import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
import { api, Me, Term, titleOf } from './api'
import Rail, { Group } from './Rail'
import TerminalPane, { TermHandle } from './TerminalPane'
import TermTabs from './TermTabs'
import KeyBar from './KeyBar'
import Gallery from './Gallery'
import Docker from './Docker'
import Alerts from './Alerts'
import Services from './Services'
import Jobs from './Jobs'
import Updates from './Updates'
import Disks from './Disks'
import Hardware from './Hardware'
import Network from './Network'
import VPN from './VPN'
import ZFS from './ZFS'
import KVM from './KVM'
import Files from './Files'
import Top from './Top'
import Machines from './Machines'
import Settings from './Settings'
import Usage from './Usage'
import Users from './Users'
import MachineSwitcher from './MachineSwitcher'
import { MachineStatus, setMachine } from './api'
import { LIST_FLOOR, useRefreshMs } from './prefs'
import Power from './Power'
import { applyAccent } from './accents'
import { Btn, PageBoundary, Toasts, askText, askYes, hasUnsaved, okToLeave, toast, useEscape } from './ui'
import { fmtLeft, useTimeLeft } from './guest'

// Inline outline icon so it matches the monochrome glyphs in the rail (emoji would be full colour).
const FolderIcon = (
  <svg viewBox="0 0 16 16" width="14" height="14" fill="none" stroke="currentColor" strokeWidth="1.6" strokeLinejoin="round" aria-hidden="true">
    <path d="M1.5 4a1 1 0 0 1 1-1h3.2l1.6 1.6h6.2a1 1 0 0 1 1 1V12a1 1 0 0 1-1 1h-11a1 1 0 0 1-1-1V4z" />
  </svg>
)

// ⏱ is an emoji on phones (full colour, its own size); an outline clock matches the rest.
const ClockIcon = (
  <svg viewBox="0 0 16 16" width="14" height="14" fill="none" stroke="currentColor" strokeWidth="1.6" strokeLinecap="round" strokeLinejoin="round" aria-hidden="true">
    <circle cx="8" cy="8" r="6.2" /><path d="M8 4.6V8l2.3 1.5" />
  </svg>
)

const DockerIcon = (
  <svg viewBox="0 0 16 16" width="14" height="14" fill="none" stroke="currentColor" strokeWidth="1.5" strokeLinejoin="round" aria-hidden="true">
    <path d="M2 5.2 8 2l6 3.2v5.6L8 14l-6-3.2z" /><path d="M2 5.2 8 8.4l6-3.2M8 8.4V14" />
  </svg>
)
const BellIcon = (
  <svg viewBox="0 0 16 16" width="14" height="14" fill="none" stroke="currentColor" strokeWidth="1.5" strokeLinecap="round" strokeLinejoin="round" aria-hidden="true">
    <path d="M4 11V7.2a4 4 0 0 1 8 0V11l1.2 1.6H2.8z" /><path d="M6.6 14.2h2.8" />
  </svg>
)

const GlobeIcon = (
  <svg viewBox="0 0 16 16" width="14" height="14" fill="none" stroke="currentColor" strokeWidth="1.4" strokeLinecap="round" aria-hidden="true">
    <circle cx="8" cy="8" r="6.2" /><path d="M1.9 8h12.2M8 1.8c1.7 1.8 2.6 3.9 2.6 6.2S9.7 12.4 8 14.2C6.3 12.4 5.4 10.3 5.4 8S6.3 3.6 8 1.8z" />
  </svg>
)

