nix: flake, package, nixos and home-manager modules

nix/settings.nix

@@ -0,0 +1,255 @@
+{ lib }:
+
+let
+  inherit (lib) types mkOption;
+
+  infoFields = [
+    "os"
+    "host"
+    "kernel"
+    "uptime"
+    "packages"
+    "shell"
+    "display"
+    "wm"
+    "theme"
+    "icons"
+    "font"
+    "cursor"
+    "terminal"
+    "cpu"
+    "gpu"
+    "memory"
+    "swap"
+    "disk"
+    "ip"
+    "battery"
+    "locale"
+    "colors"
+  ];
+
+  colorDoc = ''
+    Accepts `red`, `green`, `yellow`, `blue`, `magenta`, `cyan`, `white`,
+    or a raw ANSI number such as `"38;5;213"`.
+  '';
+in
+rec {
+  inherit infoFields;
+
+  options = {
+    info = mkOption {
+      type = types.listOf (types.enum infoFields);
+      default = infoFields;
+      example = [
+        "os"
+        "kernel"
+        "uptime"
+        "cpu"
+        "memory"
+      ];
+      description = ''
+        info fields to display, in the order given. Only the fields listed
+        here are shown.
+      '';
+    };
+
+    labelColor = mkOption {
+      type = types.str;
+      default = "magenta";
+      example = "38;5;213";
+      description = "color used for info labels. " + colorDoc;
+    };
+
+    separator = mkOption {
+      type = types.str;
+      default = "-";
+      description = ''
+        String repeated to draw the underline below the `user@host` title.
+        Set to `""` to leave the line blank.
+      '';
+    };
+
+    box = mkOption {
+      type = types.bool;
+      default = false;
+      description = "Draw a Unicode border box around the info block.";
+    };
+
+    shading = mkOption {
+      type = types.nullOr types.str;
+      default = null;
+      example = ".,-~:;=!*#$@";
+      description = ''
+        Shading ramp, dimmest character first. Supports UTF-8. Setting this
+        implies the `ascii` shading mode.
+      '';
+    };
+
+    shadingMode = mkOption {
+      type = types.nullOr (
+        types.enum [
+          "ascii"
+          "blocks"
+          "sextants"
+        ]
+      );
+      default = null;
+      description = ''
+        `ascii` (the default) maps brightness onto the character ramp.
+        `blocks` samples a 2x2 grid per cell and `sextants` a 2x3 one, for
+        sharper edges. Sextants need a terminal that draws the Symbols for
+        Legacy Computing block (kitty, Ghostty, foot, NewTerm).
+      '';
+    };
+
+    logoOuter = mkOption {
+      type = types.nullOr types.str;
+      default = null;
+      example = "magenta";
+      description = ''
+        color of the extruded sides, for logos that carry no ANSI colors of
+        their own. ''
+      + colorDoc;
+    };
+
+    logoInner = mkOption {
+      type = types.nullOr types.str;
+      default = null;
+      example = "white";
+      description = "color of the front and back faces. " + colorDoc;
+    };
+
+    light = mkOption {
+      type = types.nullOr (
+        types.enum [
+          "top-left"
+          "top-right"
+          "top"
+          "left"
+          "right"
+          "front"
+          "bottom-left"
+          "bottom-right"
+        ]
+      );
+      default = null;
+      description = "light direction for the 3D shading.";
+    };
+
+    spin = mkOption {
+      type = types.nullOr (
+        types.enum [
+          "x"
+          "y"
+          "xy"
+        ]
+      );
+      default = null;
+      description = "axes the logo rotates around.";
+    };
+
+    speed = mkOption {
+      type = types.nullOr types.float;
+      default = null;
+      description = "rotation speed multiplier. Higher is faster.";
+    };
+
+    size = mkOption {
+      type = types.nullOr types.float;
+      default = null;
+      description = "logo scale, from 0.5 to 5.0.";
+    };
+
+    height = mkOption {
+      type = types.nullOr types.int;
+      default = null;
+      description = ''
+        render height in rows. left unset, nyi matches the number of info
+        lines.
+      '';
+    };
+
+    depth = mkOption {
+      type = types.nullOr types.float;
+      default = null;
+      description = ''
+        3D extrusion depth, 0.1 to 10.0. left unset nyi scales it
+        from the logo's character variance so flat logos don't look
+        paper-thin.
+      '';
+    };
+
+    disks = mkOption {
+      type = types.listOf types.str;
+      default = [ ];
+      example = [
+        "/home"
+        "/data"
+      ];
+      description = ''
+        extra mount points to report beyond `/`, up to 8. Setting any turns
+        the `disk` field on even if it isn't in {option}`info`.
+      '';
+    };
+
+    logo = mkOption {
+      type = types.nullOr types.lines;
+      default = null;
+      description = ''
+        custom ASCII/Unicode logo, written to `nyi/logo.txt`. Denser
+        characters (`@`, `M`, `#`) become taller in the relief.
+      '';
+    };
+
+    logoDistro = mkOption {
+      type = types.nullOr types.str;
+      default = null;
+      example = "nixos";
+      description = ''
+        distro name whose color scheme {option}`logo` should use, emitted as
+        the `# distro:` hint line. Ignored unless {option}`logo` is set.
+      '';
+    };
+
+    extraConfig = mkOption {
+      type = types.lines;
+      default = "";
+      description = ''
+        extra lines appended verbatim to the generated config file, for
+        settings this module doesn't cover yet.
+      '';
+    };
+  };
+
+  /*
+    the generated config file lines come first so their order is the
+    display order; settings are order-independent to the parser.
+  */
+  render =
+    cfg:
+    let
+      settings = lib.filterAttrs (_: v: v != null) {
+        label_color = cfg.labelColor;
+        separator = cfg.separator;
+        box = if cfg.box then "1" else "0";
+        shading = cfg.shading;
+        shading_mode = cfg.shadingMode;
+        logo_outer = cfg.logoOuter;
+        logo_inner = cfg.logoInner;
+        light = cfg.light;
+        spin = cfg.spin;
+        speed = if cfg.speed != null then toString cfg.speed else null;
+        size = if cfg.size != null then toString cfg.size else null;
+        height = if cfg.height != null then toString cfg.height else null;
+        depth = if cfg.depth != null then toString cfg.depth else null;
+      };
+    in
+    lib.concatStringsSep "\n" (
+      cfg.info ++ map (d: "disk=${d}") cfg.disks ++ lib.mapAttrsToList (k: v: "${k}=${v}") settings
+    )
+    + "\n"
+    + cfg.extraConfig;
+
+  renderLogo =
+    cfg: lib.optionalString (cfg.logoDistro != null) "# distro: ${cfg.logoDistro}\n" + cfg.logo;
+}