import type { AdminUserListView, AdminUserView } from '@dorfteich/shared';
import { keepPreviousData, useQuery } from '@tanstack/react-query';
import { MailCheck, ShieldMinus, ShieldPlus, Trash2, UserCheck, UserX } from 'lucide-react';
import { useEffect, useRef, useState } from 'react';
import { useTranslation } from 'react-i18next';

import { useAuth } from '../auth/auth-context';
import { IconButton } from '../components/IconButton';
import { apiDelete, apiGet, apiPatch, apiPost } from '../lib/api';

const PAGE_SIZE = 20;

/**
 * Site-Admin user management (issue #59): a searchable, paginated list with the
 * lifecycle actions. Destructive ones use an inline two-step confirm; the api
 * enforces the "not on self / not the last Site Admin" rules — this only hides
 * the buttons on your own row.
 */
export function UserManager(): React.JSX.Element {
  const { t } = useTranslation('users');
  const { user: me } = useAuth();
  const [q, setQ] = useState('');
  const [page, setPage] = useState(1);

  const query = useQuery({
    queryKey: ['admin', 'users', q, page],
    queryFn: () =>
      apiGet<AdminUserListView>(
        `/admin/users?q=${encodeURIComponent(q)}&page=${page}&pageSize=${PAGE_SIZE}`,
      ),
    placeholderData: keepPreviousData,
  });

  const run = async (fn: () => Promise<unknown>): Promise<void> => {
    await fn();
    await query.refetch();
  };

  const data = query.data;
  const totalPages = data ? Math.max(1, Math.ceil(data.total / PAGE_SIZE)) : 1;

  return (
    <section className="settings-section user-manager">
      <h2>{t('title')}</h2>
      <input
        className="user-manager__search"
        type="search"
        value={q}
        placeholder={t('search')}
        onChange={(e) => {
          setQ(e.target.value);
          setPage(1);
        }}
      />
      <table className="table user-manager__table">
        <thead>
          <tr>
            <th>{t('columns.user')}</th>
            <th>{t('columns.status')}</th>
            <th>{t('columns.role')}</th>
            <th>{t('columns.ponds')}</th>
            <th>{t('columns.lastLogin')}</th>
            <th>{t('columns.actions')}</th>
          </tr>
        </thead>
        <tbody>
          {(data?.users ?? []).map((u) => (
            <UserRow key={u.id} user={u} isSelf={u.id === me?.id} run={run} />
          ))}
        </tbody>
      </table>
      <div className="user-manager__pager">
        <button
          type="button"
          className="button"
          disabled={page <= 1}
          onClick={() => setPage((p) => p - 1)}
        >
          {t('prev')}
        </button>
        <span>{t('page', { page })}</span>
        <button
          type="button"
          className="button"
          disabled={page >= totalPages}
          onClick={() => setPage((p) => p + 1)}
        >
          {t('next')}
        </button>
      </div>
    </section>
  );
}

function UserRow({
  user,
  isSelf,
  run,
}: {
  user: AdminUserView;
  isSelf: boolean;
  run: (fn: () => Promise<unknown>) => Promise<void>;
}): React.JSX.Element {
  const { t } = useTranslation('users');
  const [confirmingDelete, setConfirmingDelete] = useState(false);
  const confirmRef = useRef<HTMLButtonElement>(null);
  // The icon button unmounts when the confirm step appears — hand focus over
  // so keyboard users land on the confirmation instead of losing focus.
  useEffect(() => {
    if (confirmingDelete) confirmRef.current?.focus();
  }, [confirmingDelete]);
  const disabled = user.status === 'DISABLED';

  return (
    <tr className="user-row" data-username={user.username}>
      <td>
        {user.displayName}
        <span className="user-row__username"> @{user.username}</span>
        {isSelf && <span className="badge">{t('actions.you')}</span>}
        <div className="user-row__email">{user.email}</div>
      </td>
      <td className="user-row__status">{t(`status.${user.status}`)}</td>
      <td>{user.isSiteAdmin ? t('role.admin') : t('role.user')}</td>
      <td>{user.pondCount}</td>
      <td>{user.lastLoginAt ? new Date(user.lastLoginAt).toLocaleDateString() : t('never')}</td>
      <td className="user-row__actions">
        {/* Flex lives on the inner div: a td with display:flex stops behaving
            like a table cell and its bottom border no longer meets the row's. */}
        {!isSelf && (
          <div className="user-row__actions-inner">
            {user.status === 'PENDING_VERIFICATION' && (
              <IconButton
                className="user-row__resend"
                label={t('actions.resend')}
                onClick={() =>
                  void run(() => apiPost(`/admin/users/${user.id}/resend-verification`))
                }
              >
                <MailCheck aria-hidden />
              </IconButton>
            )}
            <IconButton
              className="user-row__admin"
              label={user.isSiteAdmin ? t('actions.revokeAdmin') : t('actions.grantAdmin')}
              onClick={() =>
                void run(() =>
                  apiPatch(`/admin/users/${user.id}/site-admin`, {
                    isSiteAdmin: !user.isSiteAdmin,
                  }),
                )
              }
            >
              {user.isSiteAdmin ? <ShieldMinus aria-hidden /> : <ShieldPlus aria-hidden />}
            </IconButton>
            <IconButton
              className="user-row__disable"
              label={disabled ? t('actions.enable') : t('actions.disable')}
              onClick={() =>
                void run(() =>
                  apiPatch(`/admin/users/${user.id}/disabled`, { disabled: !disabled }),
                )
              }
            >
              {disabled ? <UserCheck aria-hidden /> : <UserX aria-hidden />}
            </IconButton>
            {confirmingDelete ? (
              <button
                type="button"
                ref={confirmRef}
                className="linklike user-row__delete-confirm"
                title={t('actions.deleteConfirm', { name: user.displayName })}
                onClick={() => void run(() => apiDelete(`/admin/users/${user.id}`))}
              >
                {t('actions.delete')}?
              </button>
            ) : (
              <IconButton
                className="user-row__delete"
                label={t('actions.delete')}
                onClick={() => setConfirmingDelete(true)}
              >
                <Trash2 aria-hidden />
              </IconButton>
            )}
          </div>
        )}
      </td>
    </tr>
  );
}