from app import db
from datetime import datetime

class SystemSetting(db.Model):
    """
    Parámetros de configuración del sistema persistentes en base de datos.
    Permite almacenar enlaces de integración (e.g. Google Sheets), flags globales y metadatos.
    """
    __tablename__ = 'system_settings'

    id = db.Column(db.Integer, primary_key=True)
    key = db.Column(db.String(100), unique=True, nullable=False, index=True)
    value = db.Column(db.Text, nullable=True)
    description = db.Column(db.String(255), nullable=True)
    updated_at = db.Column(db.DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    @classmethod
    def get_value(cls, key, default=None):
        try:
            record = cls.query.filter_by(key=key).first()
            if record and record.value is not None and record.value.strip() != '':
                return record.value
        except Exception:
            pass
        return default

    @classmethod
    def set_value(cls, key, value, description=None):
        record = cls.query.filter_by(key=key).first()
        if not record:
            record = cls(key=key, value=value, description=description)
            db.session.add(record)
        else:
            record.value = value
            if description:
                record.description = description
            record.updated_at = datetime.utcnow()
        db.session.commit()
        return record

    def to_dict(self):
        return {
            'key': self.key,
            'value': self.value,
            'description': self.description,
            'updated_at': self.updated_at.isoformat() if self.updated_at else None
        }

    def __repr__(self):
        return f'<SystemSetting {self.key}={self.value}>'