import { useCallback, useEffect, useState } from 'react'
import { getJson } from '../api/postgrest'
import type { AuditTodayHourlyRow } from '../types/ems'

const POLL_MS = 30_000

function parseNum(v: string | number | null | undefined): number | null {
  if (v == null) return null
  if (typeof v === 'number' && !Number.isNaN(v)) return v
  const n = Number(v)
  return Number.isFinite(n) ? n : null
}

export type TelemetryChartPoint = {
  timeLabel: string
  ts: number
  pv_kw: number | null
  load_kw: number | null
  battery_kw: number | null
  grid_kw: number | null
}

export function useTelemetryToday(siteId: number | null) {
  const [points, setPoints] = useState<TelemetryChartPoint[]>([])
  const [ready, setReady] = useState(false)
  const [error, setError] = useState<string | null>(null)

  const load = useCallback(async () => {
    if (siteId == null) {
      setPoints([])
      setError(null)
      setReady(true)
      return
    }
    try {
      const rows = await getJson<AuditTodayHourlyRow[]>('/vw_audit_today_hourly', {
        site_id: `eq.${siteId}`,
        order: 'hour_local.asc',
      })
      if (!Array.isArray(rows) || rows.length === 0) {
        setPoints([])
        setError(null)
        return
      }
      const mapped: TelemetryChartPoint[] = rows.map((r) => {
        const d = new Date(r.hour_local)
        return {
          ts: d.getTime(),
          timeLabel: d.toLocaleTimeString('cs-CZ', {
            hour: '2-digit',
            minute: '2-digit',
            timeZone: 'Europe/Prague',
          }),
          pv_kw: parseNum(r.avg_pv_kw),
          load_kw: parseNum(r.avg_load_kw),
          battery_kw: parseNum(r.avg_battery_kw),
          grid_kw: parseNum(r.avg_grid_kw),
        }
      })
      setPoints(mapped)
      setError(null)
    } catch {
      setPoints([])
      setError('Hodinová data auditu se nepodařila načíst')
    } finally {
      setReady(true)
    }
  }, [siteId])

  useEffect(() => {
    void load()
    const id = window.setInterval(() => void load(), POLL_MS)
    return () => window.clearInterval(id)
  }, [load])

  return { points, ready, error, hasChartData: points.length > 0, reload: load }
}