MR-17 Curious Reader component logic to deal with "minimum" received sub-app payload data

app/src/main/java/org/curiouslearning/container/WebApp.java

@@ -16,15 +16,23 @@
 import android.webkit.WebView;
 import android.webkit.WebViewClient;
 import android.widget.ImageView;
+import com.google.gson.Gson;
+import com.google.gson.JsonSyntaxException;
 
 import androidx.appcompat.app.AlertDialog;
-
 import org.curiouslearning.container.firebase.AnalyticsUtils;
 import org.curiouslearning.container.presentation.base.BaseActivity;
 import org.curiouslearning.container.utilities.ConnectionUtils;
 import org.curiouslearning.container.utilities.AudioPlayer;
 import io.sentry.Sentry;
 
+import org.curiouslearning.container.core.subapp.payload.AppEventPayload;
+import org.curiouslearning.container.core.subapp.validation.AppEventPayloadValidator;
+import org.curiouslearning.container.core.subapp.validation.ValidationResult;
+import org.curiouslearning.container.core.subapp.handler.AppEventPayloadHandler;
+import org.curiouslearning.container.core.subapp.handler.DefaultAppEventPayloadHandler;
+
+
 public class WebApp extends BaseActivity {
 
     private String title;
@@ -187,6 +195,11 @@ public void onClick(DialogInterface dialog, int id) {
 
     public class WebAppInterface {
         private Context mContext;
+        private final Gson gson = new Gson();
+        private final AppEventPayloadValidator validator =
+                new AppEventPayloadValidator();
+        private final AppEventPayloadHandler handler =
+                new DefaultAppEventPayloadHandler();
 
         WebAppInterface(Context context) {
             mContext = context;
@@ -220,6 +233,36 @@ public void closeWebView(){
             audioPlayer.play(WebApp.this, R.raw.sound_button_pressed);
             finish();
         }
+
+        @JavascriptInterface
+        public void logMessage(String payloadJson) {
+
+            try {
+                if (payloadJson == null || payloadJson.trim().isEmpty()) {
+                    Log.e("WebApp", "Rejected payload: empty JSON");
+                    return;
+                }
+
+                AppEventPayload payload =
+                        gson.fromJson(payloadJson, AppEventPayload.class);
+
+                ValidationResult result = validator.validate(payload);
+
+                if (!result.isValid) {
+                    Log.e("WebApp",
+                            "Payload rejected: " + result.errorMessage);
+                    return;
+                }
+
+                handler.handle(payload);
+
+            } catch (JsonSyntaxException e) {
+                Log.e("WebApp", "Invalid JSON payload", e);
+            } catch (Exception e) {
+                Log.e("WebApp", "Unexpected error handling payload", e);
+            }
+        }
+
     }
 
     public void setAppOrientation(String orientationType) {

app/src/main/java/org/curiouslearning/container/core/subapp/handler/AppEventPayloadHandler.java

@@ -0,0 +1,7 @@
+package org.curiouslearning.container.core.subapp.handler;
+
+import org.curiouslearning.container.core.subapp.payload.AppEventPayload;
+
+public interface AppEventPayloadHandler {
+    void handle(AppEventPayload payload);
+}

app/src/main/java/org/curiouslearning/container/core/subapp/handler/DefaultAppEventPayloadHandler.java

@@ -0,0 +1,21 @@
+package org.curiouslearning.container.core.subapp.handler;
+
+import android.util.Log;
+
+import org.curiouslearning.container.core.subapp.payload.AppEventPayload;
+
+public class DefaultAppEventPayloadHandler
+        implements AppEventPayloadHandler {
+
+    private static final String TAG = "AppEventHandler";
+
+    @Override
+    public void handle(AppEventPayload payload) {
+
+        Log.d(TAG,
+                "Accepted payload | app_id=" + payload.app_id +
+                        " collection=" + payload.collection +
+                        " timestamp=" + payload.timestamp
+        );
+    }
+}

app/src/main/java/org/curiouslearning/container/core/subapp/payload/AppEventPayload.java

@@ -0,0 +1,13 @@
+package org.curiouslearning.container.core.subapp.payload;
+
+import java.util.Map;
+
+public class AppEventPayload {
+
+    public String cr_user_id;
+    public String app_id;
+    public String collection;
+    public Object data;
+    public Map<String, String> options;
+    public String timestamp;
+}

app/src/main/java/org/curiouslearning/container/core/subapp/validation/AppEventPayloadValidator.java

@@ -0,0 +1,52 @@
+package org.curiouslearning.container.core.subapp.validation;
+
+import org.curiouslearning.container.core.subapp.payload.AppEventPayload;
+
+import java.util.Map;
+
+public class AppEventPayloadValidator {
+
+    public ValidationResult validate(AppEventPayload payload) {
+
+        if (payload == null) {
+            return ValidationResult.failure("Payload is null");
+        }
+
+        if (isEmpty(payload.cr_user_id)) {
+            return ValidationResult.failure("Missing cr_user_id");
+        }
+
+        if (isEmpty(payload.app_id)) {
+            return ValidationResult.failure("Missing app_id");
+        }
+
+        if (isEmpty(payload.collection)) {
+            return ValidationResult.failure("Missing collection");
+        }
+
+        if (payload.data == null) {
+            return ValidationResult.failure("Missing data");
+        }
+
+        if (isEmpty(payload.timestamp)) {
+            return ValidationResult.failure("Missing timestamp");
+        }
+
+        if (payload.options != null) {
+            for (Map.Entry<String, String> entry : payload.options.entrySet()) {
+                String op = entry.getValue();
+                if (!"add".equals(op) && !"replace".equals(op)) {
+                    return ValidationResult.failure(
+                            "Invalid option for field: " + entry.getKey()
+                    );
+                }
+            }
+        }
+
+        return ValidationResult.success();
+    }
+
+    private boolean isEmpty(String value) {
+        return value == null || value.trim().isEmpty();
+    }
+}

app/src/main/java/org/curiouslearning/container/core/subapp/validation/ValidationResult.java

@@ -0,0 +1,20 @@
+package org.curiouslearning.container.core.subapp.validation;
+
+public class ValidationResult {
+
+    public final boolean isValid;
+    public final String errorMessage;
+
+    private ValidationResult(boolean isValid, String errorMessage) {
+        this.isValid = isValid;
+        this.errorMessage = errorMessage;
+    }
+
+    public static ValidationResult success() {
+        return new ValidationResult(true, null);
+    }
+
+    public static ValidationResult failure(String message) {
+        return new ValidationResult(false, message);
+    }
+}