import { useAuth } from '../contexts/AuthContext'
import { Link, useNavigate } from 'react-router-dom'
import { useState, useRef, useEffect } from 'react'
import { createEntry, updateUserProfile } from '../lib/api'
import { encryptEntry } from '../lib/crypto'
import BottomNav from '../components/BottomNav'
import WelcomeModal from '../components/WelcomeModal'
import { SaveBookAnimation } from '../components/SaveBookAnimation'
import { useOnboardingTour } from '../hooks/useOnboardingTour'
import { PageLoader } from '../components/PageLoader'

const AFFIRMATIONS = [
  'You showed up for yourself today 🌱',
  'Another moment beautifully captured ✨',
  'Gratitude logged. Keep growing 🌿',
  'Small moments, big growth 🍃',
  "You're building something beautiful 💚",
  'One more grateful moment preserved 🌸',
  'Your thoughts are safe and stored 🔒',
]

const SAVE_LEAVES = [
  { left: -80, dx: -30, rot: -25, delay: 0.0,  emoji: '🌱' },
  { left: -45, dx: -12, rot:  15, delay: 0.08, emoji: '🌿' },
  { left: -15, dx: -22, rot: -10, delay: 0.04, emoji: '🌱' },
  { left:   8, dx:  18, rot:  20, delay: 0.12, emoji: '🍃' },
  { left:  38, dx:  27, rot: -18, delay: 0.06, emoji: '🌿' },
  { left:  68, dx:  38, rot:  12, delay: 0.18, emoji: '🌱' },
  { left: -62, dx: -33, rot:  28, delay: 0.22, emoji: '🍃' },
  { left:  25, dx:  15, rot: -22, delay: 0.28, emoji: '🌿' },
]

export default function HomePage() {
  const { user, userId, mongoUser, secretKey, loading } = useAuth()
  const navigate = useNavigate()
  const [entry, setEntry] = useState('')
  const [title, setTitle] = useState('')
  const [phase, setPhase] = useState<'idle' | 'saving' | 'book' | 'celebrate'>('idle')
  const [affirmation, setAffirmation] = useState('')
  const [message, setMessage] = useState<{ type: 'error'; text: string } | null>(null)
  const [showWelcome, setShowWelcome] = useState(false)

  const titleInputRef = useRef<HTMLInputElement>(null)
  const contentTextareaRef = useRef<HTMLTextAreaElement>(null)

  const { startTour, isTourActive } = useOnboardingTour()

  // Check if onboarding should be shown after login
  useEffect(() => {
    if (!loading && user && userId && mongoUser && !mongoUser.tutorial) {
      setShowWelcome(true)
    }
  }, [loading, user, userId, mongoUser])

  // On-demand tour triggered from Settings (no DB read/write)
  useEffect(() => {
    if (!loading && user && localStorage.getItem('gj-force-tour') === 'true') {
      localStorage.removeItem('gj-force-tour')
      setTimeout(() => startTour(), 150)
    }
  }, [loading, user, startTour])

  async function markTutorialDone() {
    if (!user || !userId) return
    const token = await user.getIdToken()
    updateUserProfile(userId, { tutorial: true }, token).catch(console.error)
  }

  const handleStartTour = () => {
    setShowWelcome(false)
    markTutorialDone()
    startTour()
  }

  const handleSkipTour = () => {
    setShowWelcome(false)
    markTutorialDone()
  }

  if (loading) {
    return <PageLoader />
  }

  if (!user) {
    return (
      <div className="home-page" style={{ alignItems: 'center', justifyContent: 'center', gap: '1rem' }}>
        <h1 style={{ fontFamily: '"Sniglet", system-ui', color: 'var(--color-text)' }}>Grateful Journal</h1>
        <p style={{ color: 'var(--color-text-muted)' }}>Sign in to start your journal.</p>
        <Link to="/" className="home-login-link">Go to login</Link>
      </div>
    )
  }

