core/orm/community.py

import time

from sqlalchemy import Column, ForeignKey, Integer, String, func
from sqlalchemy.ext.hybrid import hybrid_property
from sqlalchemy.orm import relationship

from orm.author import Author
from services.db import Base


class CommunityFollower(Base):
    __tablename__ = "community_author"

    author = Column(ForeignKey("author.id"), primary_key=True)
    community = Column(ForeignKey("community.id"), primary_key=True)
    joined_at = Column(Integer, nullable=False, default=lambda: int(time.time()))
    role = Column(String, nullable=False)


class Community(Base):
    __tablename__ = "community"

    name = Column(String, nullable=False)
    slug = Column(String, nullable=False, unique=True)
    desc = Column(String, nullable=False, default="")
    pic = Column(String, nullable=False, default="")
    created_at = Column(Integer, nullable=False, default=lambda: int(time.time()))

    authors = relationship(Author, secondary="community_author")

    @hybrid_property
    def stat(self):
        return CommunityStats(self)


class CommunityStats:
    def __init__(self, community):
        self.community = community

    @property
    def shouts(self):
        from orm.shout import ShoutCommunity
        return self.community.session.query(func.count(ShoutCommunity.shout_id))\
            .filter(ShoutCommunity.community_id == self.community.id)\
            .scalar()

    @property
    def followers(self):
        return self.community.session.query(func.count(CommunityFollower.author))\
            .filter(CommunityFollower.community == self.community.id)\
            .scalar()