{
  pkgs,
  service_configs,
  lib,
  username,
  ...
}:
let
  heap_size = "4000M";
in
{
  nixpkgs.config.allowUnfreePredicate =
    pkg:
    builtins.elem (lib.getName pkg) [
      "minecraft-server"
    ];

  services.minecraft-servers = {
    enable = true;
    eula = true;
    dataDir = service_configs.minecraft.parent_dir;
    openFirewall = true;

    servers.${service_configs.minecraft.server_name} = {
      enable = true;
      package = pkgs.fabricServers.fabric-1_21_3;

      jvmOpts = "-Xmx${heap_size} -Xms${heap_size} -XX:+UseZGC -XX:+ZGenerational";

      serverProperties = {
        server-port = 25565;
        enforce-whitelist = true;
        gamemode = "survival";
        white-list = true;
        difficulty = "easy";
        motd = "A Minecraft Server";
      };

      whitelist = import ../secrets/minecraft-whitelist.nix;

      # provide `infocmp` command for better-fabric-console
      path = [ pkgs.ncurses ];

      symlinks = {
        "mods" = pkgs.linkFarmFromDrvs "mods" (
          with pkgs;
          builtins.attrValues {
            FabricApi = fetchurl {
              url = "https://cdn.modrinth.com/data/P7dR8mSH/versions/MawoBGbv/fabric-api-0.107.3%2B1.21.3.jar";
              sha512 = "84e6bbdcd9819999e9d8873be7b6470bc9de898cdc0b878caeb8deb26e7cf3a1c532710e239815565d40afdb06db423746506f4c174fc3938c2790b5e6d5266f";
            };

            FerriteCore = fetchurl {
              url = "https://cdn.modrinth.com/data/uXXizFIs/versions/a3QXXGz2/ferritecore-7.1.0-hotfix-fabric.jar";
              sha512 = "ae1ab30beb5938643cf2ae7b8220769f2c917e3f5441e46e9bc900295348c0a541a325c30b8dfc38039205620d872c27809acdc6741351f08e4c8edc36ae2bcc";
            };

            Lithium = fetchurl {
              url = "https://cdn.modrinth.com/data/gvQqBUqZ/versions/2Ea7RMWZ/lithium-fabric-0.14.1-snapshot%2Bmc1.21.3-build.89.jar";
              sha512 = "d122b23a520cb2573c2eaba9556c07846ae5f2f8ee9aabdf5dce914334e44027a273c8cf2ef2243fe03cf86a8858eab2ddcc247d95661dee40cd783cf444aeff";
            };

            NoChatReports = fetchurl {
              url = "https://cdn.modrinth.com/data/qQyHxfxd/versions/Cg7X9iDa/NoChatReports-FABRIC-1.21.3-v2.10.1.jar";
              sha512 = "8f1163ad515ebdfab5ef54a4985af05e643749c2efc0bf7b62e00074bbe61d91789b0c9e558bbe1b5c5d21a89b88084ce6350a11a5a9a3bea59eea9764a27171";
            };

            tick-stasis = fetchurl {
              url = "https://cdn.modrinth.com/data/t6XBQ2xn/versions/fDbxgNHz/tick-stasis-1.1.1.jar";
              sha512 = "346fae7e0f1a62636525a9331643ac4343b781c240db6ef9bafe1b3a295d24d131d2b4b20cef8edc33835e9069fcaf1c2e2b3ce9ced9a2ec6e4e3d82770f52c6";
            };

            moonrise = fetchurl {
              url = "https://cdn.modrinth.com/data/KOHu7RCS/versions/S7ZBVFid/Moonrise-Fabric-0.2.0-beta.3%2Bbad5cae.jar";
              sha512 = "84831de3f402bd2f69fba1329412064f487571527fbb4182c45433eba3d716ef52c057d4f2e9f794821ac5147dbae774ef5c83776f4e376fc10ba3d80015cfde";
            };

            mixintrace = fetchurl {
              url = "https://cdn.modrinth.com/data/sGmHWmeL/versions/1.1.1%2B1.17/mixintrace-1.1.1%2B1.17.jar";
              sha512 = "ea9034b60bc1c64629a9bcad2e619907692fe6e7464026236c55cc5a4892a20d21dd6318ad0380ab2ec245f7077939b6717d2ed58e00708c17470be14f5e0b5f";
            };

            better-fabric-console = fetchurl {
              url = "https://cdn.modrinth.com/data/Y8o1j1Sf/versions/QGfoAASu/better-fabric-console-mc1.21.3-1.2.1.jar";
              sha512 = "3a88c281a65f26e44b17b3a7a5cc9f84046b013931bd3af7f2553f462987a96357b21c104a41593ca0516038e6c4398a890ee118046fe95a7e0c7f2d743d944a";
            };

            StackDeobfuscator = fetchurl {
              url = "https://cdn.modrinth.com/data/NusMqsjF/versions/pyiVLk9R/StackDeobfuscatorFabric-1.4.3%2B08e71cc.jar";
              sha512 = "ef851d54a60e223e90cfd21da91effcdc70175dd32b194366ca3ba29646c9ebdbfb60a1eaa88070c4e9f83bd654da1344e67226dfdf5c68140db4ef693361353";
            };

            mods-command = fetchurl {
              url = "https://cdn.modrinth.com/data/PExmWQV8/versions/1F0YwdWN/mods-command-mc1.21.3-1.1.8.jar";
              sha512 = "761ee048edd6b53eac6fd922c21f7c4012970b3aa57fbd8e7613294e57a12603a7a30af6d6595c06a6a67a02c2a90cb76cd3dafd0bb647d16b4a9888454f0421";
            };

            # hasn't updated to 1.21.3 yet (https://modrinth.com/mod/vivecraft/versions)
            # vivecraft = pkgs.fetchurl {
            #   url = "https://cdn.modrinth.com/data/wGoQDPN5/versions/55ml9ENB/vivecraft-1.21.1-1.1.14-b2-fabric.jar";
            #   sha512 = "6241183987d6197a5e2b4b17f86db2ee9c594f0b6ec335153f1733c2c9ace9f21d07007150a9082e2834deead68b2c287e9443b23be5cd09a366db3f1593975b";
            # };
          }
        );
      };
    };
  };

  users.users.${username}.extraGroups = [
    "minecraft"
  ];
}