// A padlock-ish shield: the tab is about who may come in, and a keyhole reads at 14px where
// a padlock's shackle does not.
const ShieldIcon = (
  <svg viewBox="0 0 16 16" width="14" height="14" fill="none" stroke="currentColor" strokeWidth="1.4" strokeLinejoin="round" aria-hidden="true">
    <path d="M8 1.6 13.2 3.5v4.2c0 3-2.1 5.4-5.2 6.7-3.1-1.3-5.2-3.7-5.2-6.7V3.5z" /><circle cx="8" cy="7.2" r="1.3" /><path d="M8 8.5v2" />
  </svg>
)

const GROUPS: Group[] = [
  { id: 'procs', label: 'Processes', icon: '▚' },
  { id: 'terminal', label: 'Terminal', icon: '>_' },
  { id: 'services', label: 'Services', icon: '◈' },
  { id: 'jobs', label: 'Jobs', icon: ClockIcon },
  { id: 'disks', label: 'Disks', icon: '▤' },
  { id: 'files', label: 'Files', icon: FolderIcon },
  { id: 'network', label: 'Network', icon: GlobeIcon },
  { id: 'vpn', label: 'VPN', icon: ShieldIcon },
  { id: 'usage', label: 'Usage', icon: '▧' },
  { id: 'zfs', label: 'ZFS', icon: '⛁' },
  { id: 'docker', label: 'Docker', icon: DockerIcon },
  { id: 'kvm', label: 'KVM', icon: '⌨' },
  { id: 'hardware', label: 'Hardware', icon: '⬡' },
  { id: 'updates', label: 'Updates', icon: '⇪' },
  { id: 'alerts', label: 'Alerts', icon: BellIcon },
  { id: 'machines', label: 'Machines', icon: '⌂' },
  { id: 'widgets', label: 'Widgets', icon: '▦' },
  { id: 'users', label: 'Users', icon: '⚇' },
  { id: 'settings', label: 'Settings', icon: '⚙' },
]

type View = 'terminal' | 'widgets' | 'docker' | 'alerts' | 'services' | 'jobs' | 'updates' | 'disks' | 'hardware' | 'network' | 'vpn' | 'zfs' | 'usage' | 'files' | 'procs' | 'machines' | 'kvm' | 'users' | 'settings'
const VIEWS: View[] = ['terminal', 'widgets', 'docker', 'alerts', 'services', 'jobs', 'updates', 'disks', 'hardware', 'network', 'vpn', 'zfs', 'usage', 'files', 'procs', 'machines', 'kvm', 'users', 'settings']
const HUB_ONLY: View[] = ['machines', 'users', 'settings', 'alerts']

// URL hash is the source of truth for where you are: #/<machine|hub>/<view>. Back and
// forward work, reload restores the tab, and links can point at a page on a machine.
// Pages that were renamed, so a link or a bookmark made before it still lands where it meant.
const RENAMED_VIEWS: Record<string, View> = { space: 'usage', cron: 'jobs', top: 'procs', dashboard: 'procs' }

function parseHash(): { machine: string | null; view: View } | null {
  const m = location.hash.match(/^#\/([a-z0-9-]+)\/([a-z]+)(?:\/.*)?$/) // anything after the page is that page's own selection
  if (!m) return null
  const view = VIEWS.includes(m[2] as View) ? (m[2] as View) : RENAMED_VIEWS[m[2]]
  if (!view) return null
  return { machine: m[1] === 'hub' ? null : m[1], view }
}

function fmtUptime(s: number): string {
  const d = Math.floor(s / 86400), h = Math.floor((s % 86400) / 3600), m = Math.floor((s % 3600) / 60)
  return d > 0 ? `${d}d ${h}h` : h > 0 ? `${h}h ${m}m` : `${m}m`
}

