import React, { useState, useMemo } from 'react';
import { useNavigate } from 'react-router-dom';
import {
  Building2, Users, MessageSquare, Plus, Search,
  Edit, Trash2, ChevronDown, ChevronUp, ChevronsUpDown, X, CheckCircle2, Loader2, LogIn
} from 'lucide-react';
import { getTenants, createTenant, deleteTenant, updateTenant, impersonateTenant } from '../services/dataService';
import { Tenant } from '../types';
import { DateRangePicker } from '../components/DateRangePicker';
import { KPICard } from '../components/KPICard';

export const SuperAdmin: React.FC = () => {
  const navigate = useNavigate();
  const [dateRange, setDateRange] = useState({
    start: new Date(Date.now() - 30 * 24 * 60 * 60 * 1000),
    end: new Date()
  });
  const [selectedTenantId, setSelectedTenantId] = useState<string>('all');
  const [searchQuery, setSearchQuery] = useState('');
  const [tenants, setTenants] = useState<Tenant[]>([]);
  const [loading, setLoading] = useState(true);
  const [isModalOpen, setIsModalOpen] = useState(false);
  const [editingTenant, setEditingTenant] = useState<Tenant | null>(null);

  const [sortKey, setSortKey] = useState<keyof Tenant>('created_at');
  const [sortDirection, setSortDirection] = useState<'asc' | 'desc'>('desc');

  const loadTenants = async () => {
    setLoading(true);
    const data = await getTenants();
    setTenants(data);
    setLoading(false);
  };

  React.useEffect(() => {
    loadTenants();
  }, []);

  const totalTenants = tenants.length;
  const totalUsersGlobal = tenants.reduce((acc, t) => acc + (t.user_count || 0), 0);
  const totalAttendancesGlobal = tenants.reduce((acc, t) => acc + (t.attendance_count || 0), 0);

  const filteredTenants = useMemo(() => {
    let data = tenants;
    if (searchQuery) {
      const q = searchQuery.toLowerCase();
      data = data.filter(t => 
        t.name.toLowerCase().includes(q) || 
        t.admin_email?.toLowerCase().includes(q) ||
        t.slug?.toLowerCase().includes(q)
      );
    }
    if (selectedTenantId !== 'all') {
      data = data.filter(t => t.id === selectedTenantId);
    }
    return [...data].sort((a, b) => {
      const aVal = a[sortKey];
      const bVal = b[sortKey];
      if (aVal === undefined) return 1;
      if (bVal === undefined) return -1;
      if (aVal < bVal) return sortDirection === 'asc' ? -1 : 1;
      if (aVal > bVal) return sortDirection === 'asc' ? 1 : -1;
      return 0;
    });
  }, [tenants, searchQuery, selectedTenantId, sortKey, sortDirection]);

  const handleSort = (key: keyof Tenant) => {
    if (sortKey === key) {
      setSortDirection(prev => prev === 'asc' ? 'desc' : 'asc');
    } else {
      setSortKey(key);
      setSortDirection('asc');
    }
  };

  const handleEdit = (tenant: Tenant) => {
    setEditingTenant(tenant);
    setIsModalOpen(true);
  };

  const handleDelete = async (id: string) => {
    if (id === 'system') {
      alert('A organização do sistema não pode ser excluída.');
      return;
    }
    if (confirm('Tem certeza que deseja excluir esta organização? Esta ação não pode ser desfeita.')) {
      const success = await deleteTenant(id);
      if (success) {
        setTenants(prev => prev.filter(t => t.id !== id));
      } else {
        alert('Erro ao excluir a organização do servidor.');
      }
    }
  };

  const handleImpersonate = async (tenantId: string) => {
    try {
      if (tenantId === 'system') {
        alert('Você já está na organização do sistema.');
        return;
      }
      await impersonateTenant(tenantId);
      // Force a full reload to clear any cached context/state in the React app
      window.location.hash = '#/';
      window.location.reload(); 
    } catch (err: any) {
      alert(err.message || 'Erro ao tentar entrar na organização.');
    }
  };

