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

import { fileContentUrl } from '@/api/files';
import {
  COSMETICS_MAX_PER_GUILD,
  COSMETIC_MAX_BYTES,
  COSMETIC_NAME_MAX,
  deleteGuildCosmetic,
  fetchGuildCosmetics,
  guildCosmeticsQueryKey,
  renameGuildCosmetic,
  uploadGuildCosmetic,
  type CosmeticKind,
  type GuildCosmetic,
} from '@/api/cosmetics';
import { ErrorNotice } from '@/components/ui/ErrorNotice';
import { Field } from '@/components/ui/Field';
import { Button } from '@/components/ui/primitives';
import { SkeletonLines } from '@/components/ui/Skeleton';
import { useUnsavedChanges } from '@/lib/unsavedChanges';
import { SettingsSection } from '@/pages/settings/SettingsSection';

interface GuildCosmeticsSectionProps {
  guildId: string;
  canManage: boolean;
}

/**
 * «Оформление» сервера (AGENT.md 7.4): галерея рамок и иконок. Файлы хранятся
 * обычными загрузками, поэтому анимированные GIF/WebP сохраняют анимацию;
 * элементы выдаются ролям в разделе «Роли».
 */
export function GuildCosmeticsSection({ guildId, canManage }: GuildCosmeticsSectionProps) {
  const { t } = useTranslation();
  const queryClient = useQueryClient();
  const frameInput = useRef<HTMLInputElement | null>(null);
  const badgeInput = useRef<HTMLInputElement | null>(null);
  const [renaming, setRenaming] = useState<GuildCosmetic | null>(null);
  const [name, setName] = useState('');
  const [error, setError] = useState<unknown>(null);

  const cosmetics = useQuery({
    queryKey: guildCosmeticsQueryKey(guildId),
    queryFn: ({ signal }) => fetchGuildCosmetics(guildId, signal),
    enabled: canManage,
    retry: 0,
  });

  const invalidate = (): void => {
    void queryClient.invalidateQueries({ queryKey: guildCosmeticsQueryKey(guildId) });
  };

  const upload = useMutation({
    mutationFn: (input: { kind: CosmeticKind; name: string; file: File }) =>
      uploadGuildCosmetic(guildId, input),
    onSuccess: () => {
      setError(null);
      invalidate();
    },
    onError: (cause: unknown) => setError(cause),
  });

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

  const remove = useMutation({
    mutationFn: (id: string) => deleteGuildCosmetic(guildId, id),
    onSuccess: invalidate,
    onError: (cause: unknown) => setError(cause),
  });

  // Незаконченное переименование: 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() });
    },
  });

  if (!canManage) {
    return null;
  }

  /** Проверяем файл на клиенте: сервер всё равно проверит, но так быстрее. */
  const pick = (kind: CosmeticKind, file: File | undefined): void => {
    if (file === undefined) {
      return;
    }
    if (!file.type.startsWith('image/')) {
      setError(new Error(t('settings.servers.cosmetics.notImage')));
      return;
    }
    if (file.size > COSMETIC_MAX_BYTES) {
      setError(new Error(t('settings.servers.cosmetics.tooLarge')));
      return;
    }
    upload.mutate({ kind, name: file.name.replace(/\.[^.]+$/u, ''), file });
  };

  const list = cosmetics.data ?? [];
  const frames = list.filter((item) => item.kind === 'frame');
  const badges = list.filter((item) => item.kind === 'badge');

  return (
    <SettingsSection
      title={t('settings.servers.cosmetics.title')}
      description={t('settings.servers.cosmetics.description')}
    >
      <div className="mt-4 flex flex-col gap-3" data-testid="guild-cosmetics">
        {cosmetics.isPending ? <SkeletonLines rows={2} /> : null}
        {cosmetics.isError ? (
          <ErrorNotice error={cosmetics.error} onRetry={() => void cosmetics.refetch()} />
        ) : null}
        {error === null ? null : <ErrorNotice error={error} />}

        <p className="text-xs text-fg-muted">
          {t('settings.servers.cosmetics.limit', {
            used: list.length,
            total: COSMETICS_MAX_PER_GUILD,
          })}
        </p>

        {[
          { kind: 'frame' as const, items: frames, input: frameInput },
          { kind: 'badge' as const, items: badges, input: badgeInput },
        ].map((group) => (
          <div key={group.kind} className="flex flex-col gap-2">
            <div className="flex items-center gap-2">
              <span className="text-sm font-medium">
                {t(`settings.servers.cosmetics.kind.${group.kind}`)}
              </span>
              <Button
                variant="ghost"
                data-testid={`cosmetic-upload-${group.kind}`}
                disabled={upload.isPending || list.length >= COSMETICS_MAX_PER_GUILD}
                onClick={() => group.input.current?.click()}
              >
                {t('settings.servers.cosmetics.upload')}
              </Button>
              <input
                ref={group.input}
                type="file"
                accept="image/*"
                aria-label={t(`settings.servers.cosmetics.kind.${group.kind}`)}
                data-testid={`cosmetic-input-${group.kind}`}
                className="sr-only"
                onChange={(event) => {
                  pick(group.kind, event.target.files?.[0]);
                  event.target.value = '';
                }}
              />
            </div>
            {group.items.length === 0 ? (
              <p className="text-xs text-fg-muted">{t('settings.servers.cosmetics.empty')}</p>
            ) : (
              <ul className="flex flex-wrap gap-2" data-testid={`cosmetic-list-${group.kind}`}>
                {group.items.map((item) => (
                  <li
                    key={item.id}
                    data-testid={`cosmetic-${item.id}`}
                    className="flex w-40 flex-col items-center gap-1 rounded-[var(--radius-md)] border border-border/50 bg-surface-2 p-2"
                  >
                    <img
                      src={fileContentUrl(item.file_id)}
                      alt=""
                      loading="lazy"
                      className="h-14 w-14 object-contain"
                    />
                    <span className="w-full truncate text-center text-xs" title={item.name}>
                      {item.name}
                    </span>
                    <div className="flex gap-1">
                      <Button
                        variant="ghost"
                        data-testid={`cosmetic-rename-${item.id}`}
                        onClick={() => {
                          setRenaming(item);
                          setName(item.name);
                        }}
                      >
                        {t('settings.channel.webhooks.rename')}
                      </Button>
                      <Button
                        variant="ghost"
                        className="border border-danger/50 text-danger"
                        data-testid={`cosmetic-delete-${item.id}`}
                        disabled={remove.isPending}
                        onClick={() => {
                          if (window.confirm(t('settings.servers.cosmetics.deleteConfirm'))) {
                            remove.mutate(item.id);
                          }
                        }}
                      >
                        {t('common.delete')}
                      </Button>
                    </div>
                  </li>
                ))}
              </ul>
            )}
          </div>
        ))}

        {renaming === null ? null : (
          <form
            className="flex items-end gap-2"
            onSubmit={(event) => {
              event.preventDefault();
              if (name.trim() !== '') {
                rename.mutate({ id: renaming.id, name: name.trim() });
              }
            }}
          >
            <Field
              label={t('settings.servers.cosmetics.name')}
              value={name}
              maxLength={COSMETIC_NAME_MAX}
              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>
    </SettingsSection>
  );
}