"""대시보드 API — 관리자 모니터링"""

from datetime import datetime, timezone, timedelta

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

from app.database import get_db
from app.models import Charger, ChargingSession, ChargerStatus, SessionStatus
from app.schemas import DashboardSummary

router = APIRouter(prefix="/dashboard", tags=["대시보드"])


@router.get("/summary", response_model=DashboardSummary)
async def get_summary(db: AsyncSession = Depends(get_db)):
    """대시보드 요약 — 오늘/이번달 충전 현황"""
    now = datetime.now(timezone.utc)
    today_start = now.replace(hour=0, minute=0, second=0, microsecond=0)
    month_start = now.replace(day=1, hour=0, minute=0, second=0, microsecond=0)

    # 충전기 통계
    chargers = await db.execute(select(Charger).where(Charger.is_active == True))
    charger_list = chargers.scalars().all()
    total = len(charger_list)
    active = sum(1 for c in charger_list if c.status != ChargerStatus.UNAVAILABLE)
    charging = sum(1 for c in charger_list if c.status == ChargerStatus.CHARGING)

    # 오늘 세션
    today_q = await db.execute(
        select(
            func.count(ChargingSession.id),
            func.coalesce(func.sum(ChargingSession.total_bill), 0),
            func.coalesce(func.sum(ChargingSession.charged_wh), 0),
        ).where(
            and_(
                ChargingSession.status == SessionStatus.COMPLETED,
                ChargingSession.created_at >= today_start,
            )
        )
    )
    today_row = today_q.one()

    # 이번달 세션
    month_q = await db.execute(
        select(
            func.coalesce(func.sum(ChargingSession.total_bill), 0),
            func.coalesce(func.sum(ChargingSession.charged_wh), 0),
        ).where(
            and_(
                ChargingSession.status == SessionStatus.COMPLETED,
                ChargingSession.created_at >= month_start,
            )
        )
    )
    month_row = month_q.one()

    return DashboardSummary(
        total_chargers=total,
        active_chargers=active,
        charging_now=charging,
        today_sessions=today_row[0],
        today_revenue=today_row[1],
        today_kwh=round(today_row[2] / 1000, 2),
        month_revenue=month_row[0],
        month_kwh=round(month_row[1] / 1000, 2),
    )


@router.get("/recent-sessions")
async def recent_sessions(
    limit: int = 20,
    db: AsyncSession = Depends(get_db),
):
    """최근 충전 세션 목록"""
    result = await db.execute(
        select(ChargingSession)
        .order_by(ChargingSession.created_at.desc())
        .limit(limit)
    )
    sessions = result.scalars().all()

    return [
        {
            "session_uid": s.session_uid,
            "charger_id": s.charger_id,
            "status": s.status,
            "charged_kwh": round(s.charged_wh / 1000, 2) if s.charged_wh else 0,
            "total_bill": s.total_bill,
            "started_at": s.started_at,
            "stopped_at": s.stopped_at,
        }
        for s in sessions
    ]


@router.get("/daily-stats")
async def daily_stats(
    days: int = 30,
    db: AsyncSession = Depends(get_db),
):
    """일별 충전 통계 (최근 N일)"""
    cutoff = datetime.now(timezone.utc) - timedelta(days=days)

    result = await db.execute(
        select(
            func.date(ChargingSession.created_at).label("date"),
            func.count(ChargingSession.id).label("sessions"),
            func.coalesce(func.sum(ChargingSession.total_bill), 0).label("revenue"),
            func.coalesce(func.sum(ChargingSession.charged_wh), 0).label("wh"),
        )
        .where(
            and_(
                ChargingSession.status == SessionStatus.COMPLETED,
                ChargingSession.created_at >= cutoff,
            )
        )
        .group_by(func.date(ChargingSession.created_at))
        .order_by(func.date(ChargingSession.created_at))
    )

    return [
        {
            "date": str(row.date),
            "sessions": row.sessions,
            "revenue": row.revenue,
            "kwh": round(row.wh / 1000, 2),
        }
        for row in result.all()
    ]