export default function Shell({ me: hubMe, onLoggedOut }: { me: Me; onLoggedOut: () => void }) {
  // Which machine we're looking at. null = the hub itself. Set before anything renders so
  // every page's first request already goes to the right place.
  // The URL wins when it has an opinion; the last machine is only for a bare address. "hub" is
  // an opinion — it is null here — so ?? would have read straight past it to the remembered
  // machine, and a link to a page of the hub reloaded onto whichever machine was last open.
  const [machine, setMachineState] = useState<string | null>(() => { const h = parseHash(); const m = h ? h.machine : sessionStorage.getItem('hamlab.machine'); setMachine(m); return m })
  const [machines, setMachines] = useState<MachineStatus[]>([])
  const [remoteMe, setRemoteMe] = useState<Me | null>(null)
  const [remoteErr, setRemoteErr] = useState('')
  // A guest login is an account with a clock on it: nothing is hidden from it, but the header
  // says how long it has, for whoever is holding the phone.
  const leftMs = useTimeLeft(hubMe.guest_until)
  // A machine is titled by its own hostname; the name it was added under stays its identity
  // (the URL, its accent, what the hub's API calls it). See titleOf.
  const title = titleOf(machine, machines, hubMe.host)
  const me: Me = machine ? (remoteMe ?? { ...hubMe, host: title, load: '', version: '…', uptime: 0, reboot_needed: false }) : hubMe
  const listRate = useRefreshMs(LIST_FLOOR)
  const [terms, setTerms] = useState<Term[]>([])
  const [active, setActive] = useState<string | null>(null)
  const [view, setView] = useState<View>(() => parseHash()?.view ?? 'procs')
  const [drawer, setDrawer] = useState(false)
  useEscape(() => setDrawer(false), drawer) // the phone's drawer closes like every other overlay
  const [online, setOnline] = useState(true)
  const [creating, setCreating] = useState(false)
  const handles = useRef<Record<string, TermHandle>>({})

  const reload = useCallback(async () => {
    try {
      const list = await api.terminals()
      setTerms(list)
      setActive((a) => (a && list.some((t) => t.id === a) ? a : list[0]?.id ?? null))
    } catch (e) { setTerms([]); if (machine) setRemoteErr(e instanceof Error ? e.message : 'unreachable') }
  }, [machine])

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

  // One page sending you to another — the Network tab handing a tunnel over to the VPN tab.
  // A custom event rather than a hash assignment, because assigning location.hash does not
  // reliably raise popstate, which is what this shell navigates by.
  useEffect(() => {
    const h = (e: Event) => {
      const id = (e as CustomEvent<string>).detail
      if (VIEWS.includes(id as View)) { setView(id as View); setDrawer(false) }
    }
    window.addEventListener('hamlab:view', h)
    return () => window.removeEventListener('hamlab:view', h)
  }, [])

  // A shell opened inside a container from the Docker tab is a terminal like any other:
  // pick it up, show the Terminal tab, and make it the active one.
  useEffect(() => {
    const h = async (e: Event) => {
      const id = (e as CustomEvent<string>).detail
      if (!id) return
      await reload()
      setActive(id)
      setView('terminal')
    }
    window.addEventListener('hamlab:terminal', h)
    return () => window.removeEventListener('hamlab:terminal', h)
  }, [reload])

  // Machine list for the switcher (hub-local), refreshed while the console is open.
  const loadMachines = useCallback(async () => { try { setMachines((await api.machines()).nodes) } catch { /* not a hub or offline */ } }, [])
  useEffect(() => { loadMachines(); const t = setInterval(loadMachines, listRate); return () => clearInterval(t) }, [loadMachines, listRate])

  // Switching machines: reset everything that belongs to a host, then re-fetch its identity.
  const switchMachine = async (name: string | null) => {
    if (name !== machine && !(await okToLeave())) return
    setMachine(name); sessionStorage.setItem('hamlab.machine', name ?? ''); if (!name) sessionStorage.removeItem('hamlab.machine')
    handles.current = {}; setTerms([]); setActive(null); setRemoteMe(null); setRemoteErr(''); setDrawer(false); setOnline(true)
    setMachineState(name)
  }

