'use client';
import { useState } from 'react';
import { Settings2, CreditCard, TrendingUp, Users, ChevronRight, Loader2, Eye, EyeOff, Save, RefreshCw, Check, AlertCircle, BarChart3, ArrowLeft, Zap } from 'lucide-react';
import Link from 'next/link';
import AdminBilling from './admin/AdminBilling';

// ──────────────────────────────────────────────────────────────
// Sidebar navigation
// ──────────────────────────────────────────────────────────────
const SECTIONS = [
  { id: 'settings', label: 'AI-провайдеры', icon: Settings2,  desc: 'Ключи aiprimetech и routerai' },
  { id: 'engine',   label: 'Движок',         icon: Zap,         desc: 'URL, Telegram, авто-черновики' },
  { id: 'payments', label: 'ЮKassa',          icon: CreditCard, desc: 'Ключи для приёма оплат' },
  { id: 'spending', label: 'Расходы AI',       icon: TrendingUp, desc: 'aiprimetech + routerai' },
  { id: 'plans',    label: 'Тарифы',           icon: BarChart3,  desc: 'Планы, кредиты, операции' },
  { id: 'billing',  label: 'Пользователи',     icon: Users,      desc: 'Балансы и кредиты' },
];

export default function AdminPanel({ initialSection = 'settings' }) {
  const [section, setSection] = useState(initialSection);

  return (
    <div className="max-w-6xl mx-auto p-4 sm:p-6">
      {/* Breadcrumb */}
      <div className="flex items-center gap-2 mb-6 text-sm text-gray-500">
        <Link href="/" className="hover:text-gray-200 flex items-center gap-1">
          <ArrowLeft className="w-3.5 h-3.5" /> Главная
        </Link>
        <ChevronRight className="w-3.5 h-3.5" />
        <span className="text-gray-200">Администрирование</span>
        <ChevronRight className="w-3.5 h-3.5" />
        <span className="text-accent">{SECTIONS.find(s => s.id === section)?.label}</span>
      </div>

      <div className="flex gap-6">
        {/* Sidebar */}
        <aside className="w-52 shrink-0">
          <div className="card p-2 space-y-0.5 sticky top-6">
            <p className="text-xs text-gray-500 uppercase tracking-wide px-3 py-2 font-medium">Разделы</p>
            {SECTIONS.map(({ id, label, icon: Icon, desc }) => (
              <button key={id} onClick={() => setSection(id)}
                className={`w-full text-left px-3 py-2.5 rounded-lg transition-colors flex items-center gap-3 ${
                  section === id
                    ? 'bg-accent/10 text-accent'
                    : 'hover:bg-surface2 text-gray-300'
                }`}>
                <Icon className="w-4 h-4 shrink-0" />
                <div className="min-w-0">
                  <div className="text-sm font-medium truncate">{label}</div>
                  <div className="text-xs text-gray-500 truncate">{desc}</div>
                </div>
              </button>
            ))}
          </div>
        </aside>

        {/* Content */}
        <div className="flex-1 min-w-0">
          {section === 'settings' && <SettingsSection categories={['ai_providers', 'photo_search']} />}
          {section === 'engine'   && <SettingsSection categories={['engine']} />}
          {section === 'payments' && <SettingsSection categories={['payments']} />}
          {section === 'spending' && <SpendingSection />}
          {section === 'plans'    && <PlansSection />}
          {section === 'billing'  && <AdminBilling />}
        </div>
      </div>
    </div>
  );
}

// ──────────────────────────────────────────────────────────────
// Settings section (API keys)
// ──────────────────────────────────────────────────────────────
const CATEGORY_META = {
  ai_providers: {
    title: 'AI-провайдеры',
    hint: 'Ключи и URL для текстовой и картиночной генерации. Меняются на лету.',
  },
  photo_search: {
    title: 'Поиск фото',
    hint: 'Yandex Search API: ключ и folder.',
  },
  payments: {
    title: 'ЮKassa',
    hint: 'Shop ID и Secret Key из личного кабинета. Webhook: https://engine.zeropost.ru/api/billing/webhook',
  },
};

