import { useAuth } from '../contexts/AuthContext'
import { useNavigate } from 'react-router-dom'
import { useEffect, useState } from 'react'
import { GoogleSignInButton } from '../components/GoogleSignInButton'
import { TreeAnimation } from '../components/TreeAnimation'
import { PageLoader } from '../components/PageLoader'
import { usePageMeta } from '../hooks/usePageMeta'

export default function LoginPage() {
  usePageMeta({
    title: 'Private Gratitude Journal App | Grateful Journal',
    description: 'A private, end-to-end encrypted gratitude journal. No feeds, no noise — just you and your thoughts. Grow your gratitude one moment at a time.',
    canonical: 'https://gratefuljournal.online/',
  })
  const { user, loading, signInWithGoogle, authError } = useAuth()
  const navigate = useNavigate()
  const [signingIn, setSigningIn] = useState(false)
  const [error, setError] = useState<string | null>(null)

  useEffect(() => {
    if (loading) return
    if (user) {
      import('./HomePage').then(() => navigate('/write', { replace: true }))
    }
  }, [user, loading, navigate])

  async function handleGoogleSignIn() {
    setError(null)
    setSigningIn(true)
    try {
      await signInWithGoogle()
    } catch (e) {
      setError(e instanceof Error ? e.message : 'Sign-in failed')
    } finally {
      setSigningIn(false)
    }
  }

  // Keep showing the loader until the navigate effect fires.
  // Without the `user` check here, the login form flashes for one frame
  // between loading→false and the useEffect redirect.
  if (loading || signingIn || user) {
    return <PageLoader />
  }

  return (
    <div className="lp">
      {/* ── Left: animated tree hero ─────────────────── */}
      <div className="lp__hero">
        <TreeAnimation />
        <div className="lp__hero-words">
          <p className="lp__quote">Grow your gratitude.</p>
          <p className="lp__subquote">One small moment at a time.</p>
        </div>
      </div>

      {/* ── Right: login panel ───────────────────────── */}
      <div className="lp__panel">
        <div className="lp__form">
          <div className="lp__brand">
            <span className="lp__icon" aria-hidden>🌱</span>
            <h1 className="lp__title">Grateful Journal</h1>
          </div>

          <p className="lp__tagline">
            A private space for gratitude and reflection.<br />
            No feeds. No noise. Just you and your thoughts.
          </p>

          <div className="lp__actions">
            <GoogleSignInButton loading={signingIn} onClick={handleGoogleSignIn} />
            <p className="lp__privacy">🔒 End-to-end encrypted. We never read your entries.</p>
            {(error || authError) && (
              <p className="lp__error" role="alert">{error || authError}</p>
            )}
          </div>
        </div>
      </div>
    </div>
  )
}
