from fastapi import APIRouter, Depends, Query, HTTPException
from sqlalchemy import text
from sqlalchemy.ext.asyncio import AsyncSession
from core.database import get_session

router = APIRouter()


@router.get("")
async def list_alarms(
    site_id: str  = Query(...),
    state:   str  = Query("active", description="active | resolved | acknowledged | all"),
    limit:   int  = Query(50, ge=1, le=200),
    session: AsyncSession = Depends(get_session),
):
    where = "WHERE site_id = :site_id"
    if state != "all":
        where += " AND state = :state"

    result = await session.execute(text(f"""
        SELECT id, sensor_id, site_id, room_id, rack_id,
               severity, message, state, triggered_at,
               acknowledged_at, resolved_at
        FROM alarms
        {where}
        ORDER BY triggered_at DESC
        LIMIT :limit
    """), {"site_id": site_id, "state": state, "limit": limit})
    return [dict(r) for r in result.mappings().all()]


@router.post("/{alarm_id}/acknowledge")
async def acknowledge_alarm(
    alarm_id: int,
    session:  AsyncSession = Depends(get_session),
):
    result = await session.execute(text("""
        UPDATE alarms
        SET state = 'acknowledged', acknowledged_at = NOW()
        WHERE id = :id AND state = 'active'
        RETURNING id
    """), {"id": alarm_id})
    await session.commit()
    if not result.fetchone():
        raise HTTPException(status_code=404, detail="Alarm not found or not active")
    return {"id": alarm_id, "state": "acknowledged"}


@router.post("/{alarm_id}/resolve")
async def resolve_alarm(
    alarm_id: int,
    session:  AsyncSession = Depends(get_session),
):
    result = await session.execute(text("""
        UPDATE alarms
        SET state = 'resolved', resolved_at = NOW()
        WHERE id = :id AND state IN ('active', 'acknowledged')
        RETURNING id
    """), {"id": alarm_id})
    await session.commit()
    if not result.fetchone():
        raise HTTPException(status_code=404, detail="Alarm not found or already resolved")
    return {"id": alarm_id, "state": "resolved"}


@router.get("/stats")
async def alarm_stats(
    site_id: str = Query(...),
    session: AsyncSession = Depends(get_session),
):
    result = await session.execute(text("""
        SELECT
            COUNT(*) FILTER (WHERE state = 'active')                          AS active,
            COUNT(*) FILTER (WHERE state = 'acknowledged')                    AS acknowledged,
            COUNT(*) FILTER (WHERE state = 'resolved')                        AS resolved,
            COUNT(*) FILTER (WHERE state = 'active' AND severity = 'critical') AS critical,
            COUNT(*) FILTER (WHERE state = 'active' AND severity = 'warning')  AS warning
        FROM alarms
        WHERE site_id = :site_id
    """), {"site_id": site_id})
    row = result.mappings().one()
    return {k: int(v) for k, v in row.items()}