function SettingsSection({ categories }) {
  const [data,     setData]    = useState({});
  const [loaded,   setLoaded]  = useState(false);
  const [loading,  setLoading] = useState(false);

  async function load() {
    setLoading(true);
    const all = {};
    for (const cat of categories) {
      try {
        const rows = await fetch(`/api/admin/settings?category=${cat}`).then(r => r.json());
        all[cat] = Array.isArray(rows) ? rows : [];
      } catch { all[cat] = []; }
    }
    setData(all);
    setLoaded(true);
    setLoading(false);
  }

  if (!loaded && !loading) { load(); }

  return (
    <div className="space-y-6">
      {categories.map(cat => {
        const meta = CATEGORY_META[cat] || { title: cat, hint: '' };
        const rows = data[cat] || [];
        return (
          <section key={cat} className="card p-5">
            <div className="mb-4">
              <h2 className="font-semibold">{meta.title}</h2>
              {meta.hint && <p className="text-xs text-gray-500 mt-1">{meta.hint}</p>}
            </div>
            {loading && !rows.length
              ? <div className="py-4 text-center"><Loader2 className="w-4 h-4 animate-spin mx-auto" /></div>
              : rows.map(row => (
                  <SettingRow key={row.key} row={row} onSaved={load} />
                ))
            }
          </section>
        );
      })}
    </div>
  );
}

function SettingRow({ row, onSaved }) {
  const [val,     setVal]    = useState(row.value || '');
  const [show,    setShow]   = useState(false);
  const [saving,  setSaving] = useState(false);
  const [status,  setStatus] = useState(null); // 'ok' | 'error'
  const [errMsg,  setErrMsg] = useState('');
  const dirty = val !== (row.value || '');

  async function save() {
    setSaving(true); setStatus(null);
    try {
      const res = await fetch(`/api/admin/settings/${encodeURIComponent(row.key)}`, {
        method: 'PUT',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ value: val }),
      }).then(r => r.json());
      if (res.error) { setStatus('error'); setErrMsg(res.error); }
      else { setStatus('ok'); onSaved(); setTimeout(() => setStatus(null), 2000); }
    } catch (e) { setStatus('error'); setErrMsg(e.message); }
    setSaving(false);
  }

  const isSecret = row.is_secret;
  const inputType = isSecret && !show ? 'password' : 'text';

  return (
    <div className="mb-4">
      <div className="flex items-center justify-between mb-1">
        <label className="label text-xs">{row.key}</label>
        <span className="text-xs text-gray-600">{row.category}</span>
      </div>
      {row.description && <p className="text-xs text-gray-500 mb-1.5">{row.description}</p>}
      <div className="flex gap-2">
        <div className="relative flex-1">
          <input
            type={inputType}
            value={val}
            onChange={e => setVal(e.target.value)}
            className="input w-full pr-8 font-mono text-sm"
            placeholder={isSecret ? '••••••••' : 'Введите значение...'}
          />
          {isSecret && (
            <button onClick={() => setShow(s => !s)}
              className="absolute right-2 top-1/2 -translate-y-1/2 text-gray-500 hover:text-gray-300">
              {show ? <EyeOff className="w-3.5 h-3.5" /> : <Eye className="w-3.5 h-3.5" />}
            </button>
          )}
        </div>
        {dirty && (
          <button onClick={save} disabled={saving}
            className="btn-primary px-3 py-1.5 text-sm flex items-center gap-1.5">
            {saving ? <Loader2 className="w-3.5 h-3.5 animate-spin" /> : <Save className="w-3.5 h-3.5" />}
            Сохранить
          </button>
        )}
        {status === 'ok'    && <Check className="w-5 h-5 text-green-400 self-center shrink-0" />}
        {status === 'error' && <AlertCircle className="w-5 h-5 text-red-400 self-center shrink-0" title={errMsg} />}
      </div>
      <div className="text-xs text-gray-600 mt-1">
        обновлено: {row.updated_at ? new Date(row.updated_at).toLocaleString('ru-RU') : '—'}
      </div>
    </div>
  );
}

