Implement !status command

src/main/java/emu/nebula/command/commands/StatusCommand.java

@@ -0,0 +1,101 @@
+package emu.nebula.command.commands;
+
+import emu.nebula.GameConstants;
+import emu.nebula.Nebula;
+import emu.nebula.command.Command;
+import emu.nebula.command.CommandArgs;
+import emu.nebula.command.CommandHandler;
+
+import java.io.File;
+import java.lang.management.ManagementFactory;
+
+@Command(label = "status", permission = "admin.status", desc = "!status = Displays server runtime status.")
+public class StatusCommand implements CommandHandler {
+
+    @Override
+    public String execute(CommandArgs args) {
+        var sb = new StringBuilder();
+
+        if (args.getRaw().contains("@")) {
+            if (args.getTarget() == null || !args.getTarget().hasSession()) {
+                return "Error - Targeted player not found or offline";
+            }
+        }
+
+        var runtime = Runtime.getRuntime();
+        var uptimeMs = ManagementFactory.getRuntimeMXBean().getUptime();
+
+        double usedMem = (runtime.totalMemory() - runtime.freeMemory()) / 1048576.0;
+        double maxMem = runtime.maxMemory() / 1048576.0;
+
+        int players = 0;
+        if (Nebula.getGameContext() != null) {
+            players = Nebula.getGameContext().getPlayerModule().getCachedPlayers().size();
+        }
+
+        var http = Nebula.getHttpServer();
+        String addr = "-";
+        String scheme = "http";
+        int port = 0;
+        if (http != null) {
+            addr = http.getServerConfig().getPublicAddress();
+            port = http.getServerConfig().getPublicPort();
+            scheme = http.getServerConfig().isUseSSL() ? "https" : "http";
+        }
+
+        sb.append("Server Status\n");
+        sb.append("Git: ").append(Nebula.getGitHash()).append('\n');
+        sb.append("Game: ").append(GameConstants.getGameVersion()).append('\n');
+        sb.append("HTTP: ").append(scheme).append("://").append(addr).append(":").append(port).append('\n');
+        sb.append("Uptime: ").append(formatUptime(uptimeMs)).append('\n');
+        sb.append("CPU: ").append(getCpu()).append('\n');
+        sb.append("Load: ").append(getLoad()).append('\n');
+        sb.append("Disk: ").append(getDisk()).append('\n');
+        sb.append("Memory: ").append(String.format("%.1fMB (max %.1fMB)", usedMem, maxMem)).append('\n');
+        sb.append("Players: ").append(players);
+
+        return sb.toString();
+    }
+
+    private static String formatUptime(long ms) {
+        long s = ms / 1000;
+        long h = s / 3600;
+        long m = (s % 3600) / 60;
+        long sec = s % 60;
+        return String.format("%02dh:%02dm:%02ds", h, m, sec);
+    }
+
+    private static String getCpu() {
+        var os = ManagementFactory.getOperatingSystemMXBean();
+        double v = -1;
+        if (os instanceof com.sun.management.OperatingSystemMXBean) {
+            v = ((com.sun.management.OperatingSystemMXBean) os).getProcessCpuLoad();
+        }
+        return v >= 0 ? String.format("%.1f%%", v * 100.0) : "-";
+    }
+
+    private static String getLoad() {
+        var os = ManagementFactory.getOperatingSystemMXBean();
+        double v = -1;
+        if (os instanceof com.sun.management.OperatingSystemMXBean csm) {
+            v = csm.getCpuLoad();
+        }
+        if (v < 0) {
+            double avg = os.getSystemLoadAverage();
+            if (avg > 0) {
+                int cores = Runtime.getRuntime().availableProcessors();
+                v = Math.min(1.0, avg / cores);
+            }
+        }
+        return v >= 0 ? String.format("%.1f%%", v * 100.0) : "-";
+    }
+
+    private static String getDisk() {
+        var root = new File(".");
+        long total = root.getTotalSpace();
+        long usable = root.getUsableSpace();
+        if (total <= 0) return "-";
+        double usedPercent = (double) (total - usable) / (double) total * 100.0;
+        return String.format("%.1f%%", usedPercent);
+    }
+}