""" utilities for package version introspection """

from __future__ import print_function, division, absolute_import

import platform
import struct
import os
import sys
import locale
import importlib

from .utils import ignoring


required_packages = [('dask', lambda p: p.__version__),
                     ('distributed', lambda p: p.__version__),
                     ('msgpack', lambda p: '.'.join([str(v) for v in p.version])),
                     ('cloudpickle', lambda p: p.__version__),
                     ('tornado', lambda p: p.version),
                     ('toolz', lambda p: p.__version__)]

optional_packages = [('numpy', lambda p: p.__version__),
                     ('pandas', lambda p: p.__version__),
                     ('bokeh', lambda p: p.__version__),
                     ('lz4', lambda p: p.__version__),
                     ('dask_ml', lambda p: p.__version__),
                     ('blosc', lambda p: p.__version__)]


def get_versions(packages=None):
    """
    Return basic information on our software installation, and out installed versions of packages.
    """
    if packages is None:
        packages = []

    d = {'host': get_system_info(),
         'packages': {'required': get_package_info(required_packages),
                      'optional': get_package_info(optional_packages + list(packages))}
         }
    return d


def get_system_info():
    (sysname, nodename, release,
     version, machine, processor) = platform.uname()
    host = [("python", "%d.%d.%d.%s.%s" % sys.version_info[:]),
            ("python-bits", struct.calcsize("P") * 8),
            ("OS", "%s" % (sysname)),
            ("OS-release", "%s" % (release)),
            ("machine", "%s" % (machine)),
            ("processor", "%s" % (processor)),
            ("byteorder", "%s" % sys.byteorder),
            ("LC_ALL", "%s" % os.environ.get('LC_ALL', "None")),
            ("LANG", "%s" % os.environ.get('LANG', "None")),
            ("LOCALE", "%s.%s" % locale.getlocale()),
            ]

    return host


def version_of_package(pkg):
    """ Try a variety of common ways to get the version of a package """
    with ignoring(AttributeError):
        return pkg.__version__
    with ignoring(AttributeError):
        return str(pkg.version)
    with ignoring(AttributeError):
        return '.'.join(map(str, pkg.version_info))
    return None


def get_package_info(pkgs):
    """ get package versions for the passed required & optional packages """

    pversions = []
    for pkg in pkgs:
        if isinstance(pkg, (tuple, list)):
            modname, ver_f = pkg
        else:
            modname = pkg
            ver_f = version_of_package

        if ver_f is None:
            ver_f = version_of_package

        try:
            mod = importlib.import_module(modname)
            ver = ver_f(mod)
            pversions.append((modname, ver))
        except Exception:
            pversions.append((modname, None))

    return pversions