import React, { useState, useEffect, useMemo, useCallback } from 'react';
import { DomaApplication } from '../types';
import { backendApi } from '../services/apiClient';
import { readCache, saveCache } from '../hooks/useCachedFetch';
import { REFRESH_EVENTS } from '../constants/refreshEvents';
import { 
  LayoutDashboard, 
  Inbox, 
  ShieldAlert, 
  Sparkles, 
  Plus, 
  RotateCw, 
  AlertTriangle,
  Printer,
  Zap
} from 'lucide-react';

// Modular Imports
import { AppSummary } from './applications/AppSummary';
import { ApplicationsRegistry } from './applications/ApplicationsRegistry';
import { DispatcherControl } from './applications/DispatcherControl';
import { QualityControl } from './applications/QualityControl';
import { CreateApplicationCard } from './applications/CreateApplicationCard';
import { OutagesJournal } from './applications/OutagesJournal';
import { allowedSubsForSection } from '../constants/permissions';

type Tab = 'summary' | 'registry' | 'control' | 'quality' | 'mappings' | 'outages';

const REQUESTS_TABS: Tab[] = ['summary', 'registry', 'control', 'quality', 'mappings', 'outages'];
const SUBTAB_KEY = 'mkd_subTab_requests';

interface ApplicationsModuleProps {
  integrationEnabled?: boolean;
  allowedPermissions?: string[] | null;
}

export const ApplicationsModule: React.FC<ApplicationsModuleProps> = ({ integrationEnabled = true, allowedPermissions }) => {
  const visibleTabs = useMemo(() => {
    const allowed = allowedSubsForSection(allowedPermissions ?? [], 'requests');
    if (allowed === 'all') return REQUESTS_TABS;
    return REQUESTS_TABS.filter((t) => allowed.includes(t));
  }, [allowedPermissions]);

  const CACHE_KEY = 'mkd_applications_cache';
  const cached = readCache<DomaApplication[]>(CACHE_KEY, []);

  const [createCardOpen, setCreateCardOpen] = useState(false);
  const [activeTab, setActiveTab] = useState<Tab>(() => {
    const s = localStorage.getItem(SUBTAB_KEY);
    return (s && REQUESTS_TABS.includes(s as Tab)) ? s as Tab : 'summary';
  });
  const [applications, setApplications] = useState<DomaApplication[]>(cached);
  const [loading, setLoading] = useState(cached.length === 0);
  const [error, setError] = useState<string | null>(null);

  useEffect(() => {
    if (visibleTabs.length > 0 && !visibleTabs.includes(activeTab)) {
      setActiveTab(visibleTabs[0]);
    }
  }, [visibleTabs, activeTab]);

  const fetchApplications = useCallback(async (showSpinner = true) => {
    if (showSpinner) setLoading(true);
    setError(null);
    try {
      const data = await backendApi.getApplications();
      setApplications(data);
      saveCache(CACHE_KEY, data);
    } catch (err) {
      console.error('[ApplicationsModule] Ошибка загрузки заявок:', err);
      setError('Ошибка загрузки данных заявок с сервера. Проверьте подключение или логи синхронизации Doma AI.');
    } finally {
      setLoading(false);
    }
  }, []);

  useEffect(() => {
    fetchApplications(cached.length === 0);
  }, []);

  useEffect(() => {
    const onRefresh = () => fetchApplications(false);
    window.addEventListener(REFRESH_EVENTS.applications, onRefresh);
    return () => window.removeEventListener(REFRESH_EVENTS.applications, onRefresh);
  }, [fetchApplications]);

