"""Contains the Command base classes that depend on PipSession.

The classes in this module are in a separate module so the commands not
needing download / PackageFinder capability don't unnecessarily import the
PackageFinder machinery and all its vendored dependencies, etc.
"""

import logging
import os
import sys
from functools import partial
from optparse import Values
from typing import Any, List, Optional, Tuple

from pip._internal.cache import WheelCache
from pip._internal.cli import cmdoptions
from pip._internal.cli.base_command import Command
from pip._internal.cli.command_context import CommandContextMixIn
from pip._internal.exceptions import CommandError, PreviousBuildDirError
from pip._internal.index.collector import LinkCollector
from pip._internal.index.package_finder import PackageFinder
from pip._internal.models.selection_prefs import SelectionPreferences
from pip._internal.models.target_python import TargetPython
from pip._internal.network.session import PipSession
from pip._internal.operations.prepare import RequirementPreparer
from pip._internal.req.constructors import (
    install_req_from_editable,
    install_req_from_line,
    install_req_from_parsed_requirement,
    install_req_from_req_string,
)
from pip._internal.req.req_file import parse_requirements
from pip._internal.req.req_install import InstallRequirement
from pip._internal.req.req_tracker import RequirementTracker
from pip._internal.resolution.base import BaseResolver
from pip._internal.self_outdated_check import pip_self_version_check
from pip._internal.utils.temp_dir import (
    TempDirectory,
    TempDirectoryTypeRegistry,
    tempdir_kinds,
)
from pip._internal.utils.virtualenv import running_under_virtualenv

logger = logging.getLogger(__name__)


class SessionCommandMixin(CommandContextMixIn):

    """
    A class mixin for command classes needing _build_session().
    """

    def __init__(self):
        # type: () -> None
        super().__init__()
        self._session = None  # Optional[PipSession]

    @classmethod
    def _get_index_urls(cls, options):
        # type: (Values) -> Optional[List[str]]
        """Return a list of index urls from user-provided options."""
        index_urls = []
        if not getattr(options, "no_index", False):
            url = getattr(options, "index_url", None)
            if url:
                index_urls.append(url)
        urls = getattr(options, "extra_index_urls", None)
        if urls:
            index_urls.extend(urls)
        # Return None rather than an empty list
        return index_urls or None

    def get_default_session(self, options):
        # type: (Values) -> PipSession
        """Get a default-managed session."""
        if self._session is None:
            self._session = self.enter_context(self._build_session(options))
            # there's no type annotation on requests.Session, so it's
            # automatically ContextManager[Any] and self._session becomes Any,
            # then https://github.com/python/mypy/issues/7696 kicks in
            assert self._session is not None
        return self._session

    def _build_session(self, options, retries=None, timeout=None):
        # type: (Values, Optional[int], Optional[int]) -> PipSession
        assert not options.cache_dir or os.path.isabs(options.cache_dir)
        session = PipSession(
            cache=(
                os.path.join(options.cache_dir, "http") if options.cache_dir else None
            ),
            retries=retries if retries is not None else options.retries,
            trusted_hosts=options.trusted_hosts,
            index_urls=self._get_index_urls(options),
        )

        # Handle custom ca-bundles from the user
        if options.cert:
            session.verify = options.cert

        # Handle SSL client certificate
        if options.client_cert:
            session.cert = options.client_cert

        # Handle timeouts
        if options.timeout or timeout:
            session.timeout = timeout if timeout is not None else options.timeout

        # Handle configured proxies
        if options.proxy:
            session.proxies = {
                "http": options.proxy,
                "https": options.proxy,
            }

        # Determine if we can prompt the user for authentication or not
        session.auth.prompting = not options.no_input

        return session


class IndexGroupCommand(Command, SessionCommandMixin):

    """
    Abstract base class for commands with the index_group options.

    This also corresponds to the commands that permit the pip version check.
    """

    def handle_pip_version_check(self, options):
        # type: (Values) -> None
        """
        Do the pip version check if not disabled.

        This overrides the default behavior of not doing the check.
        """
        # Make sure the index_group options are present.
        assert hasattr(options, "no_index")

        if options.disable_pip_version_check or options.no_index:
            return

        # Otherwise, check if we're using the latest version of pip available.
        session = self._build_session(
            options, retries=0, timeout=min(5, options.timeout)
        )
        with session:
            pip_self_version_check(session, options)


KEEPABLE_TEMPDIR_TYPES = [
    tempdir_kinds.BUILD_ENV,
    tempdir_kinds.EPHEM_WHEEL_CACHE,
    tempdir_kinds.REQ_BUILD,
]


def warn_if_run_as_root():
    # type: () -> None
    """Output a warning for sudo users on Unix.

