dotfiles/systems/eris/config/filesystem.nix

{
  flake,
  config,
  lib,
  ...
}:
let
  inherit (flake.config.people) user0;
  rootDevice = "/dev/disk/by-label/root";
  bootDevice = "/dev/disk/by-label/BOOT";
in
{
  fileSystems = {
    "/" = {
      device = rootDevice;
      fsType = "btrfs";
      options = [
        "subvol=root"
      ];
    };
    "/nix" = {
      device = rootDevice;
      fsType = "btrfs";
      options = [
        "subvol=nix"
      ];
    };
    "/persist" = {
      device = rootDevice;
      fsType = "btrfs";
      neededForBoot = true;
      options = [
        "subvol=persist"
      ];
    };
    "/boot" = {
      device = bootDevice;
      fsType = "vfat";
      options = [
        "fmask=0077"
        "dmask=0077"
      ];
    };
    "/mnt/storage" = {
      device = "/dev/md0";
      fsType = "ext4";
      options = [
        "defaults"
        "nofail"
        "x-systemd.device-timeout=10"
      ];
    };
    "/etc/ssh" = {
      neededForBoot = true;
    };
  };
  environment.persistence."/persist" = {
    directories = [
      "/var/cache"
      "/var/lib"
      {
        directory = "/etc/ssh";
        mode = "u=rwx,g=rx,o=rx";
        user = "root";
      }
    ];
    hideMounts = true;
    users.${user0} = {
      directories = [
        ".cache"
        ".config"
        ".local/share/direnv"
        ".local/state/nix"
        {
          directory = ".ssh";
          mode = "u=rwx,g=,o=";
        }
      ];
    };
  };
  boot = {
    initrd.postResumeCommands = lib.mkAfter ''
      mkdir /btrfs_tmp
      mount -o subvolid=5 ${rootDevice} /btrfs_tmp

      if [[ -e /btrfs_tmp/root ]]; then
          mkdir -p /btrfs_tmp/old_roots
          timestamp=$(date --date="@$(stat -c %Y /btrfs_tmp/root)" "+%Y-%m-%-d_%H:%M:%S")
          mv /btrfs_tmp/root "/btrfs_tmp/old_roots/$timestamp"
      fi

      delete_subvolume_recursively() {
          IFS=$'\n'
          for i in $(btrfs subvolume list -o "$1" | cut -f 9- -d ' '); do
              delete_subvolume_recursively "/btrfs_tmp/$i"
          done
          btrfs subvolume delete "$1"
      }

      for i in $(find /btrfs_tmp/old_roots/ -maxdepth 1 -mtime +30); do
          delete_subvolume_recursively "$i"
      done

      btrfs subvolume create /btrfs_tmp/root
      umount /btrfs_tmp
    '';
    swraid = {
      enable = true;
      mdadmConf = ''
        ARRAY /dev/md0 metadata=1.2 name=eris:storage UUID=64659038:a939a18d:8cdc0f3f:97171a50
      '';
    };
  };
  systemd.tmpfiles.rules = [
    "Z ${config.home-manager.users.${user0}.home.homeDirectory} 0755 ${user0} users -"
    "d /mnt/storage 2775 root root -"
  ];
  services.udisks2.enable = true;
}

# sudo mount /dev/disk/by-label/root /mnt
# sudo btrfs subvolume create /mnt/persist
# sudo btsfs subvolume create /mnt/root
# sudo btrfs subvolume create /mnt/nix
# sudo umount /mnt

# sudo mount -o subvol=root /dev/disk/by-label/root /mnt

# sudo mount -o subvol=nix /dev/disk/by-label/root /mnt/nix
# sudo mount -o subvol=persist /dev/disk/by-label/root /mnt/persist

# sudo mount /dev/disk/by-label/BOOT /mnt/boot

# sudo nixos-generate-config --root /mnt

# sudo nixos-install --root /mnt

# sudo nixos-enter --root /mnt
# nixos-rebuild boot
# exit

# sudo reboot