'use client';

import { useState, useEffect, useMemo } from 'react';
import {
  Library, Calendar, Hash, MessageSquare, Save, Trash2, Loader2,
  CheckCircle2, AlertCircle, ArrowRight, Info, Search, Plus,
  Sparkles, Zap
} from 'lucide-react';
import Link from 'next/link';
import { useRouter } from 'next/navigation';
import { cn } from '@/lib/utils';
import { useUser } from '@/app/dashboard/useUser';
import { useI18n, formatDate } from '@/lib/i18n';
import { useGlossaries } from './useGlossaries';
import type { GlossaryListItem } from './types';
import { ProUpgradePrompt } from './ProUpgradePrompt';
import { useToast } from '@/components/ui/toast';
import { SUPPORTED_LANGUAGES } from './types';
import { useTranslationStore } from '@/lib/store';

// ── Chips de suggestions pour les consignes de contexte ─────────────────────
// Prompt bodies stay in French (LLM content); labels translate with the UI.
const CONTEXT_SUGGESTIONS: { labelKey: string; value: string }[] = [
  { labelKey: 'glossaries.suggestion.formal', value: 'Utilise toujours un ton formel et professionnel dans tes traductions.' },
  { labelKey: 'glossaries.suggestion.proprietary', value: 'Ne traduis pas les noms propres, marques et noms de personnes.' },
  { labelKey: 'glossaries.suggestion.numbers', value: 'Garde tous les chiffres, pourcentages et montants tels quels sans les modifier.' },
  { labelKey: 'glossaries.suggestion.placeholders', value: 'Ne traduis pas les variables entre accolades comme {nom}, {date}, {montant}.' },
  { labelKey: 'glossaries.suggestion.technical', value: 'Conserve les termes techniques en langue originale et ne les traduis pas.' },
  { labelKey: 'glossaries.suggestion.concise', value: 'Préfère des formulations courtes et directes. Évite les périphrases.' },
];

export default function GlossariesPage() {
  const { t, locale } = useI18n();
  const router = useRouter();
  const { data: user, isLoading: isLoadingUser } = useUser();
  const { glossaries, isLoading: isLoadingGlossaries } = useGlossaries();
  const { toast } = useToast();
  const { settings, updateSettings } = useTranslationStore();

  const [systemPrompt, setSystemPrompt] = useState(settings.systemPrompt);
  const [isSavingPrompt, setIsSavingPrompt] = useState(false);
  const [promptSaved, setPromptSaved] = useState(false);
  const [searchQuery, setSearchQuery] = useState('');
  const [activeTab, setActiveTab] = useState<'glossaries' | 'context'>('glossaries');

  // Same tier logic as the sidebar: business/enterprise are Pro-grade plans.
  const isPro = ['pro', 'business', 'enterprise'].includes(user?.tier ?? '');
  const isLoading = isLoadingUser || isLoadingGlossaries;

  const currentTargetLang = settings.defaultTargetLanguage;
  const currentTargetInfo = SUPPORTED_LANGUAGES.find(l => l.code === currentTargetLang);

  const promptHasUnsavedChanges = systemPrompt !== settings.systemPrompt;
  const promptIsActive = !!settings.systemPrompt?.trim();

  useEffect(() => {
    setSystemPrompt(settings.systemPrompt);
    setPromptSaved(false);
  }, [settings.systemPrompt]);

  const handleSavePrompt = async () => {
    setIsSavingPrompt(true);
    try {
      updateSettings({ systemPrompt });
      await new Promise(resolve => setTimeout(resolve, 300));
      setPromptSaved(true);
      toast({ title: t('context.saved'), description: t('context.savedDesc') });
      setTimeout(() => setPromptSaved(false), 3000);
    } finally {
      setIsSavingPrompt(false);
    }
  };

  const handleClearPrompt = () => {
    updateSettings({ systemPrompt: '' });
    setSystemPrompt('');
  };

