from app import db
from datetime import datetime

class Building(db.Model):
    __tablename__ = 'buildings'
    
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(100), unique=True, nullable=False, index=True)
    code = db.Column(db.String(50), unique=True, nullable=True)
    address = db.Column(db.String(255), nullable=True)
    floors = db.Column(db.Integer, default=1, nullable=False)
    description = db.Column(db.Text, nullable=True)
    is_active = db.Column(db.Boolean, default=True, nullable=False)
    created_at = db.Column(db.DateTime, default=datetime.utcnow)
    updated_at = db.Column(db.DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
    
    # Relationships
    classrooms = db.relationship('Classroom', backref='building_entity', lazy=True, foreign_keys='Classroom.building_id')
    
    @property
    def total_capacity(self):
        """Total student capacity across active classrooms in this building"""
        return sum(c.capacity for c in self.classrooms if c.is_active)
        
    @property
    def classrooms_count(self):
        """Number of active classrooms"""
        return len([c for c in self.classrooms if c.is_active])
        
    def to_dict(self):
        return {
            'id': self.id,
            'name': self.name,
            'code': self.code,
            'address': self.address,
            'floors': self.floors,
            'description': self.description,
            'is_active': self.is_active,
            'classrooms_count': self.classrooms_count,
            'total_capacity': self.total_capacity,
            'created_at': self.created_at.isoformat() if self.created_at else None
        }
        
    def __repr__(self):
        return f'<Building {self.name}>'