import { useEffect, useState } from 'react'
import { Power, Minus, Plus, RefreshCw, Loader2 } from 'lucide-react'
import { MHI_MODES, MHI_FAN_SPEEDS } from '../types'
import { fetchMhiStatus, sendMhiControl } from '../api'

// Manual on/off + mode + setpoint + fan speed controls for one assigned MHI
// aircon unit (mhi_modbus). No NewBook/scheduler integration — every change
// here is an explicit staff action via POST /devices/:id/mhi-control.
export default function MhiControlPanel({ deviceId, canControl }: { deviceId: number; canControl: boolean }) {
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState('')
  const [applying, setApplying] = useState(false)

  const [onOff, setOnOff] = useState(false)
  const [mode, setMode] = useState<string>('auto')
  const [setpoint, setSetpoint] = useState(21)
  const [fanSpeed, setFanSpeed] = useState<string>('medium')
  const [roomTemp, setRoomTemp] = useState<number | null>(null)

  function load() {
    setLoading(true); setError('')
    fetchMhiStatus(deviceId)
      .then(s => {
        setOnOff(s.onOff === 'on')
        if (s.mode) setMode(s.mode)
        if (s.setpoint != null) setSetpoint(s.setpoint)
        if (s.fanSpeed) setFanSpeed(s.fanSpeed)
        setRoomTemp(s.roomTemp ?? null)
      })
      .catch(e => setError(e instanceof Error ? e.message : 'Failed to read device status'))
      .finally(() => setLoading(false))
  }
  useEffect(load, [deviceId])

  async function apply(patch: Partial<{ onOff: boolean; mode: string; tempC: number; fanSpeed: string }>) {
    setApplying(true); setError('')
    try {
      const res = await sendMhiControl(deviceId, patch)
      if (!res.ok) setError('Device did not accept the command')
    } catch (e) {
      setError(e instanceof Error ? e.message : 'Command failed')
    } finally {
      setApplying(false)
    }
  }

  if (loading) return <p className="muted" style={{ fontSize: 12.5 }}>Reading aircon status…</p>

  return (
    <div style={{ marginTop: 8 }}>
      {error && <div className="error-banner" style={{ marginBottom: 8 }}>{error}</div>}
      <div style={{ display: 'flex', alignItems: 'center', gap: 10, flexWrap: 'wrap' }}>
        <button
          className="btn btn-sm"
          disabled={!canControl || applying}
          onClick={() => { const next = !onOff; setOnOff(next); apply({ onOff: next }) }}
          style={onOff ? { background: 'var(--gold)', borderColor: 'var(--gold)', color: 'var(--navy)' } : undefined}
        >
          <Power size={13} strokeWidth={1.75} /> {onOff ? 'On' : 'Off'}
        </button>

        <select
          disabled={!canControl || applying}
          value={mode}
          onChange={e => { setMode(e.target.value); apply({ mode: e.target.value }) }}
        >
          {MHI_MODES.map(m => <option key={m} value={m}>{m[0].toUpperCase() + m.slice(1)}</option>)}
        </select>

        <div style={{ display: 'flex', alignItems: 'center', gap: 4 }}>
          <button
            className="btn btn-sm" disabled={!canControl || applying}
            onClick={() => { const next = Math.max(16, setpoint - 0.5); setSetpoint(next); apply({ tempC: next }) }}
          >
            <Minus size={12} strokeWidth={1.75} />
          </button>
          <span style={{ minWidth: 48, textAlign: 'center', fontWeight: 600, fontSize: 13 }}>{setpoint.toFixed(1)}°C</span>
          <button
            className="btn btn-sm" disabled={!canControl || applying}
            onClick={() => { const next = Math.min(30, setpoint + 0.5); setSetpoint(next); apply({ tempC: next }) }}
          >
            <Plus size={12} strokeWidth={1.75} />
          </button>
        </div>

        <select
          disabled={!canControl || applying}
          value={fanSpeed}
          onChange={e => { setFanSpeed(e.target.value); apply({ fanSpeed: e.target.value }) }}
        >
          {MHI_FAN_SPEEDS.map(f => <option key={f} value={f}>{f[0].toUpperCase() + f.slice(1)}</option>)}
        </select>

        {roomTemp != null && <span className="muted" style={{ fontSize: 12 }}>Room: {roomTemp.toFixed(1)}°C</span>}

        <button className="btn btn-sm" disabled={loading} onClick={load} title="Refresh live status">
          {applying ? <Loader2 size={13} strokeWidth={1.75} className="spin" /> : <RefreshCw size={13} strokeWidth={1.75} />}
        </button>
      </div>
    </div>
  )
}