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

import {
  deleteInstanceGuild,
  instanceGuildsQueryKey,
  instanceUsersQueryKey,
  updateInstanceGuild,
} from '@/api/instance';
import { ErrorNotice } from '@/components/ui/ErrorNotice';
import { Field } from '@/components/ui/Field';
import { Button } from '@/components/ui/primitives';
import { useUnsavedChanges } from '@/lib/unsavedChanges';
import type { InstanceGuild } from '@/api/types';

interface InstanceGuildsPanelProps {
  guilds: InstanceGuild[];
  isPending: boolean;
  error: unknown;
  onRetry: () => void;
  /** Открыть настройки сервера: админ правит комнаты, роли и ники там. */
  onOpenSettings: (guildId: string) => void;
}

/**
 * Серверы инстанса (AGENT.md 7.19): администратор переименовывает и удаляет
 * любой сервер и открывает его настройки — комнаты, роли и ники правятся
 * обычными разделами, права администратора инстанса действуют везде.
 */
export function InstanceGuildsPanel({
  guilds,
  isPending,
  error,
  onRetry,
  onOpenSettings,
}: InstanceGuildsPanelProps) {
  const { t } = useTranslation();
  const queryClient = useQueryClient();
  const [renaming, setRenaming] = useState<InstanceGuild | null>(null);
  const [name, setName] = useState('');
  const [actionError, setActionError] = useState<unknown>(null);

  const invalidate = (): void => {
    void queryClient.invalidateQueries({ queryKey: instanceGuildsQueryKey });
    void queryClient.invalidateQueries({ queryKey: instanceUsersQueryKey });
  };

  const rename = useMutation({
    mutationFn: (input: { id: string; name: string }) =>
      updateInstanceGuild(input.id, { name: input.name }),
    onSuccess: () => {
      setActionError(null);
      setRenaming(null);
      invalidate();
    },
    onError: (cause: unknown) => setActionError(cause),
  });

  const remove = useMutation({
    mutationFn: (guildId: string) => deleteInstanceGuild(guildId),
    onSuccess: () => {
      setActionError(null);
      invalidate();
    },
    onError: (cause: unknown) => setActionError(cause),
  });

  // Незаконченное переименование сервера: черновик живёт в поле, пока форма открыта.
  useUnsavedChanges({
    dirty: renaming !== null && name.trim() !== '' && name.trim() !== renaming.name,
    save: async () => {
      if (renaming === null || name.trim() === '') {
        return;
      }
      await rename.mutateAsync({ id: renaming.id, name: name.trim() });
    },
  });

  const pending = rename.isPending || remove.isPending;

  if (isPending) {
    return <p className="mt-2 text-sm text-fg-muted">{t('common.loading')}</p>;
  }
  if (error !== null && error !== undefined) {
    return <ErrorNotice className="mt-3" error={error} onRetry={onRetry} />;
  }
  if (guilds.length === 0) {
    return <p className="mt-2 text-sm text-fg-muted">{t('settings.instance.guildsEmpty')}</p>;
  }

  return (
    <div className="mt-3 flex flex-col gap-2" data-testid="instance-guilds-actions">
      {actionError === null ? null : <ErrorNotice error={actionError} />}
      <ul className="flex flex-col gap-1 text-sm" data-testid="instance-guilds">
        {guilds.map((guild) => (
          <li
            key={guild.id}
            data-testid={`instance-guild-${guild.id}`}
            className="flex flex-wrap items-center gap-2 border-b border-border/40 py-2 last:border-b-0"
          >
            <span className="min-w-0 flex-1 truncate">{guild.name}</span>
            <span className="shrink-0 text-xs text-fg-muted">
              {guild.is_main ? `${t('settings.instance.mainBadge')} · ` : ''}
              {t('settings.instance.memberCount', { count: guild.member_count })}
            </span>
            <Button
              variant="ghost"
              data-testid={`instance-guild-open-${guild.id}`}
              onClick={() => onOpenSettings(guild.id)}
            >
              {t('settings.instance.actions.openSettings')}
            </Button>
            <Button
              variant="ghost"
              data-testid={`instance-guild-rename-${guild.id}`}
              disabled={pending}
              onClick={() => {
                setRenaming(guild);
                setName(guild.name);
              }}
            >
              {t('settings.instance.actions.rename')}
            </Button>
            <Button
              variant="ghost"
              className="border border-danger/50 text-danger"
              data-testid={`instance-guild-delete-${guild.id}`}
              disabled={pending || guild.is_main}
              onClick={() => {
                if (
                  window.confirm(
                    t('settings.instance.actions.deleteGuildConfirm', { name: guild.name }),
                  )
                ) {
                  remove.mutate(guild.id);
                }
              }}
            >
              {t('common.delete')}
            </Button>
          </li>
        ))}
      </ul>

      {renaming === null ? null : (
        <form
          className="flex items-end gap-2"
          onSubmit={(event) => {
            event.preventDefault();
            if (renaming !== null && name.trim() !== '') {
              rename.mutate({ id: renaming.id, name: name.trim() });
            }
          }}
        >
          <Field
            label={t('settings.instance.actions.newName')}
            value={name}
            maxLength={64}
            onChange={(event) => setName(event.target.value)}
          />
          <Button type="submit" disabled={rename.isPending}>
            {t('common.save')}
          </Button>
          <Button variant="ghost" onClick={() => setRenaming(null)}>
            {t('common.cancel')}
          </Button>
        </form>
      )}
    </div>
  );
}