import logging

from collections import namedtuple, defaultdict
from functools import partial

from flask_principal import identity_loaded, Permission, Identity, identity_changed


from app import app, superusers
from auth import scopes
from data import model


logger = logging.getLogger(__name__)


_ResourceNeed = namedtuple('resource', ['type', 'namespace', 'name', 'role'])
_RepositoryNeed = partial(_ResourceNeed, 'repository')
_NamespaceWideNeed = namedtuple('namespacewide', ['type', 'namespace', 'role'])
_OrganizationNeed = partial(_NamespaceWideNeed, 'organization')
_OrganizationRepoNeed = partial(_NamespaceWideNeed, 'organizationrepo')
_TeamTypeNeed = namedtuple('teamwideneed', ['type', 'orgname', 'teamname', 'role'])
_TeamNeed = partial(_TeamTypeNeed, 'orgteam')
_UserTypeNeed = namedtuple('userspecificneed', ['type', 'username', 'role'])
_UserNeed = partial(_UserTypeNeed, 'user')
_SuperUserNeed = partial(namedtuple('superuserneed', ['type']), 'superuser')


REPO_ROLES = [None, 'read', 'write', 'admin']
TEAM_ROLES = [None, 'member', 'creator', 'admin']
USER_ROLES = [None, 'read', 'admin']

TEAM_ORGWIDE_REPO_ROLES = {
  'admin': 'admin',
  'creator': None,
  'member': None,
}

SCOPE_MAX_REPO_ROLES = defaultdict(lambda: None)
SCOPE_MAX_REPO_ROLES.update({
  scopes.READ_REPO: 'read',
  scopes.WRITE_REPO: 'write',
  scopes.ADMIN_REPO: 'admin',
  scopes.DIRECT_LOGIN: 'admin',
})

SCOPE_MAX_TEAM_ROLES = defaultdict(lambda: None)
SCOPE_MAX_TEAM_ROLES.update({
  scopes.CREATE_REPO: 'creator',
  scopes.DIRECT_LOGIN: 'admin',
  scopes.ORG_ADMIN: 'admin',
})

SCOPE_MAX_USER_ROLES = defaultdict(lambda: None)
SCOPE_MAX_USER_ROLES.update({
  scopes.READ_USER: 'read',
  scopes.DIRECT_LOGIN: 'admin',
  scopes.ADMIN_USER: 'admin',
})

def repository_read_grant(namespace, repository):
  return _RepositoryNeed(namespace, repository, 'read')


def repository_write_grant(namespace, repository):
  return _RepositoryNeed(namespace, repository, 'write')


def repository_admin_grant(namespace, repository):
  return _RepositoryNeed(namespace, repository, 'admin')


class QuayDeferredPermissionUser(Identity):
  def __init__(self, uuid, auth_type, auth_scopes, user=None):
    super(QuayDeferredPermissionUser, self).__init__(uuid, auth_type)

    self._namespace_wide_loaded = set()
    self._repositories_loaded = set()
    self._personal_loaded = False

    self._scope_set = auth_scopes
    self._user_object = user

  @staticmethod
  def for_id(uuid, auth_scopes=None):
    auth_scopes = auth_scopes if auth_scopes is not None else {scopes.DIRECT_LOGIN}
    return QuayDeferredPermissionUser(uuid, 'user_uuid', auth_scopes)

  @staticmethod
  def for_user(user, auth_scopes=None):
    auth_scopes = auth_scopes if auth_scopes is not None else {scopes.DIRECT_LOGIN}
    return QuayDeferredPermissionUser(user.uuid, 'user_uuid', auth_scopes, user=user)

  def _translate_role_for_scopes(self, cardinality, max_roles, role):
    if self._scope_set is None:
      return role

    max_for_scopes = max({cardinality.index(max_roles[scope]) for scope in self._scope_set})

    if max_for_scopes < cardinality.index(role):
      logger.debug('Translated permission %s -> %s', role, cardinality[max_for_scopes])
      return cardinality[max_for_scopes]
    else:
      return role

  def _team_role_for_scopes(self, role):
    return self._translate_role_for_scopes(TEAM_ROLES, SCOPE_MAX_TEAM_ROLES, role)

  def _repo_role_for_scopes(self, role):
    return self._translate_role_for_scopes(REPO_ROLES, SCOPE_MAX_REPO_ROLES, role)

  def _user_role_for_scopes(self, role):
    return self._translate_role_for_scopes(USER_ROLES, SCOPE_MAX_USER_ROLES, role)

  def _populate_user_provides(self, user_object):
    """ Populates the provides that naturally apply to a user, such as being the admin of
        their own namespace.
    """

