import { useEffect, useRef, useState } from 'react'
import { useClerk, useOrganization, useOrganizationList, useUser } from '@clerk/react'
import { useQuery } from '@tanstack/react-query'
import { NavLink, Outlet, useLocation } from 'react-router-dom'
import { LANGS, locale, setLang, t, useLang, type Key } from '../i18n'
import { workspaceCredits } from '../api/engine'
import { Brand, Icon, type IconName } from './Icon'
import { Toaster } from './Toast'

// Learning Studio (learning-lab/frontend); both apps share one Clerk instance, so the user stays signed in.
const STUDIO_URL: string = import.meta.env.VITE_STUDIO_URL

// The Production dashboard shows what Express is making; the four settings doors run it:
// feed the Brain, give an instruction, watch the schedule, collect results.
export const NAV_GROUPS: { label: Key; items: { to: string; label: Key; icon: IconName }[] }[] = [
  { label: 'nav.dashboard', items: [{ to: '/production', label: 'nav.production', icon: 'chart' }] },
  {
    label: 'nav.settings',
    items: [
      { to: '/upload', label: 'nav.brain', icon: 'brain' },
      { to: '/brain', label: 'nav.instruction', icon: 'spark' },
      { to: '/schedule', label: 'nav.schedule', icon: 'calendar' },
      { to: '/results', label: 'nav.results', icon: 'layers' },
    ],
  },
]
export const NAV = NAV_GROUPS.flatMap(g => g.items)

export function LanguageSwitch() {
  const lang = useLang()
  return (
    <div className="lang-switch" role="group" aria-label={t('layout.language')}>
      {LANGS.map(l => (
        <button key={l.code} type="button" aria-pressed={lang === l.code} className={lang === l.code ? 'active' : undefined}
          onClick={() => setLang(l.code)}>{l.label}</button>
      ))}
    </div>
  )
}

// The four steps of Express, from the mockup's "how it works" guide.
const HELP_STEPS: { icon: IconName; title: Key; body: Key }[] = [
  { icon: 'brain', title: 'help.brainTitle', body: 'help.brainBody' },
  { icon: 'spark', title: 'help.instructionTitle', body: 'help.instructionBody' },
  { icon: 'calendar', title: 'help.scheduleTitle', body: 'help.scheduleBody' },
  { icon: 'layers', title: 'help.resultsTitle', body: 'help.resultsBody' },
]

function HelpDialog({ onClose }: { onClose: () => void }) {
  const ref = useRef<HTMLDialogElement>(null)
  // Same pattern as the Results preview: open once, let the dialog's own close event unmount it.
  useEffect(() => { if (ref.current && !ref.current.open) ref.current.showModal() }, [])
  return (
    <dialog ref={ref} aria-labelledby="help-title" onClose={onClose} onClick={e => e.target === ref.current && ref.current.close()}>
      <div className="modal-head">
        <div><h2 id="help-title">{t('help.title')}</h2><p>{t('help.subtitle')}</p></div>
        <button className="icon-btn" aria-label={t('res.close')} onClick={() => ref.current?.close()}><Icon name="close" /></button>
      </div>
      <div className="modal-body">
        <div className="help-steps">
          {HELP_STEPS.map((s, i) => (
            <div key={s.title} className="help-step"><span>{i + 1}</span><div><h3>{t(s.title)}</h3><p>{t(s.body)}</p></div></div>
          ))}
        </div>
        <div className="spacer" />
        <div className="inline-note"><Icon name="info" />{t('help.note')}</div>
      </div>
      <div className="modal-foot"><button className="btn primary" onClick={() => ref.current?.close()}>{t('help.done')}<Icon name="arrow-right" /></button></div>
    </dialog>
  )
}

// Polled because agents and schedules also spend credits outside this tab; main.tsx refreshes it after every mutation.
function CreditBalance() {
  const credits = useQuery({ queryKey: ['credits'], queryFn: workspaceCredits, refetchInterval: 30_000 })
  if (credits.data == null) return null
  return (
    <span className="credit-pill" title={t('layout.creditsTitle')}>
      <Icon name="coin" />{t('common.credits', { n: credits.data.toLocaleString(locale()) })}
    </span>
  )
}

