restructuring

lib/xlib/default.nix

@@ -0,0 +1,66 @@
+# Pure host library: no module system involved.
+#
+# Aggregates the four concerns a host record is built from:
+#   device.nix   identity + capability flags from the device type
+#   dirs.nix     well-known paths, derived from username
+#   helpers.nix  pure helper functions shared by modules
+#
+# `mkXlib` is called in flake-level code (configurations/default.nix) and
+# handed to every module as the `xlib` argument via lib/mkSystem.nix, so
+# modules read plain `xlib.*` values instead of `config.xlib.*` and nothing in
+# xlib can be overridden per host — the host record is the only place to
+# change it.
+{
+  lib,
+  ...
+}:
+let
+  inherit (import ./device.nix { inherit lib; })
+    devices
+    mkDevice
+    ;
+
+  # dirs.nix is itself a function of `username`, not an attrset.
+  mkDirs = import ./dirs.nix;
+
+  helpers = (import ./helpers.nix { inherit lib; });
+in
+{
+  inherit
+    devices
+    helpers
+    mkDevice
+    mkDirs
+    ;
+
+  # Full host record: identity + capability flags + well-known paths +
+  # shared helpers.
+  mkXlib =
+    {
+      hostname,
+      type,
+      username ? "oqyude",
+    }:
+    let
+      device = mkDevice {
+        inherit
+          hostname
+          type
+          username
+          ;
+      };
+    in
+    {
+      device = {
+        inherit
+          hostname
+          type
+          username
+          ;
+      };
+      isDesktop = device.isDesktop;
+      isHeadless = device.isHeadless;
+      dirs = mkDirs username;
+      inherit helpers;
+    };
+}

lib/xlib/device.nix

@@ -0,0 +1,65 @@
+{
+  lib,
+  ...
+}:
+# Supported device types and the identity record built from one.
+#
+# Single source of truth for host identity: hostname, type, username and the
+# capability flags derived from the type. Replaces the old `lib.types.enum`
+# in modules/options.nix and the hand-written type lists in modules/default.nix
+# and home/home.nix.
+let
+  devices = {
+    minimal = {
+      desktop = false;
+      headless = false;
+    };
+    primary = {
+      desktop = true;
+      headless = false;
+    };
+    secondary = {
+      desktop = true;
+      headless = false;
+    };
+    server = {
+      desktop = false;
+      headless = true;
+    };
+    vds = {
+      desktop = false;
+      headless = true;
+    };
+    wsl = {
+      desktop = false;
+      headless = true;
+    };
+    termux = {
+      desktop = false;
+      headless = true;
+    };
+  };
+in
+{
+  inherit devices;
+
+  # Unknown device type fails here, at flake level, with the valid list.
+  mkDevice =
+    {
+      hostname,
+      type,
+      username ? "oqyude",
+    }:
+    let
+      capabilities = devices.${type} or (throw "xlib: unknown device type '${type}', expected one of ${lib.concatStringsSep ", " (builtins.attrNames devices)}");
+    in
+    {
+      inherit
+        hostname
+        type
+        username
+        ;
+      isDesktop = capabilities.desktop;
+      isHeadless = capabilities.headless;
+    };
+}

lib/xlib/dirs.nix

@@ -0,0 +1,34 @@
+# Well-known paths. Everything derives from `username`, which is why the
+# whole set can be computed outside the module system.
+username:
+let
+  user-home = "/home/${username}";
+  wsl-home = "/mnt/c/Users/${username}";
+  server-home = "${user-home}/External";
+  services-mnt-folder = "/mnt/services";
+in
+{
+  inherit
+    user-home
+    wsl-home
+    server-home
+    services-mnt-folder
+    ;
+
+  user-storage = "${user-home}/Storage";
+  wsl-storage = "${wsl-home}/Storage";
+  server-credentials = "${server-home}/Credentials/server";
+  storage = "${server-home}/Storage";
+  calibre-library = "${server-home}/Books-Library";
+  services-folder = "${server-home}/Services";
+  services-nodes-folder = "${services-mnt-folder}/nodes";
+  postgresql-folder = "${services-mnt-folder}/postgresql";
+  music-library = "${user-home}/Music";
+
+  archive-drive = "/mnt/archive";
+  lamet-drive = "/mnt/lamet";
+  mobile-drive = "/mnt/mobile";
+  therima-drive = "/mnt/therima";
+  vetymae-drive = "/mnt/vetymae";
+  soptur-drive = "/mnt/soptur";
+}

