(feat): OnDecision Notification Listener for getFeatureVariable API (#129)

* Initial implementations.

* bug fixes.

* Initial implementations.

* Redundant keys removed.

* DemoSwiftApp updated.

* Test-cases updated.

* Test-cases updated.

* Implementation updated and testcases added.

* Recommended changes made.

* Recommended changes made.

* Recommended changes made.

Author: yasirfolio3

OptimizelySDK/Optimizely/OptimizelyManager.swift

@@ -325,7 +325,7 @@ open class OptimizelyManager: NSObject {
 
         var args: Array<Any?> = (self.notificationCenter as! DefaultNotificationCenter).getArgumentsForDecisionListener(notificationType: Constants.DecisionTypeKeys.experiment, userId: userId, attributes: attributes)
 
-        var decisionInfo = Dictionary<String,Any>()
+        var decisionInfo = [String:Any]()
         decisionInfo[Constants.NotificationKeys.experiment] = nil
         decisionInfo[Constants.NotificationKeys.variation] = nil
 
@@ -411,7 +411,7 @@ open class OptimizelyManager: NSObject {
 
         var args: Array<Any?> = (self.notificationCenter as! DefaultNotificationCenter).getArgumentsForDecisionListener(notificationType: Constants.DecisionTypeKeys.isFeatureEnabled, userId: userId, attributes: attributes)
 
-        var decisionInfo = Dictionary<String,Any>()
+        var decisionInfo = [String:Any]()
         decisionInfo[Constants.DecisionInfoKeys.feature] = featureKey
         decisionInfo[Constants.DecisionInfoKeys.source] = Constants.DecisionSource.Rollout
         decisionInfo[Constants.DecisionInfoKeys.featureEnabled] = false
@@ -561,18 +561,26 @@ open class OptimizelyManager: NSObject {
             throw OptimizelyError.variableUnknown
         }
 
+        var decisionInfo = [String:Any]()
+        decisionInfo[Constants.DecisionInfoKeys.sourceExperiment] = nil
+        decisionInfo[Constants.DecisionInfoKeys.sourceVariation] = nil
+        
+        // TODO: [Jae] optional? fallback to empty string is OK?
         var featureValue = variable.defaultValue ?? ""
 
         var _attributes = OptimizelyAttributes()
-        if attributes != nil {
-            _attributes = attributes!
+        if let attributes = attributes {
+            _attributes = attributes
         }
-        if let decision = self.decisionService.getVariationForFeature(config: config, featureFlag: featureFlag, userId: userId, attributes: _attributes) {
-            if let variation = decision.variation,
-                let featureVariableUsage = variation.variables?.filter({$0.id == variable.id}).first
-            {
-                if let featureEnabled = variation.featureEnabled, featureEnabled {
-                    featureValue = featureVariableUsage.value
+        let decision = self.decisionService.getVariationForFeature(config: config, featureFlag: featureFlag, userId: userId, attributes: _attributes)
+        if let decision = decision {
+            if let experiment = decision.experiment {
+                decisionInfo[Constants.DecisionInfoKeys.sourceExperiment] = experiment.key
+                decisionInfo[Constants.DecisionInfoKeys.sourceVariation] = decision.variation?.key
+            }
+            if let featureVariable = decision.variation?.variables?.filter({$0.id == variable.id}).first {
+                if let featureEnabled = decision.variation?.featureEnabled, featureEnabled {
+                    featureValue = featureVariable.value
                 } else {
                     // add standard log message here
                 }
@@ -605,6 +613,18 @@ open class OptimizelyManager: NSObject {
             throw OptimizelyError.variableValueInvalid(variableKey)
         }
 
+        var args: Array<Any?> = (self.notificationCenter as! DefaultNotificationCenter).getArgumentsForDecisionListener(notificationType: Constants.DecisionTypeKeys.featureVariable, userId: userId, attributes: _attributes)
+        
+        decisionInfo[Constants.DecisionInfoKeys.feature] = featureKey
+        decisionInfo[Constants.DecisionInfoKeys.featureEnabled] = decision?.variation?.featureEnabled ?? false
+        decisionInfo[Constants.DecisionInfoKeys.variable] = variableKey
+        decisionInfo[Constants.DecisionInfoKeys.variableType] = typeName
+        decisionInfo[Constants.DecisionInfoKeys.variableValue] = value
+        decisionInfo[Constants.DecisionInfoKeys.source] = (decision?.experiment != nil ? Constants.DecisionSource.Experiment : Constants.DecisionSource.Rollout)
+        args.append(decisionInfo)
+    
+        self.notificationCenter.sendNotifications(type: NotificationType.Decision.rawValue, args: args)
+        
         return value
     }