import { useEffect, useState } from 'react'
import { Wifi, WifiOff } from 'lucide-react'
import {
  fetchNewbookSites, saveExcludedSites, testNewbookConnection, syncZonesFromNewbook,
  fetchConfig, updateConfig, fetchMqttStatus, fetchStatus, createZone,
} from '../api'
import type { NewbookSite, AppConfig, HvacDefaults, HvacAcTemplate, HvacWeatherTier } from '../types'
import { DEFAULT_HVAC_TEMPLATE, MHI_MODES, MHI_FAN_SPEEDS } from '../types'

export default function Settings() {
  const [sites, setSites] = useState<NewbookSite[]>([])
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState('')
  const [msg, setMsg] = useState('')
  const [testing, setTesting] = useState(false)
  const [syncing, setSyncing] = useState(false)

  const [config, setConfig] = useState<AppConfig | null>(null)
  const [automationEnabled, setAutomationEnabled] = useState(true)
  const [automationSaving, setAutomationSaving] = useState(false)
  const [pollMinutes, setPollMinutes] = useState(10)
  const [defaultArrival, setDefaultArrival] = useState('15:00:00')
  const [defaultDeparture, setDefaultDeparture] = useState('10:00:00')
  const [maintUrl, setMaintUrl] = useState('')
  const [maintKey, setMaintKey] = useState('')
  const [daikinCidr, setDaikinCidr] = useState('')
  const [configSaving, setConfigSaving] = useState(false)

  // Default occupied/vacant templates — every room inherits these unless it sets its
  // own override (ZoneDetailModal's per-field "Override" toggles).
  const [defaults, setDefaults] = useState<HvacDefaults>(DEFAULT_HVAC_TEMPLATE)
  const [defaultsSaving, setDefaultsSaving] = useState(false)

  const [mqttConnected, setMqttConnected] = useState<boolean | null>(null)
  const [mqttNote, setMqttNote] = useState('')

  const [weatherPeakC, setWeatherPeakC] = useState<number | null>(null)
  const [weatherTier, setWeatherTier] = useState<string | null>(null)
  const [weatherLoaded, setWeatherLoaded] = useState(false)

  const [publicAreaName, setPublicAreaName] = useState('')
  const [creatingZone, setCreatingZone] = useState(false)

  function loadSites() {
    fetchNewbookSites()
      .then(res => setSites(res.sites))
      .catch(e => setError(e instanceof Error ? e.message : 'Failed to load NewBook sites'))
      .finally(() => setLoading(false))
  }

  useEffect(() => {
    loadSites()
    fetchConfig().then(cfg => {
      setConfig(cfg)
      setAutomationEnabled(cfg.automation_enabled ?? true)
      setPollMinutes(cfg.poll_interval_minutes ?? 10)
      setDefaultArrival(cfg.default_arrival_time ?? '15:00:00')
      setDefaultDeparture(cfg.default_departure_time ?? '10:00:00')
      setMaintUrl(cfg.maintenance_url ?? '')
      setMaintKey(cfg.maintenance_api_key ?? '')
      setDaikinCidr(cfg.daikin_subnet_cidr ?? '')
      // Merge onto the shipped default rather than replacing outright — an hvac_defaults
      // row saved before weather compensation existed won't have ac_occupied_tiers yet.
      setDefaults({ ...DEFAULT_HVAC_TEMPLATE, ...cfg.hvac_defaults, ac_occupied_tiers: cfg.hvac_defaults?.ac_occupied_tiers ?? DEFAULT_HVAC_TEMPLATE.ac_occupied_tiers })
    }).catch(() => {})
    fetchMqttStatus().then(s => { setMqttConnected(s.connected); setMqttNote(s.note) }).catch(() => {})
    fetchStatus()
      .then(s => { setWeatherPeakC(s.weather_peak_c); setWeatherTier(s.weather_tier) })
      .catch(() => {})
      .finally(() => setWeatherLoaded(true))
  }, [])

  function toggleExcluded(siteId: string) {
    setSites(sites.map(s => s.site_id === siteId ? { ...s, excluded: !s.excluded } : s))
  }

