"""Wheels support."""

from distutils.util import get_platform
from distutils import log
import email
import itertools
import os
import posixpath
import re
import zipfile

import pkg_resources
import setuptools
from pkg_resources import parse_version
from setuptools.extern.packaging.tags import sys_tags
from setuptools.extern.packaging.utils import canonicalize_name
from setuptools.extern.six import PY3
from setuptools.command.egg_info import write_requirements


__metaclass__ = type


WHEEL_NAME = re.compile(
    r"""^(?P<project_name>.+?)-(?P<version>\d.*?)
    ((-(?P<build>\d.*?))?-(?P<py_version>.+?)-(?P<abi>.+?)-(?P<platform>.+?)
    )\.whl$""",
    re.VERBOSE,
).match

NAMESPACE_PACKAGE_INIT = """\
try:
    __import__('pkg_resources').declare_namespace(__name__)
except ImportError:
    __path__ = __import__('pkgutil').extend_path(__path__, __name__)
"""


def unpack(src_dir, dst_dir):
    """Move everything under `src_dir` to `dst_dir`, and delete the former."""
    for dirpath, dirnames, filenames in os.walk(src_dir):
        subdir = os.path.relpath(dirpath, src_dir)
        for f in filenames:
            src = os.path.join(dirpath, f)
            dst = os.path.join(dst_dir, subdir, f)
            os.renames(src, dst)
        for n, d in reversed(list(enumerate(dirnames))):
            src = os.path.join(dirpath, d)
            dst = os.path.join(dst_dir, subdir, d)
            if not os.path.exists(dst):
                # Directory does not exist in destination,
                # rename it and prune it from os.walk list.
                os.renames(src, dst)
                del dirnames[n]
    # Cleanup.
    for dirpath, dirnames, filenames in os.walk(src_dir, topdown=True):
        assert not filenames
        os.rmdir(dirpath)


class Wheel:
    def __init__(self, filename):
        match = WHEEL_NAME(os.path.basename(filename))
        if match is None:
            raise ValueError("invalid wheel name: %r" % filename)
        self.filename = filename
        for k, v in match.groupdict().items():
            setattr(self, k, v)

    def tags(self):
        """List tags (py_version, abi, platform) supported by this wheel."""
        return itertools.product(
            self.py_version.split("."),
            self.abi.split("."),
            self.platform.split("."),
        )

    def is_compatible(self):
        """Is the wheel is compatible with the current platform?"""
        supported_tags = set((t.interpreter, t.abi, t.platform) for t in sys_tags())
        return next((True for t in self.tags() if t in supported_tags), False)

    def egg_name(self):
        return (
            pkg_resources.Distribution(
                project_name=self.project_name,
                version=self.version,
                platform=(None if self.platform == "any" else get_platform()),
            ).egg_name()
            + ".egg"
        )

    def get_dist_info(self, zf):
        # find the correct name of the .dist-info dir in the wheel file
        for member in zf.namelist():
            dirname = posixpath.dirname(member)
            if dirname.endswith(".dist-info") and canonicalize_name(dirname).startswith(
                canonicalize_name(self.project_name)
            ):
                return dirname
        raise ValueError("unsupported wheel format. .dist-info not found")

    def install_as_egg(self, destination_eggdir):
        """Install wheel as an egg directory."""
        with zipfile.ZipFile(self.filename) as zf:
            self._install_as_egg(destination_eggdir, zf)

    def _install_as_egg(self, destination_eggdir, zf):
        dist_basename = "%s-%s" % (self.project_name, self.version)
        dist_info = self.get_dist_info(zf)
        dist_data = "%s.data" % dist_basename
        egg_info = os.path.join(destination_eggdir, "EGG-INFO")

        self._convert_metadata(zf, destination_eggdir, dist_info, egg_info)
        self._move_data_entries(destination_eggdir, dist_data)
        self._fix_namespace_packages(egg_info, destination_eggdir)

