# 系统状态监控 API：返回爬虫集群运行概况（信息源数、今日抓取量、最近同步时间等）
from datetime import datetime, timedelta
from typing import Optional

from fastapi import APIRouter, Depends
from pydantic import BaseModel
from sqlalchemy import func
from sqlalchemy.orm import Session

from app.api.dependencies import get_db
from app.models.models import DataSyncTask, InfoSource, TaskStatus, utcnow

router = APIRouter()


class SystemStatsResponse(BaseModel):
    """系统运行状态汇总"""
    active_sources: int
    total_sources: int
    items_today: int
    success_tasks_today: int
    error_tasks_today: int
    last_sync_at: Optional[datetime] = None


@router.get("/system/stats", response_model=SystemStatsResponse)
def get_system_stats(db: Session = Depends(get_db)):
    """获取爬虫集群的当日运行状态。"""
    today_start = utcnow().replace(hour=0, minute=0, second=0, microsecond=0)

    # 信息源统计：总数与启用数
    total_sources = db.query(func.count(InfoSource.id)).scalar() or 0
    active_sources = (
        db.query(func.count(InfoSource.id))
        .filter(InfoSource.is_enabled.is_(True))
        .scalar() or 0
    )

    # 今日任务统计：抓取条数、成功/失败任务数
    today_tasks = (
        db.query(DataSyncTask)
        .filter(DataSyncTask.created_at >= today_start)
        .all()
    )

    items_today = sum(t.items_fetched for t in today_tasks)
    success_count = sum(1 for t in today_tasks if t.task_status == TaskStatus.SUCCESS)
    error_count = sum(1 for t in today_tasks if t.task_status == TaskStatus.ERROR)

    # 最后一次同步时间
    last_task = (
        db.query(DataSyncTask)
        .filter(DataSyncTask.task_status == TaskStatus.SUCCESS)
        .order_by(DataSyncTask.created_at.desc())
        .first()
    )

    return SystemStatsResponse(
        active_sources=active_sources,
        total_sources=total_sources,
        items_today=items_today,
        success_tasks_today=success_count,
        error_tasks_today=error_count,
        last_sync_at=last_task.created_at if last_task else None,
    )