'use client';

import { useState, useEffect } from 'react';
import { Switch } from '@/components/ui/switch';
import { Button } from '@/components/ui/button';
import { Input } from '@/components/ui/input';
import { Label } from '@/components/ui/label';
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogFooter,
  DialogHeader,
  DialogTitle,
} from '@/components/ui/dialog';
import { getPartners, createUser, updateUserRole } from '@/lib/actions/users';
import { getPartnerEndCustomers } from '@/lib/actions/end-customers';
import { Plus, Users, Mail, Eye, CheckCircle, ShieldAlert, Loader2, Ban, Unlock } from 'lucide-react';

export default function AdminSettings() {
  const [demoActive, setDemoActive] = useState(true);
  const [partners, setPartners] = useState<any[]>([]);
  const [loadingPartners, setLoadingPartners] = useState(true);

  // Modal States
  const [isCreateOpen, setIsCreateOpen] = useState(false);
  const [isCustomersOpen, setIsCustomersOpen] = useState(false);

  // Selected Partner / Customers State
  const [selectedPartner, setSelectedPartner] = useState<any | null>(null);
  const [partnerCustomers, setPartnerCustomers] = useState<any[]>([]);
  const [loadingCustomers, setLoadingCustomers] = useState(false);

  // Lock/Unlock State
  const [lockingId, setLockingId] = useState<string | null>(null);

  // Create Partner Form States
  const [email, setEmail] = useState('');
  const [password, setPassword] = useState('');
  const [createError, setCreateError] = useState<string | null>(null);
  const [creating, setCreating] = useState(false);

  useEffect(() => {
    // 1. Demo Banner Status auslesen
    const state = localStorage.getItem('demo_banner_disabled') !== 'true';
    setDemoActive(state);

    // 2. Partner laden
    loadPartners();
  }, []);

  const loadPartners = async () => {
    setLoadingPartners(true);
    try {
      const data = await getPartners();
      setPartners(data);
    } catch (err) {
      console.error('Fehler beim Laden der Partner:', err);
    } finally {
      setLoadingPartners(false);
    }
  };

  const toggleDemo = (checked: boolean) => {
    setDemoActive(checked);
    localStorage.setItem('demo_banner_disabled', (!checked).toString());
    window.dispatchEvent(new Event('storage_demo_changed'));
  };

  const handleCreatePartner = async (e: React.FormEvent) => {
    e.preventDefault();
    setCreating(true);
    setCreateError(null);

    try {
      await createUser({
        email,
        password: password || undefined,
        email_confirm: true,
      });
      setIsCreateOpen(false);
      setEmail('');
      setPassword('');
      loadPartners();
    } catch (err: any) {
      console.error('Fehler beim Erstellen des Partners:', err);
      setCreateError(err.message || 'Ein Fehler ist aufgetreten.');
    } finally {
      setCreating(false);
    }
  };

  const handleToggleLock = async (partner: any) => {
    const newRole = partner.role === 'gesperrt' ? 'partner' : 'gesperrt';
    setLockingId(partner.id);
    try {
      await updateUserRole(partner.id, newRole);
      await loadPartners();
    } catch (err) {
      console.error('Fehler beim Sperren/Entsperren:', err);
    } finally {
      setLockingId(null);
    }
  };

  const handleShowCustomers = async (partner: any) => {
    setSelectedPartner(partner);
    setPartnerCustomers([]);
    setLoadingCustomers(true);
    setIsCustomersOpen(true);

    try {
      const customers = await getPartnerEndCustomers(partner.id);
      setPartnerCustomers(customers);
    } catch (err) {
      console.error('Fehler beim Laden der Partner-Kunden:', err);
    } finally {
      setLoadingCustomers(false);
    }
  };

  return (
    <div className="p-6 max-w-4xl mx-auto text-slate-900 dark:text-white space-y-8">
      {/* Page Header */}
      <div>
        <h1 className="text-3xl font-extrabold tracking-tight">Admin Einstellungen</h1>
        <p className="text-slate-500 dark:text-slate-400 text-sm mt-1">
          Verwalten Sie globale Shopeinstellungen, Partnerkonten und Kundenzuweisungen.
        </p>
      </div>

      {/* Allgemeine Einstellungen */}
      <div className="p-5 bg-white dark:bg-slate-900/50 rounded-xl border border-slate-200 dark:border-white/10 shadow-sm space-y-4">
        <h2 className="text-lg font-bold">Allgemeine Einstellungen</h2>
        <div className="flex items-center justify-between p-4 bg-slate-50 dark:bg-white/5 rounded-lg border border-slate-100 dark:border-white/5">
          <div>
            <p className="font-medium text-sm text-slate-900 dark:text-white">Demo-Warnmeldungen</p>
            <p className="text-xs text-slate-500 dark:text-slate-400">Schaltet gelbe Banner ein oder aus.</p>
          </div>
          <Switch checked={demoActive} onCheckedChange={toggleDemo} />
        </div>
      </div>

