#!/usr/bin/env python

"""

Setuptools bootstrapping installer.

Maintained at https://github.com/pypa/setuptools/tree/bootstrap.

Run this script to install or upgrade setuptools.

"""

import os

import shutil

import sys

import tempfile

import zipfile

import optparse

import subprocess

import platform

import textwrap

import contextlib

import json

import codecs

from distutils import log

try:

    from urllib.request import urlopen

    from urllib.parse import urljoin

except ImportError:

    from urllib2 import urlopen

    from urlparse import urljoin

try:

    from site import USER_SITE

except ImportError:

    USER_SITE = None

LATEST = object()

DEFAULT_VERSION = LATEST

DEFAULT_URL = "https://pypi.io/packages/source/s/setuptools/"

DEFAULT_SAVE_DIR = os.curdir

def _python_cmd(*args):

    """

    Execute a command.

    Return True if the command succeeded.

    """

    args = (sys.executable,) + args

    return subprocess.call(args) == 0

def _install(archive_filename, install_args=()):

    """Install Setuptools."""

    with archive_context(archive_filename):

        # installing

        log.warn('Installing Setuptools')

        if not _python_cmd('setup.py', 'install', *install_args):

            log.warn('Something went wrong during the installation.')

            log.warn('See the error message above.')

            # exitcode will be 2

            return 2

def _build_egg(egg, archive_filename, to_dir):

    """Build Setuptools egg."""

    with archive_context(archive_filename):

        # building an egg

        log.warn('Building a Setuptools egg in %s', to_dir)

        _python_cmd('setup.py', '-q', 'bdist_egg', '--dist-dir', to_dir)

    # returning the result

    log.warn(egg)

    if not os.path.exists(egg):

        raise IOError('Could not build the egg.')

class ContextualZipFile(zipfile.ZipFile):

    """Supplement ZipFile class to support context manager for Python 2.6."""

    def __enter__(self):

        return self

    def __exit__(self, type, value, traceback):

        self.close()

    def __new__(cls, *args, **kwargs):

        """Construct a ZipFile or ContextualZipFile as appropriate."""

        if hasattr(zipfile.ZipFile, '__exit__'):

            return zipfile.ZipFile(*args, **kwargs)

        return super(ContextualZipFile, cls).__new__(cls)

@contextlib.contextmanager

def archive_context(filename):

    """

    Unzip filename to a temporary directory, set to the cwd.

    The unzipped target is cleaned up after.

    """

    tmpdir = tempfile.mkdtemp()

    log.warn('Extracting in %s', tmpdir)

    old_wd = os.getcwd()

    try:

        os.chdir(tmpdir)

        with ContextualZipFile(filename) as archive:

            archive.extractall()

        # going in the directory

        subdir = os.path.join(tmpdir, os.listdir(tmpdir)[0])

        os.chdir(subdir)

        log.warn('Now working in %s', subdir)

        yield

    finally:

        os.chdir(old_wd)

        shutil.rmtree(tmpdir)

def _do_download(version, download_base, to_dir, download_delay):

    """Download Setuptools."""

    py_desig = 'py{sys.version_info[0]}.{sys.version_info[1]}'.format(sys=sys)

    tp = 'setuptools-{version}-{py_desig}.egg'

    egg = os.path.join(to_dir, tp.format(**locals()))

    if not os.path.exists(egg):

        archive = download_setuptools(version, download_base,

            to_dir, download_delay)

        _build_egg(egg, archive, to_dir)

    sys.path.insert(0, egg)

    # Remove previously-imported pkg_resources if present (see

    # https://bitbucket.org/pypa/setuptools/pull-request/7/ for details).

    if 'pkg_resources' in sys.modules:

        _unload_pkg_resources()

    import setuptools

    setuptools.bootstrap_install_from = egg

def use_setuptools(

        version=DEFAULT_VERSION, download_base=DEFAULT_URL,

        to_dir=DEFAULT_SAVE_DIR, download_delay=15):

    """

    Ensure that a setuptools version is installed.