  const handleAddSuggestion = (value: string) => {
    const current = systemPrompt.trim();
    const newPrompt = current ? `${current}\n${value}` : value;
    setSystemPrompt(newPrompt);
  };

  const filteredGlossaries = useMemo(() => {
    if (!searchQuery.trim()) return glossaries;
    const q = searchQuery.toLowerCase();
    return glossaries.filter((g) => g.name.toLowerCase().includes(q));
  }, [glossaries, searchQuery]);

  if (isLoading) {
    return (
      <div className="flex items-center justify-center min-h-[60vh]">
        <div className="text-center space-y-4">
          <div className="animate-spin rounded-full h-8 w-8 border-4 border-brand-muted border-t-brand-accent mx-auto"></div>
          <p className="text-xs text-[#555555] dark:text-white/40 font-light">{t('glossaries.loading')}</p>
        </div>
      </div>
    );
  }

  if (!isPro) {
    return <ProUpgradePrompt />;
  }

  return (
    <div className="max-w-6xl mx-auto w-full p-6 lg:p-8">

      {/* ── Header ────────────────────────────────────────────────── */}
      <div className="flex flex-col sm:flex-row justify-between items-start sm:items-end mb-10 gap-6">
        <div>
          <span className="accent-pill mb-3 block w-fit font-medium text-[10px] uppercase tracking-widest">
            {t('glossaries.yourGlossaries') || 'Vos Glossaires'}
          </span>
          <h1 className="text-4xl md:text-5xl mb-3 leading-tight text-brand-dark dark:text-white font-serif font-medium tracking-tight">
            {t('glossaries.titleBase')} <span className="italic">{t('glossaries.titleAccent')}</span>
          </h1>
          <p className="text-[#555555] dark:text-white/60 text-sm font-light leading-relaxed">
            {t('glossaries.description') || 'Gérez vos glossaires et instructions de contexte pour des traductions plus précises.'}
          </p>
        </div>
        {/* Bouton principal — unique point d'entrée pour créer */}
        <Link
          href="/dashboard/glossaries/new"
          className="shrink-0 flex items-center gap-2 px-5 py-2.5 rounded-xl bg-[#1A1A1A] hover:bg-[#333333] text-white text-xs font-bold uppercase tracking-widest transition-all"
        >
          <Plus size={14} />
          {t('glossaries.new')}
        </Link>
      </div>

      {/* ── Bandeau informatif ────────────────────────────────────── */}
      <div className="mb-8 flex items-center gap-3 p-4 rounded-xl bg-[#F5F0EA] dark:bg-brand-accent/10 border border-[#D4B896] dark:border-brand-accent/20">
        <div className="w-7 h-7 rounded-full bg-[#8B6F47] text-white flex items-center justify-center shrink-0">
          <Info size={13} />
        </div>
        <p className="text-[11px] text-[#2D2D2D] dark:text-white/70 font-medium leading-relaxed flex-1">
          <strong className="font-bold text-[#1A1A1A] dark:text-white">{t('glossaries.info.title')}</strong>{' '}
          {t('glossaries.info.body')}
        </p>
        <Link
          href="/dashboard/translate"
          className="shrink-0 flex items-center gap-1.5 text-[10px] font-bold uppercase tracking-wider text-[#7A5C35] dark:text-brand-accent hover:underline whitespace-nowrap"
        >
          {t('glossaries.info.cta')} <ArrowRight size={11} />
        </Link>
      </div>