      {/* Partnerverwaltung */}
      <div className="p-5 bg-white dark:bg-slate-900/50 rounded-xl border border-slate-200 dark:border-white/10 shadow-sm space-y-6">
        <div className="flex items-center justify-between gap-4 flex-wrap">
          <div className="flex items-center gap-2">
            <Users className="w-5 h-5 text-blue-600 dark:text-blue-500" />
            <h2 className="text-lg font-bold">Partner-Management</h2>
          </div>
          <Button onClick={() => setIsCreateOpen(true)} className="bg-blue-600 hover:bg-blue-700 text-white font-semibold">
            <Plus className="w-4 h-4 mr-2" /> Partner hinzufügen
          </Button>
        </div>

        {/* Partner Liste */}
        {loadingPartners ? (
          <div className="flex justify-center items-center py-12">
            <Loader2 className="w-8 h-8 text-blue-600 dark:text-blue-500 animate-spin" />
            <span className="ml-3 text-slate-500 text-sm">Lade Partner...</span>
          </div>
        ) : partners.length === 0 ? (
          <div className="text-center py-12 border-2 border-dashed border-slate-200 dark:border-white/5 rounded-xl text-slate-500">
            Keine Partner registriert.
          </div>
        ) : (
          <div className="overflow-x-auto">
            <table className="w-full text-left">
              <thead>
                <tr className="border-b border-slate-200 dark:border-white/10 text-slate-400 text-xs font-semibold uppercase">
                  <th className="pb-3">Partner E-Mail</th>
                  <th className="pb-3">Status</th>
                  <th className="pb-3">Erstellt am</th>
                  <th className="pb-3 text-right">Aktionen</th>
                </tr>
              </thead>
              <tbody className="divide-y divide-slate-100 dark:divide-white/5">
                {partners.map((partner) => {
                  const isGesperrt = partner.role === 'gesperrt';
                  const isLocking = lockingId === partner.id;
                  return (
                  <tr key={partner.id} className="hover:bg-slate-50 dark:hover:bg-white/3 transition-colors">
                    <td className="py-4 font-medium text-slate-900 dark:text-white">
                      <div className="flex items-center gap-2">
                        <Mail className="w-4 h-4 text-slate-400" />
                        {partner.email}
                      </div>
                    </td>
                    <td className="py-4">
                      {isGesperrt ? (
                        <span className="inline-flex items-center gap-1.5 px-2.5 py-0.5 rounded-full text-xs font-medium bg-red-100 text-red-700 dark:bg-red-500/10 dark:text-red-400 border border-red-200 dark:border-red-500/20">
                          <Ban className="w-3.5 h-3.5" /> Gesperrt
                        </span>
                      ) : (
                        <span className="inline-flex items-center gap-1.5 px-2.5 py-0.5 rounded-full text-xs font-medium bg-green-100 text-green-800 dark:bg-green-500/10 dark:text-green-400 border border-green-200 dark:border-green-500/20">
                          <CheckCircle className="w-3.5 h-3.5" /> Aktiv
                        </span>
                      )}
                    </td>
                    <td className="py-4 text-sm text-slate-500 dark:text-slate-400">
                      {partner.created_at ? new Date(partner.created_at).toLocaleDateString('de-DE') : '–'}
                    </td>
                    <td className="py-4 text-right">
                      <div className="flex items-center justify-end gap-2">
                        <Button
                          variant="outline"
                          size="sm"
                          onClick={() => handleShowCustomers(partner)}
                          className="border-slate-200 hover:bg-slate-100 dark:border-white/10 dark:hover:bg-white/5 gap-1.5"
                        >
                          <Eye className="w-4 h-4 text-blue-600 dark:text-blue-500" /> Kundenliste
                        </Button>
                        <Button
                          variant="outline"
                          size="sm"
                          disabled={isLocking}
                          onClick={() => handleToggleLock(partner)}
                          className={isGesperrt
                            ? 'border-green-300 text-green-700 hover:bg-green-50 dark:border-green-500/30 dark:text-green-400 dark:hover:bg-green-500/10 gap-1.5'
                            : 'border-red-300 text-red-700 hover:bg-red-50 dark:border-red-500/30 dark:text-red-400 dark:hover:bg-red-500/10 gap-1.5'}
                        >
                          {isLocking
                            ? <Loader2 className="w-4 h-4 animate-spin" />
                            : isGesperrt
                              ? <><Unlock className="w-4 h-4" /> Entsperren</>
                              : <><Ban className="w-4 h-4" /> Sperren</>}
                        </Button>
                      </div>
                    </td>
                  </tr>
                  );
                })}
              </tbody>
            </table>
          </div>
        )}
      </div>

      {/* MODAL 1: Neuen Partner erstellen */}
      <Dialog open={isCreateOpen} onOpenChange={setIsCreateOpen}>
        <DialogContent className="bg-white dark:bg-slate-950 border-slate-200 dark:border-white/10 text-slate-900 dark:text-white shadow-2xl">
          <DialogHeader>
            <DialogTitle>Neuen Partner anlegen</DialogTitle>
            <DialogDescription className="text-slate-500 dark:text-slate-400">
              Erstellt einen Partner-Zugang. Dieser kann sich mit den Daten im Shop einloggen.
            </DialogDescription>
          </DialogHeader>

