[(oldidx + 1) : idx].decode("utf-8"))

            # intersphinx version line, project name, and project version
            ivers, proj, vers, compr = headerlines
            if "The remainder of this file is compressed using zlib" not in compr:
                raise ValueError(
                    f"The file downloaded from {baseurl}objects.inv does not seem to be"
                    "the usual Sphinx objects.inv format.  Maybe it "
                    "has changed?"
                )

            compressed = oiread[(idx + 1) :]

        decompressed = decompress(compressed).decode("utf-8")

        resurl = None

        for l in decompressed.strip().splitlines():
            ls = l.split()
            name = ls[0]
            loc = ls[3]
            if loc.endswith("$"):
                loc = loc[:-1] + name

            if name == obj:
                resurl = baseurl + loc
                break

        if resurl is None:
            raise ValueError(f"Could not find the docs for the object {obj}")
        elif openinbrowser:
            webbrowser.open(resurl)

        return resurl

    # _has_hidden_attribute() can be deleted together with deprecated is_path_hidden() and
    # walk_skip_hidden().
    if sys.platform == "win32":
        import ctypes

        def _has_hidden_attribute(filepath):
            """
            Returns True if the given filepath has the hidden attribute on
            MS-Windows.  Based on a post here:
            https://stackoverflow.com/questions/284115/cross-platform-hidden-file-detection.
            """
            if isinstance(filepath, bytes):
                filepath = filepath.decode(sys.getfilesystemencoding())
            try:
                attrs = ctypes.windll.kernel32.GetFileAttributesW(filepath)
                result = bool(attrs & 2) and attrs != -1
            except AttributeError:
                result = False
            return result

    else:

        def _has_hidden_attribute(filepath):
            return False

    @deprecated(since="6.0")
    def is_path_hidden(filepath):
        """
        Determines if a given file or directory is hidden.

        Parameters
        ----------
        filepath : str
            The path to a file or directory

        Returns
        -------
        hidden : bool
            Returns `True` if the file is hidden
        """
        name = os.path.basename(os.path.abspath(filepath))
        if isinstance(name, bytes):
            is_dotted = name.startswith(b".")
        else:
            is_dotted = name.startswith(".")
        return is_dotted or _has_hidden_attribute(filepath)

    @deprecated(since="6.0")
    def walk_skip_hidden(top, onerror=None, followlinks=False):
        """
        A wrapper for `os.walk` that skips hidden files and directories.

        This function does not have the parameter ``topdown`` from
        `os.walk`: the directories must always be recursed top-down when
        using this function.

        See Also
        --------
        os.walk : For a description of the parameters
        """
        for root, dirs, files in os.walk(
            top, topdown=True, onerror=onerror, followlinks=followlinks
        ):
            # These lists must be updated in-place so os.walk will skip
            # hidden directories
            dirs[:] = [d for d in dirs if not is_path_hidden(d)]
            files[:] = [f for f in files if not is_path_hidden(f)]
            yield root, dirs, files

    class JsonCustomEncoder(json.JSONEncoder):
        """Support for data types that JSON default encoder
        does not do.

        This includes:

            * Numpy array or number
            * Complex number
            * Set
            * Bytes
            * astropy.UnitBase
            * astropy.Quantity

        Examples
        --------
        >>> import json
        >>> import numpy as np
        >>> from astropy.utils.misc import JsonCustomEncoder
        >>> json.dumps(np.arange(3), cls=JsonCustomEncoder)
        '[0, 1, 2]'

        """

        def default(self, obj):
            import numpy as np

            from astropy import units as u

            if isinstance(obj, u.Quantity):
                return dict(value=obj.value, unit=obj.unit.to_string())
            if isinstance(obj, (np.number, np.ndarray)):
                return obj.tolist()
            elif isinstance(obj, complex):
                return [obj.real, obj.imag]
            elif isinstance(obj, set):
                return list(obj)
            elif isinstance(obj, bytes):  # pragma: py3
                return obj.decode()
            elif isinstance(obj, (u.UnitBase, u.FunctionUnitBase)):
                if obj == u.dimensionless_unscaled:
                    obj = "dimensionless_unit"
                else:
                    return obj.to_string()

            return json.JSONEncoder.default(self, obj)

    def strip_accents(s: str) -> str:
        """
        Remove accents from a Unicode string.

