import uuid from datetime import datetime from flask import g from sqlalchemy.dialects.postgresql import UUID from sqlalchemy.orm import aliased from sqlalchemy.sql import expression from sqlalchemy_utils import LtreeType from sqlalchemy_utils.types.ltree import LQUERY from teal.db import UUIDLtree from ereuse_devicehub.db import db from ereuse_devicehub.resources.device.models import Device from ereuse_devicehub.resources.models import STR_SIZE, Thing from ereuse_devicehub.resources.user.models import User class Lot(Thing): id = db.Column(UUID(as_uuid=True), primary_key=True) # uuid is generated on init by default name = db.Column(db.Unicode(STR_SIZE), nullable=False) closed = db.Column(db.Boolean, default=False, nullable=False) closed.comment = """ A closed lot cannot be modified anymore. """ devices = db.relationship(Device, backref=db.backref('parents', lazy=True, collection_class=set), secondary=lambda: LotDevice.__table__, collection_class=set) """ The **children** devices that the lot has. Note that the lot can have more devices, if they are inside descendant lots. """ def __init__(self, name: str, closed: bool = closed.default.arg) -> None: """ Initializes a lot :param name: :param closed: """ super().__init__(id=uuid.uuid4(), name=name, closed=closed) Path(self) # Lots have always one edge per default. def add_child(self, child): """Adds a child to this lot.""" if isinstance(child, Lot): Path.add(self.id, child.id) db.session.refresh(self) # todo is this useful? db.session.refresh(child) else: assert isinstance(child, uuid.UUID) Path.add(self.id, child) db.session.refresh(self) # todo is this useful? def remove_child(self, child: 'Lot'): Path.delete(self.id, child.id) @property def children(self): """The children lots.""" # From https://stackoverflow.com/a/41158890 # todo test cls = self.__class__ exp = '*.{}.*{{1}}'.format(UUIDLtree.convert(self.id)) child_lots = aliased(Lot) return self.query \ .join(cls.paths) \ .filter(Path.path.lquery(expression.cast(exp, LQUERY))) \ .join(child_lots, Path.lot) def __contains__(self, child: 'Lot'): return Path.has_lot(self.id, child.id) @classmethod def roots(cls): """Gets the lots that are not under any other lot.""" return set(cls.query.join(cls.paths).filter(db.func.nlevel(Path.path) == 1).all()) def __repr__(self) -> str: return ''.format(self) class LotDevice(db.Model): device_id = db.Column(db.BigInteger, db.ForeignKey(Device.id), primary_key=True) lot_id = db.Column(UUID(as_uuid=True), db.ForeignKey(Lot.id), primary_key=True) created = db.Column(db.DateTime, nullable=False, default=datetime.utcnow) author_id = db.Column(UUID(as_uuid=True), db.ForeignKey(User.id), nullable=False, default=lambda: g.user.id) author = db.relationship(User, primaryjoin=author_id == User.id) author_id.comment = """ The user that put the device in the lot. """ class Path(db.Model): id = db.Column(db.UUID(as_uuid=True), primary_key=True, server_default=db.text('gen_random_uuid()')) lot_id = db.Column(db.UUID(as_uuid=True), db.ForeignKey(Lot.id), nullable=False) lot = db.relationship(Lot, backref=db.backref('paths', lazy=True, collection_class=set), primaryjoin=Lot.id == lot_id) path = db.Column(LtreeType, nullable=False) created = db.Column(db.TIMESTAMP(timezone=True), server_default=db.text('CURRENT_TIMESTAMP')) created.comment = """ When Devicehub created this. """ __table_args__ = ( # dag.delete_edge needs to disable internally/temporarily the unique constraint db.UniqueConstraint(path, name='path_unique', deferrable=True, initially='immediate'), db.Index('path_gist', path, postgresql_using='gist'), db.Index('path_btree', path, postgresql_using='btree') ) def __init__(self, lot: Lot) -> None: super().__init__(lot=lot) self.path = UUIDLtree(lot.id) @classmethod def add(cls, parent_id: uuid.UUID, child_id: uuid.UUID): """Creates an edge between parent and child.""" db.session.execute(db.func.add_edge(str(parent_id), str(child_id))) @classmethod def delete(cls, parent_id: uuid.UUID, child_id: uuid.UUID): """Deletes the edge between parent and child.""" db.session.execute(db.func.delete_edge(str(parent_id), str(child_id))) @classmethod def has_lot(cls, parent_id: uuid.UUID, child_id: uuid.UUID) -> bool: parent_id = UUIDLtree.convert(parent_id) child_id = UUIDLtree.convert(child_id) return bool( db.session.execute( "SELECT 1 from path where path ~ '*.{}.*.{}.*'".format(parent_id, child_id) ).first() )