"""GET /api/operator/cohort — practice volume view (TASK-08-01, D-053, D-057).

Auth-gated (Depends(current_operator)). Returns k-anonymized practice-volume
aggregates from cohort_aggregates: sessions_count + active_learners_count per
path. Suppressed cells have value=null + cell_suppressed=true; the frontend
renders \"— (<10 learners)\". No per-learner drill-down (R-DASH-02).
last_updated = max(updated_at) for freshness (REQ-NFR-DASH-02).
"""

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-cohort"])

PRACTICE_METRICS = {"sessions_count", "active_learners_count"}


@router.get("/cohort", response_model=ViewResponse)
async def cohort_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)
    views, last_updated = group_by_path(rows, PRACTICE_METRICS)
    return ViewResponse(views=views, last_updated=last_updated)


__all__ = ["router"]