        This helps with matching "ångström" to "angstrom", for example.
        """
        return "".join(
            c for c in unicodedata.normalize("NFD", s) if unicodedata.category(c) != "Mn"
        )

    def did_you_mean(
        s: str,
        candidates: Iterable[str],
        n: int = 3,
        cutoff: float = 0.8,
        fix: Callable[[str], list[str]] | None = None,
    ) -> str:
        """
        When a string isn't found in a set of candidates, we can be nice
        to provide a list of alternatives in the exception.  This
        convenience function helps to format that part of the exception.

        Parameters
        ----------
        s : str

        candidates : iterable of str
            Note that str itself does not cause an error, but the output
            might not be what was expected.

        n : int
            The maximum number of results to include.  See
            `difflib.get_close_matches`.

        cutoff : float
            In the range [0, 1]. Possibilities that don't score at least
            that similar to word are ignored.  See
            `difflib.get_close_matches`.

        fix : callable
            A callable to modify the results after matching.  It should
            take a single string and return a list of strings
            containing the fixed matches.

        Returns
        -------
        message : str
            Returns the string "Did you mean X, Y, or Z?", or the empty
            string if no alternatives were found.
        """
        s_lower = strip_accents(s).lower()

        # Create a mapping from the lower case name to all capitalization
        # variants of that name.
        candidates_lower = defaultdict(list)
        for candidate in candidates:
            candidates_lower[candidate.lower()].append(candidate)

        # The heuristic here is to first try "singularizing" the word.  If
        # that doesn't match anything use difflib to find close matches in
        # original, lower and upper case.
        matches: Iterable[str] = (
            [s_lower[:-1]]
            if s_lower.endswith("s") and s_lower[:-1] in candidates_lower
            else difflib.get_close_matches(s_lower, candidates_lower, n=n, cutoff=cutoff)
        )

        if not matches:
            return ""
        matches = chain.from_iterable(candidates_lower[match] for match in matches)
        if fix is not None:
            matches = chain.from_iterable(fix(match) for match in matches)
        *first_matches, suggestion = sorted(set(matches))
        if first_matches:
            suggestion = ", ".join(first_matches) + " or " + suggestion
        return f"Did you mean {suggestion}?"

    LOCALE_LOCK = threading.Lock()

    @contextmanager
    def _set_locale(name):
        """
        Context manager to temporarily set the locale to ``name``.

        An example is setting locale to "C" so that the C strtod()
        function will use "." as the decimal point to enable consistent
        numerical string parsing.

        Note that one cannot nest multiple _set_locale() context manager
        statements as this causes a threading lock.

        This code taken from https://stackoverflow.com/questions/18593661/how-do-i-strftime-a-date-object-in-a-different-locale.

        Parameters
        ----------
        name : str
            Locale name, e.g. "C" or "fr_FR".
        """
        name = str(name)

        with LOCALE_LOCK:
            saved = locale.setlocale(locale.LC_ALL)
            if saved == name:
                # Don't do anything if locale is already the requested locale
                yield
            else:
                try:
                    locale.setlocale(locale.LC_ALL, name)
                    yield
                finally:
                    locale.setlocale(locale.LC_ALL, saved)

    def dtype_bytes_or_chars(dtype):
        """
        Parse the number out of a dtype.str value like '<U5' or '<f8'.

        See #5819 for discussion on the need for this function for getting
        the number of characters corresponding to a string dtype.

        Parameters
        ----------
        dtype : numpy dtype object
            Input dtype

        Returns
        -------
        bytes_or_chars : int or None
            Bits (for numeric types) or characters (for string types)
        """
        match = re.search(r"(\d+)$", dtype.str)
        out = int(match.group(1)) if match else None
        return out

    def _hungry_for(option):  # pragma: no cover
        """
        Open browser loaded with ``option`` options near you.

        *Disclaimers: Payments not included. Astropy is not
        responsible for any liability from using this function.*

        .. note:: Accuracy depends on your browser settings.

        """
        import webbrowser

        webbrowser.open(f"https://www.google.com/search?q={option}+near+me")

    def pizza():  # pragma: no cover
        """``/pizza``."""
        _hungry_for("pizza")

    def coffee(is_adam=False, is_brigitta=False):  # pragma: no cover
        """``/coffee``."""
        if is_adam and is_brigitta:
            raise ValueError("There can be only one!")
        if is_adam:
            option = "fresh+third+wave+coffee"
        elif is_brigitta:
            option = "decent+espresso"
        else:
            option = "coffee"
        _hungry_for(option)