  // Фоновый опрос: чтобы другой пользователь видел новые заявки без перезагрузки
  useEffect(() => {
    const interval = setInterval(() => fetchApplications(false), 10 * 1000);
    return () => clearInterval(interval);
  }, [fetchApplications]);

  useEffect(() => {
    localStorage.setItem(SUBTAB_KEY, activeTab);
  }, [activeTab]);


  if (loading) {
    return (
        <div className="flex flex-col items-center justify-center py-20 animate-pulse">
            <RotateCw className="w-10 h-10 text-primary-400 animate-spin mb-4" />
            <p className="text-[10px] font-black text-slate-400 uppercase tracking-[0.2em]">
              {integrationEnabled ? 'Синхронизация с doma.ai...' : 'Загрузка заявок...'}
            </p>
        </div>
    );
  }

  if (error) {
    return (
        <div className="text-center py-20">
            <AlertTriangle className="w-16 h-16 text-red-400 mx-auto mb-4" />
            <h3 className="text-lg font-bold text-slate-700">Ошибка системы</h3>
            <p className="text-sm text-slate-500 mb-6">{error}</p>
            <button onClick={() => fetchApplications(true)} className="bg-primary-600 text-white px-6 py-2 rounded-xl font-bold">Повторить</button>
        </div>
    );
  }

  return (
    <div className="animate-fade-in pb-20">
      <div className="flex justify-between items-center mb-6 px-1">
         <div>
            <h2 className="text-xl font-bold text-slate-800 leading-none">Диспетчерская 24/7</h2>
            <p className="text-[10px] text-slate-400 font-black uppercase tracking-widest mt-1">Центр управления инцидентами</p>
         </div>
         <div className="flex gap-2">
            <button 
                className="p-2.5 bg-white border border-slate-200 text-slate-400 rounded-xl hover:text-primary-600 transition-all shadow-sm" 
                title="Обновить реестр"
                onClick={() => window.dispatchEvent(new CustomEvent(REFRESH_EVENTS.applications))}
            >
                <RotateCw className="w-5 h-5"/>
            </button>
            <button 
                className="p-2.5 bg-white border border-slate-200 text-slate-400 rounded-xl hover:text-primary-600 transition-all shadow-sm" 
                title="Печать отчетов"
            >
                <Printer className="w-5 h-5"/>
            </button>
            <button 
                className="bg-primary-600 text-white p-2.5 rounded-xl shadow-lg shadow-primary-500/30 flex items-center gap-2 px-4 text-xs font-black uppercase tracking-wider active:scale-95 transition-all"
                onClick={() => setCreateCardOpen(true)}
            >
                <Plus className="w-4 h-4" /> Создать заявку
            </button>
         </div>
      </div>

      {/* Sheet Selector */}
      <div className="flex p-1 bg-slate-200/50 rounded-2xl mb-6 overflow-x-auto no-scrollbar gap-1">
        {[
          { id: 'summary', label: 'Сводка', icon: LayoutDashboard },
          { id: 'registry', label: 'Реестр', icon: Inbox },
          { id: 'control', label: 'Контроль', icon: ShieldAlert },
          { id: 'quality', label: 'Качество', icon: Sparkles },
          { id: 'outages', label: 'Журнал отключений', icon: Zap },
        ].filter((tab) => visibleTabs.includes(tab.id)).map((tab) => (
          <button 
            key={tab.id}
            onClick={() => setActiveTab(tab.id as Tab)}
            className={`flex-shrink-0 min-w-[7rem] flex items-center justify-center gap-2 py-2.5 px-4 text-[10px] font-black uppercase tracking-wider whitespace-nowrap rounded-xl transition-all ${activeTab === tab.id ? 'bg-white text-primary-600 shadow-sm border border-white' : 'text-slate-500 hover:text-slate-700'}`}
          >
            <tab.icon className="w-3.5 h-3.5"/> {tab.label}
          </button>
        ))}
      </div>

      {/* Dynamic Sheet Content */}
      <div className="min-h-[280px] sm:min-h-[360px] md:min-h-[500px]">
        {activeTab === 'summary' && <AppSummary applications={applications} onNavigate={setActiveTab} />}
        {activeTab === 'registry' && <ApplicationsRegistry applications={applications} onRefresh={fetchApplications} />}
        {activeTab === 'control' && <DispatcherControl applications={applications} />}
        {activeTab === 'quality' && <QualityControl />}
        {activeTab === 'outages' && (
          <div className="mt-2">
            <OutagesJournal />
          </div>
        )}
      </div>

      {createCardOpen && (
        <CreateApplicationCard
          isOpen={createCardOpen}
          onClose={() => setCreateCardOpen(false)}
          onSuccess={fetchApplications}
        />
      )}
    </div>
  );
};