  const [successMessage, setSuccessMessage] = useState('');
  const [errorMessage, setErrorMessage] = useState('');
  const [isSaving, setIsSaving] = useState(false);

  const handleSaveTenant = async (e: React.FormEvent) => {
    e.preventDefault();
    setErrorMessage('');
    setSuccessMessage('');
    setIsSaving(true);
    const form = e.target as HTMLFormElement;
    const name = (form.elements.namedItem('name') as HTMLInputElement).value;
    const slug = (form.elements.namedItem('slug') as HTMLInputElement).value;
    const admin_email = (form.elements.namedItem('admin_email') as HTMLInputElement).value;
    const status = (form.elements.namedItem('status') as HTMLSelectElement).value;

    try {
      if (editingTenant) {
        const success = await updateTenant(editingTenant.id, { name, slug, admin_email, status });
        if (success) {
          setSuccessMessage('Organização atualizada com sucesso!');
          loadTenants();
          setTimeout(() => {
            setIsModalOpen(false);
            setSuccessMessage('');
            setEditingTenant(null);
            setIsSaving(false);
          }, 2000);
        } else {
           setErrorMessage('Erro ao atualizar organização.');
           setIsSaving(false);
        }
      } else {
        const result = await createTenant({ name, slug, admin_email, status });
        if (result.success) {
          setSuccessMessage(result.message || 'Organização criada com sucesso!');
          loadTenants();
          setTimeout(() => {
            setIsModalOpen(false);
            setSuccessMessage('');
            setIsSaving(false);
          }, 3000);
        } else {
          setErrorMessage(result.message || 'Erro ao salvar organização.');
          setIsSaving(false);
        }
      }
    } catch (err) {
      setErrorMessage('Ocorreu um erro inesperado.');
      setIsSaving(false);
    }
  };

  const SortIcon = ({ column }: { column: keyof Tenant }) => {
    if (sortKey !== column) return <ChevronsUpDown size={14} className="text-zinc-300 dark:text-dark-muted" />;
    return sortDirection === 'asc' ? <ChevronUp size={14} className="text-brand-yellow" /> : <ChevronDown size={14} className="text-brand-yellow" />;
  };

  const StatusBadge = ({ status }: { status?: string }) => {
    const styles = {
      active: 'bg-green-100 text-green-700 border-green-200 dark:bg-green-900/30 dark:text-green-400 dark:border-green-800',
      inactive: 'bg-zinc-100 text-zinc-700 border-zinc-200 dark:bg-dark-input dark:text-dark-muted dark:border-dark-border',
      trial: 'bg-purple-100 text-purple-700 border-purple-200 dark:bg-purple-900/30 dark:text-purple-400 dark:border-purple-800',
    };
    const style = styles[status as keyof typeof styles] || styles.inactive;
    let label = status === 'active' ? 'Ativo' : status === 'inactive' ? 'Inativo' : status === 'trial' ? 'Teste' : 'Desconhecido';
    return <span className={`px-2.5 py-0.5 rounded-full text-xs font-semibold border capitalize ${style}`}>{label}</span>;
  };

  return (
    <div className="space-y-8 max-w-7xl mx-auto pb-8 transition-colors duration-300">
      <div className="flex flex-col md:flex-row md:items-center justify-between gap-4">
        <div>
          <h1 className="text-2xl font-bold text-zinc-900 dark:text-zinc-50 tracking-tight">Painel Super Admin</h1>
          <p className="text-zinc-500 dark:text-dark-muted text-sm">Gerencie organizações e visualize estatísticas globais.</p>
        </div>
        <button onClick={() => { setEditingTenant(null); setIsModalOpen(true); }} className="bg-zinc-900 dark:bg-brand-yellow text-white dark:text-zinc-950 px-4 py-2 rounded-lg flex items-center gap-2 whitespace-nowrap text-sm font-bold hover:opacity-90 transition-all shadow-sm">
          <Plus size={16} /> Adicionar Organização
        </button>
      </div>
{/* KPI Cards */}
<div className="grid grid-cols-1 md:grid-cols-3 gap-6">
  <KPICard title="Total de Organizações" value={totalTenants} icon={Building2} colorClass="text-blue-600" trend="up" trendValue="+1 este mês" />
  <KPICard title="Total de Usuários" value={totalUsersGlobal} icon={Users} colorClass="text-purple-600" subValue="Em todas as organizações" />
  <KPICard title="Total de Atendimentos" value={totalAttendancesGlobal.toLocaleString()} icon={MessageSquare} colorClass="text-green-600" trend="up" trendValue="+12%" />
</div>

