# 配置原子系统, 使用 tmpfs 作为根文件系统, 并配置持久化存储
{ inputs, config, pkgs, username, lib, ... }:
{
  imports = [
    inputs.impermanence.nixosModules.impermanence
  ];

  # 启用 tmpfs 作为根文件系统
  fileSystems."/" = lib.mkForce {
    device = "tmpfs";
    fsType = "tmpfs";
    options = [ "relatime" "mode=755" ];
  };

  # 将 /nix 目录绑定到持久化存储
  fileSystems."/nix" = lib.mkForce {
    device = "/dev/disk/by-label/nixos"; # 需要根据实际情况修改
    fsType = "btrfs";
    options = [ "compress-force=zstd" ];

  };

  # 配置持久化存储
  environment.persistence."/nix/persistent" = {
    hideMounts = true;
    directories = [
      "/etc/nixos"
      "/etc/NetworkManager/system-connections"
      "/var/log"
      "/var/lib"
      "/root"
    ];

    files = [
      "/etc/machine-id"
      "/etc/ssh/ssh_host_ed25519_key"
      "/etc/ssh/ssh_host_ed25519_key.pub"
      "/etc/ssh/ssh_host_rsa_key"
      "/etc/ssh/ssh_host_rsa_key.pub"
    ];

    users.${username} = {
      directories = [
        ".config"
        ".cache"
        ".local"
        ".ssh"
        ".vscode"
        ".npm"
        ".nix"
        "data"
        "doc"
      ];

      files = [
        ".zsh_history"
        ".gitconfig"
      ];
    };
  };
}