Fixes “Device Already Registered” error

AltStore/Operations/PrepareDeveloperAccountOperation.swift

@@ -0,0 +1,81 @@
+//
+//  PrepareDeveloperAccountOperation.swift
+//  AltStore
+//
+//  Created by Riley Testut on 1/7/20.
+//  Copyright © 2020 Riley Testut. All rights reserved.
+//
+
+import Foundation
+import Roxas
+
+import AltSign
+
+@objc(PrepareDeveloperAccountOperation)
+class PrepareDeveloperAccountOperation: ResultOperation<Void>
+{
+    let group: OperationGroup
+    
+    init(group: OperationGroup)
+    {
+        self.group = group
+        
+        super.init()
+        
+        self.progress.totalUnitCount = 2
+    }
+    
+    override func main()
+    {
+        super.main()
+        
+        if let error = self.group.error
+        {
+            self.finish(.failure(error))
+            return
+        }
+        
+        guard
+            let signer = self.group.signer,
+            let session = self.group.session
+        else { return self.finish(.failure(OperationError.invalidParameters)) }
+        
+        // Register Device
+        self.registerCurrentDevice(for: signer.team, session: session) { (result) in
+            let result = result.map { _ in () }
+            self.finish(result)
+        }
+    }
+}
+         
+private extension PrepareDeveloperAccountOperation
+{
+    func registerCurrentDevice(for team: ALTTeam, session: ALTAppleAPISession, completionHandler: @escaping (Result<ALTDevice, Error>) -> Void)
+    {
+        guard let udid = Bundle.main.object(forInfoDictionaryKey: Bundle.Info.deviceID) as? String else {
+            return completionHandler(.failure(OperationError.unknownUDID))
+        }
+        
+        ALTAppleAPI.shared.fetchDevices(for: team, session: session) { (devices, error) in
+            do
+            {
+                let devices = try Result(devices, error).get()
+                
+                if let device = devices.first(where: { $0.identifier == udid })
+                {
+                    completionHandler(.success(device))
+                }
+                else
+                {
+                    ALTAppleAPI.shared.registerDevice(name: UIDevice.current.name, identifier: udid, team: team, session: session) { (device, error) in
+                        completionHandler(Result(device, error))
+                    }
+                }
+            }
+            catch
+            {
+                completionHandler(.failure(error))
+            }
+        }
+    }
+}