import { useState, useCallback } from 'react'
import { useParams, useNavigate, useSearchParams, Link } from 'react-router'
import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query'
import { motion } from 'framer-motion'
import toast from 'react-hot-toast'
import { ArrowLeft, Heart, Clock, Users, ChefHat, ShoppingCart, Pencil, Minus, Plus, Send, Trash2 } from 'lucide-react'
import { Dices } from 'lucide-react'
import { fetchRecipe, toggleFavorite, fetchRandomRecipe } from '../api/recipes'
import { addCustomItem } from '../api/shopping'
import { IngredientPickerModal } from '../components/recipe/IngredientPickerModal'
import { createNote, deleteNote } from '../api/notes'
import { Badge } from '../components/ui/Badge'
import { Skeleton } from '../components/ui/Skeleton'

const gradients = ['from-primary/40 to-secondary/40', 'from-secondary/40 to-sage/40']

export function RecipePage() {
  const { slug } = useParams<{ slug: string }>()
  const navigate = useNavigate()
  const [searchParams] = useSearchParams()
  const fromRandom = searchParams.get('from') === 'random'
  const randomType = searchParams.get('type') // 'cook' or 'bake'
  const qc = useQueryClient()
  const [servingScale, setServingScale] = useState<number | null>(null)
  const [noteText, setNoteText] = useState('')
  const [rerolling, setRerolling] = useState(false)
  const [showIngredientPicker, setShowIngredientPicker] = useState(false)

  const COOK_CATEGORIES = ['mittag', 'abend', 'fruehstueck']
  const BAKE_CATEGORIES = ['backen', 'torten', 'desserts']

  const handleReroll = useCallback(async () => {
    setRerolling(true)
    try {
      const categories = randomType === 'bake' ? BAKE_CATEGORIES : randomType === 'cook' ? COOK_CATEGORIES : undefined
      const r = await fetchRandomRecipe(categories)
      if (r?.slug) navigate(`/recipe/${r.slug}?from=random${randomType ? `&type=${randomType}` : ''}`, { replace: true })
    } catch { /* ignore */ }
    setRerolling(false)
  }, [navigate, randomType])

  const { data: recipe, isLoading } = useQuery({
    queryKey: ['recipe', slug],
    queryFn: () => fetchRecipe(slug!),
    enabled: !!slug,
  })

  const favMutation = useMutation({
    mutationFn: () => toggleFavorite(recipe!.id),
    onSuccess: () => {
      qc.invalidateQueries({ queryKey: ['recipe', slug] })
      qc.invalidateQueries({ queryKey: ['recipes'] })
    },
    onError: () => toast.error('Fehler beim Ändern des Favoriten-Status'),
  })

  const [addingToShopping, setAddingToShopping] = useState(false)

  const handleAddToShopping = async (selected: { name: string; amount?: number; unit?: string }[]) => {
    setAddingToShopping(true)
    try {
      let count = 0
      for (const item of selected) {
        await addCustomItem({ name: item.name, amount: item.amount, unit: item.unit })
        count++
      }
      qc.invalidateQueries({ queryKey: ['shopping'] })
      toast.success(`${count} Zutaten zur Einkaufsliste hinzugefügt!`)
      setShowIngredientPicker(false)
    } catch {
      toast.error('Fehler beim Hinzufügen zur Einkaufsliste')
    } finally {
      setAddingToShopping(false)
    }
  }

  const noteMutation = useMutation({
    mutationFn: (content: string) => createNote(recipe!.id, content),
    onSuccess: () => {
      qc.invalidateQueries({ queryKey: ['recipe', slug] })
      setNoteText('')
      toast.success('Notiz gespeichert! 📝')
    },
    onError: () => toast.error('Fehler beim Speichern der Notiz'),
  })

  const deleteNoteMutation = useMutation({
    mutationFn: (noteId: string) => deleteNote(noteId),
    onSuccess: () => {
      qc.invalidateQueries({ queryKey: ['recipe', slug] })
      toast.success('Notiz gelöscht')
    },
  })

  if (isLoading) {
    return (
      <div className="p-4 space-y-4">
        <Skeleton className="w-full h-64" />
        <Skeleton className="h-8 w-3/4" />
        <Skeleton className="h-4 w-1/2" />
      </div>
    )
  }

  if (!recipe) return <div className="p-4">Rezept nicht gefunden.</div>

  const originalServings = recipe.servings || 4
  const currentServings = servingScale ?? originalServings
  const scaleFactor = currentServings / originalServings
  const totalTime = recipe.total_time_min || ((recipe.prep_time_min || 0) + (recipe.cook_time_min || 0))
  const gradient = gradients[recipe.title.length % gradients.length]

  const scaleAmount = (amount?: number) => {
    if (!amount) return ''
    const scaled = amount * scaleFactor
    // Nice formatting
    if (scaled === Math.round(scaled)) return String(Math.round(scaled))
    return scaled.toFixed(1).replace(/\.0$/, '')
  }