  async function saveSites() {
    setError(''); setMsg('')
    try {
      await saveExcludedSites(sites.filter(s => s.excluded).map(s => s.site_id))
      setMsg('Saved'); setTimeout(() => setMsg(''), 2500)
    } catch (e) {
      setError(e instanceof Error ? e.message : 'Save failed')
    }
  }

  async function handleTest() {
    setTesting(true); setError(''); setMsg('')
    try {
      const res = await testNewbookConnection()
      setMsg(res.ok ? `Connection OK: ${res.message || ''}` : `Failed: ${res.error || 'unknown'}`)
    } catch (e) {
      setError(e instanceof Error ? e.message : 'Test failed')
    } finally {
      setTesting(false)
    }
  }

  async function handleSync() {
    setSyncing(true); setError(''); setMsg('')
    try {
      const res = await syncZonesFromNewbook()
      setMsg(`Synced: ${res.created} created, ${res.updated} updated (${res.total} active sites)`)
    } catch (e) {
      setError(e instanceof Error ? e.message : 'Sync failed')
    } finally {
      setSyncing(false)
    }
  }

  async function handleAutomationToggle() {
    const next = !automationEnabled
    setAutomationSaving(true); setError(''); setMsg('')
    try {
      await updateConfig('automation_enabled', next)
      setAutomationEnabled(next)
      setMsg(next ? 'Automation resumed' : 'Automation paused — device setpoints will no longer change until resumed')
      setTimeout(() => setMsg(''), 4000)
    } catch (e) {
      setError(e instanceof Error ? e.message : 'Failed to update automation state')
    } finally {
      setAutomationSaving(false)
    }
  }

  async function saveGeneralConfig() {
    setConfigSaving(true); setError(''); setMsg('')
    try {
      await Promise.all([
        updateConfig('poll_interval_minutes', pollMinutes),
        updateConfig('default_arrival_time', defaultArrival),
        updateConfig('default_departure_time', defaultDeparture),
        updateConfig('maintenance_url', maintUrl),
        updateConfig('maintenance_api_key', maintKey),
        updateConfig('daikin_subnet_cidr', daikinCidr),
      ])
      setMsg('Settings saved'); setTimeout(() => setMsg(''), 2500)
    } catch (e) {
      setError(e instanceof Error ? e.message : 'Save failed')
    } finally {
      setConfigSaving(false)
    }
  }

  function updateAcDefault(which: 'ac_occupied' | 'ac_vacant', field: keyof HvacAcTemplate, value: string | number) {
    setDefaults(d => ({ ...d, [which]: { ...d[which], [field]: value } }))
  }

  function updateTier(index: number, field: keyof HvacWeatherTier, value: string | number) {
    setDefaults(d => ({
      ...d,
      ac_occupied_tiers: d.ac_occupied_tiers.map((t, i) => i === index ? { ...t, [field]: value } : t),
    }))
  }

  async function saveDefaults() {
    setDefaultsSaving(true); setError(''); setMsg('')
    try {
      await updateConfig('hvac_defaults', defaults)
      setMsg('Default templates saved'); setTimeout(() => setMsg(''), 2500)
    } catch (e) {
      setError(e instanceof Error ? e.message : 'Save failed')
    } finally {
      setDefaultsSaving(false)
    }
  }

  async function handleCreatePublicArea(e: React.FormEvent) {
    e.preventDefault()
    if (!publicAreaName.trim()) return
    setCreatingZone(true); setError(''); setMsg('')
    try {
      await createZone({ name: publicAreaName.trim(), zone_type: 'public_area' })
      setPublicAreaName('')
      setMsg('Public area zone created — assign devices to it on the Devices page.')
    } catch (e) {
      setError(e instanceof Error ? e.message : 'Create failed')
    } finally {
      setCreatingZone(false)
    }
  }

  if (loading) return <div className="page"><p className="muted">Loading…</p></div>

  return (
    <div className="page">
      <div className="page-header">
        <h1>Settings</h1>
      </div>

      {error && <div className="error-banner">{error}</div>}
      {msg && <div className="ok-banner">{msg}</div>}

