import { useState, useMemo } from 'react';
import { useSeoMeta } from '@unhead/react';
import { Input } from '@/components/ui/input';
import { cn } from '@/lib/utils';
import {
  GLOSSARY,
  TOTAL_TRICKS,
  searchTricks,
  type FlatTrick,
} from '@/lib/glossary';
import { BookOpen, Search, X } from 'lucide-react';
import { useTranslation } from '@/contexts/language';

function TrickRow({ trick }: { trick: { name: string; aka?: string[]; desc: string } }) {
  return (
    <div className="rounded-xl border border-white/8 bg-white/[0.02] p-4 transition-colors hover:border-red-500/25 hover:bg-white/[0.04]">
      <h3 className="text-base font-black text-white tracking-tight">{trick.name}</h3>
      {trick.aka && trick.aka.length > 0 && (
        <p className="mt-1 text-xs text-red-400/80">
          <span className="text-gray-500">a.k.a. </span>
          {trick.aka.join(' · ')}
        </p>
      )}
      <p className="mt-2 text-sm leading-relaxed text-gray-300">{trick.desc}</p>
    </div>
  );
}

export default function GlossaryPage() {
  const { t } = useTranslation();
  const [query, setQuery] = useState('');
  const [activeCat, setActiveCat] = useState<string | null>(null);

  useSeoMeta({
    title: t('settingsUi.glossary.seoTitle'),
    description: t('settingsUi.glossary.seoDescription', { count: TOTAL_TRICKS }),
  });

  const isSearching = query.trim().length > 0;
  const searchResults: FlatTrick[] = useMemo(
    () => (isSearching ? searchTricks(query) : []),
    [query, isSearching],
  );

  const visibleCategories = useMemo(
    () => (activeCat ? GLOSSARY.filter((c) => c.id === activeCat) : GLOSSARY),
    [activeCat],
  );

  return (
    <>
      <div className="min-h-screen">
        {/* Hero */}
        <div className="relative overflow-hidden border-b border-red-500/20 bg-gradient-to-b from-red-950/20 to-transparent">
          <div className="container px-4 py-10 md:py-14">
            <div className="flex items-center gap-3">
              <div className="flex h-12 w-12 items-center justify-center rounded-2xl bg-red-500/15 text-red-400 shadow-lg shadow-red-500/20">
                <BookOpen className="h-6 w-6" />
              </div>
              <div>
                <h1
                  className="font-display text-3xl md:text-4xl neon-red tracking-wide"
                  style={{ textShadow: '0 0 10px #ff0040, 0 0 20px #ff0040' }}
                >
                  {t('settingsUi.glossary.heading')}
                </h1>
                <p className="text-sm text-gray-400">
                  {t('settingsUi.glossary.subheading', { count: TOTAL_TRICKS })}
                </p>
              </div>
            </div>

            {/* Search */}
            <div className="relative mt-6 max-w-xl">
              <Search className="absolute left-3 top-1/2 h-4 w-4 -translate-y-1/2 text-gray-500" />
              <Input
                value={query}
                onChange={(e) => setQuery(e.target.value)}
                placeholder={t('settingsUi.glossary.searchPlaceholder')}
                className="h-11 rounded-xl border-white/10 bg-black/40 pl-9 pr-9 text-white placeholder:text-gray-500 focus-visible:ring-red-500/40"
              />
              {query && (
                <button
                  onClick={() => setQuery('')}
                  aria-label={t('settingsUi.glossary.clearSearch')}
                  className="absolute right-3 top-1/2 -translate-y-1/2 text-gray-500 hover:text-white"
                >
                  <X className="h-4 w-4" />
                </button>
              )}
            </div>
          </div>
        </div>

        <div className="container px-4 py-8">
          {/* Category filter pills — hidden while searching */}
          {!isSearching && (
            <div className="mb-8 flex flex-wrap gap-2">
              <button
                onClick={() => setActiveCat(null)}
                className={cn(
                  'rounded-full border px-3.5 py-1.5 text-xs font-bold uppercase tracking-wide transition-colors',
                  activeCat === null
                    ? 'border-red-500/50 bg-red-500/15 text-red-400'
                    : 'border-white/10 text-gray-400 hover:border-white/25 hover:text-white',
                )}
              >
                  {t('settingsUi.glossary.all')}
                </button>
              {GLOSSARY.map((cat) => (
                <button
                  key={cat.id}
                  onClick={() => setActiveCat(cat.id)}
                  className={cn(
                    'rounded-full border px-3.5 py-1.5 text-xs font-bold uppercase tracking-wide transition-colors',
                    activeCat === cat.id
                      ? 'border-red-500/50 bg-red-500/15 text-red-400'
                      : 'border-white/10 text-gray-400 hover:border-white/25 hover:text-white',
                  )}
                >
                  <span className="mr-1">{cat.glyph}</span>
                  {cat.title}
                </button>
              ))}
            </div>
          )}

          {/* Search results */}
          {isSearching ? (
            <div>
              <p className="mb-4 text-sm text-gray-400">
                {t('settingsUi.glossary.results', { count: searchResults.length, s: searchResults.length === 1 ? '' : 's' })}
                <span className="ml-1 font-bold text-white">“{query}”</span>
              </p>
              {searchResults.length === 0 ? (
                <div className="rounded-2xl border border-dashed border-white/10 p-10 text-center">
                  <p className="text-gray-500">
                    {t('settingsUi.glossary.noMatch')}
                  </p>
                </div>
              ) : (
                <div className="grid grid-cols-1 gap-3 md:grid-cols-2">
                  {searchResults.map((t) => (
                    <div key={`${t.categoryId}-${t.name}`}>
                      <p className="mb-1 text-[10px] font-bold uppercase tracking-widest text-gray-600">
                        {t.categoryGlyph} {t.categoryTitle}
                      </p>
                      <TrickRow trick={t} />
                    </div>
                  ))}
                </div>
              )}
            </div>
          ) : (
            /* Category sections */
            <div className="space-y-12">
              {visibleCategories.map((cat) => (
                <section key={cat.id} id={cat.id}>
                  <div className="mb-4 flex items-baseline gap-3">
                    <h2 className="text-xl font-black uppercase tracking-wide text-white">
                      <span className="mr-2">{cat.glyph}</span>
                      {cat.title}
                    </h2>
                    <span className="text-xs text-gray-500">{t('settingsUi.glossary.tricksCount', { count: cat.tricks.length })}</span>
                  </div>
                  <p className="mb-5 text-sm text-gray-400">{cat.blurb}</p>
                  <div className="grid grid-cols-1 gap-3 md:grid-cols-2">
                    {cat.tricks.map((t) => (
                      <TrickRow key={t.name} trick={t} />
                    ))}
                  </div>
                </section>
              ))}
            </div>
          )}

          {/* Footer note */}
          <div className="mt-14 rounded-2xl border border-white/8 bg-white/[0.02] p-5 text-center">
            <p className="text-sm text-gray-400">
              {t('settingsUi.glossary.footerBefore')}{' '}
              <button
                onClick={() =>
                  window.dispatchEvent(
                    new CustomEvent('sasquatch:ask', {
                      detail: { question: 'How do I suggest a trick for the glossary?' },
                    }),
                  )
                }
                className="font-bold text-red-400 hover:text-red-300"
              >
                {t('settingsUi.glossary.sasquatch')}
              </button>{' '}
              {t('settingsUi.glossary.footerAfter')}
            </p>
          </div>
        </div>
      </div>
    </>
  );
}