feat(s3): add S3 move (object & prefix) support: server handlers, API client methods, UI dialogs/picker, drag-and-drop and validation

ts_web/utilities/index.ts

@@ -1 +1,2 @@
 export * from './formatters.js';
+export * from './move-validator.js';

ts_web/utilities/move-validator.ts

@@ -0,0 +1,47 @@
+/**
+ * Move validation utilities for S3 objects
+ */
+
+export interface IMoveValidation {
+  valid: boolean;
+  error?: string;
+}
+
+/**
+ * Validates if a move operation is allowed
+ * @param sourceKey The source object key (file or folder with trailing /)
+ * @param destPrefix The destination prefix (folder)
+ * @returns Validation result with error message if invalid
+ */
+export function validateMove(sourceKey: string, destPrefix: string): IMoveValidation {
+  // Check: Moving folder into itself or a subfolder of itself
+  if (sourceKey.endsWith('/')) {
+    // It's a folder - check if destPrefix starts with sourceKey
+    if (destPrefix.startsWith(sourceKey)) {
+      return { valid: false, error: 'Cannot move a folder into itself' };
+    }
+  }
+
+  // Check: Source and dest are the same location
+  const sourceParent = getParentPrefix(sourceKey);
+  if (sourceParent === destPrefix) {
+    return { valid: false, error: 'Item is already in this location' };
+  }
+
+  return { valid: true };
+}
+
+/**
+ * Gets the parent prefix (directory) of a given key
+ * @param key The object key (file or folder)
+ * @returns The parent prefix
+ */
+export function getParentPrefix(key: string): string {
+  // "folder1/folder2/file.txt" -> "folder1/folder2/"
+  // "folder1/folder2/" -> "folder1/"
+  // "file.txt" -> ""
+  // "folder/" -> ""
+  const trimmed = key.endsWith('/') ? key.slice(0, -1) : key;
+  const lastSlash = trimmed.lastIndexOf('/');
+  return lastSlash >= 0 ? trimmed.substring(0, lastSlash + 1) : '';
+}