"""Update Mixin."""

from typing import Any

from sqlalchemy import Connection, event
from sqlalchemy.orm import Mapper

from ..contexts import get_user_id
from ..utils import current_timestamp, try_updatable


class UpdateMixin:
    """Mixin for models with update tracking.

    AUTOMATIC BEHAVIOR on any model creation or change:
    - last_modified: Set to current timestamp in SYSTEM_TIMEZONE
    - last_modified_by: Set from ctx_user_id context

    To control automatic updates:
    ```python
    disable_on_update()
    enable_on_update()
    ```

    The actual columns are defined in the model itself
    based on what exists in the database schema.

    A model using this mixin may have one or more of:
    - last_modified: When the record was last modified (including creation)
    - last_modified_by: Who made the last modification (including creation)
    """

    def touch(self) -> None:
        """Manually update last_modified fields."""
        self._on_update()

    def _on_update(self) -> None:
        """Update last_modified fields. Internal use only."""
        try_updatable(self)
        if hasattr(self, 'last_modified'):
            self.last_modified = current_timestamp()
        if hasattr(self, 'last_modified_by'):
            self.last_modified_by = get_user_id()


_on_update_enabled = True


def disable_on_update() -> None:
    """Disable automatic updates of last_modified fields."""
    global _on_update_enabled
    if not _on_update_enabled:
        return

    try:
        event.remove(UpdateMixin, 'before_update', _on_update)
    except Exception:
        pass

    try:
        event.remove(UpdateMixin, 'before_insert', _on_update)
    except Exception:
        pass

    _on_update_enabled = False


def enable_on_update() -> None:
    """Enable automatic updates of last_modified fields."""
    global _on_update_enabled
    if _on_update_enabled:
        return

    event.listen(UpdateMixin, 'before_update', _on_update, propagate=True)
    event.listen(UpdateMixin, 'before_insert', _on_update, propagate=True)
    _on_update_enabled = True


def _on_update(mapper: Mapper, connection: Connection, target: Any) -> None:
    """Automatically update last_modified fields."""
    target._on_update()


# Register listeners at module import time
event.listen(UpdateMixin, 'before_update', _on_update, propagate=True)
event.listen(UpdateMixin, 'before_insert', _on_update, propagate=True)