fix: Raise and report errors on connect.

* For native transports, raise errors for various conditions and
  properly alert them from the UI when it happens.

src-tauri/src/transport/gatt.rs

@@ -18,30 +18,30 @@ pub async fn gatt_connect(
     id: String,
     app_handle: AppHandle,
     state: State<'_, super::commands::ActiveConnection<'_>>,
-) -> Result<bool, ()> {
-    let adapter = Adapter::default().await.ok_or(())?;
+) -> Result<bool, String> {
+    let adapter = Adapter::default().await.ok_or("Failed to access the BT adapter".to_string())?;
 
-    adapter.wait_available().await.map_err(|_| ())?;
+    adapter.wait_available().await.map_err(|e| format!("Failed to wait for the BT adapter access: {}", e.message()))?;
 
     let device_id: DeviceId = serde_json::from_str(&id).unwrap();
-    let d = adapter.open_device(&device_id).await.map_err(|_| ())?;
+    let d = adapter.open_device(&device_id).await.map_err(|e| format!("Failed to open the device: {}", e.message()))?;
 
     if !d.is_connected().await {
-        adapter.connect_device(&d).await.map_err(|_| ())?;
+        adapter.connect_device(&d).await.map_err(|e| format!("Failed to connect to the device: {}", e.message()))?;
     }
 
     let service = d
         .discover_services_with_uuid(SVC_UUID)
         .await
-        .map_err(|e| ())?
+        .map_err(|e| format!("Failed to find the device services: {}", e.message()))?
         .get(0)
         .cloned();
 
     if let Some(s) = service {
         let char = s
             .discover_characteristics_with_uuid(RPC_CHRC_UUID)
             .await
-            .map_err(|_| ())?
+            .map_err(|e| format!("Failed to find the studio service characteristics: {}", e.message()))?
             .get(0)
             .cloned();
 
@@ -95,10 +95,10 @@ pub async fn gatt_connect(
 
             Ok(true)
         } else {
-            Err(())
+            Err("Failed to connect: Unable to locate the required studio GATT characteristic".to_string())
         }
     } else {
-        Err(())
+        Err("Failed to connect: Unable to locate the required studio GATT service".to_string())
     }
 }
 

src-tauri/src/transport/serial.rs

@@ -15,7 +15,7 @@ pub async fn serial_connect(
     id: String,
     app_handle: AppHandle,
     state: State<'_, super::commands::ActiveConnection<'_>>,
-) -> Result<bool, ()> {
+) -> Result<bool, String> {
     match tokio_serial::new(id, 9600).open_native_async() {
         Ok(mut port) => {
             #[cfg(unix)]
@@ -62,7 +62,7 @@ pub async fn serial_connect(
             Ok(true)
         }
         Err(e) => {
-            Err(())
+            Err(format!("Failed to open the serial port: {}", e.description))
         }
     }
 }

src/ConnectModal.tsx

@@ -77,7 +77,10 @@ function deviceList(
       }
       const dev = devices.find(([_t, d]) => keys.has(d.id));
       if (dev) {
-        onTransportCreated(await dev[0].pick_and_connect!.connect(dev[1]));
+        dev[0]
+          .pick_and_connect!.connect(dev[1])
+          .then(onTransportCreated)
+          .catch((e) => alert(e));
       }
     },
     [devices, onTransportCreated]