  // Format date: "THURSDAY, OCT 24"
  const today = new Date()
  const dateString = today
    .toLocaleDateString('en-US', { weekday: 'long', month: 'short', day: 'numeric' })
    .toUpperCase()

  const handleBookDone = () => {
    setPhase('celebrate')
    setTimeout(() => navigate('/history'), 2500)
  }

  const handleTitleKeyDown = (e: React.KeyboardEvent<HTMLInputElement>) => {
    if (e.key === 'Enter' && title.trim()) {
      e.preventDefault()
      contentTextareaRef.current?.focus()
    }
  }

  const handleWrite = async () => {
    if (!userId || !title.trim() || !entry.trim()) {
      setMessage({ type: 'error', text: 'Please add a title and entry content' })
      return
    }

    if (!secretKey) {
      setMessage({ type: 'error', text: 'Encryption key not available. Please log in again.' })
      return
    }

    setPhase('saving')
    setMessage(null)

    try {
      const token = await user.getIdToken()

      // Combine title and content for encryption
      const contentToEncrypt = `${title.trim()}\n\n${entry.trim()}`

      // Encrypt the entry with master key
      const { ciphertext, nonce } = await encryptEntry(
        contentToEncrypt,
        secretKey
      )

      // Send encrypted data to backend
      // Note: title and content are null for encrypted entries
      await createEntry(
        userId,
        {
          title: undefined,
          content: undefined,
          isPublic: false,
          encryption: {
            encrypted: true,
            ciphertext,
            nonce,
            algorithm: 'XSalsa20-Poly1305',
          },
        },
        token
      )

      setTitle('')
      setEntry('')
      setAffirmation(AFFIRMATIONS[Math.floor(Math.random() * AFFIRMATIONS.length)])
      setPhase('book')
    } catch (error) {
      const errorMessage = error instanceof Error ? error.message : 'Failed to save entry'
      setMessage({ type: 'error', text: errorMessage })
      setPhase('idle')
    }
  }

  return (
    <div className="home-page">
      {showWelcome && (
        <WelcomeModal onStart={handleStartTour} onSkip={handleSkipTour} />
      )}
      <main className="journal-container">
        <div className="journal-card">
          <div className="journal-date">{dateString}</div>

          <h2 className="journal-prompt">What are you grateful for today?</h2>

          <div className="journal-writing-area">
            <input
              type="text"
              id="tour-title-input"
              className="journal-title-input"
              placeholder="Title your thoughts..."
              value={title}
              onChange={(e) => setTitle(e.target.value)}
              onKeyDown={handleTitleKeyDown}
              enterKeyHint="next"
              ref={titleInputRef}
              disabled={phase !== 'idle' || isTourActive}
            />
            <textarea
              id="tour-content-textarea"
              className="journal-entry-textarea"
              placeholder="Start writing your entry here..."
              value={entry}
              onChange={(e) => setEntry(e.target.value)}
              enterKeyHint="enter"
              ref={contentTextareaRef}
              disabled={phase !== 'idle' || isTourActive}
            />
          </div>

          {message && (
            <div className="alert-msg alert-msg--error" style={{ marginTop: '1rem' }}>
              {message.text}
            </div>
          )}

          <div style={{ marginTop: '1.5rem', position: 'relative' }}>
            {phase === 'celebrate' && (
              <>
                <div className="save-leaves" aria-hidden>
                  {SAVE_LEAVES.map((leaf, i) => (
                    <span
                      key={i}
                      className="save-leaf"
                      style={{
                        left: `calc(50% + ${leaf.left}px)`,
                        animationDelay: `${leaf.delay}s`,
                        '--leaf-dx': `${leaf.dx}px`,
                        '--leaf-rot': `${leaf.rot}deg`,
                      } as React.CSSProperties}
                    >
                      {leaf.emoji}
                    </span>
                  ))}
                </div>
                <div className="save-inline-quote" role="status" aria-live="polite">
                  {affirmation}
                </div>
              </>
            )}
            {phase !== 'celebrate' && (
              <button
                id="tour-save-btn"
                className="journal-write-btn"
                onClick={handleWrite}
                disabled={phase !== 'idle' || isTourActive || !title.trim() || !entry.trim()}
              >
                {phase === 'saving' ? 'Saving...' : 'Save Entry'}
              </button>
            )}
          </div>

        </div>
      </main>

      {phase === 'book' && <SaveBookAnimation onDone={handleBookDone} />}

      <BottomNav />
    </div>
  )
}

