import { useCallback, useEffect, useRef, useState } from 'react'
import { Thermometer, CheckSquare, X } from 'lucide-react'
import { kioskLogin, kioskFetchStatus, KioskSessionError } from '../api'
import type { DeviceSummary, ZoneStatus } from '../types'
import { KIOSK_DEVICE_TYPES } from '../types'
import KioskZoneBlock from '../components/KioskZoneBlock'
import KioskZonePanel from '../components/KioskZonePanel'
import KioskModal from '../components/KioskModal'
import KioskBulkPanel from '../components/KioskBulkPanel'

// Control surface, not a passive display — far shorter than weather's 5-minute
// precedent, but not so aggressive it hammers the backend given the underlying
// data is already push/poll-cached (MQTT for TRV/MHI, a 60s poller for Daikin).
const POLL_MS = 12_000

function liveDevicesOf(zone: ZoneStatus): DeviceSummary[] {
  return zone.devices.filter(d => KIOSK_DEVICE_TYPES.includes(d.device_type))
}

// The wall-panel kiosk view — a dedicated route/login, deliberately outside the
// normal staff AuthGate/Layout (see App.tsx). One master panel: one tile per
// ROOM/ZONE (same as the Dashboard's ZoneCard — a room's TRV and AC show
// together, not as separate tiles) in a scrollable grid; tap a tile for that
// zone's full control modal, or toggle Select for type-aware bulk editing
// across zones. See project_hvac_kiosk memory for the design decisions behind
// this (access model, layout, bulk-edit mechanism).
export default function Kiosk() {
  const [authState, setAuthState] = useState<'checking' | 'login' | 'authed'>('checking')
  const [password, setPassword] = useState('')
  const [loginError, setLoginError] = useState('')
  const [loginLoading, setLoginLoading] = useState(false)

  const [zones, setZones] = useState<ZoneStatus[]>([])
  const [loadError, setLoadError] = useState('')

  const [selectionMode, setSelectionMode] = useState(false)
  const [selectedZoneIds, setSelectedZoneIds] = useState<Set<number>>(new Set())
  const [editingZone, setEditingZone] = useState<ZoneStatus | null>(null)
  const [bulkOpen, setBulkOpen] = useState(false)

  const pollRef = useRef<ReturnType<typeof setInterval> | null>(null)

  const load = useCallback(() => {
    kioskFetchStatus()
      .then(s => {
        setZones(s.zones.filter(z => liveDevicesOf(z).length > 0))
        setLoadError('')
        setAuthState('authed')
      })
      .catch(e => {
        if (e instanceof KioskSessionError) { setAuthState('login'); return }
        setLoadError(e instanceof Error ? e.message : 'Failed to load device status')
      })
  }, [])

  useEffect(() => { load() }, [load])

  useEffect(() => {
    if (authState !== 'authed') {
      if (pollRef.current) clearInterval(pollRef.current)
      return
    }
    pollRef.current = setInterval(load, POLL_MS)
    return () => { if (pollRef.current) clearInterval(pollRef.current) }
  }, [authState, load])

  async function handleLogin(e: React.FormEvent) {
    e.preventDefault()
    setLoginLoading(true); setLoginError('')
    try {
      await kioskLogin(password)
      setPassword('')
      load()
    } catch (e) {
      setLoginError(e instanceof Error ? e.message : 'Login failed')
    } finally {
      setLoginLoading(false)
    }
  }

  function toggleSelectionMode() {
    setSelectionMode(m => !m)
    setSelectedZoneIds(new Set())
  }

  function tapZone(zone: ZoneStatus) {
    if (selectionMode) {
      setSelectedZoneIds(prev => {
        const next = new Set(prev)
        if (next.has(zone.id)) next.delete(zone.id); else next.add(zone.id)
        return next
      })
    } else {
      setEditingZone(zone)
    }
  }

  function closeBulk() {
    setBulkOpen(false)
    setSelectionMode(false)
    setSelectedZoneIds(new Set())
    load()
  }

  // Bulk edit works across whichever zones are selected — gather every live
  // device from all of them, KioskBulkPanel sections by device type from there.
  const selectedDevices = zones.filter(z => selectedZoneIds.has(z.id)).flatMap(liveDevicesOf)

  if (authState === 'checking') {
    return <div className="kiosk-shell kiosk-center"><p className="muted">Loading…</p></div>
  }

  if (authState === 'login') {
    return (
      <div className="kiosk-shell kiosk-center">
        <div className="kiosk-login-card">
          <Thermometer size={28} strokeWidth={1.5} style={{ color: 'var(--gold)', marginBottom: 8 }} />
          <h1 style={{ fontSize: '1.3rem', margin: '0 0 1.25rem' }}>HVAC Kiosk</h1>
          <form onSubmit={handleLogin} style={{ display: 'flex', flexDirection: 'column', gap: 10 }}>
            <input
              type="password" value={password} onChange={e => setPassword(e.target.value)}
              placeholder="Kiosk password" autoFocus required autoComplete="off"
            />
            {loginError && <div className="error-banner">{loginError}</div>}
            <button className="btn btn-primary" type="submit" disabled={loginLoading}>
              {loginLoading ? 'Signing in…' : 'Unlock'}
            </button>
          </form>
        </div>
      </div>
    )
  }

  return (
    <div className="kiosk-shell">
      <header className="kiosk-header">
        <span className="kiosk-header-title">
          <Thermometer size={18} strokeWidth={1.75} /> HVAC Kiosk
        </span>
        <button className={`btn btn-sm${selectionMode ? ' btn-primary' : ''}`} onClick={toggleSelectionMode}>
          <CheckSquare size={14} strokeWidth={1.75} /> {selectionMode ? 'Cancel select' : 'Select'}
        </button>
      </header>

      {loadError && <div className="error-banner kiosk-error">{loadError}</div>}

      <div className="kiosk-grid-wrap">
        <div className="kiosk-grid">
          {zones.map(zone => (
            <KioskZoneBlock
              key={zone.id}
              zone={zone}
              liveDevices={liveDevicesOf(zone)}
              selectionMode={selectionMode}
              selected={selectedZoneIds.has(zone.id)}
              onTap={() => tapZone(zone)}
            />
          ))}
          {zones.length === 0 && !loadError && (
            <p className="muted">No live-controllable devices assigned to a zone yet.</p>
          )}
        </div>
      </div>

      {selectionMode && selectedZoneIds.size > 0 && (
        <div className="kiosk-bulk-bar">
          <span>{selectedZoneIds.size} zone{selectedZoneIds.size === 1 ? '' : 's'} selected</span>
          <button className="btn btn-primary" onClick={() => setBulkOpen(true)}>Edit selected</button>
          <button className="btn btn-sm" onClick={() => setSelectedZoneIds(new Set())} aria-label="Clear selection">
            <X size={13} strokeWidth={1.75} />
          </button>
        </div>
      )}

      {editingZone && (
        <KioskModal title={editingZone.name} onClose={() => { setEditingZone(null); load() }}>
          <KioskZonePanel devices={liveDevicesOf(editingZone)} />
        </KioskModal>
      )}

      {bulkOpen && (
        <KioskModal title={`Edit ${selectedZoneIds.size} zone${selectedZoneIds.size === 1 ? '' : 's'}`} wide onClose={closeBulk}>
          <KioskBulkPanel devices={selectedDevices} onDone={closeBulk} />
        </KioskModal>
      )}
    </div>
  )
}