    In a virtual environment, sudo pip still writes to virtualenv.
    On Windows, users may run pip as Administrator without issues.
    This warning only applies to Unix root users outside of virtualenv.
    """
    if running_under_virtualenv():
        return
    if not hasattr(os, "getuid"):
        return
    # On Windows, there are no "system managed" Python packages. Installing as
    # Administrator via pip is the correct way of updating system environments.
    #
    # We choose sys.platform over utils.compat.WINDOWS here to enable Mypy platform
    # checks: https://mypy.readthedocs.io/en/stable/common_issues.html
    if sys.platform == "win32" or sys.platform == "cygwin":
        return
    if sys.platform == "darwin" or sys.platform == "linux":
        if os.getuid() != 0:
            return
    logger.warning(
        "Running pip as root will break packages and permissions. "
        "You should install packages reliably by using venv: "
        "https://pip.pypa.io/warnings/venv"
    )


def with_cleanup(func):
    # type: (Any) -> Any
    """Decorator for common logic related to managing temporary
    directories.
    """

    def configure_tempdir_registry(registry):
        # type: (TempDirectoryTypeRegistry) -> None
        for t in KEEPABLE_TEMPDIR_TYPES:
            registry.set_delete(t, False)

    def wrapper(self, options, args):
        # type: (RequirementCommand, Values, List[Any]) -> Optional[int]
        assert self.tempdir_registry is not None
        if options.no_clean:
            configure_tempdir_registry(self.tempdir_registry)

        try:
            return func(self, options, args)
        except PreviousBuildDirError:
            # This kind of conflict can occur when the user passes an explicit
            # build directory with a pre-existing folder. In that case we do
            # not want to accidentally remove it.
            configure_tempdir_registry(self.tempdir_registry)
            raise

    return wrapper


class RequirementCommand(IndexGroupCommand):
    def __init__(self, *args, **kw):
        # type: (Any, Any) -> None
        super().__init__(*args, **kw)

        self.cmd_opts.add_option(cmdoptions.no_clean())

    @staticmethod
    def determine_resolver_variant(options):
        # type: (Values) -> str
        """Determines which resolver should be used, based on the given options."""
        if "legacy-resolver" in options.deprecated_features_enabled:
            return "legacy"

        return "2020-resolver"

    @classmethod
    def make_requirement_preparer(
        cls,
        temp_build_dir,  # type: TempDirectory
        options,  # type: Values
        req_tracker,  # type: RequirementTracker
        session,  # type: PipSession
        finder,  # type: PackageFinder
        use_user_site,  # type: bool
        download_dir=None,  # type: str
    ):
        # type: (...) -> RequirementPreparer
        """
        Create a RequirementPreparer instance for the given parameters.
        """
        temp_build_dir_path = temp_build_dir.path
        assert temp_build_dir_path is not None

        resolver_variant = cls.determine_resolver_variant(options)
        if resolver_variant == "2020-resolver":
            lazy_wheel = "fast-deps" in options.features_enabled
            if lazy_wheel:
                logger.warning(
                    "pip is using lazily downloaded wheels using HTTP "
                    "range requests to obtain dependency information. "
                    "This experimental feature is enabled through "
                    "--use-feature=fast-deps and it is not ready for "
                    "production."
                )
        else:
            lazy_wheel = False
            if "fast-deps" in options.features_enabled:
                logger.warning(
                    "fast-deps has no effect when used with the legacy resolver."
                )

        return RequirementPreparer(
            build_dir=temp_build_dir_path,
            src_dir=options.src_dir,
            download_dir=download_dir,
            build_isolation=options.build_isolation,
            req_tracker=req_tracker,
            session=session,
            progress_bar=options.progress_bar,
            finder=finder,
            require_hashes=options.require_hashes,
            use_user_site=use_user_site,
            lazy_wheel=lazy_wheel,
            in_tree_build="in-tree-build" in options.features_enabled,
        )

    @classmethod
    def make_resolver(
        cls,
        preparer,  # type: RequirementPreparer
        finder,  # type: PackageFinder
        options,  # type: Values
        wheel_cache=None,  # type: Optional[WheelCache]
        use_user_site=False,  # type: bool
        ignore_installed=True,  # type: bool
        ignore_requires_python=False,  # type: bool
        force_reinstall=False,  # type: bool
        upgrade_strategy="to-satisfy-only",  # type: str
        use_pep517=None,  # type: Optional[bool]
        py_version_info=None,  # type: Optional[Tuple[int, ...]]
    ):
        # type: (...) -> BaseResolver
        """
        Create a Resolver instance for the given parameters.
        """
        make_install_req = partial(
            install_req_from_req_string,
            isolated=options.isolated_mode,
            use_pep517=use_pep517,
        )
        resolver_variant = cls.determine_resolver_variant(options)
        # The long import name and duplicated invocation is needed to convince
        # Mypy into correctly typechecking. Otherwise it would complain the
        # "Resolver" class being redefined.
        if resolver_variant == "2020-resolver":
            import pip._internal.resolution.resolvelib.resolver

