from __future__ import absolute_import

import logging
import os

from pip.req import RequirementSet
from pip.basecommand import RequirementCommand
from pip import cmdoptions
from pip.utils import ensure_dir, normalize_path
from pip.utils.build import BuildDirectory
from pip.utils.filesystem import check_path_owner


logger = logging.getLogger(__name__)


class DownloadCommand(RequirementCommand):
    """
    Download packages from:

    - PyPI (and other indexes) using requirement specifiers.
    - VCS project urls.
    - Local project directories.
    - Local or remote source archives.

    pip also supports downloading from "requirements files", which provide
    an easy way to specify a whole environment to be downloaded.
    """
    name = 'download'

    usage = """
      %prog [options] <requirement specifier> [package-index-options] ...
      %prog [options] -r <requirements file> [package-index-options] ...
      %prog [options] [-e] <vcs project url> ...
      %prog [options] [-e] <local project path> ...
      %prog [options] <archive url/path> ..."""

    summary = 'Download packages.'

    def __init__(self, *args, **kw):
        super(DownloadCommand, self).__init__(*args, **kw)

        cmd_opts = self.cmd_opts

        cmd_opts.add_option(cmdoptions.constraints())
        cmd_opts.add_option(cmdoptions.editable())
        cmd_opts.add_option(cmdoptions.requirements())
        cmd_opts.add_option(cmdoptions.build_dir())
        cmd_opts.add_option(cmdoptions.no_deps())
        cmd_opts.add_option(cmdoptions.global_options())
        cmd_opts.add_option(cmdoptions.no_binary())
        cmd_opts.add_option(cmdoptions.only_binary())
        cmd_opts.add_option(cmdoptions.src())
        cmd_opts.add_option(cmdoptions.pre())
        cmd_opts.add_option(cmdoptions.no_clean())
        cmd_opts.add_option(cmdoptions.require_hashes())

        cmd_opts.add_option(
            '-d', '--dest', '--destination-dir', '--destination-directory',
            dest='download_dir',
            metavar='dir',
            default=os.curdir,
            help=("Download packages into <dir>."),
        )

        index_opts = cmdoptions.make_option_group(
            cmdoptions.non_deprecated_index_group,
            self.parser,
        )

        self.parser.insert_option_group(0, index_opts)
        self.parser.insert_option_group(0, cmd_opts)

    def run(self, options, args):
        options.ignore_installed = True
        options.src_dir = os.path.abspath(options.src_dir)
        options.download_dir = normalize_path(options.download_dir)

        ensure_dir(options.download_dir)

        with self._build_session(options) as session:

            finder = self._build_package_finder(options, session)
            build_delete = (not (options.no_clean or options.build_dir))
            if options.cache_dir and not check_path_owner(options.cache_dir):
                logger.warning(
                    "The directory '%s' or its parent directory is not owned "
                    "by the current user and caching wheels has been "
                    "disabled. check the permissions and owner of that "
                    "directory. If executing pip with sudo, you may want "
                    "sudo's -H flag.",
                    options.cache_dir,
                )
                options.cache_dir = None

            with BuildDirectory(options.build_dir,
                                delete=build_delete) as build_dir:

                requirement_set = RequirementSet(
                    build_dir=build_dir,
                    src_dir=options.src_dir,
                    download_dir=options.download_dir,
                    ignore_installed=True,
                    ignore_dependencies=options.ignore_dependencies,
                    session=session,
                    isolated=options.isolated_mode,
                    require_hashes=options.require_hashes
                )
                self.populate_requirement_set(
                    requirement_set,
                    args,
                    options,
                    finder,
                    session,
                    self.name,
                    None
                )

                if not requirement_set.has_requirements:
                    return

                requirement_set.prepare_files(finder)

                downloaded = ' '.join([
                    req.name for req in requirement_set.successfully_downloaded
                ])
                if downloaded:
                    logger.info(
                        'Successfully downloaded %s', downloaded
                    )

                # Clean up
                if not options.no_clean:
                    requirement_set.cleanup_files()

        return requirement_set