    @staticmethod
    def _convert_metadata(zf, destination_eggdir, dist_info, egg_info):
        def get_metadata(name):
            with zf.open(posixpath.join(dist_info, name)) as fp:
                value = fp.read().decode("utf-8") if PY3 else fp.read()
                return email.parser.Parser().parsestr(value)

        wheel_metadata = get_metadata("WHEEL")
        # Check wheel format version is supported.
        wheel_version = parse_version(wheel_metadata.get("Wheel-Version"))
        wheel_v1 = parse_version("1.0") <= wheel_version < parse_version("2.0dev0")
        if not wheel_v1:
            raise ValueError("unsupported wheel format version: %s" % wheel_version)
        # Extract to target directory.
        os.mkdir(destination_eggdir)
        zf.extractall(destination_eggdir)
        # Convert metadata.
        dist_info = os.path.join(destination_eggdir, dist_info)
        dist = pkg_resources.Distribution.from_location(
            destination_eggdir,
            dist_info,
            metadata=pkg_resources.PathMetadata(destination_eggdir, dist_info),
        )

        # Note: Evaluate and strip markers now,
        # as it's difficult to convert back from the syntax:
        # foobar; "linux" in sys_platform and extra == 'test'
        def raw_req(req):
            req.marker = None
            return str(req)

        install_requires = list(sorted(map(raw_req, dist.requires())))
        extras_require = {
            extra: sorted(
                req
                for req in map(raw_req, dist.requires((extra,)))
                if req not in install_requires
            )
            for extra in dist.extras
        }
        os.rename(dist_info, egg_info)
        os.rename(
            os.path.join(egg_info, "METADATA"),
            os.path.join(egg_info, "PKG-INFO"),
        )
        setup_dist = setuptools.Distribution(
            attrs=dict(
                install_requires=install_requires,
                extras_require=extras_require,
            ),
        )
        # Temporarily disable info traces.
        log_threshold = log._global_log.threshold
        log.set_threshold(log.WARN)
        try:
            write_requirements(
                setup_dist.get_command_obj("egg_info"),
                None,
                os.path.join(egg_info, "requires.txt"),
            )
        finally:
            log.set_threshold(log_threshold)

    @staticmethod
    def _move_data_entries(destination_eggdir, dist_data):
        """Move data entries to their correct location."""
        dist_data = os.path.join(destination_eggdir, dist_data)
        dist_data_scripts = os.path.join(dist_data, "scripts")
        if os.path.exists(dist_data_scripts):
            egg_info_scripts = os.path.join(destination_eggdir, "EGG-INFO", "scripts")
            os.mkdir(egg_info_scripts)
            for entry in os.listdir(dist_data_scripts):
                # Remove bytecode, as it's not properly handled
                # during easy_install scripts install phase.
                if entry.endswith(".pyc"):
                    os.unlink(os.path.join(dist_data_scripts, entry))
                else:
                    os.rename(
                        os.path.join(dist_data_scripts, entry),
                        os.path.join(egg_info_scripts, entry),
                    )
            os.rmdir(dist_data_scripts)
        for subdir in filter(
            os.path.exists,
            (
                os.path.join(dist_data, d)
                for d in ("data", "headers", "purelib", "platlib")
            ),
        ):
            unpack(subdir, destination_eggdir)
        if os.path.exists(dist_data):
            os.rmdir(dist_data)

    @staticmethod
    def _fix_namespace_packages(egg_info, destination_eggdir):
        namespace_packages = os.path.join(egg_info, "namespace_packages.txt")
        if os.path.exists(namespace_packages):
            with open(namespace_packages) as fp:
                namespace_packages = fp.read().split()
            for mod in namespace_packages:
                mod_dir = os.path.join(destination_eggdir, *mod.split("."))
                mod_init = os.path.join(mod_dir, "__init__.py")
                if not os.path.exists(mod_dir):
                    os.mkdir(mod_dir)
                if not os.path.exists(mod_init):
                    with open(mod_init, "w") as fp:
                        fp.write(NAMESPACE_PACKAGE_INIT)