diff --git a/main.go b/main.go
index 9788284..0ac464e 100644
--- a/main.go
+++ b/main.go
@@ -8,6 +8,7 @@ import (
 	"io"
 	"log"
 	"net/http"
+	"os"
 	"os/signal"
 	"syscall"
 	"time"
@@ -43,8 +44,16 @@ func main() {
 		}
 
 		for _, item := range items {
-			b, _ := json.MarshalIndent(item, "", "   ")
-			log.Fatalf("%s", b)
+			if item.IsFolder {
+				folders = append([]FolderItem{item}, folders...)
+			} else if userData, err := jellyFrom.UserDataOf(ctx, item); err != nil {
+				log.Fatal(err)
+			} else if userData.PlayCount == 0 && userData.PlaybackPositionTicks == 0 {
+			} else if userDataB, err := jellyTo.UserDataOf(ctx, item); err != nil {
+				log.Fatal(err)
+			} else if err := jellyTo.SetUserData(ctx, userData.Plus(userDataB)); err != nil {
+				log.Fatalf("failed to set user data of %+v: %v", userData, err)
+			}
 		}
 	}
 
@@ -74,10 +83,10 @@ type FolderItem struct {
 	Name     string
 	Id       string
 	IsFolder bool
-	Parent   Folder
+	Parent   *FolderItem
 }
 
-func (jelly Jelly) ListFolder(ctx context.Context, folder Folder) ([]FolderItem, error) {
+func (jelly Jelly) ListFolder(ctx context.Context, folder FolderItem) ([]FolderItem, error) {
 	resp, err := jelly.do(ctx, http.MethodGet, fmt.Sprintf("/Items?parentId=%s", folder.Id), nil)
 	if err != nil {
 		return nil, err
@@ -90,7 +99,7 @@ func (jelly Jelly) ListFolder(ctx context.Context, folder Folder) ([]FolderItem,
 			Name:     m["Name"].(string),
 			Id:       m["Id"].(string),
 			IsFolder: m["IsFolder"].(bool),
-			Parent:   folder,
+			Parent:   &folder,
 		}
 	}
 	return result, nil
@@ -98,24 +107,72 @@ func (jelly Jelly) ListFolder(ctx context.Context, folder Folder) ([]FolderItem,
 
 // get+set item via /UserItems/{itemId}/UserData
 
-type Folder struct {
-	Name string
-	Id   string
+type UserData struct {
+	IsFavorite            bool
+	ItemId                string
+	Key                   string
+	PlayCount             float64
+	PlaybackPositionTicks float64
+	Played                bool
+	FolderItem            FolderItem `json:",omitempty"`
 }
 
-func (jelly Jelly) VirtualFolders(ctx context.Context) ([]Folder, error) {
+func (this UserData) Plus(that UserData) UserData {
+	this.IsFavorite = this.IsFavorite || that.IsFavorite
+	//this.ItemId
+	//this.Key
+	if this.PlayCount < that.PlayCount {
+		this.PlayCount = that.PlayCount
+	}
+	if this.PlaybackPositionTicks < that.PlaybackPositionTicks {
+		this.PlaybackPositionTicks = that.PlaybackPositionTicks
+	}
+	this.Played = this.Played || that.Played
+	return this
+}
+
+func (jelly Jelly) SetUserData(ctx context.Context, userData UserData) error {
+	fi := userData.FolderItem
+	if os.Getenv("DRY_RUN") != "false" {
+		b, _ := json.Marshal(userData)
+		log.Printf("SET %s", b)
+		return nil
+	}
+	userData.FolderItem = FolderItem{}
+	_, err := jelly.do(ctx, http.MethodPost, "/UserItems/"+fi.Id+"/UserData", userData)
+	return err
+}
+
+func (jelly Jelly) UserDataOf(ctx context.Context, folderItem FolderItem) (UserData, error) {
+	resp, err := jelly.do(ctx, http.MethodGet, "/UserItems/"+folderItem.Id+"/UserData", nil)
+	if err != nil {
+		return UserData{}, err
+	}
+	return UserData{
+		IsFavorite:            resp.(map[string]any)["IsFavorite"].(bool),
+		ItemId:                resp.(map[string]any)["ItemId"].(string),
+		Key:                   resp.(map[string]any)["Key"].(string),
+		PlayCount:             resp.(map[string]any)["PlayCount"].(float64),
+		PlaybackPositionTicks: resp.(map[string]any)["PlaybackPositionTicks"].(float64),
+		Played:                resp.(map[string]any)["Played"].(bool),
+		FolderItem:            folderItem,
+	}, nil
+}
+
+func (jelly Jelly) VirtualFolders(ctx context.Context) ([]FolderItem, error) {
 	resp, err := jelly.do(ctx, http.MethodGet, "/Library/VirtualFolders", nil)
 	if err != nil {
 		return nil, err
 	}
 
 	a := resp.([]any)
-	result := make([]Folder, len(a))
+	result := make([]FolderItem, len(a))
 	for i, v := range a {
 		m := v.(map[string]any)
-		result[i] = Folder{
-			Id:   m["ItemId"].(string),
-			Name: m["Name"].(string),
+		result[i] = FolderItem{
+			Id:       m["ItemId"].(string),
+			Name:     m["Name"].(string),
+			IsFolder: true,
 		}
 	}
 	return result, nil