  // keep the hash in step, and follow it when the browser navigates
  const [firing, setFiring] = useState(0)
  useEffect(() => {
    const tick = () => { if (document.visibilityState === 'visible') api.alerts().then((a) => setFiring(a.firing.length)).catch(() => {}) }
    tick(); const t = setInterval(tick, 15000); window.addEventListener('hamlab:alerts', tick)
    return () => { clearInterval(t); window.removeEventListener('hamlab:alerts', tick) }
  }, [])
  // The machine's colour: set on <html>, so the header stripe and the switcher pick it up.
  // Hub-only pages make no sense on a remote machine. Judged once both have settled, not while
  // the machine is changing: the URL sets the machine and the page in one go, and deciding from
  // inside the machine change read the page we were leaving — so a link from Settings to a
  // machine's Disks arrived at its Dashboard.
  useEffect(() => { if (machine && HUB_ONLY.includes(view)) setView('procs') }, [machine, view])

  useEffect(() => { const paint = () => applyAccent(machine ?? hubMe.host); paint(); window.addEventListener('hamlab:accents', paint); return () => window.removeEventListener('hamlab:accents', paint) }, [machine, hubMe.host])
  // The tab's title says where you are, so history entries and open tabs can be told apart.
  useEffect(() => { document.title = `${GROUPS.find((g) => g.id === view)?.label ?? view} · ${title} — Ham Lab` }, [view, title])
  useEffect(() => {
    const want = `#/${machine ?? 'hub'}/${view}`
    if (location.hash !== want && !location.hash.startsWith(want + '/')) history.pushState(null, '', want)
  }, [machine, view])
  useEffect(() => {
    const h = async () => {
      const p = parseHash(); if (!p) return
      if (hasUnsaved() && (p.machine !== machine || p.view !== view)) { // Back/Forward away from unsaved work: stay put until answered
        const there = location.hash
        history.pushState(null, '', `#/${machine ?? 'hub'}/${view}`)
        if (!(await okToLeave())) return
        history.replaceState(null, '', there)
      }
      if (p.machine !== machine) switchMachine(p.machine); if (p.view !== view) setView(p.view)
    }
    window.addEventListener('popstate', h)
    return () => window.removeEventListener('popstate', h)
  }) // no deps: needs the latest switchMachine/view each time
  useEffect(() => {
    if (!machine) { setRemoteMe(null); return }
    let stop = false
    const tick = async () => { try { const m = await api.me(); if (!stop) { setRemoteMe(m); setRemoteErr('') } } catch (e) { if (!stop) setRemoteErr(e instanceof Error ? e.message : 'unreachable') } }
    tick()
    const t = setInterval(tick, listRate)
    return () => { stop = true; clearInterval(t) }
  }, [machine, listRate])

  async function create() {
    setCreating(true)
    try {
      const t = await api.createTerminal()
      await reload()
      setActive(t.id)
      setView('terminal')
      setDrawer(false)
    } catch (e) { toast(`new terminal — ${e instanceof Error ? e.message : 'failed'}`, 'err') }
    finally { setCreating(false) }
  }
  async function rename(t: Term) {
    const name = await askText('Rename terminal', t.name)
    if (name && name.trim() && name !== t.name) {
      try { await api.renameTerminal(t.id, name.trim()); await reload() } catch (e) { toast(`rename — ${e instanceof Error ? e.message : 'failed'}`, 'err') }
    }
  }
  async function close(t: Term) {
    if (t.running && !await askYes(`Close "${t.name}"? The shell will be hung up.`)) return
    try { await api.deleteTerminal(t.id); delete handles.current[t.id]; await reload() }
    catch (e) { toast(`close — ${e instanceof Error ? e.message : 'failed'}`, 'err') }
  }
  async function logout() { await api.logout(); onLoggedOut() }

