Introduce status code into invalid channel state error

I didn't do this in cb427d8 because the specification hadn't yet
specified the status code (it was an outstanding question on the PR at
time of implementing), but the newly-written spec [1] for other LiveMap
getter methods _does_ specify the status code as being 400. So DRY up
the creation of these errors, and supply a status code (assuming that
the spec will be updated to specify 400 for these existing ones too).

[1] ably/specification#341

Author: lawrence-forooghian

Sources/AblyLiveObjects/DefaultRealtimeObjects.swift

@@ -90,7 +90,11 @@ internal final class DefaultRealtimeObjects: RealtimeObjects, LiveMapObjectPoolD
         // RTO1b: If the channel is in the DETACHED or FAILED state, the library should indicate an error with code 90001
         let currentChannelState = coreSDK.channelState
         if currentChannelState == .detached || currentChannelState == .failed {
-            throw ARTErrorInfo.create(withCode: Int(ARTErrorCode.channelOperationFailedInvalidState.rawValue), message: "getRoot operation failed (invalid channel state: \(currentChannelState))")
+            throw LiveObjectsError.objectsOperationFailedInvalidChannelState(
+                operationDescription: "getRoot",
+                channelState: currentChannelState,
+            )
+            .toARTErrorInfo()
         }
 
         let syncStatus = mutex.withLock {

Sources/AblyLiveObjects/Internal/DefaultLiveCounter.swift

@@ -69,7 +69,11 @@ internal final class DefaultLiveCounter: LiveCounter {
             // RTLC5b: If the channel is in the DETACHED or FAILED state, the library should indicate an error with code 90001
             let currentChannelState = coreSDK.channelState
             if currentChannelState == .detached || currentChannelState == .failed {
-                throw ARTErrorInfo.create(withCode: Int(ARTErrorCode.channelOperationFailedInvalidState.rawValue), message: "LiveCounter.value operation failed (invalid channel state: \(currentChannelState))")
+                throw LiveObjectsError.objectsOperationFailedInvalidChannelState(
+                    operationDescription: "LiveCounter.value",
+                    channelState: currentChannelState,
+                )
+                .toARTErrorInfo()
             }
 
             return mutex.withLock {

Sources/AblyLiveObjects/Internal/DefaultLiveMap.swift

@@ -108,7 +108,11 @@ internal final class DefaultLiveMap: LiveMap {
         // RTLM5c: If the channel is in the DETACHED or FAILED state, the library should indicate an error with code 90001
         let currentChannelState = coreSDK.channelState
         if currentChannelState == .detached || currentChannelState == .failed {
-            throw ARTErrorInfo.create(withCode: Int(ARTErrorCode.channelOperationFailedInvalidState.rawValue), message: "LiveMap.get operation failed (invalid channel state: \(currentChannelState))")
+            throw LiveObjectsError.objectsOperationFailedInvalidChannelState(
+                operationDescription: "LiveMap.get",
+                channelState: currentChannelState,
+            )
+            .toARTErrorInfo()
         }
 
         let entry = mutex.withLock {

Sources/AblyLiveObjects/Utility/Errors.swift

@@ -0,0 +1,41 @@
+import Ably
+
+/**
+ Describes the errors that can be thrown by the LiveObjects SDK. Use ``toARTErrorInfo()`` to convert to an `ARTErrorInfo` that you can throw.
+ */
+internal enum LiveObjectsError {
+    // operationDescription should be a description of a method like "LiveCounter.value"; it will be interpolated into an error message
+    case objectsOperationFailedInvalidChannelState(operationDescription: String, channelState: ARTRealtimeChannelState)
+
+    /// The ``ARTErrorInfo/code`` that should be returned for this error.
+    internal var code: ARTErrorCode {
+        switch self {
+        case .objectsOperationFailedInvalidChannelState:
+            .channelOperationFailedInvalidState
+        }
+    }
+
+    /// The ``ARTErrorInfo/statusCode`` that should be returned for this error.
+    internal var statusCode: Int {
+        switch self {
+        case .objectsOperationFailedInvalidChannelState:
+            400
+        }
+    }
+
+    /// The ``ARTErrorInfo/localizedDescription`` that should be returned for this error.
+    internal var localizedDescription: String {
+        switch self {
+        case let .objectsOperationFailedInvalidChannelState(operationDescription: operationDescription, channelState: channelState):
+            "\(operationDescription) operation failed (invalid channel state: \(channelState))"
+        }
+    }
+
+    internal func toARTErrorInfo() -> ARTErrorInfo {
+        ARTErrorInfo.create(
+            withCode: Int(code.rawValue),
+            status: statusCode,
+            message: localizedDescription,
+        )
+    }
+}

Tests/AblyLiveObjectsTests/DefaultLiveCounterTests.swift

@@ -18,7 +18,7 @@ struct DefaultLiveCounterTests {
                     return false
                 }
 
-                return errorInfo.code == 90001
+                return errorInfo.code == 90001 && errorInfo.statusCode == 400
             }
         }
 

Tests/AblyLiveObjectsTests/DefaultLiveMapTests.swift

@@ -18,7 +18,7 @@ struct DefaultLiveMapTests {
                     return false
                 }
 
-                return errorInfo.code == 90001
+                return errorInfo.code == 90001 && errorInfo.statusCode == 400
             }
         }
 

Tests/AblyLiveObjectsTests/DefaultRealtimeObjectsTests.swift

@@ -660,7 +660,7 @@ struct DefaultRealtimeObjectsTests {
                     return false
                 }
 
-                return errorInfo.code == 90001
+                return errorInfo.code == 90001 && errorInfo.statusCode == 400
             }
         }
     }