    Return None. Raise SystemExit if the requested version

    or later cannot be installed.

    """

    version = _resolve_version(version)

    to_dir = os.path.abspath(to_dir)

    # prior to importing, capture the module state for

    # representative modules.

    rep_modules = 'pkg_resources', 'setuptools'

    imported = set(sys.modules).intersection(rep_modules)

    try:

        import pkg_resources

        pkg_resources.require("setuptools>=" + version)

        # a suitable version is already installed

        return

    except ImportError:

        # pkg_resources not available; setuptools is not installed; download

        pass

    except pkg_resources.DistributionNotFound:

        # no version of setuptools was found; allow download

        pass

    except pkg_resources.VersionConflict as VC_err:

        if imported:

            _conflict_bail(VC_err, version)

        # otherwise, unload pkg_resources to allow the downloaded version to

        #  take precedence.

        del pkg_resources

        _unload_pkg_resources()

    return _do_download(version, download_base, to_dir, download_delay)

def _conflict_bail(VC_err, version):

    """

    Setuptools was imported prior to invocation, so it is

    unsafe to unload it. Bail out.

    """

    conflict_tmpl = textwrap.dedent("""

        The required version of setuptools (>={version}) is not available,

        and can't be installed while this script is running. Please

        install a more recent version first, using

        'easy_install -U setuptools'.

        (Currently using {VC_err.args[0]!r})

        """)

    msg = conflict_tmpl.format(**locals())

    sys.stderr.write(msg)

    sys.exit(2)

def _unload_pkg_resources():

    sys.meta_path = [

        importer

        for importer in sys.meta_path

        if importer.__class__.__module__ != 'pkg_resources.extern'

    ]

    del_modules = [

        name for name in sys.modules

        if name.startswith('pkg_resources')

    ]

    for mod_name in del_modules:

        del sys.modules[mod_name]

def _clean_check(cmd, target):

    """

    Run the command to download target.

    If the command fails, clean up before re-raising the error.

    """

    try:

        subprocess.check_call(cmd)

    except subprocess.CalledProcessError:

        if os.access(target, os.F_OK):

            os.unlink(target)

        raise

def download_file_powershell(url, target):

    """

    Download the file at url to target using Powershell.

    Powershell will validate trust.

    Raise an exception if the command cannot complete.

    """

    target = os.path.abspath(target)

    ps_cmd = (

        "[System.Net.WebRequest]::DefaultWebProxy.Credentials = "

        "[System.Net.CredentialCache]::DefaultCredentials; "

        '(new-object System.Net.WebClient).DownloadFile("%(url)s", "%(target)s")'

        % locals()

    )

    cmd = [

        'powershell',

        '-Command',

        ps_cmd,

    ]

    _clean_check(cmd, target)

def has_powershell():

    """Determine if Powershell is available."""

    if platform.system() != 'Windows':

        return False

    cmd = ['powershell', '-Command', 'echo test']

    with open(os.path.devnull, 'wb') as devnull:

        try:

            subprocess.check_call(cmd, stdout=devnull, stderr=devnull)

        except Exception:

            return False

    return True

download_file_powershell.viable = has_powershell

def download_file_curl(url, target):

    cmd = ['curl', url, '--location', '--silent', '--output', target]

    _clean_check(cmd, target)

def has_curl():

    cmd = ['curl', '--version']

    with open(os.path.devnull, 'wb') as devnull:

        try:

            subprocess.check_call(cmd, stdout=devnull, stderr=devnull)

        except Exception:

            return False

    return True

download_file_curl.viable = has_curl

def download_file_wget(url, target):

    cmd = ['wget', url, '--quiet', '--output-document', target]

    _clean_check(cmd, target)

def has_wget():

    cmd = ['wget', '--version']

    with open(os.path.devnull, 'wb') as devnull:

        try:

            subprocess.check_call(cmd, stdout=devnull, stderr=devnull)

        except Exception:

            return False

    return True

download_file_wget.viable = has_wget

def download_file_insecure(url, target):

