from .writer import GitWriter

from tftp.backend import IBackend
from tftp.errors import Unsupported, AccessViolation
from tftp.util import deferred

from twisted.python.context import get
from twisted.python.filepath import FilePath, InsecurePath

from zope import interface


class GitBackend(object):
    interface.implements(IBackend)

    def __init__(self, base_path):
        self.base_path = base_path
        self.base = FilePath(base_path)

    @deferred
    def get_reader(self,  file_name):
        raise Unsupported("Reading not supported")

    @deferred
    def get_writer(self, file_name):
        try:
            target_path = self.base.descendant(file_name.split("/"))
        except InsecurePath, e:
            raise AccessViolation("Insecure path: %s" % e)
        return GitWriter(target_path, self.base_path, get('remote'))