      <div className="section-title">Automation</div>
      <div className="card" style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', gap: 16, marginBottom: 24 }}>
        <div>
          <div style={{ fontWeight: 600, color: automationEnabled ? 'var(--health-healthy)' : 'var(--danger)' }}>
            {automationEnabled ? 'Automation is ON' : 'Automation is PAUSED'}
          </div>
          <div className="muted" style={{ fontSize: 13, marginTop: 2 }}>
            Master switch for every zone — overrides each zone's own auto mode. While paused, NewBook polling,
            room-state tracking and activity logging all keep running as normal — only setpoint changes to
            TRVs/aircon devices are skipped.
          </div>
        </div>
        <button
          className={`btn ${automationEnabled ? '' : 'btn-primary'}`}
          disabled={automationSaving}
          onClick={handleAutomationToggle}
        >
          {automationSaving ? 'Saving…' : automationEnabled ? 'Pause Automation' : 'Resume Automation'}
        </button>
      </div>

      <div className="section-title">MQTT Broker</div>
      <div className="card" style={{ display: 'flex', alignItems: 'center', gap: 8 }}>
        {mqttConnected ? <Wifi size={16} strokeWidth={1.75} color="var(--health-healthy)" /> : <WifiOff size={16} strokeWidth={1.75} color="var(--danger)" />}
        <span>{mqttNote || 'Checking…'}</span>
      </div>

      <div className="section-title">NewBook Rooms</div>
      <p className="field-hint" style={{ marginBottom: 10 }}>
        Untick rooms that shouldn't get NewBook-driven heating scheduling (e.g. owner-occupied or out-of-service rooms).
      </p>
      <div style={{ display: 'flex', flexDirection: 'column', gap: 6, marginBottom: 12 }}>
        {sites.map(s => (
          <label key={s.site_id} className="field-check" style={{
            padding: '8px 12px', border: '1px solid var(--card-border)', borderRadius: 8,
            background: s.excluded ? 'var(--body-bg)' : 'var(--card-bg)',
          }}>
            <input type="checkbox" checked={!s.excluded} onChange={() => toggleExcluded(s.site_id)} />
            <span style={{ flex: 1, textDecoration: s.excluded ? 'line-through' : 'none', color: s.excluded ? 'var(--text-mid)' : 'var(--text-dark)' }}>
              {s.site_name}
            </span>
            {s.category_name && <span className="muted" style={{ fontSize: 12 }}>{s.category_name}</span>}
          </label>
        ))}
        {sites.length === 0 && <p className="muted">No sites returned — check NewBook connection.</p>}
      </div>
      <div style={{ display: 'flex', gap: 8, flexWrap: 'wrap', marginBottom: 24 }}>
        <button className="btn btn-primary" onClick={saveSites}>Save Visibility</button>
        <button className="btn" disabled={testing} onClick={handleTest}>{testing ? 'Testing…' : 'Test NewBook Connection'}</button>
        <button className="btn" disabled={syncing} onClick={handleSync}>{syncing ? 'Syncing…' : 'Sync Zones from NewBook'}</button>
      </div>

      <div className="section-title">Add a Public Area</div>
      <form onSubmit={handleCreatePublicArea} style={{ display: 'flex', gap: 8, marginBottom: 24 }}>
        <input
          type="text" placeholder="e.g. Lobby, Restaurant, Bar"
          value={publicAreaName} onChange={e => setPublicAreaName(e.target.value)}
          style={{ flex: 1, border: '1px solid var(--card-border)', borderRadius: 8, padding: '8px 10px' }}
        />
        <button className="btn btn-primary" disabled={creatingZone} type="submit">Add zone</button>
      </form>

      <div className="section-title">Scheduling</div>
      <div className="field-row">
        <div className="field">
          <label>Poll interval (minutes)</label>
          <input type="number" min={1} value={pollMinutes} onChange={e => setPollMinutes(parseInt(e.target.value) || 10)} />
        </div>
        <div className="field">
          <label>Default arrival time</label>
          <input type="text" value={defaultArrival} onChange={e => setDefaultArrival(e.target.value)} placeholder="15:00:00" />
        </div>
        <div className="field">
          <label>Default departure time</label>
          <input type="text" value={defaultDeparture} onChange={e => setDefaultDeparture(e.target.value)} placeholder="10:00:00" />
        </div>
      </div>

