{
  inputs,
  pkgs,
  ...
}: let
  # neoforgeVersion = "21.1.219";
  # vanillaServer = pkgs.fetchurl {
  #   url = "https://piston-data.mojang.com/v1/objects/59353fb40c36d304f2035d51e7d6e6baa98dc05c/server.jar";
  #   name = "minecraft_server.1.21.1.jar";
  #   hash = "sha256-XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX="; # Replace with actual hash: run `nix-prefetch-url 'https://piston-data.mojang.com/v1/objects/59353fb40c36d304f2035d51e7d6e6baa98dc05c/server.jar' --name 'minecraft_server.1.21.1.jar'`
  # };
  # neoforgeInstaller = pkgs.fetchurl {
  #   url = "https://maven.neoforged.net/releases/net/neoforged/neoforge/${neoforgeVersion}/neoforge-${neoforgeVersion}-installer.jar";
  #   hash = "sha256-FA3w+hf9Q4hIBR7Po9CRCBUVrRK/40+hJkBQN7oB3kQ="; # Replace with actual hash: run `nix-prefetch-url 'https://maven.neoforged.net/releases/net/neoforged/neoforge/21.1.219/neoforge-21.1.219-installer.jar'`
  # };
  # modpackZip = pkgs.fetchurl {
  #   url = "https://git.xunuwu.xyz/xun/nixos-config/releases/download/create-ultimate-bundle-thing/Create%20Ultimate%20Selection%202%20MC%201.21.1-5.2.0.zip";
  #   name = "Create Ultimate Selection 2 MC 1.21.1-5.2.0.zip";
  #   hash = "sha256-+ykE2GE5lWQVLfcKyleKmQ+GXC+yN54yIgh7mPxxj4g="; # Replace with actual hash: run `nix-prefetch-url --name 'Create Ultimate Selection 2 MC 1.21.1-5.2.0.zip' 'https://www.curseforge.com/minecraft/modpacks/create-ultimate-selection-2/download/7634594/file'` and paste the output here
  # };
  modpackZip = pkgs.fetchurl {
    url = "https://git.xunuwu.xyz/xun/nixos-config/releases/download/create-ultimate-thing-full/Create%20Ultimate%20Selection%202%20Serverpack%20MC%201.21.1-5.3.0.zip";
    name = "Create Ultimate Selection 2 MC 1.21.1-5.3.0.zip";
    # hash = ""; # Replace with actual hash: run `nix-prefetch-url --name 'Create Ultimate Selection 2 MC 1.21.1-5.2.0.zip' 'https://www.curseforge.com/minecraft/modpacks/create-ultimate-selection-2/download/7634594/file'` and paste the output here
    hash = "sha256-xDChlZWivNNjYnmSCUIyrxfvqXAHrbvql7jyEDvVXvA=";
  };
  # baseModpack = inputs.nix-minecraft.legacyPackages.${pkgs.stdenv.hostPlatform.system}.fetchPackwizModpack {
  #   src = ./create-ultimate-selection-2;
  #   packHash = "sha256-0i4RWfJLWayYkefzeePbQY48nr/TdbX/sUVFfppkKvM="; # Leave empty initially; update with the correct value after the first failed build (see instructions below)
  # };
  # modpack = baseModpack.overrideAttrs (old: {
  #   buildPhase =
  #     ''
  #       cp ${modpackZip} "Create Ultimate Selection 2 MC 1.21.1-5.2.0.zip"
  #     ''
  #     + old.buildPhase;
  # });
  neoforge = inputs.nix-minecraft.legacyPackages.${pkgs.stdenv.hostPlatform.system}.neoforgeServers.neoforge-1_21_1;
  serverPackage = pkgs.stdenv.mkDerivation {
    name = "minecraft-createpack-server";
    nativeBuildInputs = [pkgs.unzip];
    dontUnpack = true;
    installPhase = ''
      # mkdir -p $out
      # cp -r ${neoforge}/* $out
      # unzip ${modpackZip} -d temp
      # cp -r temp/overrides/* $out/
      # rm -rf temp

      mkdir -p $out
      # 1. Base NeoForge from nix-minecraft
      cp -r ${neoforge}/* $out/

