完善前端直连oss功能，新增重命名以及删除文件功能，完善后端接口

front/src/pages/files-state.ts

@@ -0,0 +1,55 @@
+export interface FilesUiItem {
+  id: number;
+  name: string;
+  type: string;
+  size: string;
+  modified: string;
+}
+
+export function getNextAvailableName(name: string, existingNames: Set<string>) {
+  if (!existingNames.has(name)) {
+    return name;
+  }
+
+  let index = 1;
+  let nextName = `${name} (${index})`;
+
+  while (existingNames.has(nextName)) {
+    index += 1;
+    nextName = `${name} (${index})`;
+  }
+
+  return nextName;
+}
+
+export function replaceUiFile<T extends FilesUiItem>(files: T[], nextFile: T) {
+  return files.map((file) => (file.id === nextFile.id ? nextFile : file));
+}
+
+export function removeUiFile<T extends FilesUiItem>(files: T[], fileId: number) {
+  return files.filter((file) => file.id !== fileId);
+}
+
+export function syncSelectedFile<T extends FilesUiItem>(selectedFile: T | null, nextFile: T) {
+  if (!selectedFile || selectedFile.id !== nextFile.id) {
+    return selectedFile;
+  }
+
+  return nextFile;
+}
+
+export function clearSelectionIfDeleted<T extends FilesUiItem>(selectedFile: T | null, fileId: number) {
+  if (!selectedFile || selectedFile.id !== fileId) {
+    return selectedFile;
+  }
+
+  return null;
+}
+
+export function getActionErrorMessage(error: unknown, fallbackMessage: string) {
+  if (error instanceof Error && error.message) {
+    return error.message;
+  }
+
+  return fallbackMessage;
+}