Restore contacts from backup

XXClient library

• Improve error handling in UdMultiLookupCallback.

xx-messenger example

• Improve backup restoration.
• Restore contacts.
• Add contact lookup feature.
• Display contact ids.
• Improve sending requests.
• Restore username from restored facts, not from restored params.

Examples/xx-messenger/Sources/RegisterFeature/RegisterFeature.swift

@@ -7,6 +7,10 @@ import XXMessengerClient
 import XXModels
 
 public struct RegisterState: Equatable {
+  public enum Error: Swift.Error, Equatable {
+    case usernameMismatch(registering: String, registered: String?)
+  }
+
   public enum Field: String, Hashable {
     case username
   }
@@ -82,14 +86,22 @@ public let registerReducer = Reducer<RegisterState, RegisterAction, RegisterEnvi
       do {
         let db = try env.db()
         try env.messenger.register(username: username)
-        var contact = try env.messenger.e2e.tryGet().getContact()
-        try contact.setFact(.username, username)
+        let contact = try env.messenger.myContact()
+        let facts = try contact.getFacts()
         try db.saveContact(Contact(
           id: try contact.getId(),
           marshaled: contact.data,
-          username: username,
+          username: facts.get(.username)?.value,
+          email: facts.get(.email)?.value,
+          phone: facts.get(.phone)?.value,
           createdAt: env.now()
         ))
+        guard facts.get(.username)?.value == username else {
+          throw RegisterState.Error.usernameMismatch(
+            registering: username,
+            registered: facts.get(.username)?.value
+          )
+        }
         fulfill(.success(.finished))
       }
       catch {
@@ -106,6 +118,7 @@ public let registerReducer = Reducer<RegisterState, RegisterAction, RegisterEnvi
     return .none
 
   case .finished:
+    state.isRegistering = false
     return .none
   }
 }