"""Pending-action service — curator-proposed mutations awaiting user approval.

See models/pending_curator_action.py for the schema rationale. This module
is the API everything else uses:

- `create_pending(...)` is called from execute_tool's curator-authority
  interceptor when the curator tries to call a mutating tool. The caller
  has already captured a snapshot of the target's current state.

- `list_pending(user_id)` is what the Needs Review panel reads.

- `approve(action_id, user_id)` replays the original tool call via
  `execute_tool` with `authority="user"`, which bypasses the curator
  interceptor and just runs. On success, the row moves to status='approved'.

- `reject(action_id, user_id)` marks the row 'rejected' without executing.
  History row stays around for audit; nothing runs.
"""
from __future__ import annotations

import datetime
import logging
from datetime import timezone
from typing import Any

from sqlalchemy import select, update

from fabledassistant.models import async_session
from fabledassistant.models.pending_curator_action import PendingCuratorAction

logger = logging.getLogger(__name__)


async def create_pending(
    *,
    user_id: int,
    conv_id: int | None,
    action_type: str,
    target_type: str | None,
    target_id: int | None,
    target_label: str | None,
    payload: dict,
    current_snapshot: dict,
) -> PendingCuratorAction:
    """Persist a curator-proposed mutation for later review.

    Returns the created row so the interceptor can include its id in the
    tool-result envelope (handy for tests, logs, and future UI deep-links).
    """
    async with async_session() as session:
        row = PendingCuratorAction(
            user_id=user_id,
            conv_id=conv_id,
            action_type=action_type,
            target_type=target_type,
            target_id=target_id,
            target_label=target_label,
            payload=payload or {},
            current_snapshot=current_snapshot or {},
            status="pending",
        )
        session.add(row)
        await session.commit()
        await session.refresh(row)
        logger.info(
            "Curator proposed %s on %s/%s (label=%r) — action_id=%d, conv=%s",
            action_type, target_type, target_id, target_label, row.id, conv_id,
        )
        return row


async def list_pending(user_id: int, limit: int = 50) -> list[dict]:
    """Return the user's pending actions, newest first.

    Only `status='pending'` — once a row is approved or rejected, it
    drops off this list. Use the index `ix_pending_curator_actions_user_pending`.
    """
    async with async_session() as session:
        result = await session.execute(
            select(PendingCuratorAction)
            .where(
                PendingCuratorAction.user_id == user_id,
                PendingCuratorAction.status == "pending",
            )
            .order_by(PendingCuratorAction.created_at.desc())
            .limit(limit)
        )
        return [row.to_dict() for row in result.scalars().all()]


async def _load_for_user(action_id: int, user_id: int) -> PendingCuratorAction | None:
    async with async_session() as session:
        result = await session.execute(
            select(PendingCuratorAction).where(
                PendingCuratorAction.id == action_id,
                PendingCuratorAction.user_id == user_id,
            )
        )
        return result.scalar_one_or_none()


async def _mark_reviewed(action_id: int, status: str) -> None:
    async with async_session() as session:
        await session.execute(
            update(PendingCuratorAction)
            .where(PendingCuratorAction.id == action_id)
            .values(status=status, reviewed_at=datetime.datetime.now(timezone.utc))
        )
        await session.commit()


async def approve(action_id: int, user_id: int) -> dict[str, Any]:
    """Replay the curator's proposed action with user authority and mark approved.

    The replay path goes through `execute_tool` with `authority="user"` so
    the curator interceptor doesn't intercept its own replay (which would
    create another pending row and loop forever).

    Returns the tool-result dict from execute_tool. Action stays in
    `pending` if replay returns an error so the user can retry; only
    transitions to `approved` on success.
    """
    row = await _load_for_user(action_id, user_id)
    if row is None:
        return {"success": False, "error": "Pending action not found"}
    if row.status != "pending":
        return {
            "success": False,
            "error": f"Action already {row.status}",
        }

    from fabledassistant.services.tools import execute_tool
    try:
        # authority="user" bypasses the curator interceptor — required so
        # the replay actually executes the mutating tool instead of
        # creating another pending row (which would infinite-loop).
        result = await execute_tool(
            user_id,
            row.action_type,
            row.payload,
            conv_id=row.conv_id,
            authority="user",
        )
    except Exception as e:
        logger.exception(
            "Replay of curator action %d (%s) failed",
            action_id, row.action_type,
        )
        return {"success": False, "error": f"{type(e).__name__}: {e}"}

    if result.get("success", True) and not result.get("error"):
        await _mark_reviewed(action_id, "approved")
    return result


async def reject(action_id: int, user_id: int) -> dict[str, Any]:
    """Mark the pending action as rejected without executing anything."""
    row = await _load_for_user(action_id, user_id)
    if row is None:
        return {"success": False, "error": "Pending action not found"}
    if row.status != "pending":
        return {
            "success": False,
            "error": f"Action already {row.status}",
        }
    await _mark_reviewed(action_id, "rejected")
    return {"success": True, "id": action_id, "status": "rejected"}