import { useEffect, useState } from 'react'
import Creator from './Creator.jsx'
import Rules from './Rules.jsx'
import Maps from './Maps.jsx'
import Characters from './Characters.jsx'
import Presets from './Presets.jsx'
import Lobbies from './Lobbies.jsx'
import Login from './Login.jsx'
import Account from './Account.jsx'
import Editor from './Editor.jsx'
import { claimLegacy } from './legacy.js'

const useHash = () => {
  const [h, setH] = useState(window.location.hash.slice(1) || 'creator')
  useEffect(() => {
    const f = () => setH(window.location.hash.slice(1) || 'creator')
    window.addEventListener('hashchange', f)
    return () => window.removeEventListener('hashchange', f)
  }, [])
  return h
}

export default function App() {
  const hash = useHash()
  const [auth, setAuth] = useState(null) // null = checking, {user, registration_open}
  const [rules, setRules] = useState(null)
  const [error, setError] = useState('')
  // Used to load a saved character into the creator
  const [loadRequest, setLoadRequest] = useState(null)
  const [charName, setCharName] = useState('') // name of the character being worked on, shown in the nav

  // Ask the server who we are; any later 401 (session expired) sends us back to the login
  useEffect(() => {
    fetch('/api/auth/me').then((r) => r.json()).then(setAuth).catch(() => setError('Could not reach the server.'))
    const out = () => { setAuth((a) => ({ user: null, registration_open: a?.registration_open })); setRules(null) }
    window.addEventListener('aw-unauthorized', out)
    return () => window.removeEventListener('aw-unauthorized', out)
  }, [])

  const username = auth?.user?.username
  const loadRules = () => fetch('/api/rules').then((r) => r.json()).then(setRules).catch(() => setError('Could not load the rules.'))
  useEffect(() => {
    if (!username) return
    claimLegacy().finally(loadRules)
  }, [username]) // eslint-disable-line

  const logout = async () => {
    await fetch('/api/auth/logout', { method: 'POST' }).catch(() => {})
    window.location.hash = 'creator'
    setAuth({ user: null, registration_open: auth.registration_open }); setRules(null)
  }

  if (error) return <main><p className="warn">{error}</p></main>
  if (!auth) return <main><p className="muted">Loading …</p></main>
  if (!auth.user) return <main><Login registrationOpen={auth.registration_open} onDone={(u) => setAuth({ ...auth, user: u })} /></main>

  const page = hash.split('/')[0]
  const nav = [['creator', charName ? `Character: ${charName}` : 'Character'], ['rules', 'Rules'], ['presets', 'Presets'], ['maps', 'Maps'], ['characters', 'My characters'], ['lobbies', 'Lobbies'], ...(auth.user.admin ? [['editor', 'Editor']] : [])]

  return (
    <>
      <header className="top">
        <a className="brand" href="#creator">
          <span className="brand-mark" aria-hidden="true" />
          <span>Arcane Wasteland</span>
        </a>
        <nav>
          {nav.map(([id, label]) => (
            <a key={id} href={`#${id}`} className={`${page === id ? 'active' : ''} ${id === 'creator' ? 'navchar' : ''}`}>{label}</a>
          ))}
          <a href="#account" className={page === 'account' ? 'active' : ''} title="Account">{username}</a>
        </nav>
      </header>
      <main>
        {!rules && <p className="muted">Loading rules …</p>}
        {rules && page === 'creator' && <Creator rules={rules} user={username} loadRequest={loadRequest} clearLoad={() => setLoadRequest(null)} onName={setCharName} />}
        {rules && page === 'rules' && <Rules rules={rules} section={hash.split('/')[1]} />}
        {rules && page === 'presets' && <Presets rules={rules} reload={loadRules} />}
        {page === 'maps' && <Maps />}
        {rules && page === 'characters' && (
          <Characters onOpen={(entry) => { setLoadRequest(entry); window.location.hash = 'creator' }}
            onNew={() => { setLoadRequest({ new: true }); window.location.hash = 'creator' }} />
        )}
        {rules && page === 'lobbies' && (
          <Lobbies section={hash.split('/')[1]} rules={rules} user={username} onOpen={(entry) => { setLoadRequest(entry); window.location.hash = 'creator' }} />
        )}
        {rules && page === 'editor' && auth.user.admin && <Editor rules={rules} onReload={loadRules} />}
        {page === 'account' && <Account user={username} onLogout={logout} />}
      </main>
    </>
  )
}