      <div className="section-title">Default Templates</div>
      <p className="field-hint" style={{ marginBottom: 10 }}>
        Fallback occupied/vacant state for every room's TRVs and aircon. Any room can override
        individual values on its own card (Dashboard → click the room → Schedule section).
      </p>
      <div className="field-row">
        <div className="field">
          <label>Default arrival preparing offset (mins)</label>
          <input
            type="number" value={defaults.arrival_prep_offset_min}
            onChange={e => setDefaults(d => ({ ...d, arrival_prep_offset_min: parseInt(e.target.value) || 0 }))}
          />
        </div>
        <div className="field">
          <label>Default departing preparation offset (mins)</label>
          <input
            type="number" value={defaults.departure_prep_offset_min}
            onChange={e => setDefaults(d => ({ ...d, departure_prep_offset_min: parseInt(e.target.value) || 0 }))}
          />
        </div>
      </div>

      <div style={{ fontWeight: 600, fontSize: 13, margin: '10px 0 6px' }}>Default Aircon</div>
      <div className="table-wrap" style={{ marginBottom: 16 }}>
        <table className="data">
          <thead><tr><th></th><th>Occupied</th><th>Vacant</th></tr></thead>
          <tbody>
            <tr>
              <td>On/Off</td>
              {(['ac_occupied', 'ac_vacant'] as const).map(which => (
                <td key={which}>
                  <select value={defaults[which].power} onChange={e => updateAcDefault(which, 'power', e.target.value)}>
                    <option value="on">On</option>
                    <option value="off">Off</option>
                  </select>
                </td>
              ))}
            </tr>
            <tr>
              <td>Mode</td>
              {(['ac_occupied', 'ac_vacant'] as const).map(which => (
                <td key={which}>
                  <select value={defaults[which].mode} onChange={e => updateAcDefault(which, 'mode', e.target.value)}>
                    {MHI_MODES.map(m => <option key={m} value={m}>{m[0].toUpperCase() + m.slice(1)}</option>)}
                  </select>
                </td>
              ))}
            </tr>
            <tr>
              <td>Setpoint (°C)</td>
              {(['ac_occupied', 'ac_vacant'] as const).map(which => (
                <td key={which}>
                  <input
                    type="number" step="0.5" style={{ width: 90 }}
                    value={defaults[which].setpoint}
                    onChange={e => updateAcDefault(which, 'setpoint', parseFloat(e.target.value) || 0)}
                  />
                </td>
              ))}
            </tr>
            <tr>
              <td>Fan speed</td>
              {(['ac_occupied', 'ac_vacant'] as const).map(which => (
                <td key={which}>
                  <select value={defaults[which].fan_speed} onChange={e => updateAcDefault(which, 'fan_speed', e.target.value)}>
                    {MHI_FAN_SPEEDS.map(f => <option key={f} value={f}>{f[0].toUpperCase() + f.slice(1)}</option>)}
                  </select>
                </td>
              ))}
            </tr>
          </tbody>
        </table>
      </div>

