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

from app.db import get_db
from app.deps import require_admin
from app.models import AuditLog, Document, Message, User
from app.schemas.audit import StatsOverviewResponse

router = APIRouter()


@router.get("/overview", response_model=StatsOverviewResponse)
def overview(db: Session = Depends(get_db), _: User = Depends(require_admin)) -> StatsOverviewResponse:
    question_count = db.scalar(select(func.count(Message.id))) or 0
    active_user_count = db.scalar(select(func.count(User.id)).where(User.status == "active")) or 0
    document_count = db.scalar(select(func.count(Document.id)).where(Document.status != "deleted")) or 0
    audit_count = db.scalar(select(func.count(AuditLog.id))) or 0
    token_usage = db.scalar(select(func.coalesce(func.sum(Message.token_usage), 0))) or 0
    pu_usage = db.scalar(select(func.coalesce(func.sum(Message.pu_usage), 0))) or 0
    return StatsOverviewResponse(
        question_count=question_count,
        active_user_count=active_user_count,
        document_count=document_count,
        audit_count=audit_count,
        token_usage=token_usage,
        pu_usage=pu_usage,
    )