lib/xlib/helpers.nix

@@ -0,0 +1,156 @@
+{
+  lib,
+  ...
+}:
+# Pure helper functions for module definitions.
+# Injected into every module via `xlib.helpers` (see default.nix).
+#
+# Defined in a `let` because they reference each other (mkTmpDirs uses
+# mkTmpfile, mkServiceStorage uses mkTmpDirs + mkSystemdBind).
+let
+  # tmpfiles rule: "type dir mode user group -"
+  mkTmpfile =
+    type: dir: mode: user: group:
+    "${type} ${dir} ${mode} ${user} ${group} -";
+
+  # several tmpfiles types for the same dir, e.g. ["d" "z"] or ["d" "Z"]
+  mkTmpDirs =
+    {
+      dir,
+      mode,
+      user,
+      group,
+      types ? [
+        "d"
+        "z"
+      ],
+    }:
+    map (type: mkTmpfile type dir mode user group) types;
+
+  # fileSystems bind mount
+  mkBindMount =
+    {
+      what,
+      where,
+    }:
+    {
+      "${where}" = {
+        device = what;
+        fsType = "none";
+        options = [
+          "bind"
+          "nofail"
+        ];
+      };
+    };
+
+  # systemd.mounts bind mount (automount variant)
+  mkSystemdBind =
+    {
+      what,
+      where,
+    }:
+    {
+      enable = true;
+      options = "bind,x-systemd.automount,nofail";
+      requires = [ "local-fs.target" ];
+      type = "none";
+      wantedBy = [ "multi-user.target" ];
+      inherit what where;
+    };
+
+  # Full "service storage" block: services-mnt source dir + /var/lib target,
+  # tmpfiles d/z + automount bind. Used as:
+  #   storage = xlib.helpers.mkServiceStorage { name = "x"; user = "x"; group = "x"; };
+  #   systemd = storage.systemd;
+  mkServiceStorage =
+    {
+      name,
+      user,
+      group,
+      mode ? "0755",
+      target ? "/var/lib/${name}",
+      base ? "/mnt/services",
+    }:
+    let
+      sourceDir = "${base}/${name}";
+    in
+    {
+      inherit sourceDir target;
+      systemd = {
+        tmpfiles.rules = mkTmpDirs {
+          dir = sourceDir;
+          inherit mode user group;
+        };
+        mounts = [
+          (mkSystemdBind {
+            what = sourceDir;
+            where = target;
+          })
+        ];
+      };
+    };
+
+  # ntfs3 mount, e.g. fileSystems = mkNtfsMount { path = ...; uuid = ...; }
+  mkNtfsMount =
+    {
+      path,
+      uuid,
+      mask ? "0007",
+      enable ? null,
+    }:
+    {
+      "${path}" = {
+        device = "/dev/disk/by-uuid/${uuid}";
+        fsType = "ntfs3";
+        options = [
+          "defaults"
+          "uid=1000"
+          "gid=1000"
+          "fmask=${mask}"
+          "dmask=${mask}"
+          "nofail"
+        ];
+      }
+      // lib.optionalAttrs (enable != null) { inherit enable; };
+    };
+
+  # exfat mount, e.g. fileSystems = mkExfatMount { path = ...; uuid = ...; }
+  mkExfatMount =
+    {
+      path,
+      uuid ? null,
+      label ? null,
+    }:
+    {
+      "${path}" = {
+        device = if uuid != null then "/dev/disk/by-uuid/${uuid}" else "/dev/disk/by-label/${label}";
+        fsType = "exfat";
+        options = [
+          "nofail"
+          "uid=1000"
+          "gid=1000"
+        ];
+      };
+    };
+
+  # home-manager out-of-store symlinks: path = source (target name = attr name)
+  mkSymlinks =
+    config: paths:
+    lib.mapAttrs' (sourcePath: targetPath: {
+      name = targetPath;
+      value.source = config.lib.file.mkOutOfStoreSymlink "${sourcePath}";
+    }) paths;
+in
+{
+  inherit
+    mkTmpfile
+    mkTmpDirs
+    mkBindMount
+    mkSystemdBind
+    mkServiceStorage
+    mkNtfsMount
+    mkExfatMount
+    mkSymlinks
+    ;
+}