备份：大改造前的完整版本 - 修复合同细节/付款节点/文件上传/施工管理/项目保存等BUG

frontend/src/hooks/useFormGuard.ts

@@ -0,0 +1,52 @@
+import { useEffect } from 'react';
+import { FormInstance } from 'antd';
+
+interface UseFormGuardOptions {
+  form: FormInstance;
+  enabled?: boolean;
+  onSaveDraft?: () => void;
+}
+
+/**
+ * 表单离开拦截 Hook
+ * - 浏览器刷新/关闭拦截 (beforeunload)
+ * - 移动端切后台时保存草稿 (visibilitychange + pagehide)
+ * 
+ * 注意：路由跳转拦截需要在使用组件中手动处理（因为 BrowserRouter 不支持 useBlocker）
+ */
+function useFormGuard(options: UseFormGuardOptions) {
+  const { form, enabled = true, onSaveDraft } = options;
+
+  // 浏览器刷新/关闭拦截
+  useEffect(() => {
+    if (!enabled) return;
+    const handler = (e: BeforeUnloadEvent) => {
+      if (form.isFieldsTouched()) {
+        e.preventDefault();
+      }
+    };
+    window.addEventListener('beforeunload', handler);
+    return () => window.removeEventListener('beforeunload', handler);
+  }, [form, enabled]);
+
+  // 移动端：页面切到后台时保存草稿
+  useEffect(() => {
+    if (!enabled || !onSaveDraft) return;
+    const handler = () => {
+      if (document.visibilityState === 'hidden' && form.isFieldsTouched()) {
+        onSaveDraft();
+      }
+    };
+    document.addEventListener('visibilitychange', handler);
+    const pageHideHandler = () => {
+      if (form.isFieldsTouched()) onSaveDraft();
+    };
+    window.addEventListener('pagehide', pageHideHandler);
+    return () => {
+      document.removeEventListener('visibilitychange', handler);
+      window.removeEventListener('pagehide', pageHideHandler);
+    };
+  }, [form, enabled, onSaveDraft]);
+}
+
+export default useFormGuard;