  // Group ingredients
  const ingredientGroups = (recipe.ingredients || []).reduce<Record<string, typeof recipe.ingredients>>((acc, ing) => {
    const group = ing.group_name || 'Zutaten'
    if (!acc[group]) acc[group] = []
    acc[group]!.push(ing)
    return acc
  }, {})

  return (
    <motion.div initial={{ opacity: 0 }} animate={{ opacity: 1 }} transition={{ duration: 0.3 }}>
      {/* Hero */}
      <div className="relative">
        {recipe.image_url ? (
          <img src={recipe.image_url} alt={recipe.title} className="w-full h-64 object-cover" />
        ) : (
          <div className={`w-full h-64 bg-gradient-to-br ${gradient} flex items-center justify-center`}>
            <span className="text-6xl">🍰</span>
          </div>
        )}
        <button onClick={() => navigate(-1)} className="absolute top-4 left-4 bg-surface/80 backdrop-blur-sm rounded-full p-2 min-w-[44px] min-h-[44px] flex items-center justify-center">
          <ArrowLeft size={20} className="text-espresso" />
        </button>
        <div className="absolute top-4 right-4 flex gap-2">
          <Link to={`/recipe/${recipe.slug}/edit`} className="bg-surface/80 backdrop-blur-sm rounded-full p-2 min-w-[44px] min-h-[44px] flex items-center justify-center">
            <Pencil size={20} className="text-espresso" />
          </Link>
          <button onClick={() => favMutation.mutate()} className="bg-surface/80 backdrop-blur-sm rounded-full p-2 min-w-[44px] min-h-[44px] flex items-center justify-center active:scale-125 transition-transform">
            <Heart size={22} className={recipe.is_favorite ? 'fill-primary text-primary' : 'text-espresso'} />
          </button>
        </div>
      </div>

      <div className="p-4 space-y-6">
        {/* Title & Meta */}
        <div>
          <h1 className="font-display text-2xl sm:text-3xl text-espresso">{recipe.title}</h1>
          <div className="flex flex-wrap items-center gap-2 mt-2">
            {recipe.category_name ? (
              <Badge>{recipe.category_name}</Badge>
            ) : (
              <Badge>🍽️ Allgemein</Badge>
            )}
            {totalTime > 0 && (
              <span className="flex items-center gap-1 text-warm-grey text-sm"><Clock size={14} /> {totalTime} min</span>
            )}
            {recipe.difficulty && (
              <span className="flex items-center gap-1 text-warm-grey text-sm"><ChefHat size={14} /> {recipe.difficulty}</span>
            )}
          </div>
          {recipe.description && <p className="text-warm-grey mt-2 text-sm">{recipe.description}</p>}
        </div>

        {/* Tags */}
        {recipe.tags && recipe.tags.length > 0 && (
          <div className="flex flex-wrap gap-1">
            {recipe.tags.map((tag) => (
              <span key={tag} className="text-xs bg-sand/50 text-warm-grey px-2 py-0.5 rounded-full">#{tag}</span>
            ))}
          </div>
        )}

        {/* Serving Calculator */}
        <div className="bg-primary-light/30 rounded-2xl p-4">
          <div className="flex items-center justify-between">
            <span className="flex items-center gap-2 text-sm font-medium text-espresso">
              <Users size={16} /> Portionen
            </span>
            <div className="flex items-center gap-3">
              <button
                onClick={() => setServingScale(Math.max(1, currentServings - 1))}
                className="w-9 h-9 rounded-full bg-surface border border-sand flex items-center justify-center text-espresso active:bg-sand transition-colors"
              >
                <Minus size={16} />
              </button>
              <span className="font-display text-xl text-espresso min-w-[2ch] text-center">{currentServings}</span>
              <button
                onClick={() => setServingScale(currentServings + 1)}
                className="w-9 h-9 rounded-full bg-surface border border-sand flex items-center justify-center text-espresso active:bg-sand transition-colors"
              >
                <Plus size={16} />
              </button>
            </div>
          </div>
          {servingScale !== null && servingScale !== originalServings && (
            <button
              onClick={() => setServingScale(null)}
              className="text-xs text-primary mt-2 underline"
            >
              Original ({originalServings}) zurücksetzen
            </button>
          )}
        </div>

        {/* Ingredients */}
        {Object.keys(ingredientGroups).length > 0 && (
          <div>
            <h2 className="font-display text-lg text-espresso mb-3">Zutaten</h2>
            {Object.entries(ingredientGroups).map(([group, items]) => (
              <div key={group} className="mb-3">
                {Object.keys(ingredientGroups).length > 1 && (
                  <h3 className="font-semibold text-sm text-warm-grey mb-1">{group}</h3>
                )}
                <ul className="space-y-1">
                  {items!.map((ing, i) => (
                    <motion.li
                      key={i}
                      className="flex gap-2 text-sm sm:text-base text-espresso py-1 border-b border-sand/50"
                      initial={{ opacity: 0, x: -10 }}
                      animate={{ opacity: 1, x: 0 }}
                      transition={{ delay: i * 0.03 }}
                    >
                      <span className="text-warm-grey min-w-[60px]">
                        {ing.amount ? `${scaleAmount(ing.amount)} ${ing.unit || ''}`.trim() : ''}
                      </span>
                      <span>{ing.name}</span>
                    </motion.li>
                  ))}
                </ul>
              </div>
            ))}
          </div>
        )}