// The Learning space card switches the active organization. AuthGate keys the pages by orgId and
// clears the query cache, so Brain, schedules, results and credits all reload for the new one.
function OrgSwitcher() {
  const [open, setOpen] = useState(false)
  const ref = useRef<HTMLDivElement>(null)
  const { organization } = useOrganization()
  const { setActive, userMemberships } = useOrganizationList({ userMemberships: { infinite: true } })

  useEffect(() => {
    if (!open) return
    const onClick = (e: MouseEvent) => { if (!ref.current?.contains(e.target as Node)) setOpen(false) }
    const onKey = (e: KeyboardEvent) => { if (e.key === 'Escape') setOpen(false) }
    document.addEventListener('mousedown', onClick)
    document.addEventListener('keydown', onKey)
    return () => { document.removeEventListener('mousedown', onClick); document.removeEventListener('keydown', onKey) }
  }, [open])

  const choose = (id: string) => {
    setOpen(false)
    if (id !== organization?.id) void setActive?.({ organization: id })
  }

  return (
    <div className="workspace-switch" ref={ref}>
      <button type="button" className="workspace" aria-haspopup="listbox" aria-expanded={open}
        title={t('layout.switchOrg')} onClick={() => setOpen(o => !o)}>
        <span className="workspace-icon">{(organization?.name || 'L').charAt(0).toUpperCase()}</span>
        <div>{t('layout.learningSpace')}<small>{organization?.name ?? '-'}</small></div>
        <Icon name="chevron-updown" />
      </button>
      {open && (
        <ul className="workspace-menu" role="listbox" aria-label={t('layout.switchOrg')}>
          {userMemberships.data?.map(({ organization: org }) => (
            <li key={org.id} role="option" aria-selected={org.id === organization?.id}>
              <button type="button" onClick={() => choose(org.id)}>
                <span className="workspace-icon">{org.name.charAt(0).toUpperCase()}</span>
                <span>{org.name}</span>
                {org.id === organization?.id && <Icon name="check" />}
              </button>
            </li>
          ))}
        </ul>
      )}
    </div>
  )
}

export function AppLayout() {
  useLang()
  const [help, setHelp] = useState(false)
  const { user } = useUser()
  const { signOut } = useClerk()
  const { pathname } = useLocation()
  const current = NAV.find(n => pathname.startsWith(n.to))
  // Nav groups stay closed unless they hold the current page; a click on the label overrides that until the next route.
  const [toggled, setToggled] = useState<Partial<Record<Key, boolean>>>({})
  useEffect(() => setToggled({}), [pathname])
  const name = user?.fullName || user?.primaryEmailAddress?.emailAddress || '-'

  return (
    <div className="app">
      <aside className="sidebar">
        <NavLink to="/production"><Brand /></NavLink>
        <OrgSwitcher />
        <nav aria-label={t('layout.mainNav')}>
          {NAV_GROUPS.map(g => {
            const open = toggled[g.label] ?? g.items.some(n => pathname.startsWith(n.to))
            return [
              <button key={g.label} type="button" className="nav-label" aria-expanded={open} aria-controls={`nav-${g.label}`}
                onClick={() => setToggled(s => ({ ...s, [g.label]: !open }))}>
                {t(g.label)}<Icon name="chevron-down" />
              </button>,
              <div key={`${g.label}-items`} id={`nav-${g.label}`} className={open ? 'nav-items' : 'nav-items closed'}>
                {g.items.map(n => (
                  <NavLink key={n.to} to={n.to} className={({ isActive }) => (isActive ? 'active' : undefined)}>
                    <Icon name={n.icon} />{t(n.label)}
                  </NavLink>
                ))}
              </div>,
            ]
          })}
        </nav>
        <div className="sidebar-help">
          <Icon name="info" />
          <b>{t('help.boxTitle')}</b>
          <p>{t('help.boxBody')}</p>
          <button type="button" onClick={() => setHelp(true)}>{t('help.open')} <Icon name="arrow-right" /></button>
        </div>
        <div className="profile">
          <span className="avatar">{name.charAt(0).toUpperCase()}</span>
          <div><b>{name}</b><small>{user?.primaryEmailAddress?.emailAddress}</small></div>
          <button className="icon-btn" aria-label={t('layout.signOut')} onClick={() => signOut({ redirectUrl: '/' })}><Icon name="logout" /></button>
        </div>
      </aside>
      <div className="workspace-main">
        <header className="topbar">
          <div className="breadcrumb">{t('layout.breadcrumb')} <span>/</span> <b>{current ? t(current.label) : ''}</b></div>
          <div className="topbar-right">
            <span className="demo-indicator"><i></i> {t('layout.engine')}</span>
            <CreditBalance />
            <a className="studio-link" href={STUDIO_URL}><Icon name="external" />{t('layout.toStudio')}</a>
            <LanguageSwitch />
          </div>
        </header>
        {/* Keyed by route so each page plays the fade-in from theme.css. */}
        <main tabIndex={-1} key={pathname}><Outlet /></main>
        <footer className="app-footer">Learning Lab Express <span>by Bawana</span><span>{t('layout.footer')}</span></footer>
      </div>
      {help && <HelpDialog onClose={() => setHelp(false)} />}
      <Toaster />
    </div>
  )
}