"""Append-only audit trail for admin write actions."""
from datetime import datetime
from sqlalchemy import JSON
from app.extensions import db


class AuditLog(db.Model):
    __tablename__ = "audit_logs"

    id = db.Column(db.BigInteger().with_variant(db.Integer, "sqlite"),
                   primary_key=True, autoincrement=True)
    actor_id = db.Column(db.BigInteger().with_variant(db.Integer, "sqlite"),
                         db.ForeignKey("users.id"), nullable=True, index=True)
    action = db.Column(db.String(60), nullable=False, index=True)
    target_type = db.Column(db.String(40), nullable=False)
    target_id = db.Column(db.BigInteger().with_variant(db.Integer, "sqlite"),
                          nullable=True, index=True)
    meta = db.Column(JSON, nullable=True)
    created_at = db.Column(db.DateTime, default=datetime.utcnow, nullable=False)

    actor = db.relationship("User", backref=db.backref("audit_logs", lazy="dynamic"))

    def __repr__(self):
        return f"<AuditLog {self.action} {self.target_type}:{self.target_id}>"