ios: add bluetoothAvailable to state

So the frontend can show a helpful message.

Author: benma

backend/devices/bluetooth/bluetooth.go

@@ -30,8 +30,10 @@ type Peripheral struct {
 
 // State contains everything needed to render bluetooth peripherals and other data in the frontend.
 type State struct {
-	Peripherals []*Peripheral `json:"peripherals"`
-	Connecting  bool          `json:"connecting"`
+	// BluetoothAvailable is false if bluetooth is powered off or otherwise unavailable.
+	BluetoothAvailable bool          `json:"bluetoothAvailable"`
+	Peripherals        []*Peripheral `json:"peripherals"`
+	Connecting         bool          `json:"connecting"`
 }
 
 // Bluetooth manages a list of peripherals.

frontends/ios/BitBoxApp/BitBoxApp/Bluetooth.swift

@@ -9,6 +9,7 @@ import CoreBluetooth
 import Mobileserver
 
 struct State {
+    var bluetoothAvailable: Bool
     var discoveredPeripherals: [UUID: PeripheralMetadata]
     var connecting: Bool
 }
@@ -30,7 +31,7 @@ var pairedDeviceIdentifiers: Set<String> {
 }
 
 class BluetoothManager: NSObject, ObservableObject, CBCentralManagerDelegate, CBPeripheralDelegate {
-    private var state: State = State(discoveredPeripherals: [:], connecting: false)
+    private var state: State = State(bluetoothAvailable: false, discoveredPeripherals: [:], connecting: false)
 
     var centralManager: CBCentralManager!
     var connectedPeripheral: CBPeripheral?
@@ -49,6 +50,8 @@ class BluetoothManager: NSObject, ObservableObject, CBCentralManagerDelegate, CB
     override init() {
         super.init()
         centralManager = CBCentralManager(delegate: self, queue: nil)
+        state.bluetoothAvailable = centralManager.state == .poweredOn
+        updateBackendState()
     }
 
     func isConnected() -> Bool {
@@ -77,6 +80,9 @@ class BluetoothManager: NSObject, ObservableObject, CBCentralManagerDelegate, CB
     }
 
     func centralManagerDidUpdateState(_ central: CBCentralManager) {
+        state.bluetoothAvailable = centralManager.state == .poweredOn
+        updateBackendState()
+        
         switch central.state {
         case .poweredOn:
             print("BLE: on")
@@ -285,6 +291,7 @@ class BluetoothManager: NSObject, ObservableObject, CBCentralManagerDelegate, CB
         }
 
         struct StateJSON: Codable {
+            let bluetoothAvailable: Bool
             let peripherals: [PeripheralJSON]
             let connecting: Bool
         }
@@ -298,7 +305,7 @@ class BluetoothManager: NSObject, ObservableObject, CBCentralManagerDelegate, CB
             )
         }
 
-        let state = StateJSON(peripherals: peripherals, connecting: state.connecting)
+        let state = StateJSON(bluetoothAvailable: state.bluetoothAvailable, peripherals: peripherals, connecting: state.connecting)
 
         do {
             let encoder = JSONEncoder()

frontends/web/src/api/bluetooth.ts

@@ -24,6 +24,7 @@ export type TPeripheral = {
 };
 
 export type TState = {
+  bluetoothAvailable: boolean;
   peripherals: TPeripheral[];
   connecting: boolean;
 };

frontends/web/src/components/bluetooth/bluetooth.tsx

@@ -28,6 +28,9 @@ const _Bluetooth = () => {
   if (!state) {
     return null;
   }
+  if (!state.bluetoothAvailable) {
+    return <>Please turn on Bluetooth</>;
+  }
   return (
     <>
       <div className={styles.label}>