#! /usr/bin/env python
"""minimal PyPI like server for use with pip/easy_install"""

import functools
import hashlib
import io
import itertools
import logging
import mimetypes
import os
import re
import sys

try:  # PY3
    from urllib.parse import quote
except ImportError:  # PY2
    from urllib import quote

import pkg_resources

from . import Configuration


log = logging.getLogger(__name__)


def configure(**kwds):
    """
    :return: a 2-tuple (Configure, package-list)
    """
    c = Configuration(**kwds)
    log.info("+++Pypiserver invoked with: %s", c)

    if c.root is None:
        c. root = os.path.expanduser("~/packages")
    roots = c.root if isinstance(c.root, (list, tuple)) else [c.root]
    roots = [os.path.abspath(r) for r in roots]
    for r in roots:
        try:
            os.listdir(r)
        except OSError:
            err = sys.exc_info()[1]
            msg = "Error: while trying to list root(%s): %s"
            sys.exit(msg % (r, err))

    packages = lambda: itertools.chain(*[listdir(r) for r in roots])
    packages.root = roots[0]

    if not c.authenticated:
        c.authenticated = []
    if not callable(c.auther):
        if c.password_file and c.password_file != '.':
            from passlib.apache import HtpasswdFile
            htPsswdFile = HtpasswdFile(c.password_file)
        else:
            c.password_file = htPsswdFile = None
        c.auther = functools.partial(auth_by_htpasswd_file, htPsswdFile)

    # Read welcome-msg from external file,
    #     or failback to the embedded-msg (ie. in standalone mode).
    #
    try:
        if not c.welcome_file:
            c.welcome_file = "welcome.html"
            c.welcome_msg = pkg_resources.resource_string(  # @UndefinedVariable
                __name__, "welcome.html").decode("utf-8")  # @UndefinedVariable
        else:
            with io.open(c.welcome_file, 'r', encoding='utf-8') as fd:
                c.welcome_msg = fd.read()
    except Exception:
        log.warning(
            "Could not load welcome-file(%s)!", c.welcome_file, exc_info=1)

    if c.fallback_url is None:
        c.fallback_url = "https://pypi.org/simple"

    if c.hash_algo:
        try:
            halgos = hashlib.algorithms_available
        except AttributeError:
            halgos = ['md5', 'sha1', 'sha224', 'sha256', 'sha384', 'sha512']

        if c.hash_algo not in halgos:
            sys.exit('Hash-algorithm %s not one of: %s' % (c.hash_algo, halgos))

    log.info("+++Pypiserver started with: %s", c)

    return c, packages


def auth_by_htpasswd_file(htPsswdFile, username, password):
    """The default ``config.auther``."""
    if htPsswdFile is not None:
        htPsswdFile.load_if_changed()
        return htPsswdFile.check_password(username, password)


mimetypes.add_type("application/octet-stream", ".egg")
mimetypes.add_type("application/octet-stream", ".whl")
mimetypes.add_type("text/plain", ".asc")


# ### Next 2 functions adapted from :mod:`distribute.pkg_resources`.
#
component_re = re.compile(r'(\d+ | [a-z]+ | \.| -)', re.I | re.VERBOSE)
replace = {'pre': 'c', 'preview': 'c', '-': 'final-', 'rc': 'c', 'dev': '@'}.get


def _parse_version_parts(s):
    for part in component_re.split(s):
        part = replace(part, part)
        if part in ['', '.']:
            continue
        if part[:1] in '0123456789':
            yield part.zfill(8)  # pad for numeric comparison
        else:
            yield '*' + part

    yield '*final'  # ensure that alpha/beta/candidate are before final


def parse_version(s):
    parts = []
    for part in _parse_version_parts(s.lower()):
        if part.startswith('*'):
            # remove trailing zeros from each series of numeric parts
            while parts and parts[-1] == '00000000':
                parts.pop()
        parts.append(part)
    return tuple(parts)
#
#### -- End of distribute's code.


_archive_suffix_rx = re.compile(
    r"(\.zip|\.tar\.gz|\.tgz|\.tar\.bz2|-py[23]\.\d-.*|"
    r"\.win-amd64-py[23]\.\d\..*|\.win32-py[23]\.\d\..*|\.egg)$",
    re.I)
wheel_file_re = re.compile(
    r"""^(?P<namever>(?P<name>.+?)-(?P<ver>\d.*?))
    ((-(?P<build>\d.*?))?-(?P<pyver>.+?)-(?P<abi>.+?)-(?P<plat>.+?)
    \.whl|\.dist-info)$""",
    re.VERBOSE)
_pkgname_re = re.compile(r'-\d+[a-z_.!+]', re.I)
_pkgname_parts_re = re.compile(
    r"[\.\-](?=cp\d|py\d|macosx|linux|sunos|solaris|irix|aix|cygwin|win)",
    re.I)


def _guess_pkgname_and_version_wheel(basename):
    m = wheel_file_re.match(basename)
    if not m:
        return None, None
    name = m.group("name")
    ver = m.group("ver")
    build = m.group("build")
    if build:
        return name, ver + "-" + build
    else:
        return name, ver