      <div className="section-title">Weather Compensation</div>
      <p className="field-hint" style={{ marginBottom: 10 }}>
        Overrides the Occupied aircon template above on a hot day. At check-in/arrival, the scheduler
        checks today's forecast peak (from Settings → Integrations → Hotel Location / Met Office DataHub,
        falls back to Open-Meteo with no key needed) and uses the highest tier below whose threshold it
        clears — below every threshold, the Default Aircon "Occupied" row above still applies unchanged.
        Only re-checked at the moment a room becomes occupied, never mid-stay, so it can't override a
        guest's own adjustment later in their booking.
        {weatherPeakC != null && (
          <> Today's forecast peak: <strong>{weatherPeakC}°C</strong>{weatherTier ? <> — currently in the <strong>{weatherTier}</strong> tier</> : ' — below every tier'}.</>
        )}
      </p>
      {weatherLoaded && weatherPeakC == null && (
        <p className="field-hint" style={{ marginBottom: 10, color: 'var(--danger)' }}>
          No forecast available right now — check Hotel Location and Met Office DataHub under Settings →
          Integrations are saved correctly (both need a Test to pass), or check hvac-backend's logs for
          a "[weather]" line explaining why.
        </p>
      )}
      <div className="table-wrap" style={{ marginBottom: 24 }}>
        <table className="data">
          <thead><tr><th>Tier</th><th>If peak above (°C)</th><th>On/Off</th><th>Mode</th><th>Setpoint (°C)</th><th>Fan speed</th></tr></thead>
          <tbody>
            {defaults.ac_occupied_tiers.map((tier, i) => (
              <tr key={tier.name}>
                <td style={{ fontWeight: 600, textTransform: 'capitalize' }}>{tier.name}</td>
                <td>
                  <input
                    type="number" step="0.5" style={{ width: 80 }}
                    value={tier.peak_above_c}
                    onChange={e => updateTier(i, 'peak_above_c', parseFloat(e.target.value) || 0)}
                  />
                </td>
                <td>
                  <select value={tier.power} onChange={e => updateTier(i, 'power', e.target.value)}>
                    <option value="on">On</option>
                    <option value="off">Off</option>
                  </select>
                </td>
                <td>
                  <select value={tier.mode} onChange={e => updateTier(i, 'mode', e.target.value)}>
                    {MHI_MODES.map(m => <option key={m} value={m}>{m[0].toUpperCase() + m.slice(1)}</option>)}
                  </select>
                </td>
                <td>
                  <input
                    type="number" step="0.5" style={{ width: 90 }}
                    value={tier.setpoint}
                    onChange={e => updateTier(i, 'setpoint', parseFloat(e.target.value) || 0)}
                  />
                </td>
                <td>
                  <select value={tier.fan_speed} onChange={e => updateTier(i, 'fan_speed', e.target.value)}>
                    {MHI_FAN_SPEEDS.map(f => <option key={f} value={f}>{f[0].toUpperCase() + f.slice(1)}</option>)}
                  </select>
                </td>
              </tr>
            ))}
          </tbody>
        </table>
      </div>

      <div style={{ fontWeight: 600, fontSize: 13, margin: '10px 0 6px' }}>Default TRVs</div>
      <div className="field-row">
        <div className="field">
          <label>Occupied setpoint (°C)</label>
          <input
            type="number" step="0.5" value={defaults.trv_occupied_temp}
            onChange={e => setDefaults(d => ({ ...d, trv_occupied_temp: parseFloat(e.target.value) || 0 }))}
          />
        </div>
        <div className="field">
          <label>Vacant setpoint (°C)</label>
          <input
            type="number" step="0.5" value={defaults.trv_vacant_temp}
            onChange={e => setDefaults(d => ({ ...d, trv_vacant_temp: parseFloat(e.target.value) || 0 }))}
          />
        </div>
      </div>
      <div style={{ marginBottom: 24 }}>
        <button className="btn btn-primary" disabled={defaultsSaving} onClick={saveDefaults}>
          {defaultsSaving ? 'Saving…' : 'Save Default Templates'}
        </button>
      </div>

      <div className="section-title">Daikin Aircon</div>
      <p className="field-hint" style={{ marginBottom: 10 }}>
        Daikin units are WiFi/DHCP, so their IP changes over time. Instead of a fixed IP, hvac
        periodically sweeps this LAN range over HTTP and matches units by their MAC address —
        set it once and it self-heals if a unit's IP changes. Run "Discover Daikin Split" on the
        Devices page after saving to find units for the first time.
      </p>
      <div className="field-row">
        <div className="field">
          <label>Daikin subnet (CIDR)</label>
          <input type="text" value={daikinCidr} onChange={e => setDaikinCidr(e.target.value)} placeholder="10.4.0.0/22" />
        </div>
      </div>

      <div className="section-title">Maintenance Integration</div>
      <p className="field-hint" style={{ marginBottom: 10 }}>
        Not yet available — maintenance needs its own Settings → API Keys page first.
        Once that lands, generate a key there and paste it here to enable "Create asset in Maintenance" on the Devices page.
      </p>
      <div className="field-row">
        <div className="field">
          <label>Maintenance URL</label>
          <input type="text" value={maintUrl} onChange={e => setMaintUrl(e.target.value)} placeholder="https://hotel.example.com/maintenance" />
        </div>
        <div className="field">
          <label>Maintenance API key</label>
          <input type="text" value={maintKey} onChange={e => setMaintKey(e.target.value)} placeholder="paste key" />
        </div>
      </div>

      <div style={{ marginBottom: 24 }}>
        <button className="btn btn-primary" disabled={configSaving} onClick={saveGeneralConfig}>
          {configSaving ? 'Saving…' : 'Save Settings'}
        </button>
      </div>
    </div>
  )
}