// ──────────────────────────────────────────────────────────────
// Spending section
// ──────────────────────────────────────────────────────────────
const PERIODS = [
  { v: 'today', label: 'Сегодня' },
  { v: 'week',  label: '7 дней' },
  { v: 'month', label: '30 дней' },
  { v: 'alltime', label: 'Всё время' },
];

const TYPE_LABELS = {
  'chat':                '💬 Текст',
  'image':               '🖼 Изображение',
  'image_via_responses': '🖼 Изображение',
  'article':             '📝 Статья',
  'topic':               '🔍 Топики',
};

function fmt(n)    { return Number(n || 0).toFixed(2); }
function fmtI(n)   { return Number(n || 0).toLocaleString('ru-RU'); }

function SpendingSection() {
  const [period,   setPeriod]   = useState('month');
  const [data,     setData]     = useState(null);
  const [byProv,   setByProv]   = useState(null);
  const [loading,  setLoading]  = useState(false);

  async function load(p) {
    setLoading(true);
    try {
      const [r1, r2] = await Promise.all([
        fetch(`/api/usage/summary?range=${p}&group_by=request_type`).then(r => r.json()),
        fetch(`/api/usage/summary?range=${p}&group_by=provider`).then(r => r.json()),
      ]);
      setData(r1); setByProv(r2);
    } catch {}
    setLoading(false);
  }

  if (!data && !loading) load(period);

  const totals = data?.totals || {};
  const aiprimetech = byProv?.breakdown?.find(b => b.key === 'aiprimetech');
  const routerai    = byProv?.breakdown?.find(b => b.key === 'routerai');

  return (
    <div className="space-y-5">
      <div className="flex items-center justify-between">
        <h2 className="font-semibold">Расходы на AI</h2>
        <div className="flex gap-1">
          {PERIODS.map(p => (
            <button key={p.v} onClick={() => { setPeriod(p.v); load(p.v); }}
              className={`px-2.5 py-1 rounded-lg text-xs transition-colors ${period === p.v ? 'bg-accent text-white' : 'btn-ghost'}`}>
              {p.label}
            </button>
          ))}
          <button onClick={() => load(period)} className="btn-ghost p-1.5 ml-1">
            <RefreshCw className="w-3.5 h-3.5" />
          </button>
        </div>
      </div>

      {loading && <div className="py-8 text-center"><Loader2 className="w-5 h-5 animate-spin mx-auto text-accent" /></div>}

      {!loading && data && (<>
        {/* Итого */}
        <div className="grid grid-cols-4 gap-3">
          {[
            { label: 'Итого, ₽',  value: `₽ ${fmt(totals.cost_rub)}`,    accent: true },
            { label: 'Запросов',  value: fmtI(totals.calls) },
            { label: 'Токенов',   value: fmtI((totals.prompt_tokens||0)+(totals.completion_tokens||0)) },
            { label: 'Картинок',  value: fmtI(totals.image_count) },
          ].map(s => (
            <div key={s.label} className={`card p-3 ${s.accent ? 'border-accent/40 bg-accent/5' : ''}`}>
              <div className={`text-xl font-bold ${s.accent ? 'text-accent' : ''}`}>{s.value}</div>
              <div className="text-xs text-gray-500 mt-0.5">{s.label}</div>
            </div>
          ))}
        </div>

        {/* По провайдерам */}
        <div className="grid grid-cols-2 gap-3">
          {[
            { key: 'aiprimetech', label: 'aiprimetech.io', icon: '💬', desc: 'Текст', data: aiprimetech },
            { key: 'routerai',    label: 'routerai.ru',    icon: '🖼', desc: 'Картинки', data: routerai },
          ].map(p => (
            <div key={p.key} className="card p-4">
              <div className="flex items-center gap-2 mb-2">
                <span className="text-lg">{p.icon}</span>
                <div>
                  <div className="font-medium text-sm">{p.label}</div>
                  <div className="text-xs text-gray-500">{p.desc}</div>
                </div>
                <div className="ml-auto text-accent font-bold">₽ {fmt(p.data?.cost_rub)}</div>
              </div>
              <div className="grid grid-cols-3 gap-1 text-xs text-gray-400">
                <div><div className="font-medium text-gray-200">{fmtI(p.data?.calls)}</div>запросов</div>
                <div><div className="font-medium text-red-400">{p.data?.failed||0}</div>ошибок</div>
                <div><div className="font-medium text-gray-200">{fmtI(p.data?.image_count || (p.data?.prompt_tokens||0)+(p.data?.completion_tokens||0))}</div>{p.key==='routerai'?'картинок':'токенов'}</div>
              </div>
            </div>
          ))}
        </div>