      {/* ── Onglets ───────────────────────────────────────────────── */}
      <div className="flex border-b border-black/10 dark:border-white/10 mb-8">
        <button
          onClick={() => setActiveTab('glossaries')}
          aria-selected={activeTab === 'glossaries'}
          role="tab"
          className={cn(
            'pb-4 px-6 text-xs uppercase tracking-widest font-bold border-b-2 transition-all cursor-pointer',
            activeTab === 'glossaries'
              ? 'border-brand-accent text-[#1A1A1A] dark:text-white'
              : 'border-transparent text-[#555555] dark:text-white/40 hover:text-[#1A1A1A] dark:hover:text-white/80'
          )}
        >
          {t('glossaries.tabs.glossaries') || 'Glossaires terminologiques'}
        </button>
        <button
          onClick={() => setActiveTab('context')}
          aria-selected={activeTab === 'context'}
          role="tab"
          className={cn(
            'pb-4 px-6 text-xs uppercase tracking-widest font-bold border-b-2 transition-all cursor-pointer',
            activeTab === 'context'
              ? 'border-brand-accent text-[#1A1A1A] dark:text-white'
              : 'border-transparent text-[#555555] dark:text-white/40 hover:text-[#1A1A1A] dark:hover:text-white/80'
          )}
        >
          {t('glossaries.tabs.context') || 'Consignes de contexte (IA)'}
        </button>
      </div>

      <div className="space-y-10">
        {activeTab === 'context' ? (

          /* ── Onglet Consignes de Contexte ─────────────────────── */
          <section className="editorial-card p-8 lg:p-10 bg-white dark:bg-[#141414] border border-black/5 dark:border-white/5 rounded-2xl shadow-sm animate-fade-in">

            {/* En-tête section */}
            <div className="flex items-start justify-between mb-6 gap-4">
              <div className="flex items-start gap-3">
                <div className="w-9 h-9 rounded-xl bg-brand-accent/10 flex items-center justify-center text-[#8B6F47] shrink-0">
                  <MessageSquare size={18} />
                </div>
                <div>
                  <h2 className="text-base font-serif font-semibold text-[#1A1A1A] dark:text-white tracking-tight">
                    {t('glossaries.context.title')}
                  </h2>
                  <p className="text-[11px] text-[#555555] dark:text-white/50 font-light mt-0.5">
                    {t('glossaries.context.desc')}
                  </p>
                </div>
              </div>
              {/* Badge d'état */}
              {promptHasUnsavedChanges ? (
                <span className="shrink-0 flex items-center gap-1.5 text-[10px] font-bold uppercase tracking-wider text-amber-700 bg-amber-100 dark:text-amber-400 dark:bg-amber-500/10 px-3 py-1.5 rounded-full border border-amber-300 dark:border-amber-500/20">
                  <AlertCircle size={11} />
                  {t('glossaries.context.unsaved')}
                </span>
              ) : promptIsActive ? (
                <span className="shrink-0 flex items-center gap-1.5 text-[10px] font-bold uppercase tracking-wider text-emerald-700 bg-emerald-100 dark:text-emerald-400 dark:bg-emerald-500/10 px-3 py-1.5 rounded-full border border-emerald-300 dark:border-emerald-500/20">
                  <CheckCircle2 size={11} />
                  {t('glossaries.context.active')}
                </span>
              ) : (
                <span className="shrink-0 flex items-center gap-1.5 text-[10px] font-bold uppercase tracking-wider text-[#555555] bg-[#EBEBEB] dark:text-white/30 dark:bg-white/5 px-3 py-1.5 rounded-full border border-[#CCCCCC] dark:border-white/10">
                  {t('glossaries.context.inactive')}
                </span>
              )}
            </div>

            {/* Chips de suggestions rapides */}
            <div className="mb-5">
              <div className="flex items-center gap-2 mb-3">
                <Sparkles size={13} className="text-[#8B6F47]" />
                <span className="text-[10px] font-bold uppercase tracking-widest text-[#555555] dark:text-white/40">
                  {t('glossaries.context.suggestions')}
                </span>
              </div>
              <div className="flex flex-wrap gap-2">
                {CONTEXT_SUGGESTIONS.map((s) => (
                  <button
                    key={s.labelKey}
                    onClick={() => handleAddSuggestion(s.value)}
                    className="px-3 py-1.5 rounded-lg text-[11px] font-semibold text-[#3D3D3D] dark:text-white/70 bg-[#F0EDE8] dark:bg-white/5 border border-[#D9D5CE] dark:border-white/10 hover:bg-[#E8E2DA] hover:border-[#C5A17A] dark:hover:bg-brand-accent/10 dark:hover:border-brand-accent/30 transition-all cursor-pointer"
                  >
                    + {t(s.labelKey)}
                  </button>
                ))}
              </div>
            </div>

