import { useEffect, useRef, useState } from 'react'
import type { User } from '../types'

function getInactivityMs(): number | undefined {
  if (window.matchMedia('(display-mode: standalone)').matches) return undefined
  const c = document.cookie.split(';').map(s => s.trim()).find(s => s.startsWith('hnf_inactivity_mins='))
  if (!c) return undefined
  const mins = parseInt(c.split('=')[1])
  return isNaN(mins) || mins <= 0 ? undefined : mins * 60 * 1000
}


interface Props {
  children: (user: User) => React.ReactNode
}

const inputStyle: React.CSSProperties = {
  background: 'var(--navy-dark)', border: '1px solid var(--surface-2)',
  borderRadius: '6px', color: 'var(--text)', padding: '0.625rem 0.75rem',
  fontSize: '1rem', width: '100%', outline: 'none',
}
const btnStyle: React.CSSProperties = {
  background: 'var(--hk-green)', color: '#fff', border: 'none',
  borderRadius: '6px', padding: '0.625rem', fontSize: '1rem',
  fontWeight: 600, marginTop: '0.25rem', width: '100%',
}

export function AuthGate({ children }: Props) {
  const [state, setState] = useState<'checking' | 'authed' | 'login'>('checking')
  const [user, setUser] = useState<User | null>(null)
  const [email, setEmail] = useState('')
  const [password, setPassword] = useState('')
  const [error, setError] = useState('')
  const [loading, setLoading] = useState(false)
  const timerRef = useRef<ReturnType<typeof setTimeout> | null>(null)

  useEffect(() => {
    fetch('/api/auth/verify?app=hk-planner', { credentials: 'include' })
      .then(async r => {
        if (r.ok) { setUser(await r.json()); setState('authed') }
        else setState('login')
      })
      .catch(() => setState('login'))
  }, [])

  useEffect(() => {
    const ms = getInactivityMs()
    if (state !== 'authed' || !ms) return

    async function forceLogout() {
      await fetch('/api/auth/logout', { method: 'POST', credentials: 'include' }).catch(() => {})
      setUser(null)
      setState('login')
    }

    function reset() {
      if (timerRef.current) clearTimeout(timerRef.current)
      timerRef.current = setTimeout(forceLogout, ms)
    }

    const events = ['mousemove', 'keydown', 'click', 'touchstart'] as const
    events.forEach(e => window.addEventListener(e, reset, { passive: true }))
    reset()

    return () => {
      if (timerRef.current) clearTimeout(timerRef.current)
      events.forEach(e => window.removeEventListener(e, reset))
    }
  }, [state])

  async function login(e: React.FormEvent) {
    e.preventDefault()
    setLoading(true)
    setError('')
    try {
      const res = await fetch('/api/auth/login', {
        method: 'POST', credentials: 'include',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ email, password }),
      })
      if (!res.ok) { setError('Invalid email or password'); return }
      const verify = await fetch('/api/auth/verify?app=hk-planner', { credentials: 'include' })
      if (verify.ok) { setUser(await verify.json()); setState('authed') }
      else setError("You don't have access to this app.")
    } catch {
      setError('Connection error — please try again')
    } finally {
      setLoading(false)
    }
  }

  if (state === 'checking') {
    return (
      <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'center', height: '100dvh' }}>
        <div style={{ color: 'var(--text-muted)' }}>Loading…</div>
      </div>
    )
  }

  if (state === 'login') {
    return (
      <div style={{
        display: 'flex', flexDirection: 'column', alignItems: 'center',
        justifyContent: 'center', height: '100dvh', padding: '1.5rem',
        background: 'var(--navy-dark)',
      }}>
        <div style={{
          background: 'var(--navy)', borderRadius: 'var(--radius)',
          padding: '2rem', width: '100%', maxWidth: '360px',
          border: '1px solid var(--surface-2)',
        }}>
          <h1 style={{ fontSize: '1.4rem', marginBottom: '0.25rem', color: '#74c69d' }}>
            HK Planner
          </h1>
          <p style={{ color: 'var(--text-muted)', fontSize: '0.875rem', marginBottom: '1.5rem' }}>
            {import.meta.env.VITE_HOTEL_NAME}
          </p>
          <form onSubmit={login} style={{ display: 'flex', flexDirection: 'column', gap: '0.75rem' }}>
            <input type="email" value={email} onChange={e => setEmail(e.target.value)}
              placeholder="Email" required autoComplete="email" style={inputStyle} />
            <input type="password" value={password} onChange={e => setPassword(e.target.value)}
              placeholder="Password" required autoComplete="current-password" style={inputStyle} />
            {error && <p style={{ color: '#f87171', fontSize: '0.875rem' }}>{error}</p>}
            <button type="submit" disabled={loading} style={btnStyle}>
              {loading ? 'Signing in…' : 'Sign in'}
            </button>
          </form>
        </div>
      </div>
    )
  }

  return <>{children(user!)}</>
}