import Link from 'next/link';

import {
  ChevronLeft,
  ChevronRight,
  Mail,
  Plus,
  Send,
  Users,
} from 'lucide-react';

import { createNewsletterApi } from '@kit/newsletter/api';
import { formatDate } from '@kit/shared/dates';
import { getSupabaseServerClient } from '@kit/supabase/server-client';
import { Badge } from '@kit/ui/badge';
import { Button } from '@kit/ui/button';
import { Card, CardContent, CardHeader, CardTitle } from '@kit/ui/card';
import { ListToolbar } from '@kit/ui/list-toolbar';

import { AccountNotFound } from '~/components/account-not-found';
import { CmsPageShell } from '~/components/cms-page-shell';
import { EmptyState } from '~/components/empty-state';
import { StatsCard } from '~/components/stats-card';
import {
  NEWSLETTER_STATUS_VARIANT,
  NEWSLETTER_STATUS_LABEL,
} from '~/lib/status-badges';

const PAGE_SIZE = 25;

interface PageProps {
  params: Promise<{ account: string }>;
  searchParams: Promise<Record<string, string | string[] | undefined>>;
}

function buildQuery(
  base: Record<string, string | undefined>,
  overrides: Record<string, string | number | undefined>,
): string {
  const params = new URLSearchParams();
  for (const [key, value] of Object.entries({ ...base, ...overrides })) {
    if (value !== undefined && value !== '') {
      params.set(key, String(value));
    }
  }
  const qs = params.toString();
  return qs ? `?${qs}` : '';
}

export default async function NewsletterPage({
  params,
  searchParams,
}: PageProps) {
  const { account } = await params;
  const search = await searchParams;
  const client = getSupabaseServerClient();

  const { data: acct } = await client
    .from('accounts')
    .select('id')
    .eq('slug', account)
    .single();

  if (!acct) return <AccountNotFound />;

  const q = typeof search.q === 'string' ? search.q : undefined;
  const status = typeof search.status === 'string' ? search.status : undefined;
  const page = Math.max(1, Number(search.page) || 1);

  const api = createNewsletterApi(client);
  const result = await api.listNewsletters(acct.id, {
    search: q,
    status,
    page,
    pageSize: PAGE_SIZE,
  });

  const newsletters = result.data;
  const totalItems = result.total;
  const totalPages = result.totalPages;
  const safePage = result.page;

  const sentCount = newsletters.filter(
    (n: Record<string, unknown>) => n.status === 'sent',
  ).length;

  const totalRecipients = newsletters.reduce(
    (sum: number, n: Record<string, unknown>) =>
      sum + (Number(n.total_recipients) || 0),
    0,
  );

  const queryBase = { q, status };

  return (
    <CmsPageShell account={account} title="Newsletter">
      <div className="flex w-full flex-col gap-6">
        {/* Header */}
        <div className="flex items-center justify-between">
          <div>
            <h1 className="text-2xl font-bold">Newsletter</h1>
            <p className="text-muted-foreground">
              Newsletter erstellen und versenden
            </p>
          </div>

          <Link href={`/home/${account}/newsletter/new`}>
            <Button data-test="newsletter-new-btn">
              <Plus className="mr-2 h-4 w-4" />
              Neuer Newsletter
            </Button>
          </Link>
        </div>

        {/* Stats */}
        <div className="grid grid-cols-1 gap-4 sm:grid-cols-3">
          <StatsCard
            title="Newsletter"
            value={totalItems}
            icon={<Mail className="h-5 w-5" />}
          />
          <StatsCard
            title="Gesendet"
            value={sentCount}
            icon={<Send className="h-5 w-5" />}
          />
          <StatsCard
            title="Empfänger gesamt"
            value={totalRecipients}
            icon={<Users className="h-5 w-5" />}
          />
        </div>

