Split commands into separate classes

src/main/java/org/asamk/signal/commands/AddDeviceCommand.java

@@ -0,0 +1,43 @@
+package org.asamk.signal.commands;
+
+import net.sourceforge.argparse4j.inf.Namespace;
+import net.sourceforge.argparse4j.inf.Subparser;
+import org.asamk.signal.manager.Manager;
+import org.whispersystems.libsignal.InvalidKeyException;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+
+import static org.asamk.signal.util.ErrorUtils.handleAssertionError;
+
+public class AddDeviceCommand implements LocalCommand {
+
+    @Override
+    public void attachToSubparser(final Subparser subparser) {
+        subparser.addArgument("--uri")
+                .required(true)
+                .help("Specify the uri contained in the QR code shown by the new device.");
+    }
+
+    @Override
+    public int handleCommand(final Namespace ns, final Manager m) {
+        if (!m.isRegistered()) {
+            System.err.println("User is not registered.");
+            return 1;
+        }
+        try {
+            m.addDeviceLink(new URI(ns.getString("uri")));
+            return 0;
+        } catch (IOException e) {
+            e.printStackTrace();
+            return 3;
+        } catch (InvalidKeyException | URISyntaxException e) {
+            e.printStackTrace();
+            return 2;
+        } catch (AssertionError e) {
+            handleAssertionError(e);
+            return 1;
+        }
+    }
+}