fix: enforce only one instance of the app

src-tauri/Cargo.lock

@@ -108,6 +108,7 @@ dependencies = [
  "tauri-plugin-log",
  "tauri-plugin-notification",
  "tauri-plugin-os",
+ "tauri-plugin-single-instance",
  "tauri-plugin-updater",
  "thiserror 2.0.12",
  "tokio",
@@ -4846,6 +4847,21 @@ dependencies = [
  "thiserror 2.0.12",
 ]
 
+[[package]]
+name = "tauri-plugin-single-instance"
+version = "2.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1320af4d866a7fb5f5721d299d14d0dd9e4e6bc0359ff3e263124a2bf6814efa"
+dependencies = [
+ "serde",
+ "serde_json",
+ "tauri",
+ "thiserror 2.0.12",
+ "tracing",
+ "windows-sys 0.59.0",
+ "zbus",
+]
+
 [[package]]
 name = "tauri-plugin-updater"
 version = "2.7.0"

src-tauri/Cargo.toml

@@ -40,3 +40,4 @@ custom-protocol = ["tauri/custom-protocol"]
 
 [target.'cfg(not(any(target_os = "android", target_os = "ios")))'.dependencies]
 tauri-plugin-autostart = "2.3.0"
+tauri-plugin-single-instance = "2"

src-tauri/src/commands/fansly/mod.rs

@@ -1,3 +1,4 @@
+use crate::handlers::fansly::{SyncProgress, PROGRESS};
 use crate::{
     handlers::fansly::Fansly,
     structs::{FanslyAccountResponse, FanslyBaseResponse, SyncDataResponse},
@@ -5,7 +6,6 @@ use crate::{
 use lazy_static::lazy_static;
 use serde_json::Value;
 use tokio::sync::Mutex;
-use crate::handlers::fansly::{SyncProgress, PROGRESS};
 
 lazy_static! {
     static ref FANSLY: Mutex<Fansly> = Mutex::new(Fansly::new(None));

src-tauri/src/handlers/fansly/mod.rs

@@ -404,7 +404,6 @@ impl Fansly {
                 "[sync::process] Got {} followers from API.",
                 response.response.len()
             );
-            
 
             // Collect followers
             for follower in response.response.clone() {

src-tauri/src/main.rs

@@ -20,6 +20,8 @@ use tauri::tray::TrayIconBuilder;
 use tauri::AppHandle;
 use tauri::Manager;
 use tauri_plugin_autostart::MacosLauncher;
+use tauri_plugin_dialog::DialogExt;
+use tauri_plugin_dialog::MessageDialogKind;
 use tauri_plugin_log::{Target, TargetKind};
 
 fn get_log_path() -> io::Result<String> {
@@ -108,6 +110,14 @@ async fn main() {
                 .max_file_size(1024 * 1024 * 5)
                 .build(),
         )
+        .plugin(tauri_plugin_single_instance::init(|app,_args,_cwd| {
+            // Show a dialog if the app is already running
+            app.dialog()
+                .message("FanslySync is already running in the background. Please left click the tray icon -> Show Window to open the app.")
+                .title("FanslySync")
+                .kind(MessageDialogKind::Warning)
+                .blocking_show();
+        }))
         .invoke_handler(tauri::generate_handler![
             init_config,
             get_config,