            {/* Zone de texte */}
            <textarea
              value={systemPrompt}
              onChange={e => { setSystemPrompt(e.target.value); setPromptSaved(false); }}
              placeholder={t('glossaries.context.placeholder')}
              aria-label={t('glossaries.context.title')}
              className="w-full h-44 p-4 bg-[#FAFAF8] dark:bg-white/[0.02] rounded-xl border border-[#D9D6D0] dark:border-white/10 text-[#1A1A1A] dark:text-white text-xs leading-relaxed focus:ring-2 focus:ring-brand-accent/30 focus:border-brand-accent/50 transition-all outline-none resize-y placeholder:text-[#AAAAAA] dark:placeholder:text-white/25"
            />

            {/* Pied de section */}
            <div className="flex justify-between items-center mt-4">
              <p className="text-[10px] text-[#777777] dark:text-white/25 font-light">
                {systemPrompt.length > 0
                  ? t('glossaries.context.chars', { count: systemPrompt.length })
                  : t('glossaries.context.noPrompt')}
              </p>
              <div className="flex gap-3">
                <button
                  onClick={handleClearPrompt}
                  disabled={!systemPrompt}
                  className="px-5 py-2.5 bg-[#EBEBEB] dark:bg-white/5 text-[#444444] dark:text-white/40 rounded-lg text-xs font-bold uppercase tracking-wider hover:text-[#1A1A1A] hover:bg-[#E0E0E0] dark:hover:text-white transition-all cursor-pointer disabled:opacity-40 disabled:cursor-not-allowed"
                >
                  <Trash2 size={12} className="inline mr-1.5" />
                  {t('glossaries.context.clear')}
                </button>
                <button
                  onClick={handleSavePrompt}
                  disabled={isSavingPrompt || !promptHasUnsavedChanges}
                  className="premium-button px-8 py-2.5 text-xs uppercase tracking-widest !rounded-lg flex items-center gap-2 disabled:opacity-50 cursor-pointer font-bold"
                >
                  {isSavingPrompt
                    ? <><Loader2 size={14} className="animate-spin" /> {t('glossaries.context.saving')}</>
                    : promptSaved
                    ? <><CheckCircle2 size={14} /> {t('glossaries.context.saved')}</>
                    : <><Save size={14} /> {t('glossaries.context.save')}</>
                  }
                </button>
              </div>
            </div>
          </section>

        ) : (

          /* ── Onglet Glossaires ──────────────────────────────────── */
          <div className="space-y-6 animate-fade-in">

            {/* En-tête de section + compteur */}
            <div className="flex items-center justify-between gap-4">
              <div>
                <h2 className="text-lg font-serif font-medium text-[#1A1A1A] dark:text-white tracking-tight">
                  {t('glossaries.grid.title') || 'Vos'}{' '}
                  <span className="italic">{t('glossaries.grid.titleHighlight') || 'glossaires'}</span>
                </h2>
                <p className="text-[11px] text-[#555555] dark:text-white/40 font-light mt-1">
                  {glossaries.length > 0
                    ? t('glossaries.countMany', { count: glossaries.length })
                    : t('glossaries.countNone')}
                </p>
              </div>
              {currentTargetInfo && (
                <span className="flex items-center gap-1.5 text-[10px] font-bold text-[#444444] dark:text-white/40 bg-[#EBEBEB] dark:bg-white/5 border border-[#CCCCCC] dark:border-white/5 px-3 py-1.5 rounded-full shrink-0">
                  <span>{t('glossaries.activeTarget')}</span>
                  <span>{currentTargetInfo.flag} {currentTargetInfo.label}</span>
                </span>
              )}
            </div>

