import { useCallback, useRef, useState } from 'react';
import { useMutation, useQueryClient } from '@tanstack/react-query';
import { useTranslation } from 'react-i18next';
import { useNavigate } from 'react-router';

import { logout } from '@/api/auth';
import { currentUserQueryKey, updateProfile } from '@/api/users';
import { userStatuses, type UserStatus } from '@/api/types';
import { Avatar } from '@/components/ui/Avatar';
import { Menu, MenuGroupLabel, MenuItem, MenuSeparator } from '@/components/ui/Menu';
import { useCurrentUser } from '@/lib/hooks';
import { useApiErrorMessage } from '@/lib/useApiErrorMessage';
import { useGatewayStore } from '@/stores/gateway';
import { useSessionStore } from '@/stores/session';

/** Статусы, которые можно выставить из меню: «не в сети» сервер выводит сам. */
const selectableStatuses = userStatuses.filter((value) => value !== 'offline');

/**
 * Панель пользователя внизу слева: аватар, имя и статус. Клик по аватару,
 * имени или шестерёнке открывает всплывающее вверх меню с настройками,
 * сменой статуса и выходом (см. `Menu`).
 */
export function UserPanel() {
  const { t } = useTranslation();
  const navigate = useNavigate();
  const queryClient = useQueryClient();
  const currentUser = useCurrentUser();
  const describeError = useApiErrorMessage();
  const sessionUser = useSessionStore((state) => state.user);
  const disconnect = useGatewayStore((state) => state.disconnect);

  const [menuOpen, setMenuOpen] = useState(false);
  const triggerRef = useRef<HTMLButtonElement | null>(null);

  const name = sessionUser?.display_name ?? currentUser.data?.display_name ?? '';
  const username = sessionUser?.username ?? currentUser.data?.username ?? '';
  const displayName = name === '' ? username : name;
  const status: UserStatus = sessionUser?.status ?? currentUser.data?.status ?? 'online';
  const customStatus = sessionUser?.custom_status ?? '';
  const emoji = sessionUser?.custom_status_emoji ?? '';
  const seed = currentUser.data?.id ?? sessionUser?.id ?? username;
  const avatarFileId = sessionUser?.avatar_file_id ?? currentUser.data?.avatar_file_id;

  const signOut = useMutation({
    mutationFn: () => logout(),
    onSuccess: () => {
      // Сессия в cookie уже погашена — сбрасываем локальное состояние.
      disconnect();
      useSessionStore.getState().reset();
      queryClient.clear();
      void navigate('/login', { replace: true });
    },
  });

  const changeStatus = useMutation({
    mutationFn: (next: UserStatus) => updateProfile({ status: next }),
    onSuccess: (updated) => {
      queryClient.setQueryData(currentUserQueryKey, updated);
      useSessionStore.getState().patchUser(updated);
      setMenuOpen(false);
    },
  });

  const statusLabel = userStatuses.includes(status)
    ? t(`user.status.${status}`)
    : t('user.status.offline');

  const onCopyId = useCallback(() => {
    if (currentUser.data === undefined) {
      return;
    }
    void navigator.clipboard?.writeText(currentUser.data.id);
  }, [currentUser.data]);

  const toggleMenu = useCallback(() => setMenuOpen((value) => !value), []);
  const closeMenu = useCallback(() => setMenuOpen(false), []);

  const goTo = (path: string) => (): void => {
    setMenuOpen(false);
    void navigate(path);
  };

  const error = changeStatus.error ?? signOut.error;
  const errorText = error === null || error === undefined ? null : describeError(error);

  return (
    <footer
      aria-label={t('user.panelLabel')}
      className="relative flex flex-col border-t border-border/40 bg-surface-2/80"
    >
      <div className="flex items-center gap-1 px-2 py-2">
        <button
          ref={triggerRef}
          type="button"
          aria-haspopup="menu"
          aria-expanded={menuOpen}
          aria-label={t('user.menu.open')}
          onClick={toggleMenu}
          className="flex min-w-0 flex-1 items-center gap-2 rounded-[var(--radius-md)] px-1 py-1 text-left transition-colors duration-[var(--duration-fast)] hover:bg-surface-3/70 active:bg-surface-3"
        >
          <Avatar name={displayName} seed={seed} fileId={avatarFileId} size="md" />
          <span className="min-w-0 flex-1">
            <span className="block truncate text-sm font-medium" title={displayName}>
              {displayName}
            </span>
            <span className="block truncate text-xs text-fg-muted" title={statusLabel}>
              {emoji === '' ? null : (
                <span aria-hidden="true" className="mr-1">
                  {emoji}
                </span>
              )}
              {customStatus === '' ? statusLabel : `${statusLabel} · ${customStatus}`}
            </span>
          </span>
        </button>

        <button
          type="button"
          aria-label={t('user.copyId')}
          title={t('user.copyId')}
          className="rounded-[var(--radius-sm)] px-2 py-1 text-fg-muted transition-colors duration-[var(--duration-fast)] hover:bg-surface-3 hover:text-fg active:scale-95"
          onClick={onCopyId}
        >
          #
        </button>
        <button
          type="button"
          aria-haspopup="menu"
          aria-expanded={menuOpen}
          aria-label={t('user.settings')}
          title={t('user.settings')}
          className="rounded-[var(--radius-sm)] px-2 py-1 text-fg-muted transition-colors duration-[var(--duration-fast)] hover:bg-surface-3 hover:text-fg active:scale-95"
          onClick={toggleMenu}
        >
          ⚙
        </button>
      </div>

      <Menu
        open={menuOpen}
        label={t('user.menu.label')}
        onClose={closeMenu}
        anchorRef={triggerRef}
      >
        <MenuGroupLabel>{displayName}</MenuGroupLabel>
        <MenuItem icon="👤" onClick={goTo('/settings/account/profile')}>
          {t('user.menu.account')}
        </MenuItem>
        <MenuItem icon="🗄" onClick={goTo('/settings/servers')}>
          {t('user.menu.guilds')}
        </MenuItem>
        <MenuSeparator />
        <div role="group" aria-label={t('user.menu.status')}>
          <MenuGroupLabel>{t('user.menu.status')}</MenuGroupLabel>
          {selectableStatuses.map((value) => (
            <MenuItem
              key={value}
              role="menuitemradio"
              selected={value === status}
              disabled={changeStatus.isPending}
              onClick={() => {
                changeStatus.reset();
                changeStatus.mutate(value);
              }}
            >
              {t(`user.status.${value}`)}
            </MenuItem>
          ))}
        </div>
        <MenuSeparator />
        <MenuItem
          danger
          icon="⏻"
          disabled={signOut.isPending}
          onClick={() => {
            signOut.reset();
            signOut.mutate();
          }}
        >
          {t(signOut.isPending ? 'user.loggingOut' : 'user.logout')}
        </MenuItem>
      </Menu>

      {errorText === null ? null : (
        <p role="alert" className="px-3 pb-2 text-xs text-danger">
          {errorText}
        </p>
      )}
    </footer>
  );
}