        {/* Таблица по операциям */}
        <div className="card overflow-hidden">
          <table className="w-full text-sm">
            <thead className="bg-surface2 text-xs text-gray-400">
              <tr>
                <th className="px-4 py-2.5 text-left">Операция</th>
                <th className="px-4 py-2.5 text-right">Запросов</th>
                <th className="px-4 py-2.5 text-right">Ошибок</th>
                <th className="px-4 py-2.5 text-right">Объём</th>
                <th className="px-4 py-2.5 text-right">Стоимость</th>
              </tr>
            </thead>
            <tbody>
              {(data.breakdown || []).map((row, i) => (
                <tr key={i} className="border-t border-border hover:bg-surface2/50">
                  <td className="px-4 py-2.5">{TYPE_LABELS[row.key] || row.key}</td>
                  <td className="px-4 py-2.5 text-right text-gray-300">{fmtI(row.calls)}</td>
                  <td className="px-4 py-2.5 text-right text-red-400">{row.failed || 0}</td>
                  <td className="px-4 py-2.5 text-right text-gray-400 text-xs">
                    {row.image_count > 0 ? `${row.image_count} шт.` : fmtI((row.prompt_tokens||0)+(row.completion_tokens||0))}
                  </td>
                  <td className="px-4 py-2.5 text-right font-medium">₽ {fmt(row.cost_rub)}</td>
                </tr>
              ))}
            </tbody>
            <tfoot className="bg-surface2 border-t border-border">
              <tr>
                <td className="px-4 py-2.5 font-semibold">Итого</td>
                <td className="px-4 py-2.5 text-right font-semibold">{fmtI(totals.calls)}</td>
                <td className="px-4 py-2.5 text-right text-red-400 font-semibold">{totals.failed||0}</td>
                <td className="px-4 py-2.5 text-right text-gray-400 text-xs">—</td>
                <td className="px-4 py-2.5 text-right font-bold text-accent">₽ {fmt(totals.cost_rub)}</td>
              </tr>
            </tfoot>
          </table>
        </div>
      </>)}
    </div>
  );
}

// ──────────────────────────────────────────────────────────────
// Plans & Credits section
// ──────────────────────────────────────────────────────────────
function PlansSection() {
  const [plans,   setPlans]   = useState([]);
  const [costs,   setCosts]   = useState([]);
  const [loading, setLoading] = useState(true);
  const [saving,  setSaving]  = useState({});
  const [msg,     setMsg]     = useState('');

  async function load() {
    setLoading(true);
    try {
      const res = await fetch('/api/billing/plans').then(r => r.json());
      setPlans(res.plans || []);
      setCosts(res.costs || []);
    } catch {}
    setLoading(false);
  }

  async function savePlan(plan) {
    setSaving(s => ({ ...s, [plan.id]: true }));
    try {
      await fetch(`/api/admin/plans/${plan.id}`, {
        method: 'PATCH',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ price_rub: plan.price_rub, credits_month: plan.credits_month, channels_max: plan.channels_max }),
      });
      setMsg('Сохранено ✓');
      setTimeout(() => setMsg(''), 2000);
    } catch {}
    setSaving(s => ({ ...s, [plan.id]: false }));
  }

  async function saveCost(cost) {
    setSaving(s => ({ ...s, [`cost_${cost.operation}`]: true }));
    try {
      await fetch(`/api/admin/credit-costs/${cost.operation}`, {
        method: 'PATCH',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ credits: cost.credits }),
      });
      setMsg('Сохранено ✓');
      setTimeout(() => setMsg(''), 2000);
    } catch {}
    setSaving(s => ({ ...s, [`cost_${cost.operation}`]: false }));
  }

  if (loading && !plans.length) { load(); }

  const PLAN_LABELS = { free: 'Free', starter: 'Starter', pro: 'Pro', business: 'Business' };

  return (
    <div className="space-y-6">
      {msg && <div className="text-sm text-green-400 flex items-center gap-1"><Check className="w-4 h-4" />{msg}</div>}