        {/* Add to shopping list */}
        {recipe.ingredients && recipe.ingredients.length > 0 && (
          <>
            <button
              onClick={() => setShowIngredientPicker(true)}
              className="w-full flex items-center justify-center gap-2 bg-secondary text-white px-4 py-3 rounded-xl font-medium transition-colors hover:bg-secondary/90 min-h-[44px]"
            >
              <ShoppingCart size={18} />
              🛒 Zur Einkaufsliste
            </button>
            <IngredientPickerModal
              open={showIngredientPicker}
              onClose={() => setShowIngredientPicker(false)}
              ingredients={recipe.ingredients.map((ing) => ({
                name: ing.name,
                amount: ing.amount,
                unit: ing.unit,
              }))}
              onSubmit={handleAddToShopping}
              loading={addingToShopping}
            />
          </>
        )}

        {/* Steps */}
        {recipe.steps && recipe.steps.length > 0 && (
          <div>
            <h2 className="font-display text-lg text-espresso mb-3">Zubereitung</h2>
            <ol className="space-y-4">
              {recipe.steps.map((step, i) => (
                <motion.li
                  key={i}
                  className="flex gap-3"
                  initial={{ opacity: 0, y: 10 }}
                  animate={{ opacity: 1, y: 0 }}
                  transition={{ delay: i * 0.05 }}
                >
                  <span className="flex-shrink-0 w-7 h-7 rounded-full bg-primary text-white text-sm flex items-center justify-center font-medium">
                    {step.step_number || i + 1}
                  </span>
                  <div className="text-sm sm:text-base text-espresso pt-1">
                    <p>{step.instruction}</p>
                    {step.timer_minutes && (
                      <span className="inline-flex items-center gap-1 mt-1 text-xs text-primary">
                        <Clock size={12} /> {step.timer_label || 'Timer'}: {step.timer_minutes} min
                      </span>
                    )}
                  </div>
                </motion.li>
              ))}
            </ol>
          </div>
        )}

        {/* Notes */}
        <div>
          <h2 className="font-display text-lg text-espresso mb-3">Notizen</h2>

          {/* Existing notes */}
          {recipe.notes && recipe.notes.length > 0 && (
            <div className="space-y-2 mb-3">
              {recipe.notes.map((note) => (
                <motion.div
                  key={note.id}
                  className="bg-primary-light/30 rounded-xl p-3 text-sm text-espresso flex items-start gap-2"
                  initial={{ opacity: 0, scale: 0.95 }}
                  animate={{ opacity: 1, scale: 1 }}
                >
                  <span className="flex-1">📝 {note.content}</span>
                  <button
                    onClick={() => deleteNoteMutation.mutate(note.id)}
                    className="text-warm-grey hover:text-berry p-1 flex-shrink-0"
                  >
                    <Trash2 size={14} />
                  </button>
                </motion.div>
              ))}
            </div>
          )}

          {/* Add note */}
          <div className="flex gap-2">
            <input
              type="text"
              value={noteText}
              onChange={(e) => setNoteText(e.target.value)}
              onKeyDown={(e) => { if (e.key === 'Enter' && noteText.trim()) noteMutation.mutate(noteText.trim()) }}
              placeholder="Notiz hinzufügen..."
              className="flex-1 bg-surface border border-sand rounded-xl px-4 py-3 text-sm text-espresso placeholder:text-warm-grey/50 focus:outline-none focus:ring-2 focus:ring-primary/30 min-h-[44px]"
            />
            <button
              onClick={() => noteText.trim() && noteMutation.mutate(noteText.trim())}
              disabled={!noteText.trim() || noteMutation.isPending}
              className="bg-primary text-white rounded-xl px-4 min-h-[44px] min-w-[44px] flex items-center justify-center disabled:opacity-50 transition-colors"
            >
              <Send size={18} />
            </button>
          </div>
        </div>
      </div>

      {/* Floating Re-Roll Button */}
      {fromRandom && (
        <button
          onClick={handleReroll}
          disabled={rerolling}
          className="fixed bottom-20 right-4 z-50 w-12 h-12 rounded-full bg-gradient-to-r from-primary to-secondary text-white shadow-lg flex items-center justify-center active:scale-95 transition-transform disabled:opacity-50"
          title="Nochmal würfeln"
        >
          <Dices size={20} className={rerolling ? 'animate-spin' : ''} />
        </button>
      )}
    </motion.div>
  )
}