      # 2. Overlay the full official server pack (this brings ALL mods + libraries)
      unzip ${modpackZip} -d temp
      cp -r temp/* $out/ 2>/dev/null || true
      rm -rf temp
    '';
  };
  # serverPackage = pkgs.stdenv.mkDerivation {
  #   name = "minecraft-createpack-server";
  #   src = modpackZip;
  #   # nativeBuildInputs = [pkgs.unzip pkgs.jdk21 pkgs.breakpointHook];
  #   nativeBuildInputs = [pkgs.unzip pkgs.jdk21];
  #   dontPatch = true;
  #   buildPhase = ''
  #     mkdir server
  #   #   unzip ${modpackZip}
  #     cp -r overrides/* server/
  #   '';
  #   # buildPhase = ''
  #   #   mkdir server
  #   #   cd server
  #   #   java -jar ${neoforgeInstaller} --installServer
  #   #   cd ..
  #   #   unzip ${modpackZip}
  #   #   cp -r overrides/* server/
  #   # '';
  #   installPhase = ''
  #     mkdir -p $out
  #     cp -r server/* $out
  #   '';
  # };
in {
  users.users.minecraft-createpack = {
    isSystemUser = true;
    group = "minecraft-createpack";
  };
  users.groups.minecraft-createpack = {};

  networking.firewall.allowedTCPPorts = [25565];

  systemd.tmpfiles.rules = [
    "d /srv/minecraft            0755 root                 root                 - -"
    "d /srv/minecraft/createpack 0770 minecraft-createpack minecraft-createpack - -"
    "Z /srv/minecraft/createpack -    minecraft-createpack minecraft-createpack - -"
  ];
  systemd.services.minecraft-createpack = {
    description = "Minecraft Create Ultimate Selection 2 Server";
    wantedBy = ["multi-user.target"];
    after = ["network.target"];
    serviceConfig = {
      User = "minecraft-createpack";
      Group = "minecraft-createpack";
      WorkingDirectory = "/srv/minecraft/createpack";
      Restart = "always";
      RestartSec = "5s";
      # ExecStart = "${pkgs.jdk21}/bin/java -Xms1024M -Xmx6144M -jar ${serverPackage}/neoforge-1.21.1-21.1.219.jar nogui";
      ExecStart = ''
        ${pkgs.jdk21}/bin/java \
          @user_jvm_args.txt \
          @libraries/net/neoforged/neoforge/21.1.219/unix_args.txt \
          nogui
      '';
      # ExecStart = "${pkgs.bash}/bin/bash ${serverPackage}/run.sh nogui";
    };
    # preStart = ''
    #   set -euo pipefail
    #
    #   echo "=== minecraft-createpack preStart running as $(whoami) in $(pwd) ==="
    #
    #   # Preserve world across restarts
    #   if [ -d world ]; then
    #     mv world ../world-tmp || true
    #   fi
    #
    #   # Clean slate + copy fresh files from the derivation
    #   rm -rf ./* .[!.]* ..?* || true
    #   cp -r ${serverPackage}/* .
    #
    #   # Restore world
    #   if [ -d ../world-tmp ]; then
    #     mv ../world-tmp world
    #   fi
    #
    #   chmod -R u+rwX .
    #   chown -R minecraft-createpack:minecraft-createpack .
    #
    #   echo "eula=true" > eula.txt
    #
    #   cat > server.properties <<EOF
    #   motd=createpack!!
    #   max-players=5
    #   difficulty=normal
    #   allow-flight=true
    #   view-distance=16
    #   EOF
    #
    #   # NeoForge 1.21+ uses this file for JVM flags
    #   cat > user_jvm_args.txt <<EOF
    #   -Xms1024M
    #   -Xmx6144M
    #   EOF
    #
    #   echo "preStart finished successfully"
    # '';
    preStart = ''
      set -euo pipefail
      echo "=== minecraft-createpack preStart ==="

      # Preserve user data
      for dir in world logs crash-reports backups screenshots; do
        if [ -d "$dir" ]; then
          mv "$dir" "../$dir-tmp" 2>/dev/null || true
        fi
      done

