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devicehub-teal/ereuse_devicehub/resources/lot/models.py

102 lines
3.9 KiB
Python

import uuid
from datetime import datetime
from typing import Set
from flask import g
from sqlalchemy.dialects.postgresql import UUID
from sqlalchemy.sql import expression
from sqlalchemy_utils import LtreeType
from sqlalchemy_utils.types.ltree import LQUERY
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,
server_default=db.text('gen_random_uuid()'))
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)
def __repr__(self) -> str:
return '<Lot {0.name} devices={0.devices!r}>'.format(self)
def add_child(self, child: 'Lot'):
"""Adds a child to this lot."""
Edge.add(self.id, child.id)
db.session.refresh(self) # todo is this useful?
db.session.refresh(child)
def remove_child(self, child: 'Lot'):
Edge.delete(self.id, child.id)
def __contains__(self, child: 'Lot'):
return Edge.has_lot(self.id, child.id)
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 Edge(Thing):
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('edges', lazy=True, collection_class=set),
primaryjoin=Lot.id == lot_id)
path = db.Column(LtreeType, unique=True, nullable=False)
__table_args__ = (
db.UniqueConstraint(path, name='edge_path_unique', deferrable=True, initially='immediate'),
db.Index('path_gist', path, postgresql_using='gist'),
db.Index('path_btree', path, postgresql_using='btree')
)
def children(self) -> Set['Edge']:
"""Get the children edges."""
# From https://stackoverflow.com/a/41158890
exp = '*.{}.*{{1}}'.format(self.lot_id)
return set(self.query
.filter(self.path.lquery(expression.cast(exp, LQUERY)))
.distinct(self.__class__.lot_id)
.all())
@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:
return bool(db.session.execute(
"SELECT 1 from edge where path ~ '*.{}.*.{}.*'".format(
str(parent_id).replace('-', '_'), str(child_id).replace('-', '_'))
).first())