check subfolders email counts in exchange (#2900)

<!-- PR description-->

check that no of emails in all subfolders is equivalent in restores. 

#### Does this PR need a docs update or release note?

- [ ] ✅ Yes, it's included
- [ ] 🕐 Yes, but in a later PR
- [ ] ⛔ No

#### Type of change

<!--- Please check the type of change your PR introduces: --->
- [ ] 🌻 Feature
- [ ] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Supportability/Tests
- [ ] 💻 CI/Deployment
- [ ] 🧹 Tech Debt/Cleanup

#### Issue(s)

<!-- Can reference multiple issues. Use one of the following "magic
words" - "closes, fixes" to auto-close the Github issue. -->
* #<issue>

#### Test Plan

<!-- How will this be tested prior to merging.-->
- [ ] 💪 Manual

src/cmd/sanity_test/sanity_tests.go

@@ -46,13 +46,21 @@ func main() {
 	}
 }
 
-func checkEmailRestoration(client *msgraphsdk.GraphServiceClient, testUser, folderName string, startTime time.Time) {
+// checkEmailRestoration verifies that the emails count in restored folder is equivalent to
+// emails in actual m365 account
+func checkEmailRestoration(
+	client *msgraphsdk.GraphServiceClient,
+	testUser,
+	folderName string,
+	startTime time.Time,
+) {
 	var (
 		messageCount  = make(map[string]int32)
 		restoreFolder models.MailFolderable
 	)
 
-	builder := client.UsersById(testUser).MailFolders()
+	user := client.UsersById(testUser)
+	builder := user.MailFolders()
 
 	for {
 		result, err := builder.Get(context.Background(), nil)
@@ -64,7 +72,10 @@ func checkEmailRestoration(client *msgraphsdk.GraphServiceClient, testUser, fold
 		res := result.GetValue()
 
 		for _, r := range res {
-			name := *r.GetDisplayName()
+			name, ok := ptr.ValOK(r.GetDisplayName())
+			if !ok {
+				continue
+			}
 
 			var rStartTime time.Time
 
@@ -82,7 +93,9 @@ func checkEmailRestoration(client *msgraphsdk.GraphServiceClient, testUser, fold
 				continue
 			}
 
-			messageCount[*r.GetDisplayName()] = *r.GetTotalItemCount()
+			getAllSubFolder(client, testUser, r, name, messageCount)
+
+			messageCount[name], _ = ptr.ValOK(r.GetTotalItemCount())
 		}
 
 		link, ok := ptr.ValOK(result.GetOdataNextLink())
@@ -93,8 +106,13 @@ func checkEmailRestoration(client *msgraphsdk.GraphServiceClient, testUser, fold
 		builder = users.NewItemMailFoldersRequestBuilder(link, client.GetAdapter())
 	}
 
-	user := client.UsersById(testUser)
-	folder := user.MailFoldersById(*restoreFolder.GetId())
+	folderID, ok := ptr.ValOK(restoreFolder.GetId())
+	if !ok {
+		fmt.Printf("can't find ID of restore folder")
+		os.Exit(1)
+	}
+
+	folder := user.MailFoldersById(folderID)
 
 	childFolder, err := folder.ChildFolders().Get(context.Background(), nil)
 	if err != nil {
@@ -103,15 +121,113 @@ func checkEmailRestoration(client *msgraphsdk.GraphServiceClient, testUser, fold
 	}
 
 	for _, restore := range childFolder.GetValue() {
-		if messageCount[*restore.GetDisplayName()] != *restore.GetTotalItemCount() {
-			fmt.Println("Restore was not succesfull for: ",
-				*restore.GetDisplayName(),
-				"Folder count: ",
-				messageCount[*restore.GetDisplayName()],
-				"Restore count: ",
-				*restore.GetTotalItemCount())
+		restoreDisplayName, ok := ptr.ValOK(restore.GetDisplayName())
+		if !ok {
+			continue
+		}
+
+		restoreItemCount, _ := ptr.ValOK(restore.GetTotalItemCount())
+
+		if messageCount[restoreDisplayName] != restoreItemCount {
+			fmt.Println("Restore was not succesfull for: ", restoreDisplayName,
+				"Folder count: ", messageCount[restoreDisplayName],
+				"Restore count: ", restoreItemCount)
 			os.Exit(1)
 		}
+
+		checkAllSubFolder(client, testUser, restore, restoreDisplayName, messageCount)
+	}
+}
+
+// getAllSubFolder will recursively check for all subfolders and get the corresponding
+// email count.
+func getAllSubFolder(
+	client *msgraphsdk.GraphServiceClient,
+	testUser string,
+	r models.MailFolderable,
+	parentFolder string,
+	messageCount map[string]int32,
+) {
+	folderID, ok := ptr.ValOK(r.GetId())
+
+	if !ok {
+		fmt.Println("unable to get sub folder ID")
+		return
+	}
+
+	user := client.UsersById(testUser)
+	folder := user.MailFoldersById(folderID)
+
+	childFolder, err := folder.ChildFolders().Get(context.Background(), nil)
+	if err != nil {
+		fmt.Printf("Error getting the drive: %v\n", err)
+		os.Exit(1)
+	}
+
+	for _, child := range childFolder.GetValue() {
+		childDisplayName, _ := ptr.ValOK(child.GetDisplayName())
+
+		fullFolderName := parentFolder + "/" + childDisplayName
+
+		messageCount[fullFolderName], _ = ptr.ValOK(child.GetTotalItemCount())
+
+		childFolderCount, _ := ptr.ValOK(child.GetChildFolderCount())
+
+		// recursively check for subfolders
+		if childFolderCount > 0 {
+			parentFolder := fullFolderName
+
+			getAllSubFolder(client, testUser, child, parentFolder, messageCount)
+		}
+	}
+}
+
+// checkAllSubFolder will recursively traverse inside the restore folder and
+// verify that data matched in all subfolders
+func checkAllSubFolder(
+	client *msgraphsdk.GraphServiceClient,
+	testUser string,
+	r models.MailFolderable,
+	parentFolder string,
+	messageCount map[string]int32,
+) {
+	folderID, ok := ptr.ValOK(r.GetId())
+
+	if !ok {
+		fmt.Println("unable to get sub folder ID")
+		return
+	}
+
+	user := client.UsersById(testUser)
+	folder := user.MailFoldersById(folderID)
+
+	childFolder, err := folder.ChildFolders().Get(context.Background(), nil)
+	if err != nil {
+		fmt.Printf("Error getting the drive: %v\n", err)
+		os.Exit(1)
+	}
+
+	for _, child := range childFolder.GetValue() {
+		childDisplayName, _ := ptr.ValOK(child.GetDisplayName())
+
+		fullFolderName := parentFolder + "/" + childDisplayName
+
+		childTotalCount, _ := ptr.ValOK(child.GetTotalItemCount())
+
+		if messageCount[fullFolderName] != childTotalCount {
+			fmt.Println("Restore was not succesfull for: ", fullFolderName,
+				"Folder count: ", messageCount[fullFolderName],
+				"Restore count: ", childTotalCount)
+			os.Exit(1)
+		}
+
+		childFolderCount, _ := ptr.ValOK(child.GetChildFolderCount())
+
+		if childFolderCount > 0 {
+			parentFolder := fullFolderName
+
+			checkAllSubFolder(client, testUser, child, parentFolder, messageCount)
+		}
 	}
 }