      <div className="bg-white dark:bg-dark-card p-4 rounded-xl border border-zinc-200 dark:border-dark-border shadow-sm flex flex-col md:flex-row gap-4 justify-between items-center transition-colors">
        <div className="flex items-center gap-3 w-full md:w-auto">
          <DateRangePicker dateRange={dateRange} onChange={setDateRange} />
          <div className="h-8 w-px bg-zinc-200 dark:bg-dark-border hidden md:block" />
          <select className="bg-zinc-50 dark:bg-dark-bg border border-zinc-200 dark:border-dark-border px-3 py-2 rounded-lg text-sm text-zinc-700 dark:text-zinc-200 outline-none focus:ring-2 focus:ring-brand-yellow/20 cursor-pointer hover:border-zinc-300 dark:hover:border-dark-border w-full md:w-48 transition-all" value={selectedTenantId} onChange={(e) => setSelectedTenantId(e.target.value)}>
            <option value="all">Todas Organizações</option>
            {tenants.map(t => <option key={t.id} value={t.id}>{t.name}</option>)}
          </select>
        </div>
        <div className="relative w-full md:w-64">
          <Search size={16} className="absolute left-3 top-1/2 -translate-y-1/2 text-zinc-400 dark:text-dark-muted" />
          <input type="text" placeholder="Buscar organizações..." value={searchQuery} onChange={(e) => setSearchQuery(e.target.value)} className="w-full pl-9 pr-4 py-2 bg-zinc-50 dark:bg-dark-bg border border-zinc-200 dark:border-dark-border rounded-lg text-sm text-zinc-900 dark:text-zinc-100 outline-none focus:ring-2 focus:ring-brand-yellow/20 transition-all" />
        </div>
      </div>

