import logging

from flask.ext.principal import (identity_loaded, UserNeed, Permission,
                                 Identity, identity_changed)
from collections import namedtuple
from functools import partial

from data import model
from app import app


logger = logging.getLogger(__name__)


_ResourceNeed = namedtuple('resource', ['type', 'namespace', 'name', 'role'])
_RepositoryNeed = partial(_ResourceNeed, 'repository')


class QuayDeferredPermissionUser(Identity):
  def __init__(self, id, auth_type=None):
    super(QuayDeferredPermissionUser, self).__init__(id, auth_type)

    self._permissions_loaded = False

  def can(self, permission):
    if not self._permissions_loaded:
      logger.debug('Loading user permissions after deferring.')
      user_object = model.get_user(self.id)

      for user in model.get_all_user_permissions(user_object):
        grant = _RepositoryNeed(user.repositorypermission.repository.namespace,
                                user.repositorypermission.repository.name,
                                user.repositorypermission.role.name)
        logger.debug('User added permission: {0}'.format(grant))
        self.provides.add(grant)

      self._permissions_loaded = True

    return super(QuayDeferredPermissionUser, self).can(permission)


class ModifyRepositoryPermission(Permission):
  def __init__(self, namespace, name):
    admin_need = _RepositoryNeed(namespace, name, 'admin')
    write_need = _RepositoryNeed(namespace, name, 'write')
    super(ModifyRepositoryPermission, self).__init__(admin_need, write_need)


class ReadRepositoryPermission(Permission):
  def __init__(self, namespace, name):
    admin_need = _RepositoryNeed(namespace, name, 'admin')
    write_need = _RepositoryNeed(namespace, name, 'write')
    read_need = _RepositoryNeed(namespace, name, 'read')
    super(ReadRepositoryPermission, self).__init__(admin_need, write_need,
                                                   read_need)


class AdministerRepositoryPermission(Permission):
  def __init__(self, namespace, name):
    admin_need = _RepositoryNeed(namespace, name, 'admin')
    super(AdministerRepositoryPermission, self).__init__(admin_need)


class UserPermission(Permission):
  def __init__(self, username):
    user_need = UserNeed(username)
    super(UserPermission, self).__init__(user_need)


@identity_loaded.connect_via(app)
def on_identity_loaded(sender, identity):
  logger.debug('Identity loaded: %s' % identity)
  # We have verified an identity, load in all of the permissions

  if isinstance(identity, QuayDeferredPermissionUser):
    logger.debug('Deferring permissions for user: %s' % identity.id)

  elif identity.auth_type == 'username':
    switch_to_deferred = QuayDeferredPermissionUser(identity.id, 'username')
    identity_changed.send(app, identity=switch_to_deferred)

  elif identity.auth_type == 'token':
    logger.debug('Computing permissions for token: %s' % identity.id)

    token = model.get_token(identity.id)

    if token.user:
      query = model.get_user_repo_permissions(token.user, token.repository)
      for permission in query:
        t_grant = _RepositoryNeed(token.repository.namespace,
                                  token.repository.name, permission.role.name)
        logger.debug('Token added permission: {0}'.format(t_grant))
        identity.provides.add(t_grant)
    else:
      logger.debug('Token was anonymous.')

  else:
    logger.error('Unknown identity auth type: %s' % identity.auth_type)