      # Gentle sync — only updates static server files, never touches your world
      ${pkgs.rsync}/bin/rsync -a --delete \
        --exclude='world' --exclude='logs' --exclude='crash-reports' \
        --exclude='backups' --exclude='screenshots' \
        --exclude='user_jvm_args.txt' --exclude='server.properties' --exclude='eula.txt' \
        ${serverPackage}/ ./

      # Restore user data
      for dir in world logs crash-reports backups screenshots; do
        if [ -d "../$dir-tmp" ]; then
          mv "../$dir-tmp" "$dir"
        fi
      done

      chown -R minecraft-createpack:minecraft-createpack .
      chmod -R u+rwX .

      echo "eula=true" > eula.txt

      cat > server.properties <<'EOF'
      motd=createpack!!
      max-players=5
      difficulty=normal
      allow-flight=true
      view-distance=16
      EOF

      cat > user_jvm_args.txt <<'EOF'
      -Xms1024M
      -Xmx6144M
      EOF

      echo "=== preStart finished ==="
    '';
  };

  services.minecraft-servers = {
    enable = false;
    eula = true;
    openFirewall = true;
    managementSystem.systemd-socket.enable = true;
    # servers.createpack = {
    #   enable = true;
    #   package = inputs.nix-minecraft.legacyPackages.${pkgs.stdenv.hostPlatform.system}.neoforgeServers.neoforge-1_21_1;
    #   serverProperties = {
    #     motd = "createpack!!";
    #     max-players = 5;
    #     difficulty = "normal";
    #     allow-flight = true;
    #     view-distance = 16;
    #   };
    #   jvmOpts = "-Xms1024M -Xmx6144M";
    #   symlinks.mods = "${modpack}/mods";
    # };
    servers.owo = {
      enable = false;
      package = inputs.nix-minecraft.legacyPackages.${pkgs.stdenv.hostPlatform.system}.fabricServers.fabric-1_21_5;
      serverProperties = {
        max-players = 5;
        motd = "owo";
        difficulty = "normal";
        allow-flight = true;
        view-distance = 16;
      };
      jvmOpts = "-Xms1024M -Xmx4096M";
      symlinks.mods = pkgs.linkFarmFromDrvs "mods" (
        builtins.attrValues {
          Fabric-API = pkgs.fetchurl {
            url = "https://cdn.modrinth.com/data/P7dR8mSH/versions/hBmLTbVB/fabric-api-0.121.0%2B1.21.5.jar";
            hash = "sha256-GbKETZqAN5vfXJF0yNgwTiogDAI434S3Rj9rZw6B53E=";
          };
          Lithium = pkgs.fetchurl {
            url = "https://cdn.modrinth.com/data/gvQqBUqZ/versions/VWYoZjBF/lithium-fabric-0.16.2%2Bmc1.21.5.jar";
            hash = "sha256-XqvnQxASa4M0l3JJxi5Ej6TMHUWgodOmMhwbzWuMYGg=";
          };
          FerriteCore = pkgs.fetchurl {
            url = "https://cdn.modrinth.com/data/uXXizFIs/versions/CtMpt7Jr/ferritecore-8.0.0-fabric.jar";
            hash = "sha256-K5C/AMKlgIw8U5cSpVaRGR+HFtW/pu76ujXpxMWijuo=";
          };
          C2ME = pkgs.fetchurl {
            url = "https://cdn.modrinth.com/data/VSNURh3q/versions/VEjpHAOG/c2me-fabric-mc1.21.5-0.3.2%2Brc.1.0.jar";
            hash = "sha256-D7Ho8N4vZwHeacmfNe8YMcxsQCSlyNWFsxOp2b+vujE=";
          };
          Krypton = pkgs.fetchurl {
            url = "https://cdn.modrinth.com/data/fQEb0iXm/versions/neW85eWt/krypton-0.2.9.jar";
            hash = "sha256-uGYia+H2DPawZQxBuxk77PMKfsN8GEUZo3F1zZ3MY6o=";
          };
        }
      );
    };
  };

  environment.persistence."/persist".directories = ["/srv/minecraft"];
  services.restic.backups.hopper.paths = ["/srv/minecraft"];
}