      <div className="bg-white dark:bg-dark-card border border-zinc-200 dark:border-dark-border rounded-xl shadow-sm overflow-hidden transition-colors">
        <div className="overflow-x-auto">
          <table className="w-full text-left border-collapse">
            <thead>
              <tr className="bg-zinc-50/50 dark:bg-dark-bg/50 text-zinc-500 dark:text-dark-muted text-xs uppercase tracking-wider border-b border-zinc-100 dark:border-dark-border">
                <th className="px-6 py-4 font-semibold cursor-pointer hover:bg-zinc-50 dark:hover:bg-dark-border select-none" onClick={() => handleSort('name')}>
                  <div className="flex items-center gap-2">Organização <SortIcon column="name" /></div>
                </th>
                <th className="px-6 py-4 font-semibold">Slug</th>
                <th className="px-6 py-4 font-semibold cursor-pointer hover:bg-zinc-50 dark:hover:bg-dark-border select-none" onClick={() => handleSort('status')}>
                  <div className="flex items-center gap-2">Status <SortIcon column="status" /></div>
                </th>
                <th className="px-6 py-4 font-semibold text-center cursor-pointer hover:bg-zinc-50 dark:hover:bg-dark-border select-none" onClick={() => handleSort('user_count')}>
                  <div className="flex items-center justify-center gap-2">Usuários <SortIcon column="user_count" /></div>
                </th>
                <th className="px-6 py-4 font-semibold text-center cursor-pointer hover:bg-zinc-50 dark:hover:bg-dark-border select-none" onClick={() => handleSort('attendance_count')}>
                  <div className="flex items-center justify-center gap-2">Atendimentos <SortIcon column="attendance_count" /></div>
                </th>
                <th className="px-6 py-4 font-semibold text-right">Ações</th>
              </tr>
            </thead>
            <tbody className="divide-y divide-zinc-100 dark:divide-dark-border text-sm">
              {filteredTenants.map((tenant) => (
                <tr key={tenant.id} className="hover:bg-zinc-50/50 dark:hover:bg-zinc-800/50 transition-colors group">
                  <td className="px-6 py-4">
                    <div className="flex items-center gap-3">
                      <div className="w-10 h-10 rounded-lg bg-zinc-100 dark:bg-dark-bg flex items-center justify-center text-zinc-400 dark:text-dark-muted font-bold border border-zinc-200 dark:border-dark-border">
                        {tenant.logo_url ? <img src={tenant.logo_url} className="w-full h-full object-cover rounded-lg" alt="" /> : <Building2 size={20} />}
                      </div>
                      <div>
                        <div className="font-semibold text-zinc-900 dark:text-zinc-100">{tenant.name}</div>
                        <div className="text-xs text-zinc-500 dark:text-dark-muted">{tenant.admin_email}</div>
                      </div>
                    </div>
                  </td>
                  <td className="px-6 py-4 text-zinc-600 dark:text-dark-muted font-mono text-xs">{tenant.slug}</td>
                  <td className="px-6 py-4"><StatusBadge status={tenant.status} /></td>
                  <td className="px-6 py-4 text-center font-medium text-zinc-700 dark:text-zinc-300">{tenant.user_count}</td>
                  <td className="px-6 py-4 text-center font-medium text-zinc-700 dark:text-zinc-300">{tenant.attendance_count?.toLocaleString()}</td>
                  <td className="px-6 py-4 text-right">
                    <div className="flex items-center justify-end gap-2 transition-opacity">
                      {tenant.id !== 'system' && (
                        <button onClick={() => handleImpersonate(tenant.id)} title="Entrar na Organização" className="p-2 text-zinc-400 hover:text-green-600 hover:bg-green-50 dark:hover:bg-green-900/30 rounded-lg transition-colors">
                          <LogIn size={16} />
                        </button>
                      )}
                      <button onClick={() => handleEdit(tenant)} title="Editar" className="p-2 text-zinc-400 hover:text-brand-yellow hover:bg-zinc-50 dark:hover:bg-dark-bg rounded-lg transition-colors"><Edit size={16} /></button>
                      <button onClick={() => handleDelete(tenant.id)} title="Excluir" className="p-2 text-zinc-400 hover:text-red-600 hover:bg-red-50 dark:hover:bg-red-900/30 rounded-lg transition-colors"><Trash2 size={16} /></button>
                    </div>
                  </td>
                </tr>
              ))}
            </tbody>
          </table>
        </div>
        <div className="px-6 py-4 border-t border-zinc-100 dark:border-dark-border bg-zinc-50/30 dark:bg-dark-bg/30 text-xs text-zinc-500 dark:text-dark-muted flex justify-between items-center transition-colors">
          <span>Mostrando {filteredTenants.length} de {tenants.length} organizações</span>
          <div className="flex gap-2">
            <button disabled className="px-3 py-1 border dark:border-dark-border rounded bg-white dark:bg-dark-card disabled:opacity-50">Ant</button>
            <button disabled className="px-3 py-1 border dark:border-dark-border rounded bg-white dark:bg-dark-card disabled:opacity-50">Próx</button>
          </div>
        </div>
      </div>