            {/* Barre de recherche (si > 3 glossaires) */}
            {glossaries.length > 3 && (
              <div className="relative">
                <Search size={14} className="absolute left-3 top-1/2 -translate-y-1/2 text-[#888888] dark:text-white/30" />
                <input
                  type="text"
                  value={searchQuery}
                  onChange={e => setSearchQuery(e.target.value)}
                  placeholder={t('glossaries.searchPlaceholder')}
                  aria-label={t('glossaries.searchPlaceholder')}
                  className="w-full pl-9 pr-3 py-2.5 text-xs rounded-lg border border-[#D9D6D0] dark:border-white/10 bg-white dark:bg-[#141414] text-[#1A1A1A] dark:text-white placeholder:text-[#AAAAAA] dark:placeholder:text-white/25 focus:outline-none focus:ring-2 focus:ring-brand-accent/20 focus:border-brand-accent/30"
                />
              </div>
            )}

            {/* État vide */}
            {glossaries.length === 0 ? (
              <div className="editorial-card p-16 bg-white dark:bg-[#141414] border border-black/5 dark:border-white/5 rounded-2xl shadow-sm text-center">
                <div className="w-14 h-14 bg-[#F0EDE8] dark:bg-white/10 rounded-2xl flex items-center justify-center text-[#8B6F47] mx-auto mb-5">
                  <Library size={28} />
                </div>
                <p className="text-base font-serif font-semibold text-[#1A1A1A] dark:text-white mb-2">
                  {t('glossaries.empty') || 'Aucun glossaire'}
                </p>
                <p className="text-sm text-[#555555] dark:text-white/40 font-light mb-6 max-w-xs mx-auto">
                  {t('glossaries.emptyDesc') || 'Créez votre premier glossaire pour garantir une terminologie cohérente dans vos traductions.'}
                </p>
                <Link
                  href="/dashboard/glossaries/new"
                  className="inline-flex items-center gap-2 px-6 py-2.5 rounded-xl bg-[#1A1A1A] hover:bg-[#333333] text-white text-xs font-bold uppercase tracking-widest transition-all"
                >
                  <Plus size={12} />
                  {t('glossaries.createFirst')}
                </Link>
              </div>
            ) : filteredGlossaries.length === 0 ? (
              <div className="p-8 bg-white dark:bg-[#141414] border border-black/5 dark:border-white/5 rounded-2xl text-center">
                <p className="text-sm text-[#555555] dark:text-white/40 font-light">
                  {t('glossaries.noResults', { query: searchQuery })}
                </p>
              </div>
            ) : (
              <div className="grid md:grid-cols-2 lg:grid-cols-3 gap-5">
                {filteredGlossaries.map((glossary: GlossaryListItem) => {
                  const termCount = glossary.terms_count ?? 0;
                  const srcInfo = SUPPORTED_LANGUAGES.find(l => l.code === glossary.source_language);
                  const tgtInfo = SUPPORTED_LANGUAGES.find(l => l.code === glossary.target_language);
                  const isMultilingual = glossary.target_language === 'multi';
                  const matchesTarget = currentTargetLang && (isMultilingual || glossary.target_language === currentTargetLang);
                  const mismatch = currentTargetLang && !isMultilingual && glossary.target_language && glossary.target_language !== currentTargetLang;

                  return (
                    <div
                      key={glossary.id}
                      className={cn(
                        'bg-white dark:bg-[#141414] border rounded-2xl p-6 shadow-sm group transition-all relative flex flex-col justify-between min-h-[200px]',
                        matchesTarget
                          ? 'border-brand-accent/50 ring-1 ring-brand-accent/20 hover:border-brand-accent/70'
                          : mismatch
                          ? 'border-amber-300/50 dark:border-amber-500/20 hover:border-amber-400/70 opacity-80 hover:opacity-100'
                          : 'border-[#E5E3DF] dark:border-white/5 hover:border-[#C5A17A]/40'
                      )}
                    >
                      {/* Badge compatible / autre langue */}
                      {matchesTarget && (
                        <div className="absolute top-3 right-3 flex items-center gap-1 bg-emerald-100 dark:bg-emerald-500/10 text-emerald-700 dark:text-emerald-400 px-2 py-0.5 rounded-full text-[9px] font-black uppercase tracking-wider border border-emerald-300 dark:border-emerald-500/20">
                          <CheckCircle2 size={9} /> {t('glossaries.badge.compatible')}
                        </div>
                      )}
                      {mismatch && (
                        <div className="absolute top-3 right-3 flex items-center gap-1 bg-amber-100 dark:bg-amber-500/10 text-amber-700 dark:text-amber-400 px-2 py-0.5 rounded-full text-[9px] font-black uppercase tracking-wider border border-amber-300 dark:border-amber-500/20">
                          <AlertCircle size={9} /> {t('glossaries.badge.otherLang')}
                        </div>
                      )}

