FlatLaf look-and-feel with better Dark mode support. (#23)

This PR configures Symon to use the FlatLaf Swing look-and-feel, giving both a slightly more modern look but also much better support for Dark/Light UI modes. Additional small tweaks to make the UI more readable in both Dark/Light modes.

Detection of system theme also added, selecting the Dark/Light FlatLaf variant accordingly.

Gets rid of need for the hardcoded Metal UI for text fields in StatusPanel workaround as well, as FlatLaf renders these small fields correctly.

Reviewed-on: https://codeberg.org/sethm/symon/pulls/23
Reviewed-by: Seth Morabito <sethm@noreply.codeberg.org>

src/main/java/com/loomcom/symon/Main.java

@@ -25,14 +25,15 @@
 package com.loomcom.symon;
 
 import com.loomcom.symon.machines.*;
+import com.loomcom.symon.ui.Ui;
+
 import org.apache.commons.cli.*;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.util.Locale;
-import javax.swing.JOptionPane;
+
 import javax.swing.SwingUtilities;
-import javax.swing.UIManager;
 
 public class Main {
     private final static Logger logger = LoggerFactory.getLogger(Main.class.getName());
@@ -58,6 +59,7 @@ public class Main {
         CommandLineParser parser = new DefaultParser();
 
         try {
+
             CommandLine line = parser.parse(options, args);
             InstructionTable.CpuBehavior cpuBehavior = null;
             String romFile = null;
@@ -116,27 +118,11 @@ public class Main {
                 haltOnBreak = true;
             }
 
+            Ui.initUi();
+
             while (true) {
                 if (machineClass == null) {
-                    Object[] possibilities = { "Symon", "Multicomp", "Simple", "BenEater" };
-                    String s = (String) JOptionPane.showInputDialog(
-                            null,
-                            "Please choose the machine type to be emulated:",
-                            "Machine selection",
-                            JOptionPane.PLAIN_MESSAGE,
-                            null,
-                            possibilities,
-                            "Symon");
-
-                    if (s != null && s.equals("Multicomp")) {
-                        machineClass = MulticompMachine.class;
-                    } else if (s != null && s.equals("Simple")) {
-                        machineClass = SimpleMachine.class;
-                    } else if (s != null && s.equals("BenEater")) {
-                        machineClass = BenEaterMachine.class;
-                    } else {
-                        machineClass = SymonMachine.class;
-                    }
+                    machineClass = Ui.showMachineSelectionDialog();
                 }
 
                 if (cpuBehavior == null) {
@@ -146,9 +132,8 @@ public class Main {
                 final Simulator simulator = new Simulator(machineClass, cpuBehavior, romFile, haltOnBreak);
 
                 SwingUtilities.invokeLater(() -> {
+                    // Create the main UI window:
                     try {
-                        UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
-                        // Create the main UI window
                         simulator.createAndShowUi();
                     } catch (Exception e) {
                         logger.error("Error during Symon UI initialization: {}", e.getMessage());
@@ -168,4 +153,5 @@ public class Main {
             logger.error("Could not start Symon. Reason: {}", ex.getMessage());
         }
     }
+
 }