from __future__ import with_statement

from glob import glob
from os import path, makedirs, remove
from shutil import copyfileobj, rmtree
from distutils.version import LooseVersion

from zope.interface import implements
from twisted.application.service import Service

from .interfaces import IEggStorage

class FilesystemEggStorage(Service):

    implements(IEggStorage)

    def __init__(self, config):
        self.basedir = config.get('eggs_dir', 'eggs')

    def put(self, eggfile, project, version):
        eggpath = self._eggpath(project, version)
        eggdir = path.dirname(eggpath)
        if not path.exists(eggdir):
            makedirs(eggdir)
        with open(eggpath, 'wb') as f:
            copyfileobj(eggfile, f)

    def get(self, project, version=None):
        if version is None:
            version = self.list(project)[-1]
        return version, open(self._eggpath(project, version), 'rb')

    def list(self, project):
        eggdir = path.join(self.basedir, project)
        versions = [path.splitext(path.basename(x))[0] \
            for x in glob("%s/*.egg" % eggdir)]
        return sorted(versions, key=LooseVersion)

    def delete(self, project, version=None):
        if version is None:
            rmtree(path.join(self.basedir, project))
        else:
            remove(self._eggpath(project, version))
            if not self.list(project): # remove project if no versions left
                self.delete(project)

    def _eggpath(self, project, version):
        x = path.join(self.basedir, project, "%s.egg" % version)
        return x