"""统计 API"""
from datetime import datetime, timedelta
from typing import Optional

from fastapi import APIRouter, Depends, Query
from sqlalchemy import select, func, and_, case
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.deps import get_db
from app.core.auth import get_current_user
from app.models.device import Device
from app.models.ping_record import PingRecord
from app.models.alert_event import AlertEvent, AlertTypeEnum
from app.models.user import User
from app.schemas.stats import DeviceStatusSummary, DeviceStatsItem, TimeSeriesPoint, DashboardStats

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


@router.get("/summary", response_model=DeviceStatusSummary)
async def get_summary(
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """获取当前设备状态汇总"""
    result = await db.execute(select(Device))
    devices = list(result.scalars().all())

    total = len(devices)
    online = sum(1 for d in devices if d.current_status == "online")
    offline = sum(1 for d in devices if d.current_status == "offline")
    checking = sum(1 for d in devices if d.current_status == "checking")
    unknown = sum(1 for d in devices if d.current_status == "unknown")
    online_rate = round(online / max(total, 1) * 100, 2)

    return DeviceStatusSummary(
        total=total, online=online, offline=offline,
        checking=checking, unknown=unknown, online_rate=online_rate,
    )


@router.get("/offline-trend", response_model=list[TimeSeriesPoint])
async def get_offline_trend(
    days: int = Query(7, ge=1, le=90),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """获取指定天数内的每日离线次数趋势"""
    start = datetime.now() - timedelta(days=days)
    result = await db.execute(
        select(
            func.date(AlertEvent.start_at).label("day"),
            func.count(AlertEvent.id).label("count"),
        )
        .where(AlertEvent.alert_type == AlertTypeEnum.offline)
        .where(AlertEvent.start_at >= start)
        .group_by(func.date(AlertEvent.start_at))
        .order_by("day")
    )
    rows = result.all()
    return [TimeSeriesPoint(time=datetime.strptime(r.day, "%Y-%m-%d"), value=r.count) for r in rows]


@router.get("/online-rate-trend", response_model=list[TimeSeriesPoint])
async def get_online_rate_trend(
    days: int = Query(7, ge=1, le=90),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """获取每日在线率趋势"""
    start = datetime.now() - timedelta(days=days)
    # 按天统计每轮的存活/总数比例
    result = await db.execute(
        select(
            func.date(PingRecord.created_at).label("day"),
            func.round(
                func.sum(case((PingRecord.is_alive == True, 1), else_=0)) /
                func.count(PingRecord.id) * 100, 2
            ).label("rate"),
        )
        .where(PingRecord.created_at >= start)
        .group_by(func.date(PingRecord.created_at))
        .order_by("day")
    )
    rows = result.all()
    return [TimeSeriesPoint(time=datetime.strptime(r.day, "%Y-%m-%d"), value=r.rate) for r in rows]


@router.get("/packet-loss-top", response_model=list[DeviceStatsItem])
async def get_packet_loss_top(
    limit: int = Query(10, ge=1, le=50),
    days: int = Query(7, ge=1, le=90),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """获取丢包率最高的设备排名"""
    start = datetime.now() - timedelta(days=days)

    subq = (
        select(
            PingRecord.device_id,
            func.count(PingRecord.id).label("total_pings"),
            func.sum(case((PingRecord.is_alive == True, 1), else_=0)).label("alive_pings"),
            func.avg(PingRecord.response_time_ms).label("avg_rtt"),
        )
        .where(PingRecord.created_at >= start)
        .group_by(PingRecord.device_id)
        .subquery()
    )

    result = await db.execute(
        select(
            subq.c.device_id,
            subq.c.total_pings,
            subq.c.alive_pings,
            subq.c.avg_rtt,
            Device.name,
            Device.ip,
            Device.device_type,
            Device.location,
            Device.project_name,
        )
        .join(Device, subq.c.device_id == Device.id)
        .order_by(
            (subq.c.total_pings - subq.c.alive_pings) * 1.0 / subq.c.total_pings
        )
        .limit(limit)
    )
    rows = result.all()

    items = []
    for r in rows:
        loss_rate = round((r.total_pings - r.alive_pings) / max(r.total_pings, 1) * 100, 2)

        # 离线次数和总时长
        alert_result = await db.execute(
            select(
                func.count(AlertEvent.id),
                func.coalesce(func.sum(AlertEvent.duration_minutes), 0),
                func.coalesce(func.max(AlertEvent.duration_minutes), 0),
            )
            .where(AlertEvent.device_id == r.device_id)
            .where(AlertEvent.alert_type == AlertTypeEnum.offline)
            .where(AlertEvent.start_at >= start)
        )
        cnt, total_dur, max_dur = alert_result.one()

        items.append(DeviceStatsItem(
            device_id=r.device_id,
            device_name=r.name,
            device_ip=r.ip,
            device_type=r.device_type.value if hasattr(r.device_type, 'value') else str(r.device_type),
            location=r.location or "",
            project_name=r.project_name or "",
            total_pings=r.total_pings,
            alive_pings=r.alive_pings,
            packet_loss_rate=loss_rate,
            avg_response_time=round(r.avg_rtt, 2) if r.avg_rtt else None,
            offline_count=cnt,
            total_offline_duration=total_dur,
            max_offline_duration=max_dur,
        ))
    return items


@router.get("/dashboard", response_model=DashboardStats)
async def get_dashboard(
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """仪表盘聚合数据"""
    summary = await get_summary(db, current_user)
    recent = await get_latest_alerts(limit=10, db=db, current_user=current_user)
    trend = await get_offline_trend(7, db, current_user)
    top_loss = await get_packet_loss_top(10, 7, db, current_user)
    return DashboardStats(
        summary=summary, recent_offline=recent,
        offline_trend=trend, packet_loss_top=top_loss,
    )


# 复用上面定义的函数
from app.api.alerts import get_latest_alerts