          <form onSubmit={handleCreatePartner} className="space-y-4 mt-2">
            <div className="space-y-2">
              <Label htmlFor="email">E-Mail Adresse</Label>
              <Input
                id="email"
                type="email"
                required
                placeholder="partner@example.com"
                value={email}
                onChange={(e) => setEmail(e.target.value)}
                className="bg-slate-50 dark:bg-white/5 border-slate-200 dark:border-white/10"
              />
            </div>
            <div className="space-y-2">
              <Label htmlFor="password">Passwort (optional)</Label>
              <Input
                id="password"
                type="password"
                placeholder="Leer lassen für Zufallspasswort"
                value={password}
                onChange={(e) => setPassword(e.target.value)}
                className="bg-slate-50 dark:bg-white/5 border-slate-200 dark:border-white/10"
              />
            </div>

            {createError && (
              <p className="text-sm text-red-600 dark:text-red-400 flex items-center gap-1.5">
                <ShieldAlert className="w-4 h-4" /> {createError}
              </p>
            )}

            <DialogFooter className="pt-2">
              <Button type="button" variant="outline" onClick={() => setIsCreateOpen(false)} disabled={creating}>
                Abbrechen
              </Button>
              <Button type="submit" disabled={creating} className="bg-blue-600 hover:bg-blue-700 text-white font-semibold">
                {creating ? <Loader2 className="w-4 h-4 mr-2 animate-spin" /> : null}
                Partner erstellen
              </Button>
            </DialogFooter>
          </form>
        </DialogContent>
      </Dialog>

      {/* MODAL 2: Kundenliste eines Partners anzeigen */}
      <Dialog open={isCustomersOpen} onOpenChange={setIsCustomersOpen}>
        <DialogContent className="bg-white dark:bg-slate-950 border-slate-200 dark:border-white/10 text-slate-900 dark:text-white shadow-2xl max-w-2xl max-h-[85vh] overflow-y-auto">
          <DialogHeader>
            <DialogTitle>Kunden von {selectedPartner?.email}</DialogTitle>
            <DialogDescription className="text-slate-500 dark:text-slate-400">
              Liste aller angelegten Endkunden dieses Partners.
            </DialogDescription>
          </DialogHeader>

          <div className="mt-4">
            {loadingCustomers ? (
              <div className="flex justify-center items-center py-12">
                <Loader2 className="w-8 h-8 text-blue-600 dark:text-blue-500 animate-spin" />
                <span className="ml-3 text-slate-500 text-sm">Lade Kunden...</span>
              </div>
            ) : partnerCustomers.length === 0 ? (
              <div className="text-center py-12 border border-dashed border-slate-200 dark:border-white/10 rounded-xl text-slate-500">
                Dieser Partner hat noch keine Kunden angelegt.
              </div>
            ) : (
              <div className="overflow-x-auto">
                <table className="w-full text-left">
                  <thead>
                    <tr className="border-b border-slate-200 dark:border-white/10 text-slate-400 text-xs font-semibold uppercase">
                      <th className="pb-3">Unternehmen</th>
                      <th className="pb-3">Ansprechpartner</th>
                      <th className="pb-3">Ort</th>
                      <th className="pb-3">Status</th>
                    </tr>
                  </thead>
                  <tbody className="divide-y divide-slate-100 dark:divide-white/5">
                    {partnerCustomers.map((customer) => (
                      <tr key={customer.id} className="hover:bg-slate-50 dark:hover:bg-white/3 transition-colors">
                        <td className="py-4 font-semibold text-slate-900 dark:text-white">
                          {customer.company_name}
                        </td>
                        <td className="py-4 text-sm text-slate-700 dark:text-slate-300">
                          {[customer.first_name, customer.last_name].filter(Boolean).join(' ') || '–'}
                        </td>
                        <td className="py-4 text-sm text-slate-500 dark:text-slate-400">
                          {[customer.zip, customer.city].filter(Boolean).join(' ') || '–'}
                        </td>
                        <td className="py-4">
                          {customer.is_anonymized ? (
                            <span className="inline-flex items-center px-2 py-0.5 rounded text-xs font-medium bg-red-100 text-red-800 dark:bg-red-500/10 dark:text-red-400 border border-red-200 dark:border-red-500/20">
                              Anonymisiert
                            </span>
                          ) : (
                            <span className="inline-flex items-center px-2 py-0.5 rounded text-xs font-medium bg-green-100 text-green-800 dark:bg-green-500/10 dark:text-green-400 border border-green-200 dark:border-green-500/20">
                              Aktiv
                            </span>
                          )}
                        </td>
                      </tr>
                    ))}
                  </tbody>
                </table>
              </div>
            )}
          </div>

          <DialogFooter className="pt-4 border-t border-slate-100 dark:border-white/5">
            <Button type="button" onClick={() => setIsCustomersOpen(false)}>
              Schließen
            </Button>
          </DialogFooter>
        </DialogContent>
      </Dialog>
    </div>
  );
}