    # Add the user specific permissions, only for non-oauth permission
    user_grant = _UserNeed(user_object.username, self._user_role_for_scopes('admin'))
    logger.debug('User permission: {0}'.format(user_grant))
    self.provides.add(user_grant)

    # Every user is the admin of their own 'org'
    user_namespace = _OrganizationNeed(user_object.username, self._team_role_for_scopes('admin'))
    logger.debug('User namespace permission: {0}'.format(user_namespace))
    self.provides.add(user_namespace)

    # Org repo roles can differ for scopes
    user_repos = _OrganizationRepoNeed(user_object.username, self._repo_role_for_scopes('admin'))
    logger.debug('User namespace repo permission: {0}'.format(user_repos))
    self.provides.add(user_repos)

    if ((scopes.SUPERUSER in self._scope_set or scopes.DIRECT_LOGIN in self._scope_set) and
        superusers.is_superuser(user_object.username)):
      logger.debug('Adding superuser to user: %s', user_object.username)
      self.provides.add(_SuperUserNeed())

  def _populate_namespace_wide_provides(self, user_object, namespace_filter):
    """ Populates the namespace-wide provides for a particular user under a particular namespace.
        This method does *not* add any provides for specific repositories.
    """

    for team in model.permission.get_org_wide_permissions(user_object, org_filter=namespace_filter):
      team_org_grant = _OrganizationNeed(team.organization.username,
                                         self._team_role_for_scopes(team.role.name))
      logger.debug('Organization team added permission: {0}'.format(team_org_grant))
      self.provides.add(team_org_grant)

      team_repo_role = TEAM_ORGWIDE_REPO_ROLES[team.role.name]
      org_repo_grant = _OrganizationRepoNeed(team.organization.username,
                                             self._repo_role_for_scopes(team_repo_role))
      logger.debug('Organization team added repo permission: {0}'.format(org_repo_grant))
      self.provides.add(org_repo_grant)

      team_grant = _TeamNeed(team.organization.username, team.name,
                             self._team_role_for_scopes(team.role.name))
      logger.debug('Team added permission: {0}'.format(team_grant))
      self.provides.add(team_grant)

  def _populate_repository_provides(self, user_object, namespace_filter, repository_name):
    """ Populates the repository-specific provides for a particular user and repository. """

    if namespace_filter and repository_name:
      permissions = model.permission.get_user_repository_permissions(user_object, namespace_filter,
                                                                     repository_name)
    else:
      permissions = model.permission.get_all_user_repository_permissions(user_object)

    for perm in permissions:
      repo_grant = _RepositoryNeed(perm.repository.namespace_user.username, perm.repository.name,
                                   self._repo_role_for_scopes(perm.role.name))
      logger.debug('User added permission: {0}'.format(repo_grant))
      self.provides.add(repo_grant)

  def can(self, permission):
    logger.debug('Loading user permissions after deferring for: %s', self.id)
    user_object = self._user_object or model.user.get_user_by_uuid(self.id)
    if user_object is None:
      return super(QuayDeferredPermissionUser, self).can(permission)

    # Add the user-specific provides.
    if not self._personal_loaded:
      self._populate_user_provides(user_object)
      self._personal_loaded = True

    # If we now have permission, no need to load any more permissions.
    if super(QuayDeferredPermissionUser, self).can(permission):
      return super(QuayDeferredPermissionUser, self).can(permission)

    # Check for namespace and/or repository permissions.
    perm_namespace = permission.namespace
    perm_repo_name = permission.repo_name
    perm_repository = None

    if perm_namespace and perm_repo_name:
      perm_repository = '%s/%s' % (perm_namespace, perm_repo_name)

    if not perm_namespace and not perm_repo_name:
      # Nothing more to load, so just check directly.
      return super(QuayDeferredPermissionUser, self).can(permission)

    # Lazy-load the repository-specific permissions.
    if perm_repository and perm_repository not in self._repositories_loaded:
      self._populate_repository_provides(user_object, perm_namespace, perm_repo_name)
      self._repositories_loaded.add(perm_repository)

      # If we now have permission, no need to load any more permissions.
      if super(QuayDeferredPermissionUser, self).can(permission):
        return super(QuayDeferredPermissionUser, self).can(permission)

    # Lazy-load the namespace-wide-only permissions.
    if perm_namespace and perm_namespace not in self._namespace_wide_loaded:
      self._populate_namespace_wide_provides(user_object, perm_namespace)
      self._namespace_wide_loaded.add(perm_namespace)