  // Files → "open in terminal": type into the active shell (creating one if needed) and switch to it.
  async function runInTerminal(cmd: string) {
    let id = active
    if (!id || !terms.some((t) => t.id === id && t.running)) {
      try { const t = await api.createTerminal(); await reload(); id = t.id; setActive(t.id) } catch (e) { toast(`terminal — ${e instanceof Error ? e.message : 'failed'}`, 'err'); return }
    }
    setView('terminal'); setDrawer(false)
    const send = (tries: number) => { const h = handles.current[id!]; if (h) h.input(cmd + '\n'); else if (tries > 0) window.setTimeout(() => send(tries - 1), 100) }
    window.setTimeout(() => send(20), 50)
  }

  // Tab order is the user's, kept per machine in this browser; new terminals join at the end.
  const orderKey = `hamlab.termorder.${machine ?? 'hub'}`
  const [order, setOrder] = useState<string[]>([])
  useEffect(() => { try { setOrder(JSON.parse(localStorage.getItem(orderKey) ?? '[]')) } catch { setOrder([]) } }, [orderKey])
  const ordered = useMemo(() => [...terms].sort((a, b) => { const i = order.indexOf(a.id), j = order.indexOf(b.id); return (i < 0 ? 1e9 : i) - (j < 0 ? 1e9 : j) }), [terms, order])
  const moveTab = (id: string, before: string | null) => {
    const ids = ordered.map((t) => t.id).filter((x) => x !== id)
    const at = before ? ids.indexOf(before) : -1
    ids.splice(at < 0 ? ids.length : at, 0, id)
    setOrder(ids); localStorage.setItem(orderKey, JSON.stringify(ids))
  }
  // Alt+Shift+←/→ switches tabs, Alt+Shift+T opens one. Caught before xterm sees the keys.
  useEffect(() => {
    if (view !== 'terminal') return
    const h = (e: KeyboardEvent) => {
      if (!e.altKey || !e.shiftKey || e.ctrlKey || e.metaKey) return
      const dir = e.key === 'ArrowLeft' ? -1 : e.key === 'ArrowRight' ? 1 : 0
      if (dir && ordered.length > 1) { const i = ordered.findIndex((t) => t.id === active); setActive(ordered[(i + dir + ordered.length) % ordered.length].id) }
      else if (e.key.toLowerCase() === 't') create()
      else return
      e.preventDefault(); e.stopPropagation()
    }
    window.addEventListener('keydown', h, true)
    return () => window.removeEventListener('keydown', h, true)
  }) // no deps: needs the latest tabs each time

  const activeRef = useRef(active); activeRef.current = active
  const activeTerm = terms.find((t) => t.id === active)
  const termView = view === 'terminal'

  return (
    <div className={'app' + (drawer ? ' drawer-open' : '')}>
      <Toasts />
      <header className="header">
        <button className="icon-btn menu" onClick={() => setDrawer(!drawer)} aria-label="menu">☰</button>
        <span className="brand">Ham Lab</span>
        <span className="host">{me.user}@{me.host}</span>
        {machine && remoteErr && <span className="badge bad" title={remoteErr}>offline</span>}
        <span className="spacer" />
        <span className="stat" title="load average, 1 · 5 · 15 min">load {me.load}</span>
        <span className={'dot ' + (online && !remoteErr ? 'ok' : 'bad')} title={remoteErr ? `${title} unreachable` : online ? 'connected' : 'disconnected'} />
        <Power host={me.host} label={title} rebootNeeded={me.reboot_needed} />
        {hubMe.guest && <span className="badge guest" title={`this guest login expires ${new Date(hubMe.guest_until ?? '').toLocaleTimeString()}`}>guest · {fmtLeft(leftMs)}</span>}
        {hubMe.account && <span className="host account" title="signed in as">{hubMe.account}</span>}
        <Btn className="link" onClick={logout}>logout</Btn>
      </header>

