{ config, pkgs, lib, ... }:

let
  mcDataDir = "/srv/minecraft/data";

  modrinthMods = builtins.concatStringsSep "," [
    # Performance
    "lithium"
    "krypton"
    "ferrite-core"
    "c2me-fabric"
    "noisium"
    "linearly-optimized"
    "vmp-fabric"
    "ksyxis"
    "scalablelux"
    "lmd"
    "structure-layout-optimizer"
    "threadtweak"
    "crashexploitfixer"

    # Anti-cheat
    "anti-xray"
    "grimac"
    "no-chat-reports"

    # Worldgen — terrain (Stardust Labs suite)
    "terralith"
    "tectonic"
    "amplified-nether"
    "nullscape"

    # Worldgen — structures (YUNG's suite)
    "yungs-api"
    "yungs-better-dungeons"
    "yungs-better-strongholds"
    "yungs-better-ocean-monuments"
    "yungs-better-mineshafts"
    "yungs-better-desert-temples"
    "yungs-better-jungle-temples"
    "yungs-better-witch-huts"
    "yungs-better-nether-fortresses"
    "yungs-better-end-island"
    "yungs-extras"
    "yungs-bridges"

    # Client mod compatibility (optional on client side)
    "appleskin"
    "simple-voice-chat"

    # QoL
    "oneplayersleep"
    "netherportalfix"
    "blossomlib"
    "blossomtpa"
    "double-shulker-shell-drops"
    "afkplus"

    # Moderation
    "ledger"
    "styled-chat"

    # Discord bridge
    "discord-mc-chat"

    # Utilities
    "chunky"
  ];

  jvmFlags = builtins.concatStringsSep " " [
    "-XX:+UseG1GC"
    "-XX:+ParallelRefProcEnabled"
    "-XX:MaxGCPauseMillis=200"
    "-XX:+UnlockExperimentalVMOptions"
    "-XX:+DisableExplicitGC"
    "-XX:G1NewSizePercent=30"
    "-XX:G1MaxNewSizePercent=40"
    "-XX:G1HeapRegionSize=8M"
    "-XX:G1ReservePercent=20"
    "-XX:G1MixedGCCountTarget=4"
    "-XX:InitiatingHeapOccupancyPercent=15"
    "-XX:G1MixedGCLiveThresholdPercent=90"
    "-XX:SurvivorRatio=32"
    "-XX:+PerfDisableSharedMem"
    "-XX:MaxTenuringThreshold=1"
  ];
in
{
  virtualisation.docker.enable = true;

  virtualisation.oci-containers.backend = "docker";
  virtualisation.oci-containers.containers.minecraft = {
    image = "itzg/minecraft-server:java21";
    ports = [
      "25565:25565"       # Minecraft
      "24454:24454/udp"   # Simple Voice Chat
    ];
    volumes = [
      "${mcDataDir}:/data"
    ];
    environment = {
      EULA = "TRUE";
      TYPE = "FABRIC";
      VERSION = "1.21.4";
      MEMORY = "2560M";
      MAX_PLAYERS = "10";
      DIFFICULTY = "hard";
      PVP = "FALSE";
      VIEW_DISTANCE = "10";
      SIMULATION_DISTANCE = "10";
      ENABLE_WHITELIST = "TRUE";
      ENFORCE_WHITELIST = "TRUE";
      WHITELIST = "jetpham";
      OPS = "jetpham";
      MOTD = "meet cool people \\u00A7e\\u0026\\u0026\\u00A7r build cool things";
      OVERRIDE_ICON = "TRUE";
      MODRINTH_PROJECTS = modrinthMods;
      JVM_XX_OPTS = jvmFlags;
    };
    environmentFiles = [ "/run/minecraft-seed.env" ];
    extraOptions = [
      "--memory=3g"
      "--cpus=2"
      "--restart=unless-stopped"
      "--pids-limit=256"
      "--security-opt=no-new-privileges"
    ];
  };

  # Ensure data directory exists
  systemd.tmpfiles.rules = [
    "d ${mcDataDir} 0755 root root -"
  ];

  # Write seed env file and copy mod configs before container starts
  systemd.services.minecraft-mod-configs = {
    description = "Set up mod configs and seed for Minecraft container";
    wantedBy = [ "multi-user.target" ];
    before = [ "docker-minecraft.service" ];
    after = [ "agenix.service" ];
    serviceConfig = {
      Type = "oneshot";
      ExecStart = pkgs.writeShellScript "setup-mod-configs" ''
        set -euo pipefail

        # Write seed from agenix secret
        SEED=$(cat ${config.age.secrets.minecraft-seed.path})
        printf 'SEED=%s\n' "$SEED" > /run/minecraft-seed.env
        chmod 600 /run/minecraft-seed.env

        # Server icon
        cp ${../server-icon.png} ${mcDataDir}/server-icon.png

        # Mod configs
        mkdir -p ${mcDataDir}/plugins/Chunky
        cp ${../configs/chunky.yml} ${mcDataDir}/plugins/Chunky/config.yml

        mkdir -p ${mcDataDir}/config
        cp ${../configs/anti-xray.toml} ${mcDataDir}/config/anti-xray.toml
      '';
    };
  };
}