Fix issue with duplicate images (#30073)

* ensure export file paths are unique

* add unit test for filepath uniqueness. fix createMessagesRequest mock.

* add return types

test/unit-tests/utils/exportUtils/HTMLExport-test.ts

@@ -104,8 +104,8 @@ describe("HTMLExport", () => {
             const chunk = events.slice(from, limit);
             return Promise.resolve({
                 chunk,
-                from: from.toString(),
-                to: (from + limit).toString(),
+                start: from.toString(),
+                end: (from + limit).toString(),
             });
         });
     }
@@ -419,6 +419,36 @@ describe("HTMLExport", () => {
         expect(text).toBe(attachmentBody);
     });
 
+    it("should handle attachments with identical names and dates", async () => {
+        mockMessages(EVENT_MESSAGE, EVENT_ATTACHMENT, EVENT_ATTACHMENT);
+
+        const exporter = new HTMLExporter(
+            room,
+            ExportType.LastNMessages,
+            {
+                attachmentsIncluded: true,
+                maxSize: 1_024 * 1_024,
+                numberOfMessages: 40,
+            },
+            () => {},
+        );
+
+        await exporter.export();
+
+        const files = getFiles(exporter);
+
+        // There should be 5 files: 2 attachments, 1 html file, 1 css file and 1 js file
+        expect(Object.keys(files)).toHaveLength(5);
+
+        // Ensure that the attachment is present
+        const file = files[Object.keys(files).find((k) => k.endsWith(".txt"))!];
+        expect(file).not.toBeUndefined();
+
+        // Ensure that the duplicate attachment has been uniquely named
+        const duplicateFile = files[Object.keys(files).find((k) => k.endsWith("(1).txt"))!];
+        expect(duplicateFile).not.toBeUndefined();
+    });
+
     it("should handle when attachment cannot be fetched", async () => {
         mockMessages(EVENT_MESSAGE, EVENT_ATTACHMENT_MALFORMED, EVENT_ATTACHMENT);
         const attachmentBody = "Lorem ipsum dolor sit amet";