实现快传，完善快传和网盘的功能，实现文件的互传等一系列功能

front/src/lib/file-share.ts

@@ -0,0 +1,49 @@
+import { apiRequest } from './api';
+import { getTransferRouterMode, type TransferRouterMode } from './transfer-links';
+import type { CreateFileShareLinkResponse, FileMetadata, FileShareDetailsResponse } from './types';
+
+export const FILE_SHARE_ROUTE_PREFIX = '/share';
+
+export function buildFileShareUrl(
+  origin: string,
+  token: string,
+  routerMode: TransferRouterMode = 'browser',
+) {
+  const normalizedOrigin = origin.replace(/\/+$/, '');
+  const encodedToken = encodeURIComponent(token);
+
+  if (routerMode === 'hash') {
+    return `${normalizedOrigin}/#${FILE_SHARE_ROUTE_PREFIX}/${encodedToken}`;
+  }
+
+  return `${normalizedOrigin}${FILE_SHARE_ROUTE_PREFIX}/${encodedToken}`;
+}
+
+export function getPostLoginRedirectPath(nextPath: string | null, fallback = '/overview') {
+  if (!nextPath || !nextPath.startsWith('/') || nextPath.startsWith('//')) {
+    return fallback;
+  }
+
+  return nextPath;
+}
+
+export function createFileShareLink(fileId: number) {
+  return apiRequest<CreateFileShareLinkResponse>(`/files/${fileId}/share-links`, {
+    method: 'POST',
+  });
+}
+
+export function getFileShareDetails(token: string) {
+  return apiRequest<FileShareDetailsResponse>(`/files/share-links/${encodeURIComponent(token)}`);
+}
+
+export function importSharedFile(token: string, path: string) {
+  return apiRequest<FileMetadata>(`/files/share-links/${encodeURIComponent(token)}/import`, {
+    method: 'POST',
+    body: { path },
+  });
+}
+
+export function getCurrentFileShareUrl(token: string) {
+  return buildFileShareUrl(window.location.origin, token, getTransferRouterMode());
+}