def guess_pkgname_and_version(path):
    path = os.path.basename(path)
    if path.endswith(".asc"):
        path = path.rstrip(".asc")
    if path.endswith(".whl"):
        return _guess_pkgname_and_version_wheel(path)
    if not _archive_suffix_rx.search(path):
        return
    path = _archive_suffix_rx.sub('', path)
    if '-' not in path:
        pkgname, version = path, ''
    elif path.count('-') == 1:
        pkgname, version = path.split('-', 1)
    elif '.' not in path:
        pkgname, version = path.rsplit('-', 1)
    else:
        pkgname = _pkgname_re.split(path)[0]
        ver_spec = path[len(pkgname) + 1:]
        parts = _pkgname_parts_re.split(ver_spec)
        version = parts[0]
    return pkgname, version


def normalize_pkgname(name):
    """Perform PEP 503 normalization"""
    return re.sub(r"[-_.]+", "-", name).lower()


def normalize_pkgname_for_url(name):
    """Perform PEP 503 normalization and ensure the value is safe for URLs."""
    return quote(re.sub(r"[-_.]+", "-", name).lower())


def is_allowed_path(path_part):
    p = path_part.replace("\\", "/")
    return not (p.startswith(".") or "/." in p)


class PkgFile(object):

    __slots__ = ['fn', 'root', '_fname_and_hash',
                 'relfn', 'relfn_unix',
                 'pkgname_norm',
                 'pkgname',
                 'version',
                 'parsed_version',
                 'replaces']

    def __init__(self, pkgname, version, fn=None, root=None, relfn=None, replaces=None):
        self.pkgname = pkgname
        self.pkgname_norm = normalize_pkgname(pkgname)
        self.version = version
        self.parsed_version = parse_version(version)
        self.fn = fn
        self.root = root
        self.relfn = relfn
        self.relfn_unix = None if relfn is None else relfn.replace("\\", "/")
        self.replaces = replaces

    def __repr__(self):
        return "%s(%s)" % (
            self.__class__.__name__,
            ", ".join(["%s=%r" % (k, getattr(self, k, 'AttributeError'))
                                  for k in sorted(self.__slots__)]))

    def fname_and_hash(self, hash_algo):
        if not hasattr(self, '_fname_and_hash'):
            if hash_algo:
                self._fname_and_hash = '%s#%s=%s' % (
                    self.relfn_unix, hash_algo, digest_file(self.fn, hash_algo)
                )
            else:
                self._fname_and_hash = self.relfn_unix
        return self._fname_and_hash


def _listdir(root):
    root = os.path.abspath(root)
    for dirpath, dirnames, filenames in os.walk(root):
        dirnames[:] = [x for x in dirnames if is_allowed_path(x)]
        for x in filenames:
            fn = os.path.join(root, dirpath, x)
            if not is_allowed_path(x) or not os.path.isfile(fn):
                continue
            res = guess_pkgname_and_version(x)
            if not res:
                # #Seems the current file isn't a proper package
                continue
            pkgname, version = res
            if pkgname:
                yield PkgFile(pkgname=pkgname,
                              version=version,
                              fn=fn, root=root,
                              relfn=fn[len(root) + 1:])


def read_lines(filename):
    """
    Read the contents of `filename`, stripping empty lines and '#'-comments.
    Return a list of strings, containing the lines of the file.
    """
    lines = []

    try:
        with open(filename) as f:
            lines = [
                line 
                for line in (ln.strip() for ln in f.readlines()) 
                if line and not line.startswith('#')
            ]
    except Exception:
        log.error('Failed to read package blacklist file "%s". '
                  'Aborting server startup, please fix this.'
                  % filename)
        raise

    return lines


def find_packages(pkgs, prefix=""):
    prefix = normalize_pkgname(prefix)
    for x in pkgs:
        if prefix and x.pkgname_norm != prefix:
            continue
        yield x


def get_prefixes(pkgs):
    normalized_pkgnames = set()
    for x in pkgs:
        if x.pkgname:
            normalized_pkgnames.add(x.pkgname_norm)
    return normalized_pkgnames


def exists(root, filename):
    assert "/" not in filename
    dest_fn = os.path.join(root, filename)
    return os.path.exists(dest_fn)


def store(root, filename, save_method):
    assert "/" not in filename
    dest_fn = os.path.join(root, filename)
    save_method(dest_fn, overwrite=True)  # Overwite check earlier.


def get_bad_url_redirect_path(request, prefix):
    """Get the path for a bad root url."""
    p = request.custom_fullpath
    if p.endswith("/"):
        p = p[:-1]
    p = p.rsplit('/', 1)[0]
    prefix = quote(prefix)
    p += "/simple/{}/".format(prefix)
    return p


def _digest_file(fpath, hash_algo):
    """
    Reads and digests a file according to specified hashing-algorith.

    :param str sha256: any algo contained in :mod:`hashlib`
    :return: <hash_algo>=<hex_digest>

    From http://stackoverflow.com/a/21565932/548792
    """
    blocksize = 2**16
    digester = getattr(hashlib, hash_algo)()
    with open(fpath, 'rb') as f:
        for block in iter(lambda: f.read(blocksize), b''):
            digester.update(block)
    return digester.hexdigest()


try:
    from .cache import cache_manager

    def listdir(root):
        # root must be absolute path
        return cache_manager.listdir(root, _listdir)

    def digest_file(fpath, hash_algo):
        # fpath must be absolute path
        return cache_manager.digest_file(fpath, hash_algo, _digest_file)

except ImportError:
    listdir = _listdir
    digest_file = _digest_file