            return pip._internal.resolution.resolvelib.resolver.Resolver(
                preparer=preparer,
                finder=finder,
                wheel_cache=wheel_cache,
                make_install_req=make_install_req,
                use_user_site=use_user_site,
                ignore_dependencies=options.ignore_dependencies,
                ignore_installed=ignore_installed,
                ignore_requires_python=ignore_requires_python,
                force_reinstall=force_reinstall,
                upgrade_strategy=upgrade_strategy,
                py_version_info=py_version_info,
            )
        import pip._internal.resolution.legacy.resolver

        return pip._internal.resolution.legacy.resolver.Resolver(
            preparer=preparer,
            finder=finder,
            wheel_cache=wheel_cache,
            make_install_req=make_install_req,
            use_user_site=use_user_site,
            ignore_dependencies=options.ignore_dependencies,
            ignore_installed=ignore_installed,
            ignore_requires_python=ignore_requires_python,
            force_reinstall=force_reinstall,
            upgrade_strategy=upgrade_strategy,
            py_version_info=py_version_info,
        )

    def get_requirements(
        self,
        args,  # type: List[str]
        options,  # type: Values
        finder,  # type: PackageFinder
        session,  # type: PipSession
    ):
        # type: (...) -> List[InstallRequirement]
        """
        Parse command-line arguments into the corresponding requirements.
        """
        requirements = []  # type: List[InstallRequirement]
        for filename in options.constraints:
            for parsed_req in parse_requirements(
                filename,
                constraint=True,
                finder=finder,
                options=options,
                session=session,
            ):
                req_to_add = install_req_from_parsed_requirement(
                    parsed_req,
                    isolated=options.isolated_mode,
                    user_supplied=False,
                )
                requirements.append(req_to_add)

        for req in args:
            req_to_add = install_req_from_line(
                req,
                None,
                isolated=options.isolated_mode,
                use_pep517=options.use_pep517,
                user_supplied=True,
            )
            requirements.append(req_to_add)

        for req in options.editables:
            req_to_add = install_req_from_editable(
                req,
                user_supplied=True,
                isolated=options.isolated_mode,
                use_pep517=options.use_pep517,
            )
            requirements.append(req_to_add)

        # NOTE: options.require_hashes may be set if --require-hashes is True
        for filename in options.requirements:
            for parsed_req in parse_requirements(
                filename, finder=finder, options=options, session=session
            ):
                req_to_add = install_req_from_parsed_requirement(
                    parsed_req,
                    isolated=options.isolated_mode,
                    use_pep517=options.use_pep517,
                    user_supplied=True,
                )
                requirements.append(req_to_add)

        # If any requirement has hash options, enable hash checking.
        if any(req.has_hash_options for req in requirements):
            options.require_hashes = True

        if not (args or options.editables or options.requirements):
            opts = {"name": self.name}
            if options.find_links:
                raise CommandError(
                    "You must give at least one requirement to {name} "
                    '(maybe you meant "pip {name} {links}"?)'.format(
                        **dict(opts, links=" ".join(options.find_links))
                    )
                )
            else:
                raise CommandError(
                    "You must give at least one requirement to {name} "
                    '(see "pip help {name}")'.format(**opts)
                )

        return requirements

    @staticmethod
    def trace_basic_info(finder):
        # type: (PackageFinder) -> None
        """
        Trace basic information about the provided objects.
        """
        # Display where finder is looking for packages
        search_scope = finder.search_scope
        locations = search_scope.get_formatted_locations()
        if locations:
            logger.info(locations)

    def _build_package_finder(
        self,
        options,  # type: Values
        session,  # type: PipSession
        target_python=None,  # type: Optional[TargetPython]
        ignore_requires_python=None,  # type: Optional[bool]
    ):
        # type: (...) -> PackageFinder
        """
        Create a package finder appropriate to this requirement command.

        :param ignore_requires_python: Whether to ignore incompatible
            "Requires-Python" values in links. Defaults to False.
        """
        link_collector = LinkCollector.create(session, options=options)
        selection_prefs = SelectionPreferences(
            allow_yanked=True,
            format_control=options.format_control,
            allow_all_prereleases=options.pre,
            prefer_binary=options.prefer_binary,
            ignore_requires_python=ignore_requires_python,
        )

        return PackageFinder.create(
            link_collector=link_collector,
            selection_prefs=selection_prefs,
            target_python=target_python,
        )
