"""steward/core/audit.py

Helpers for writing audit log entries. Each call opens its own DB
session so audit events are committed independently of the calling
route's transaction (audit is only written after the main action
succeeds, by calling this after the main `async with db.begin()` block).
"""
from __future__ import annotations
import json
import logging
from datetime import datetime, timezone

logger = logging.getLogger(__name__)


async def log_audit(
    app,
    user_id: str | None,
    username: str,
    action: str,
    entity_type: str | None = None,
    entity_id: str | None = None,
    detail: dict | None = None,
) -> None:
    """Write one audit event, and its timeline entry when the action has one
    (steward.timeline.catalog.audit_type). Never raises — failures are logged
    and swallowed."""
    from steward.core.ids import time_ordered_id
    from steward.models.audit import AuditEvent
    from steward.timeline.record import from_audit
    try:
        async with app.db_sessionmaker() as db:
            async with db.begin():
                event = AuditEvent(
                    id=time_ordered_id(),
                    user_id=user_id,
                    username=username or "unknown",
                    action=action,
                    entity_type=entity_type,
                    entity_id=entity_id,
                    detail_json=json.dumps(detail) if detail else None,
                    timestamp=datetime.now(timezone.utc),
                )
                db.add(event)
                try:
                    # In a savepoint: an entry that fails leaves the audit row standing.
                    async with db.begin_nested():
                        await from_audit(db, event, detail)
                except Exception:
                    logger.exception("Audit event %r: its timeline entry could not be written", action)
    except Exception:
        logger.exception("Failed to write audit event action=%r", action)


async def audit_request(action: str, entity_type: str | None = None,
                        entity_id: str | None = None, detail: dict | None = None) -> None:
    """log_audit for the logged-in user of the current web request."""
    from quart import current_app, session
    await log_audit(current_app, session.get("user_id"), session.get("username", ""),
                    action, entity_type=entity_type, entity_id=entity_id, detail=detail)