      {isModalOpen && (
        <div className="fixed inset-0 z-50 flex items-center justify-center p-4 bg-zinc-950/80 backdrop-blur-sm">
          <div className="bg-white dark:bg-dark-card rounded-xl shadow-xl w-full max-w-lg overflow-hidden animate-in fade-in zoom-in duration-200 border border-transparent dark:border-dark-border transition-colors">
            <div className="px-6 py-4 border-b border-zinc-100 dark:border-dark-border flex justify-between items-center bg-zinc-50/50 dark:bg-dark-bg/50">
              <h3 className="font-bold text-zinc-900 dark:text-zinc-50">{editingTenant ? 'Editar Organização' : 'Adicionar Nova Organização'}</h3>
              <button onClick={() => setIsModalOpen(false)} className="text-zinc-400 hover:text-zinc-600 dark:hover:text-zinc-300"><X size={20} /></button>
            </div>
            <form onSubmit={handleSaveTenant} className="p-6 space-y-4">
              {successMessage && (
                <div className="bg-green-50 dark:bg-green-900/20 border border-green-100 dark:border-green-900/30 p-3 rounded-lg flex items-center gap-2 text-green-700 dark:text-green-400 text-sm animate-in fade-in slide-in-from-top-1">
                  <CheckCircle2 size={16} /> {successMessage}
                </div>
              )}
              {errorMessage && (
                <div className="bg-red-50 dark:bg-red-900/20 border border-red-100 dark:border-red-900/30 p-3 rounded-lg flex items-center gap-2 text-red-700 dark:text-red-400 text-sm animate-in fade-in slide-in-from-top-1">
                  <X size={16} /> {errorMessage}
                </div>
              )}
              <div className="space-y-2">
                <label className="text-sm font-medium text-zinc-700 dark:text-zinc-300">Nome da Organização</label>
                <input type="text" name="name" defaultValue={editingTenant?.name} className="w-full px-3 py-2 bg-zinc-50 dark:bg-dark-bg border border-zinc-200 dark:border-dark-border rounded-lg text-sm text-zinc-900 dark:text-zinc-100 focus:ring-2 focus:ring-brand-yellow/20 outline-none transition-all" required />
              </div>
              <div className="grid grid-cols-2 gap-4">
                <div className="space-y-2">
                  <label className="text-sm font-medium text-zinc-700 dark:text-zinc-300">Slug</label>
                  <input type="text" name="slug" defaultValue={editingTenant?.slug} className="w-full px-3 py-2 bg-zinc-50 dark:bg-dark-bg border border-zinc-200 dark:border-dark-border rounded-lg text-sm text-zinc-900 dark:text-zinc-100 focus:ring-2 focus:ring-brand-yellow/20 outline-none transition-all" />
                </div>
                <div className="space-y-2">
                  <label className="text-sm font-medium text-zinc-700 dark:text-zinc-300">Status</label>
                  <select name="status" defaultValue={editingTenant?.status || 'active'} className="w-full px-3 py-2 bg-zinc-50 dark:bg-dark-bg border border-zinc-200 dark:border-dark-border rounded-lg text-sm text-zinc-900 dark:text-zinc-100 outline-none transition-all">
                    <option value="active">Ativo</option>
                    <option value="inactive">Inativo</option>
                    <option value="trial">Teste</option>
                  </select>
                </div>
              </div>
              <div className="space-y-2">
                <label className="text-sm font-medium text-zinc-700 dark:text-zinc-300">E-mail do Admin</label>
                <input type="email" name="admin_email" defaultValue={editingTenant?.admin_email} className="w-full px-3 py-2 bg-zinc-50 dark:bg-dark-bg border border-zinc-200 dark:border-dark-border rounded-lg text-sm text-zinc-900 dark:text-zinc-100 focus:ring-2 focus:ring-brand-yellow/20 outline-none transition-all" required />
              </div>
              <div className="pt-4 flex justify-end gap-3 border-t dark:border-dark-border mt-6">
                <button type="button" onClick={() => setIsModalOpen(false)} className="px-4 py-2 text-zinc-600 dark:text-zinc-400 hover:bg-zinc-100 dark:hover:bg-dark-border rounded-lg text-sm font-medium transition-colors">Cancelar</button>
                <button type="submit" disabled={isSaving} className="px-4 py-2 bg-zinc-900 dark:bg-brand-yellow text-white dark:text-zinc-950 rounded-lg text-sm font-bold flex items-center gap-2 hover:opacity-90 transition-all shadow-sm disabled:opacity-70">
                  {isSaving ? <Loader2 className="animate-spin" size={16} /> : (editingTenant ? 'Salvar Alterações' : 'Criar Organização')}
                </button>
              </div>
            </form>
          </div>
        </div>
      )}
    </div>
  );
};