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


class QuayPermission(Permission):
  """ Base for all permissions in Quay. """
  namespace = None
  repo_name = None


class ModifyRepositoryPermission(QuayPermission):
  def __init__(self, namespace, name):
    admin_need = _RepositoryNeed(namespace, name, 'admin')
    write_need = _RepositoryNeed(namespace, name, 'write')
    org_admin_need = _OrganizationRepoNeed(namespace, 'admin')
    org_write_need = _OrganizationRepoNeed(namespace, 'write')

    self.namespace = namespace
    self.repo_name = name

    super(ModifyRepositoryPermission, self).__init__(admin_need, write_need, org_admin_need,
                                                     org_write_need)


class ReadRepositoryPermission(QuayPermission):
  def __init__(self, namespace, name):
    admin_need = _RepositoryNeed(namespace, name, 'admin')
    write_need = _RepositoryNeed(namespace, name, 'write')
    read_need = _RepositoryNeed(namespace, name, 'read')
    org_admin_need = _OrganizationRepoNeed(namespace, 'admin')
    org_write_need = _OrganizationRepoNeed(namespace, 'write')
    org_read_need = _OrganizationRepoNeed(namespace, 'read')

    self.namespace = namespace
    self.repo_name = name

    super(ReadRepositoryPermission, self).__init__(admin_need, write_need, read_need,
                                                   org_admin_need, org_read_need, org_write_need)


class AdministerRepositoryPermission(QuayPermission):
  def __init__(self, namespace, name):
    admin_need = _RepositoryNeed(namespace, name, 'admin')
    org_admin_need = _OrganizationRepoNeed(namespace, 'admin')

    self.namespace = namespace
    self.repo_name = name

    super(AdministerRepositoryPermission, self).__init__(admin_need,
                                                         org_admin_need)


class CreateRepositoryPermission(QuayPermission):
  def __init__(self, namespace):
    admin_org = _OrganizationNeed(namespace, 'admin')
    create_repo_org = _OrganizationNeed(namespace, 'creator')

    self.namespace = namespace

    super(CreateRepositoryPermission, self).__init__(admin_org,
                                                     create_repo_org)

class SuperUserPermission(QuayPermission):
  def __init__(self):
    need = _SuperUserNeed()
    super(SuperUserPermission, self).__init__(need)


class UserAdminPermission(QuayPermission):
  def __init__(self, username):
    user_admin = _UserNeed(username, 'admin')
    super(UserAdminPermission, self).__init__(user_admin)


class UserReadPermission(QuayPermission):
  def __init__(self, username):
    user_admin = _UserNeed(username, 'admin')
    user_read = _UserNeed(username, 'read')
    super(UserReadPermission, self).__init__(user_read, user_admin)


class AdministerOrganizationPermission(QuayPermission):
  def __init__(self, org_name):
    admin_org = _OrganizationNeed(org_name, 'admin')

    self.namespace = org_name

    super(AdministerOrganizationPermission, self).__init__(admin_org)


class OrganizationMemberPermission(QuayPermission):
  def __init__(self, org_name):
    admin_org = _OrganizationNeed(org_name, 'admin')
    repo_creator_org = _OrganizationNeed(org_name, 'creator')
    org_member = _OrganizationNeed(org_name, 'member')

    self.namespace = org_name

    super(OrganizationMemberPermission, self).__init__(admin_org, org_member,
                                                       repo_creator_org)


class ViewTeamPermission(QuayPermission):
  def __init__(self, org_name, team_name):
    team_admin = _TeamNeed(org_name, team_name, 'admin')
    team_creator = _TeamNeed(org_name, team_name, 'creator')
    team_member = _TeamNeed(org_name, team_name, 'member')
    admin_org = _OrganizationNeed(org_name, 'admin')

    self.namespace = org_name

    super(ViewTeamPermission, self).__init__(team_admin, team_creator,
                                             team_member, admin_org)


class AlwaysFailPermission(QuayPermission):
  def can(self):
    return False


@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 with uuid: %s', identity.id)

  elif identity.auth_type == 'user_uuid':
    logger.debug('Switching username permission to deferred object with uuid: %s', identity.id)
    switch_to_deferred = QuayDeferredPermissionUser.for_id(identity.id)
    identity_changed.send(app, identity=switch_to_deferred)

  elif identity.auth_type == 'token':
    logger.debug('Loading permissions for token: %s', identity.id)
    token_data = model.token.load_token_data(identity.id)

    repo_grant = _RepositoryNeed(token_data.repository.namespace_user.username,
                                 token_data.repository.name,
                                 token_data.role.name)
    logger.debug('Delegate token added permission: %s', repo_grant)
    identity.provides.add(repo_grant)

  elif identity.auth_type == 'signed_grant' or identity.auth_type == 'signed_jwt':
    logger.debug('Loaded %s identity for: %s', identity.auth_type, identity.id)

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