"""Base model class with common fields."""

from datetime import datetime, timezone
from shopdb.extensions import db


def _utcnow():
    # naive UTC for DB columns (stored without tzinfo)
    return datetime.now(timezone.utc).replace(tzinfo=None)


class BaseModel(db.Model):
    """
    Abstract base model with common fields.
    All models should inherit from this.
    """
    __abstract__ = True

    createddate = db.Column(
        db.DateTime,
        default=_utcnow,
        nullable=False
    )
    modifieddate = db.Column(
        db.DateTime,
        default=_utcnow,
        onupdate=_utcnow,
        nullable=False
    )
    isactive = db.Column(db.Boolean, default=True, nullable=False)

    # Columns the default to_dict NEVER emits, whatever model carries them.
    #
    # The default serialiser walks __table__.columns and publishes every one, so
    # a model that does not override it publishes whatever it has - including
    # columns added to it later, by someone who was not thinking about this
    # method. User is the live example: it does not override to_dict, so
    # User.to_dict() returns passwordhash. Nothing calls it in a response path
    # today, which is luck rather than design.
    #
    # A blanket allowlist would be the stronger rule, but it would also silently
    # empty the output of all 34 models that rely on this default. This is the
    # part that can be fixed without breaking anything: name the columns that
    # must never be published, and let a model add its own.
    #
    # A model with something sensitive should still override to_dict and say
    # exactly what it emits. This is a floor, not permission to skip that.
    HIDDEN_COLUMNS = frozenset({
        'passwordhash',
        'tokenhash',
        'apikey',
        'clientsecret',
        'collectorkey',
    })

    def to_dict(self):
        """Convert model to dictionary, minus anything secret-bearing."""
        hidden = self.HIDDEN_COLUMNS
        result = {}
        for c in self.__table__.columns:
            if c.name in hidden:
                continue
            value = getattr(self, c.name)
            if isinstance(value, datetime):
                value = value.isoformat() + 'Z'
            result[c.name] = value
        return result

    def update(self, **kwargs):
        """Update model attributes."""
        for key, value in kwargs.items():
            if hasattr(self, key):
                setattr(self, key, value)

    @classmethod
    def get_active(cls):
        """Return query for active records only."""
        return cls.query.filter_by(isactive=True)


class SoftDeleteMixin:
    """Mixin for soft delete functionality."""

    deleteddate = db.Column(db.DateTime, nullable=True)
    deletedby = db.Column(db.String(100), nullable=True)

    def soft_delete(self, deleted_by: str = None):
        """Mark record as deleted."""
        self.isactive = False
        self.deleteddate = datetime.now(timezone.utc).replace(tzinfo=None)
        self.deletedby = deleted_by


class AuditMixin:
    """Mixin for audit fields."""

    createdby = db.Column(db.String(100), nullable=True)
    modifiedby = db.Column(db.String(100), nullable=True)