      {/* Тарифные планы */}
      <section className="card p-5">
        <h2 className="font-semibold mb-1">Тарифные планы</h2>
        <p className="text-xs text-gray-500 mb-4">Цены и лимиты. -1 = безлимит.</p>
        {loading ? <Loader2 className="w-4 h-4 animate-spin" /> : (
          <div className="space-y-3">
            {plans.map(plan => {
              const [p, setP] = [plan, (updates) => setPlans(pp => pp.map(x => x.id === plan.id ? { ...x, ...updates } : x))];
              return (
                <div key={p.id} className="flex items-center gap-3 p-3 rounded-lg bg-surface2">
                  <div className="w-20 font-medium text-sm">{PLAN_LABELS[p.code] || p.code}</div>
                  <div className="flex items-center gap-1">
                    <span className="text-xs text-gray-500">₽/мес:</span>
                    <input type="number" value={p.price_rub} onChange={e => setP({ price_rub: +e.target.value })}
                      className="input w-20 text-sm py-1" />
                  </div>
                  <div className="flex items-center gap-1">
                    <span className="text-xs text-gray-500">кредитов:</span>
                    <input type="number" value={p.credits_month} onChange={e => setP({ credits_month: +e.target.value })}
                      className="input w-20 text-sm py-1" />
                  </div>
                  <div className="flex items-center gap-1">
                    <span className="text-xs text-gray-500">каналов:</span>
                    <input type="number" value={p.channels_max} onChange={e => setP({ channels_max: +e.target.value })}
                      className="input w-16 text-sm py-1" />
                  </div>
                  <button onClick={() => savePlan(p)} disabled={saving[p.id]}
                    className="btn-primary text-xs px-2.5 py-1.5 ml-auto flex items-center gap-1">
                    {saving[p.id] ? <Loader2 className="w-3 h-3 animate-spin" /> : <Save className="w-3 h-3" />}
                    Сохранить
                  </button>
                </div>
              );
            })}
          </div>
        )}
      </section>

      {/* Стоимость операций */}
      <section className="card p-5">
        <h2 className="font-semibold mb-1">Стоимость операций (кредиты)</h2>
        <p className="text-xs text-gray-500 mb-4">Сколько кредитов списывается за каждую операцию.</p>
        {loading ? <Loader2 className="w-4 h-4 animate-spin" /> : (
          <div className="space-y-2">
            {costs.map(cost => {
              const [c, setC] = [cost, (updates) => setCosts(cc => cc.map(x => x.operation === cost.operation ? { ...x, ...updates } : x))];
              const icons = { image: '🖼', text_post: '✍️', article: '📝', autopublish: '📤' };
              return (
                <div key={c.operation} className="flex items-center gap-3 p-3 rounded-lg bg-surface2">
                  <span className="text-lg w-7 text-center">{icons[c.operation] || '⚙️'}</span>
                  <div className="flex-1 text-sm">{c.description || c.operation}</div>
                  <div className="flex items-center gap-2">
                    <input type="number" value={c.credits} onChange={e => setC({ credits: +e.target.value })}
                      className="input w-16 text-sm py-1 text-center" min={0} />
                    <span className="text-xs text-gray-500">кр</span>
                  </div>
                  <button onClick={() => saveCost(c)} disabled={saving[`cost_${c.operation}`]}
                    className="btn-primary text-xs px-2.5 py-1.5 flex items-center gap-1">
                    {saving[`cost_${c.operation}`] ? <Loader2 className="w-3 h-3 animate-spin" /> : <Save className="w-3 h-3" />}
                    Сохранить
                  </button>
                </div>
              );
            })}
          </div>
        )}
      </section>
    </div>
  );
}