'use client';

import { useMemo, useState } from 'react';
import { useTranslations } from 'next-intl';
import { Bell, CheckCheck } from 'lucide-react';
import { Button } from '@/components/ui/button';
import { PageHeader } from '@/components/ui/PageHeader';
import { EmptyState, ErrorState, Skeleton } from '@/components/ui/states';
import { NotificationRow } from '@/components/notifications/notification-row';
import { useNotificationLabels } from '@/components/notifications/use-notification-labels';
import {
  notificationKind,
  type NotificationKind,
} from '@/components/notifications/notification-kind';
import { useNotifications } from '@/hooks/useNotifications';
import { cn } from '@/lib/utils';
import type { NotificationResponse } from '@/types/api';

/** Familles proposées au filtre, dans l'ordre où elles comptent au quotidien. */
const FILTERS = ['all', 'unread', 'booking', 'account', 'system'] as const;
type Filter = (typeof FILTERS)[number];

const PAGE_SIZE = 50;

/**
 * Toutes les notifications.
 *
 * Cette page existait déjà mais n'était liée de nulle part : « Voir tout »
 * ouvrait un panneau latéral qui rejouait le menu. Elle est désormais la seule
 * destination, et partage ses lignes avec la cloche — une notification se
 * présente pareil où qu'on la lise.
 */
export default function NotificationsPage() {
  const t = useTranslations('components.notifications');
  const [filter, setFilter] = useState<Filter>('all');

  const {
    notifications,
    unreadCount,
    isLoading,
    isError,
    refetch,
    markAsRead,
    markAllAsRead,
    isMarkingAll,
  } = useNotifications({ limit: PAGE_SIZE });

  const labels = useNotificationLabels();

  const visible = useMemo(() => {
    if (filter === 'all') return notifications;
    if (filter === 'unread') return notifications.filter(n => !n.read);
    return notifications.filter(n => matchesKind(n, filter));
  }, [notifications, filter]);

  const countFor = (value: Filter) => {
    if (value === 'all') return notifications.length;
    if (value === 'unread') return unreadCount;
    return notifications.filter(n => matchesKind(n, value)).length;
  };

  return (
    <>
      <PageHeader
        title={t('pageTitle')}
        description={t('pageDescription')}
        actions={
          unreadCount > 0 && (
            <Button
              variant="outline"
              size="sm"
              onClick={() => markAllAsRead()}
              loading={isMarkingAll}
            >
              <CheckCheck aria-hidden="true" />
              {t('markAllRead')}
            </Button>
          )
        }
        tabs={
          <div className="flex flex-wrap gap-2" role="tablist" aria-label={t('filterLabel')}>
            {FILTERS.map(value => {
              const active = filter === value;
              const count = countFor(value);
              return (
                <button
                  key={value}
                  type="button"
                  role="tab"
                  aria-selected={active}
                  onClick={() => setFilter(value)}
                  className={cn(
                    'inline-flex items-center gap-2 rounded-full border px-3 py-1.5 text-body-sm transition-colors duration-150 ease-out focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2',
                    active
                      ? 'border-brand-navy bg-brand-navy text-white'
                      : 'border-border bg-white text-neutral-700 hover:bg-neutral-50'
                  )}
                >
                  {t(`filters.${value}`)}
                  {count > 0 && (
                    <span
                      className={cn(
                        'tabular-nums text-body-xs',
                        active ? 'text-white/70' : 'text-neutral-400'
                      )}
                    >
                      {count}
                    </span>
                  )}
                </button>
              );
            })}
          </div>
        }
      />

      <div className="overflow-hidden rounded-lg border border-border bg-white">
        {isLoading ? (
          <div className="space-y-4 p-5" aria-hidden="true">
            {Array.from({ length: 5 }).map((_, index) => (
              <div key={index} className="flex gap-3">
                <Skeleton className="size-9 shrink-0 rounded-md" />
                <div className="flex-1 space-y-2">
                  <Skeleton className="h-3 w-1/3" />
                  <Skeleton className="h-3 w-3/4" />
                </div>
              </div>
            ))}
          </div>
        ) : isError ? (
          <ErrorState
            title={t('errorTitle')}
            description={t('errorBody')}
            retryLabel={t('retry')}
            onRetry={() => refetch()}
          />
        ) : visible.length === 0 ? (
          <EmptyState
            icon={Bell}
            title={filter === 'all' ? t('emptyTitle') : t('emptyFilterTitle')}
            description={filter === 'all' ? t('emptyBody') : t('emptyFilterBody')}
            action={
              filter !== 'all' && (
                <Button variant="outline" size="sm" onClick={() => setFilter('all')}>
                  {t('filters.all')}
                </Button>
              )
            }
          />
        ) : (
          <ul className="divide-y divide-border">
            {visible.map(notification => (
              <li key={notification.id}>
                <NotificationRow
                  notification={notification}
                  labels={labels}
                  density="comfortable"
                  onOpen={n => !n.read && markAsRead(n.id)}
                />
              </li>
            ))}
          </ul>
        )}
      </div>
    </>
  );
}

/** `document` et `rate` se rangent avec les réservations : c'est le même dossier. */
function matchesKind(notification: NotificationResponse, filter: Filter): boolean {
  const kind = notificationKind(notification.type);
  const family: Record<Exclude<Filter, 'all' | 'unread'>, NotificationKind[]> = {
    booking: ['booking', 'document', 'rate'],
    account: ['account'],
    system: ['system'],
  };
  return family[filter as Exclude<Filter, 'all' | 'unread'>].includes(kind);
}