Add OSInAppMessagePreviewHandler kotlin file

* Refactor from Java to Kotlin

Author: Jeasmine

OneSignalSDK/onesignal/src/main/java/com/onesignal/OSInAppMessagePreviewHandler.java

@@ -0,0 +1,47 @@
+package com.onesignal
+
+import android.content.Context
+import android.os.Build
+import android.os.Bundle
+import org.json.JSONException
+import org.json.JSONObject
+
+internal object OSInAppMessagePreviewHandler {
+    @JvmStatic
+    fun inAppMessagePreviewHandled(context: Context?, bundle: Bundle?): Boolean {
+        val pushPayloadJson = NotificationBundleProcessor.bundleAsJSONObject(bundle)
+        // Show In-App message preview it is in the payload & the app is in focus
+        val previewUUID = inAppPreviewPushUUID(pushPayloadJson) ?: return false
+
+        // If app is in focus display the IAMs preview now
+        if (OneSignal.isAppActive()) {
+            OneSignal.getInAppMessageController().displayPreviewMessage(previewUUID)
+        } else if (shouldDisplayNotification()) {
+            val generationJob = OSNotificationGenerationJob(context, pushPayloadJson)
+            GenerateNotification.displayIAMPreviewNotification(generationJob)
+        }
+        return true
+    }
+
+    @JvmStatic
+    fun inAppPreviewPushUUID(payload: JSONObject): String? {
+        val osCustom: JSONObject = try {
+            NotificationBundleProcessor.getCustomJSONObject(payload)
+        } catch (e: JSONException) {
+            return null
+        }
+
+        if (!osCustom.has(NotificationBundleProcessor.PUSH_ADDITIONAL_DATA_KEY))
+            return null
+
+        return osCustom.optJSONObject(NotificationBundleProcessor.PUSH_ADDITIONAL_DATA_KEY)?.let { additionalData ->
+            if (additionalData.has(NotificationBundleProcessor.IAM_PREVIEW_KEY))
+                additionalData.optString(NotificationBundleProcessor.IAM_PREVIEW_KEY)
+            else
+                null
+        }
+    }
+
+    // Validate that the current Android device is Android 4.4 or higher
+    private fun shouldDisplayNotification(): Boolean = Build.VERSION.SDK_INT > Build.VERSION_CODES.JELLY_BEAN_MR2
+}