        {/* Toolbar */}
        <ListToolbar
          searchPlaceholder="Newsletter suchen..."
          filters={[
            {
              param: 'status',
              label: 'Status',
              options: [
                { value: '', label: 'Alle' },
                { value: 'draft', label: 'Entwurf' },
                { value: 'scheduled', label: 'Geplant' },
                { value: 'sending', label: 'Wird gesendet' },
                { value: 'sent', label: 'Gesendet' },
                { value: 'failed', label: 'Fehlgeschlagen' },
              ],
            },
          ]}
        />

        {/* Table or Empty State */}
        {totalItems === 0 ? (
          <EmptyState
            icon={<Mail className="h-8 w-8" />}
            title="Keine Newsletter vorhanden"
            description="Erstellen Sie Ihren ersten Newsletter, um loszulegen."
            actionLabel="Neuer Newsletter"
            actionHref={`/home/${account}/newsletter/new`}
          />
        ) : (
          <Card>
            <CardHeader>
              <CardTitle>Alle Newsletter ({totalItems})</CardTitle>
            </CardHeader>
            <CardContent>
              <div className="rounded-md border">
                <table className="w-full text-sm">
                  <thead>
                    <tr className="bg-muted/50 border-b">
                      <th className="p-3 text-left font-medium">Betreff</th>
                      <th className="p-3 text-left font-medium">Status</th>
                      <th className="p-3 text-right font-medium">Empfänger</th>
                      <th className="p-3 text-left font-medium">Erstellt</th>
                      <th className="p-3 text-left font-medium">Gesendet</th>
                    </tr>
                  </thead>
                  <tbody>
                    {newsletters.map((nl: Record<string, unknown>) => (
                      <tr
                        key={String(nl.id)}
                        className="hover:bg-muted/30 border-b"
                      >
                        <td className="p-3 font-medium">
                          <Link
                            href={`/home/${account}/newsletter/${String(nl.id)}`}
                            className="hover:underline"
                          >
                            {String(nl.subject ?? '(Kein Betreff)')}
                          </Link>
                        </td>
                        <td className="p-3">
                          <Badge
                            variant={
                              NEWSLETTER_STATUS_VARIANT[String(nl.status)] ??
                              'secondary'
                            }
                          >
                            {NEWSLETTER_STATUS_LABEL[String(nl.status)] ??
                              String(nl.status)}
                          </Badge>
                        </td>
                        <td className="p-3 text-right">
                          {nl.total_recipients != null
                            ? String(nl.total_recipients)
                            : '—'}
                        </td>
                        <td className="p-3">{formatDate(nl.created_at)}</td>
                        <td className="p-3">{formatDate(nl.sent_at)}</td>
                      </tr>
                    ))}
                  </tbody>
                </table>
              </div>

              {/* Pagination */}
              {totalPages > 1 && (
                <div className="flex items-center justify-between pt-4">
                  <p className="text-muted-foreground text-sm">
                    Seite {safePage} von {totalPages}
                  </p>
                  <div className="flex items-center gap-1">
                    {safePage > 1 ? (
                      <Link
                        href={`/home/${account}/newsletter${buildQuery(queryBase, { page: safePage - 1 })}`}
                      >
                        <Button variant="outline" size="sm">
                          <ChevronLeft className="h-4 w-4" />
                        </Button>
                      </Link>
                    ) : (
                      <Button variant="outline" size="sm" disabled>
                        <ChevronLeft className="h-4 w-4" />
                      </Button>
                    )}

                    <span className="px-3 text-sm font-medium">
                      {safePage} / {totalPages}
                    </span>

                    {safePage < totalPages ? (
                      <Link
                        href={`/home/${account}/newsletter${buildQuery(queryBase, { page: safePage + 1 })}`}
                      >
                        <Button variant="outline" size="sm">
                          <ChevronRight className="h-4 w-4" />
                        </Button>
                      </Link>
                    ) : (
                      <Button variant="outline" size="sm" disabled>
                        <ChevronRight className="h-4 w-4" />
                      </Button>
                    )}
                  </div>
                </div>
              )}
            </CardContent>
          </Card>
        )}
      </div>
    </CmsPageShell>
  );
}