[FFM-11847]: Extend SDK client to expose FeatureSnapshot

src/main/java/io/harness/cf/client/api/InnerClient.java

@@ -1,12 +1,17 @@
 package io.harness.cf.client.api;
 
+import com.google.gson.Gson;
 import com.google.gson.JsonObject;
 import io.harness.cf.client.common.SdkCodes;
 import io.harness.cf.client.connector.*;
 import io.harness.cf.client.dto.Message;
 import io.harness.cf.client.dto.Target;
 import io.harness.cf.model.FeatureConfig;
+import io.harness.cf.model.FeatureSnapshot;
 import io.harness.cf.model.Variation;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Optional;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.function.Consumer;
@@ -307,6 +312,40 @@ public synchronized void waitForInitialization()
     }
   }
 
+  public List<FeatureSnapshot> getFeatureSnapshots() {
+    // TODO return null/empty list if snapshot is not enabled in config.
+    return getFeatureSnapshots("");
+  }
+
+  public List<FeatureSnapshot> getFeatureSnapshots(String prefix) {
+    // TODO return null/empty list if snapshot is not enabled in config.
+    List<String> identifiers = repository.getAllFeatureIdentifiers(prefix);
+    List<FeatureSnapshot> snapshots = new LinkedList<>();
+
+    for (String identifier : identifiers) {
+      FeatureSnapshot snapshot = getFeatureSnapshot(identifier);
+      snapshots.add(snapshot);
+    }
+
+    return snapshots;
+  }
+
+  public FeatureSnapshot getFeatureSnapshot(@NonNull String identifier) {
+    // TODO return null/empty list if snapshot is not enabled in config.
+    Optional<FeatureConfig[]> ofc = repository.getCurrentAndPreviousFeatureConfig(identifier);
+    FeatureSnapshot result = new FeatureSnapshot();
+    if (ofc.isPresent()) {
+      FeatureConfig[] fc = ofc.get();
+      result.setPrevious(fc[0]);
+      result.setCurrent(fc[1]);
+    }
+    // this is here to create a deep copy of the object before its returned.
+    // this way we protect the cache.
+    Gson gson = new Gson();
+    FeatureSnapshot deepCopySnapshot = gson.fromJson(gson.toJson(result), FeatureSnapshot.class);
+    return deepCopySnapshot;
+  }
+
   public void on(@NonNull final Event event, @NonNull final Consumer<String> consumer) {
     final CopyOnWriteArrayList<Consumer<String>> consumers =
         events.getOrDefault(event, new CopyOnWriteArrayList<>());

src/main/resources/client-v1.yaml

@@ -561,6 +561,13 @@ components:
             type: string
       required:
         - variation
+    FeatureSnapshot:
+      type: object
+      properties:
+        current:
+          $ref: '#/components/schemas/FeatureConfig'
+        previous:
+          $ref: '#/components/schemas/FeatureConfig'
     FeatureConfig:
       type: object
       properties: