Implement json output for receive

src/main/java/org/asamk/signal/JsonMessageEnvelope.java

@@ -0,0 +1,36 @@
+package org.asamk.signal;
+
+import org.whispersystems.signalservice.api.messages.SignalServiceContent;
+import org.whispersystems.signalservice.api.messages.SignalServiceEnvelope;
+import org.whispersystems.signalservice.api.push.SignalServiceAddress;
+
+class JsonMessageEnvelope {
+    String source;
+    int sourceDevice;
+    String relay;
+    long timestamp;
+    boolean isReceipt;
+    JsonDataMessage dataMessage;
+    JsonSyncMessage syncMessage;
+    JsonCallMessage callMessage;
+
+    public JsonMessageEnvelope(SignalServiceEnvelope envelope, SignalServiceContent content) {
+        SignalServiceAddress source = envelope.getSourceAddress();
+        this.source = source.getNumber();
+        this.sourceDevice = envelope.getSourceDevice();
+        this.relay = source.getRelay().isPresent() ? source.getRelay().get() : null;
+        this.timestamp = envelope.getTimestamp();
+        this.isReceipt = envelope.isReceipt();
+        if (content != null) {
+            if (content.getDataMessage().isPresent()) {
+                this.dataMessage = new JsonDataMessage(content.getDataMessage().get());
+            }
+            if (content.getSyncMessage().isPresent()) {
+                this.syncMessage = new JsonSyncMessage(content.getSyncMessage().get());
+            }
+            if (content.getCallMessage().isPresent()) {
+                this.callMessage = new JsonCallMessage(content.getCallMessage().get());
+            }
+        }
+    }
+}