    """Use Python to download the file, without connection authentication."""

    src = urlopen(url)

    try:

        # Read all the data in one block.

        data = src.read()

    finally:

        src.close()

    # Write all the data in one block to avoid creating a partial file.

    with open(target, "wb") as dst:

        dst.write(data)

download_file_insecure.viable = lambda: True

def get_best_downloader():

    downloaders = (

        download_file_powershell,

        download_file_curl,

        download_file_wget,

        download_file_insecure,

    )

    viable_downloaders = (dl for dl in downloaders if dl.viable())

    return next(viable_downloaders, None)

def download_setuptools(

        version=DEFAULT_VERSION, download_base=DEFAULT_URL,

        to_dir=DEFAULT_SAVE_DIR, delay=15,

        downloader_factory=get_best_downloader):

    """

    Download setuptools from a specified location and return its filename.

    `version` should be a valid setuptools version number that is available

    as an sdist for download under the `download_base` URL (which should end

    with a '/'). `to_dir` is the directory where the egg will be downloaded.

    `delay` is the number of seconds to pause before an actual download

    attempt.

    ``downloader_factory`` should be a function taking no arguments and

    returning a function for downloading a URL to a target.

    """

    version = _resolve_version(version)

    # making sure we use the absolute path

    to_dir = os.path.abspath(to_dir)

    zip_name = "setuptools-%s.zip" % version

    url = download_base + zip_name

    saveto = os.path.join(to_dir, zip_name)

    if not os.path.exists(saveto):  # Avoid repeated downloads

        log.warn("Downloading %s", url)

        downloader = downloader_factory()

        downloader(url, saveto)

    return os.path.realpath(saveto)

def _resolve_version(version):

    """

    Resolve LATEST version

    """

    if version is not LATEST:

        return version

    meta_url = urljoin(DEFAULT_URL, '/pypi/setuptools/json')

    resp = urlopen(meta_url)

    with contextlib.closing(resp):

        try:

            charset = resp.info().get_content_charset()

        except Exception:

            # Python 2 compat; assume UTF-8

            charset = 'UTF-8'

        reader = codecs.getreader(charset)

        doc = json.load(reader(resp))

    return str(doc['info']['version'])

def _build_install_args(options):

    """

    Build the arguments to 'python setup.py install' on the setuptools package.

    Returns list of command line arguments.

    """

    return ['--user'] if options.user_install else []

def _parse_args():

    """Parse the command line for options."""

    parser = optparse.OptionParser()

    parser.add_option(

        '--user', dest='user_install', action='store_true', default=False,

        help='install in user site package')

    parser.add_option(

        '--download-base', dest='download_base', metavar="URL",

        default=DEFAULT_URL,

        help='alternative URL from where to download the setuptools package')

    parser.add_option(

        '--insecure', dest='downloader_factory', action='store_const',

        const=lambda: download_file_insecure, default=get_best_downloader,

        help='Use internal, non-validating downloader'

    )

    parser.add_option(

        '--version', help="Specify which version to download",

        default=DEFAULT_VERSION,

    )

    parser.add_option(

        '--to-dir',

        help="Directory to save (and re-use) package",

        default=DEFAULT_SAVE_DIR,

    )

    options, args = parser.parse_args()

    # positional arguments are ignored

    return options

def _download_args(options):

    """Return args for download_setuptools function from cmdline args."""

    return dict(

        version=options.version,

        download_base=options.download_base,

        downloader_factory=options.downloader_factory,

        to_dir=options.to_dir,

    )

def main():

    """Install or upgrade setuptools and EasyInstall."""

    options = _parse_args()

    archive = download_setuptools(**_download_args(options))

    return _install(archive, _build_install_args(options))

if __name__ == '__main__':

    sys.exit(main())