from __future__ import annotations

import uuid
from datetime import UTC, datetime
from typing import Any

from fastapi import APIRouter, Depends, Header
from sqlalchemy import select
from sqlalchemy.orm import Session

from app.api.deps import get_db
from app.core.config import get_settings
from app.core.errors import AppError
from app.models.audit import AuditEvent
from app.models.outbox import OutboxEvent
from app.services.audit import record_audit_event

router = APIRouter(prefix="/api/v1/integrations/n8n", tags=["integrations"])
settings = get_settings()


@router.post("/return-callback")
def return_callback(
    body: dict[str, Any],
    idempotency_key: str = Header(..., alias="Idempotency-Key"),
    service_token: str = Header(..., alias="X-Service-Token"),
    db: Session = Depends(get_db),
) -> dict:
    if service_token != settings.n8n_callback_token:
        raise AppError("UNAUTHORIZED_SERVICE", "Invalid service token.", status_code=401)

    try:
        event_id = uuid.UUID(idempotency_key)
    except ValueError as exc:
        raise AppError(
            "INVALID_IDEMPOTENCY_KEY", "Idempotency-Key must be the event's UUID.", status_code=422
        ) from exc

    event = db.scalar(select(OutboxEvent).where(OutboxEvent.event_id == event_id))
    if event is None:
        raise AppError("EVENT_NOT_FOUND", "No outbox event matches this event ID.", status_code=404)

    # Idempotent by event ID: n8n or our own dispatcher may redeliver the same event
    # (e.g. a lost response after a timeout), so this callback must not double-record.
    already_recorded = (
        db.scalar(
            select(AuditEvent.id).where(
                AuditEvent.action == "n8n_return_followup_recorded",
                AuditEvent.metadata_json["event_id"].astext == str(event_id),
            )
        )
        is not None
    )
    if not already_recorded:
        record_audit_event(
            db,
            actor_type="service",
            actor_label="n8n",
            action="n8n_return_followup_recorded",
            entity_type="booking",
            correlation_id=uuid.UUID(body.get("correlation_id"))
            if body.get("correlation_id")
            else None,
            after={"follow_up": body.get("follow_up"), "summary": body.get("summary")},
            metadata={"event_id": str(event_id)},
        )
        db.commit()

    return {
        "status": "recorded",
        "event_id": str(event_id),
        "occurred_at": datetime.now(UTC).isoformat(),
    }