from six.moves.urllib.parse import urlparse
from . import main
from . import errors

class PackageSpec(object):
    def __init__(self, package=None, version=None, basename=None, attrs=None, spec_str=None):
        self._package = package
        self._version = version
        self._basename = basename
        self.attrs = attrs
        if spec_str:
            self.spec_str = spec_str
        else:
            # spec_str = str(channel)
            if package:
                spec_str = '%s/%s' % (spec_str, package)
            if version:
                spec_str = '%s/%s' % (spec_str, version)
            if basename:
                spec_str = '%s/%s' % (spec_str, basename)
            self.spec_str = spec_str

    def __str__(self):
        return self.spec_str

    def __repr__(self):
        return '<PackageSpec %r>' % (self.spec_str)

    # @property
    # def user(self):
    #     if self._channel is None:
    #         raise errors.UserError('Channel not given (got %r expected <username> )' % (self.spec_str,))
    #     return self._channel

    @staticmethod
    def from_string(spec):
        package = specversion = basename = None
        attrs = {}
        if '/' in package:
            package, version = package.split('/', 1)

        if version and '/' in version:
            version, basename = version.split('/', 1)

        if basename and '?' in basename:
            basename, qsl = basename.rsplit('?', 1)
            attrs = dict(urlparse.parse_qsl(qsl))

        return PackageSpec(package, version, basename, attrs, spec)

    @property
    def name(self):
        if self._package is None:
            raise errors.UserError('package not given in spec (got %r expected <username>/<package> )' % (self.spec_str,))
        return self._package

    @property
    def package(self):
        if self._package is None:
            raise errors.UserError('package not given in spec (got %r expected <username>/<package> )' % (self.spec_str,))
        return self._package

    @property
    def version(self):
        if self._version is None:
            raise errors.UserError('version not given in spec (got %r expected <username>/<package>/<version> )' % (self.spec_str,))
        return self._version

    @property
    def basename(self):
        if self._basename is None:
            raise errors.UserError('basename not given in spec (got %r expected <username>/<package>/<version>/<filename> )' % (self.spec_str,))
        return self._basename