                      {/* Corps cliquable → page de détail */}
                      <button
                        type="button"
                        onClick={() => router.push(`/dashboard/glossaries/${glossary.id}`)}
                        className="cursor-pointer flex-1 text-start"
                        aria-label={`${t('glossaries.card.edit')} — ${glossary.name}`}
                      >
                        <div className="flex items-start gap-3 mb-4">
                          <div className="w-10 h-10 bg-[#F0EDE8] dark:bg-white/10 rounded-xl flex items-center justify-center text-[#8B6F47] shrink-0">
                            <Library size={18} />
                          </div>
                          <div className="flex-1 min-w-0 pt-0.5">
                            <h3 className="text-sm font-serif font-semibold text-[#1A1A1A] dark:text-white tracking-tight leading-snug line-clamp-2 group-hover:text-[#8B6F47] transition-colors">
                              {glossary.name}
                            </h3>
                            <p className="text-[11px] text-[#555555] dark:text-white/50 font-medium flex items-center gap-1 mt-0.5">
                              <span>{srcInfo?.flag ?? '🌐'}</span>
                              <span>{srcInfo?.label ?? glossary.source_language}</span>
                              <span className="text-[#7A5C35] dark:text-brand-accent font-bold">→</span>
                              <span>{tgtInfo?.flag ?? '🌐'}</span>
                              <span>{tgtInfo?.label ?? glossary.target_language}</span>
                            </p>
                          </div>
                        </div>

                        <div className="flex justify-between items-center pb-4">
                          <span className="flex items-center gap-1 text-xs font-semibold text-[#333333] dark:text-white/65">
                            <Hash size={12} className="text-[#8B6F47] dark:text-brand-accent" />
                            {termCount > 1 ? t('glossaries.termsMany', { count: termCount }) : t('glossaries.termsOne')}
                          </span>
                          <span className="flex items-center gap-1 font-mono text-[10px] text-[#666666] dark:text-white/40">
                            <Calendar size={11} />
                            {formatDate(new Date(glossary.created_at), locale)}
                          </span>
                        </div>
                      </button>

                      {/* Actions */}
                      <div className="flex gap-2 pt-4 border-t border-[#F0EDE8] dark:border-white/10 mt-auto shrink-0">
                        <Link
                          href={`/dashboard/glossaries/${glossary.id}`}
                          className="flex-none px-3 py-2 rounded-lg bg-[#EBEBEB] dark:bg-white/5 hover:bg-[#E0D9D1] text-[#333333] dark:text-white/50 hover:text-[#1A1A1A] text-[10px] font-bold uppercase tracking-wider transition-all border border-[#CCCCCC] dark:border-white/10"
                        >
                          {t('glossaries.card.edit')}
                        </Link>
                        <Link
                          href={`/dashboard/translate?glossaryId=${glossary.id}`}
                          className="flex-1 text-center py-2 rounded-lg bg-[#1A1A1A] hover:bg-[#333333] text-white text-[10px] font-bold uppercase tracking-wider transition-all flex items-center justify-center gap-1.5"
                        >
                          {t('glossaries.card.use')} <ArrowRight size={11} />
                        </Link>
                      </div>
                    </div>
                  );
                })}
              </div>
            )}
          </div>
        )}
      </div>
    </div>
  );
}