      <div className="body">
        <Rail groups={machine ? GROUPS.filter((g) => !HUB_ONLY.includes(g.id as View)) : GROUPS} view={view} badges={{ alerts: firing, settings: hubMe.update_available ? 1 : 0 }}
          header={<MachineSwitcher hub={hubMe.host} hubAddr={hubMe.addr} current={machine} machines={machines} onChange={switchMachine} onManage={() => { setView('machines'); setDrawer(false) }} />}
          onView={async (id) => { if (id !== view && !(await okToLeave())) return; setView(id as View); setDrawer(false) }} />
        <div className="backdrop" onClick={() => setDrawer(false)} />

        <main className="main" key={machine ?? 'hub'}>
          <PageBoundary page={GROUPS.find((g) => g.id === view)?.label ?? view}>
          {view === 'settings' && <Settings me={hubMe} />}
          {view === 'users' && <Users me={hubMe} />}
          {view === 'kvm' && <KVM key={machine ?? 'hub'} machine={machine} title={title} />}
          {view === 'usage' && <Usage key={machine ?? ''} />}
          {view === 'machines' && <Machines hub={hubMe} onChanged={loadMachines} onOpen={(n) => { switchMachine(n); setView('procs') }} />}
          {view === 'widgets' && <Gallery />}
          {view === 'docker' && <Docker />}
          {view === 'alerts' && <Alerts machines={machines.map((m) => m.name)} titleOf={(n) => titleOf(n === hubMe.host ? null : n, machines, hubMe.host)} />}
          {view === 'procs' && <Top />}
          {view === 'services' && <Services />}
          {view === 'jobs' && <Jobs />}
          {view === 'updates' && <Updates />}
          {view === 'disks' && <Disks />}
          {view === 'hardware' && <Hardware />}
          {view === 'network' && <Network />}
          {view === 'vpn' && <VPN />}
          {view === 'zfs' && <ZFS />}
          {view === 'files' && <Files onOpenInTerminal={runInTerminal} />}
          </PageBoundary>
          {termView && <TermTabs terms={ordered} active={active} creating={creating}
            onSelect={setActive} onNew={create} onRename={rename} onClose={close} onMove={moveTab}
            onFocusTerm={() => window.setTimeout(() => { const id = activeRef.current; if (id) handles.current[id]?.armCtrl(false) }, 0)} />}
          {termView && terms.length === 0 && (
            <div className="center muted">
              <div>No terminals.</div>
              <Btn className="primary" busy={creating} onClick={create}>+ New Terminal</Btn>
            </div>
          )}
          {terms.map((t) => (
            <TerminalPane key={t.id} id={t.id} active={termView && t.id === active}
              register={(h) => { if (h) handles.current[t.id] = h; else delete handles.current[t.id] }}
              onStatus={(ok) => { if (t.id === active) setOnline(ok) }}
              onExit={reload} />
          ))}
        </main>
      </div>

      {termView && activeTerm && <KeyBar send={(s) => handles.current[activeTerm.id]?.input(s)}
        setCtrl={(v) => handles.current[activeTerm.id]?.armCtrl(v)} />}

      <footer className="footer">
        <span>{machine ? `${title} · ` : ''}{me.version.startsWith('v') ? me.version : 'v' + me.version}</span>
        <span>up {fmtUptime(me.uptime)}</span>
        <span className="spacer" />
        <span className="muted">{view === 'widgets' ? 'Widgets' : view === 'docker' ? 'Docker' : view === 'alerts' ? 'Alerts' : view === 'services' ? 'Services' : view === 'jobs' ? 'Jobs' : view === 'updates' ? 'Updates' : view === 'disks' ? 'Disks' : view === 'hardware' ? 'Hardware' : view === 'network' ? 'Network' : view === 'vpn' ? 'VPN' : view === 'zfs' ? 'ZFS' : view === 'usage' ? 'Usage' : view === 'files' ? 'Files' : view === 'procs' ? 'Processes' : view === 'machines' ? 'Machines' : view === 'kvm' ? 'KVM' : view === 'users' ? 'Users' : view === 'settings' ? 'Settings' : activeTerm ? activeTerm.name : ''}</span>
      </footer>
    </div>
  )
}