"""GET /api/operator/failure-patterns — failure patterns view (TASK-08-03, D-053).

Auth-gated. Returns failure pattern metrics: failure_mode frequency (cells
with metric prefix `failure_mode:`) + branch outcome distribution (cells
with metric prefix `branch:`). Weak-spot rubric criteria (mean < 3.0) are
highlighted by the frontend. All k-anonymized.
"""

from __future__ import annotations

import datetime as _dt

from fastapi import APIRouter, Depends, Request

from server.auth.dependencies import current_operator
from server.auth.models import Operator
from server.operator._common import (
    ViewResponse,
    all_recent_aggregates,
    group_by_path,
    require_pg_store,
)

router = APIRouter(prefix="/api/operator", tags=["operator-failure-patterns"])


def _is_failure_metric(metric: str) -> bool:
    return metric.startswith("failure_mode:") or metric.startswith("branch:")


@router.get("/failure-patterns", response_model=ViewResponse)
async def failure_patterns_view(
    request: Request,
    op: Operator = Depends(current_operator),
) -> ViewResponse:
    pg_store = await require_pg_store(request)
    since = _dt.date.today() - _dt.timedelta(days=30)
    rows = await all_recent_aggregates(pg_store, since)
    failure_rows = [r for r in rows if _is_failure_metric(r.get("metric", ""))]
    views, last_updated = group_by_path(failure_rows)
    return ViewResponse(views=views, last_updated=last_updated)


__all__ = ["router"]