feat(nemesis): add gtnh server module

nix/hosts.nix

@@ -61,6 +61,8 @@ in
         cfg.modules.nixos.steam
         cfg.modules.nixos.prismlauncher
         cfg.modules.nixos.daily-midnight-poweroff
+        cfg.modules.nixos.gtnh-server
+        cfg.modules.nixos.gtnh-backups
         (
           {
             config,

nix/modules/gtnh-backups.nix

@@ -0,0 +1,50 @@
+{
+  config.flake.modules.nixos.gtnh-backups =
+    { pkgs, ... }:
+    let
+      backupDir = "/srv/gtnh-backups";
+    in
+    {
+      systemd = {
+        tmpfiles.rules = [ "d ${backupDir} 0750 root root -" ];
+        services.gtnh-backup = {
+          description = "Backup GTNH server";
+          serviceConfig = {
+            Type = "oneshot";
+            ExecStart = pkgs.writeShellScript "gtnh-backup" ''
+              set -euo pipefail
+
+              ts="$(${pkgs.coreutils}/bin/date +%Y%m%d-%H%M%S)"
+              dest="${backupDir}/gtnh-$ts.tar.zst"
+
+              echo "say Starting server backup" > /run/gtnh-server.stdin || true
+              echo "save-all" > /run/gtnh-server.stdin || true
+              ${pkgs.coreutils}/bin/sleep 10
+
+              ${pkgs.gnutar}/bin/tar \
+                --exclude='/srv/gtnh/backups' \
+                -C /srv \
+                -I '${pkgs.zstd}/bin/zstd -T0 -10' \
+                -cf "$dest" \
+                gtnh
+
+              ${pkgs.findutils}/bin/find ${backupDir} \
+                -name 'gtnh-*.tar.zst' \
+                -type f \
+                -mtime +14 \
+                -delete
+
+              echo "say Server backup complete" > /run/gtnh-server.stdin || true
+            '';
+          };
+        };
+        timers.gtnh-backup = {
+          wantedBy = [ "timers.target" ];
+          timerConfig = {
+            OnCalendar = "03:30";
+            Persistent = true;
+          };
+        };
+      };
+    };
+}

nix/modules/gtnh-server.nix

@@ -0,0 +1,102 @@
+{
+  config.flake.modules.nixos.gtnh-server =
+    { pkgs, ... }:
+    let
+      gtnhDir = "/srv/gtnh";
+      java = pkgs.jdk25_headless;
+      stopScript = pkgs.writeShellScript "gtnh-stop" ''
+        set -euo pipefail
+
+        if [ -p /run/gtnh-server.stdin ]; then
+          echo "stop" > /run/gtnh-server.stdin || true
+        fi
+
+        timeout=120
+        while kill -0 "$1" 2>/dev/null && [ "$timeout" -gt 0 ]; do
+          sleep 1
+          timeout=$((timeout - 1))
+        done
+
+        if kill -0 "$1" 2>/dev/null; then
+          kill -TERM "$1"
+        fi
+      '';
+    in
+    {
+      users = {
+        users.gtnh = {
+          description = "GT New Horizons server user";
+          isSystemUser = true;
+          group = "gtnh";
+          home = gtnhDir;
+          createHome = true;
+        };
+        groups.gtnh = { };
+      };
+      systemd = {
+        tmpfiles.rules = [ "d ${gtnhDir} 0750 gtnh gtnh -" ];
+        sockets.gtnh-server = {
+          bindsTo = [ "gtnh-server.service" ];
+          socketConfig = {
+            ListenFIFO = "/run/gtnh-server.stdin";
+            SocketMode = "0660";
+            SocketUser = "gtnh";
+            SocketGroup = "gtnh";
+            RemoveOnStop = true;
+            FlushPending = true;
+          };
+        };
+        services.gtnh-server = {
+          description = "GT New Horizons 2.8.4 Server";
+          wantedBy = [ "multi-user.target" ];
+          requires = [ "gtnh-server.socket" ];
+          after = [
+            "network-online.target"
+            "gtnh-server.socket"
+          ];
+          wants = [ "network-online.target" ];
+          unitConfig.ConditionPathExists = [
+            "${gtnhDir}/java9args.txt"
+            "${gtnhDir}/lwjgl3ify-forgePatches.jar"
+          ];
+          path = [
+            java
+            pkgs.bash
+            pkgs.coreutils
+          ];
+          serviceConfig = {
+            User = "gtnh";
+            Group = "gtnh";
+            WorkingDirectory = gtnhDir;
+            Restart = "on-failure";
+            RestartSec = "30s";
+            SuccessExitStatus = "0 143";
+            StandardInput = "socket";
+            StandardOutput = "journal";
+            StandardError = "journal";
+            ExecStart = ''
+              ${java}/bin/java \
+                -Xms6G \
+                -Xmx10G \
+                -XX:+UseZGC \
+                -Dfml.readTimeout=180 \
+                @java9args.txt \
+                -jar lwjgl3ify-forgePatches.jar \
+                nogui
+            '';
+            ExecStop = "${stopScript} $MAINPID";
+            UMask = "0027";
+            NoNewPrivileges = true;
+            PrivateTmp = true;
+            ProtectSystem = "strict";
+            ReadWritePaths = [ gtnhDir ];
+            ProtectHome = true;
+          };
+        };
+      };
+      networking.firewall = {
+        allowedTCPPorts = [ 25565 ];
+        allowedUDPPorts = [ 25565 ];
+      };
+    };
+}

nix/modules/prismlauncher.nix

@@ -10,8 +10,13 @@ in
     darwin.prismlauncher = osModule;
     nixos.prismlauncher = osModule;
     homeManager.prismlauncher =
-      { pkgs, ... }:
+      { config, pkgs, ... }:
       {
+        xdg.desktopEntries.gtnh = {
+          name = "GregTech New Horizons";
+          icon = "${config.home.homeDirectory}/.local/share/PrismLauncher/instances/GT_New_Horizons_2.8.4_Java_17-25/icon.png";
+          exec = "prismlauncher --launch GT_New_Horizons_2.8.4_Java_17-25";
+        };
         home.packages = [
           (pkgs.prismlauncher.override {
             jdks = [ pkgs.jdk25 ];