[Messenger example] join group

xx-messenger example

• Display group details
• Accept pending group invitations (join group)

Examples/xx-messenger/Sources/GroupFeature/GroupComponent.swift

 import AppCore
 import ComposableArchitecture
 import Foundation
+import XXMessengerClient
 import XXModels
 
 public struct GroupComponent: ReducerProtocol {
   public struct State: Equatable {
     public init(
       groupId: XXModels.Group.ID,
-      groupInfo: XXModels.GroupInfo? = nil
+      groupInfo: XXModels.GroupInfo? = nil,
+      isJoining: Bool = false,
+      joinFailure: String? = nil
     ) {
       self.groupId = groupId
       self.groupInfo = groupInfo
+      self.isJoining = isJoining
+      self.joinFailure = joinFailure
     }
 
     public var groupId: XXModels.Group.ID
     public var groupInfo: XXModels.GroupInfo?
+    public var isJoining: Bool
+    public var joinFailure: String?
   }
 
   public enum Action: Equatable {
     case start
     case didFetchGroupInfo(XXModels.GroupInfo?)
+    case joinButtonTapped
+    case didJoin
+    case didFailToJoin(String)
   }
 
   public init() {}
 
+  @Dependency(\.app.messenger) var messenger: Messenger
   @Dependency(\.app.dbManager.getDB) var db: DBManagerGetDB
   @Dependency(\.app.mainQueue) var mainQueue: AnySchedulerOf<DispatchQueue>
   @Dependency(\.app.bgQueue) var bgQueue: AnySchedulerOf<DispatchQueue>
@@ -47,6 +58,36 @@ public struct GroupComponent: ReducerProtocol {
       case .didFetchGroupInfo(let groupInfo):
         state.groupInfo = groupInfo
         return .none
+
+      case .joinButtonTapped:
+        guard let info = state.groupInfo else { return .none }
+        state.isJoining = true
+        state.joinFailure = nil
+        return Effect.result {
+          do {
+            let groupChat = try messenger.groupChat.tryGet()
+            try groupChat.joinGroup(serializedGroupData: info.group.serialized)
+            var group = info.group
+            group.authStatus = .participating
+            try db().saveGroup(group)
+            return .success(.didJoin)
+          } catch {
+            return .success(.didFailToJoin(error.localizedDescription))
+          }
+        }
+        .subscribe(on: bgQueue)
+        .receive(on: mainQueue)
+        .eraseToEffect()
+
+      case .didJoin:
+        state.isJoining = false
+        state.joinFailure = nil
+        return .none
+
+      case .didFailToJoin(let failure):
+        state.isJoining = false
+        state.joinFailure = failure
+        return .none
       }
     }
   }