"""操作日志与统计 API（仅管理员）。"""
import csv
import io
import json
from datetime import datetime, timedelta

from fastapi import APIRouter, Depends, HTTPException, Query
from fastapi.responses import StreamingResponse
from sqlalchemy import func
from sqlalchemy.orm import Session

from ..database import get_db
from ..deps import get_current_user
from ..models import OperationLog

router = APIRouter(prefix="/api/operations", tags=["operations"])


def _require_admin(user: dict):
    if not user.get("is_admin"):
        raise HTTPException(status_code=403, detail="需要管理员权限")


def _query_logs(db: Session, days: int, username: str = "", action: str = ""):
    since = datetime.utcnow() - timedelta(days=max(1, min(days, 365)))
    query = db.query(OperationLog).filter(OperationLog.created_at >= since)
    if username:
        query = query.filter(OperationLog.username == username)
    if action:
        query = query.filter(OperationLog.action == action)
    return query


@router.get("/summary")
async def operation_summary(days: int = Query(30, ge=1, le=365), user: dict = Depends(get_current_user), db: Session = Depends(get_db)):
    _require_admin(user)
    query = _query_logs(db, days)
    total = query.count()
    action_counts = dict(query.with_entities(OperationLog.action, func.count()).group_by(OperationLog.action).all())
    users = query.with_entities(OperationLog.username, func.count()).group_by(OperationLog.username).order_by(func.count().desc()).limit(10).all()
    apps = query.filter(OperationLog.app_name.isnot(None)).with_entities(OperationLog.app_name, func.count()).group_by(OperationLog.app_name).order_by(func.count().desc()).limit(10).all()
    return {"days": days, "total": total, "action_counts": action_counts,
            "top_users": [{"name": name, "count": count} for name, count in users],
            "top_apps": [{"name": name, "count": count} for name, count in apps]}


@router.get("")
async def list_operations(days: int = Query(30, ge=1, le=365), username: str = "", action: str = "", limit: int = Query(100, ge=1, le=500), user: dict = Depends(get_current_user), db: Session = Depends(get_db)):
    _require_admin(user)
    logs = _query_logs(db, days, username, action).order_by(OperationLog.created_at.desc()).limit(limit).all()
    return [{"id": log.id, "created_at": log.created_at, "username": log.username,
             "action": log.action, "app_name": log.app_name, "task_id": log.task_id,
             "resource_type": log.resource_type, "resource_name": log.resource_name,
             "detail": json.loads(log.detail_json or "{}"), "client_ip": log.client_ip} for log in logs]


@router.get("/export")
async def export_operations(days: int = Query(30, ge=1, le=365), user: dict = Depends(get_current_user), db: Session = Depends(get_db)):
    _require_admin(user)
    output = io.StringIO()
    writer = csv.writer(output)
    writer.writerow(["时间", "用户", "操作", "App", "资源类型", "资源名称", "IP", "详情"])
    for log in _query_logs(db, days).order_by(OperationLog.created_at.desc()).all():
        writer.writerow([log.created_at, log.username, log.action, log.app_name or "", log.resource_type or "", log.resource_name or "", log.client_ip or "", log.detail_json or ""])
    return StreamingResponse(iter(["\ufeff" + output.getvalue()]), media_type="text/csv", headers={"Content-Disposition": "attachment; filename=operation-logs.csv"})