import Link from 'next/link';

import {
  ChevronLeft,
  ChevronRight,
  GraduationCap,
  Plus,
  Users,
  Calendar,
} from 'lucide-react';
import { getTranslations } from 'next-intl/server';

import { createCourseManagementApi } from '@kit/course-management/api';
import { formatDate, formatCurrencyAmount } 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 {
  COURSE_STATUS_VARIANT,
  COURSE_STATUS_LABEL_KEYS,
} from '~/lib/status-badges';

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

const PAGE_SIZE = 25;

export default async function CoursesPage({ params, searchParams }: PageProps) {
  const { account } = await params;
  const search = await searchParams;
  const client = getSupabaseServerClient();
  const t = await getTranslations('courses');

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

  if (!acct) return <AccountNotFound />;

  const api = createCourseManagementApi(client);
  const page = Number(search.page) || 1;

  const [courses, stats] = await Promise.all([
    api.courses.list(acct.id, {
      search: search.q as string,
      status: search.status as string,
      page,
      pageSize: PAGE_SIZE,
    }),
    api.statistics.getQuickStats(acct.id),
  ]);

  const totalPages = Math.ceil(courses.total / PAGE_SIZE);

  return (
    <CmsPageShell account={account} title={t('pages.coursesTitle')}>
      <div className="flex w-full flex-col gap-6">
        {/* Header */}
        <div className="flex items-center justify-between">
          <p className="text-muted-foreground">
            {t('pages.coursesDescription')}
          </p>

          <Button data-test="courses-new-btn" asChild>
            <Link href={`/home/${account}/courses/new`}>
              <Plus className="mr-2 h-4 w-4" />
              {t('nav.newCourse')}
            </Link>
          </Button>
        </div>

        {/* Stats */}
        <div className="grid grid-cols-1 gap-4 sm:grid-cols-2 lg:grid-cols-4">
          <StatsCard
            title={t('stats.total')}
            value={stats.totalCourses}
            icon={<GraduationCap className="h-5 w-5" />}
          />
          <StatsCard
            title={t('stats.active')}
            value={stats.openCourses}
            icon={<Calendar className="h-5 w-5" />}
          />
          <StatsCard
            title={t('stats.completed')}
            value={stats.completedCourses}
            icon={<GraduationCap className="h-5 w-5" />}
          />
          <StatsCard
            title={t('stats.participants')}
            value={stats.totalParticipants}
            icon={<Users className="h-5 w-5" />}
          />
        </div>

        {/* Search & Filters */}
        <ListToolbar
          searchPlaceholder={t('list.searchPlaceholder')}
          filters={[
            {
              param: 'status',
              label: t('common.status'),
              options: [
                { value: '', label: t('common.all') },
                { value: 'planned', label: t('status.planned') },
                { value: 'open', label: t('status.open') },
                { value: 'running', label: t('status.running') },
                { value: 'completed', label: t('status.completed') },
                { value: 'cancelled', label: t('status.cancelled') },
              ],
            },
          ]}
        />

        {/* Table or Empty State */}
        {courses.data.length === 0 ? (
          <EmptyState
            icon={<GraduationCap className="h-8 w-8" />}
            title={t('list.noCourses')}
            description={t('list.createFirst')}
            actionLabel={t('nav.newCourse')}
            actionHref={`/home/${account}/courses/new`}
          />
        ) : (
          <Card>
            <CardHeader>
              <CardTitle>{t('list.title', { count: courses.total })}</CardTitle>
            </CardHeader>
            <CardContent>
              <div className="overflow-x-auto rounded-md border">
                <table className="w-full min-w-[640px] text-sm">
                  <thead>
                    <tr className="bg-muted/50 border-b">
                      <th scope="col" className="p-3 text-left font-medium">
                        {t('list.courseNumber')}
                      </th>
                      <th scope="col" className="p-3 text-left font-medium">
                        {t('list.courseName')}
                      </th>
                      <th scope="col" className="p-3 text-left font-medium">
                        {t('list.startDate')}
                      </th>
                      <th scope="col" className="p-3 text-left font-medium">
                        {t('list.endDate')}
                      </th>
                      <th scope="col" className="p-3 text-left font-medium">
                        {t('list.status')}
                      </th>
                      <th scope="col" className="p-3 text-right font-medium">
                        {t('list.capacity')}
                      </th>
                      <th scope="col" className="p-3 text-right font-medium">
                        {t('list.fee')}
                      </th>
                    </tr>
                  </thead>
                  <tbody>
                    {courses.data.map((course: Record<string, unknown>) => (
                      <tr
                        key={String(course.id)}
                        className="hover:bg-muted/30 border-b"
                      >
                        <td className="p-3 font-mono text-xs">
                          {String(course.course_number ?? '—')}
                        </td>
                        <td className="p-3 font-medium">
                          <Link
                            href={`/home/${account}/courses/${String(course.id)}`}
                            className="hover:underline"
                          >
                            {String(course.name)}
                          </Link>
                        </td>
                        <td className="p-3">
                          {formatDate(course.start_date as string)}
                        </td>
                        <td className="p-3">
                          {formatDate(course.end_date as string)}
                        </td>
                        <td className="p-3">
                          <Badge
                            variant={
                              COURSE_STATUS_VARIANT[String(course.status)] ??
                              'secondary'
                            }
                          >
                            {t(
                              COURSE_STATUS_LABEL_KEYS[String(course.status)] ??
                                String(course.status),
                            )}
                          </Badge>
                        </td>
                        <td className="p-3 text-right">
                          {course.capacity != null
                            ? String(course.capacity)
                            : '—'}
                        </td>
                        <td className="p-3 text-right">
                          {course.fee != null
                            ? formatCurrencyAmount(course.fee as number)
                            : '—'}
                        </td>
                      </tr>
                    ))}
                  </tbody>
                </table>
              </div>

              {/* Pagination */}
              {totalPages > 1 && (
                <div className="flex items-center justify-between border-t px-2 py-4">
                  <p className="text-muted-foreground text-sm">
                    {t('common.page')} {page} {t('common.of')} {totalPages} (
                    {courses.total} {t('common.entries')})
                  </p>
                  <div className="flex items-center gap-2">
                    {page > 1 ? (
                      <Button variant="outline" size="sm" asChild>
                        <Link
                          href={`/home/${account}/courses?page=${page - 1}`}
                        >
                          <ChevronLeft className="mr-1 h-4 w-4" />
                          {t('common.previous')}
                        </Link>
                      </Button>
                    ) : (
                      <Button variant="outline" size="sm" disabled>
                        <ChevronLeft className="mr-1 h-4 w-4" />
                        {t('common.previous')}
                      </Button>
                    )}

                    {page < totalPages ? (
                      <Button variant="outline" size="sm" asChild>
                        <Link
                          href={`/home/${account}/courses?page=${page + 1}`}
                        >
                          {t('common.next')}
                          <ChevronRight className="ml-1 h-4 w-4" />
                        </Link>
                      </Button>
                    ) : (
                      <Button variant="outline" size="sm" disabled>
                        {t('common.next')}
                        <ChevronRight className="ml-1 h-4 w-4" />
                      </Button>
                    )}
                  </div>
                </div>
              )}
            </CardContent>
          </Card>
        )}
      </div>
    </CmsPageShell>
  );
}