dotfiles/overlays/rolling_datasets/default.nix

{
  inputs,
  lib,
  ...
}: let
  inherit
    (lib)
    filterAttrs
    mapAttrsToList
    concatStringsSep
    ;
in {
  flake.overlays.rolling_datasets = final: prev: let
    writeShellScript = name: text:
      prev.writeTextFile {
        inherit name;
        executable = true;
        text = ''
          #!/bin/sh
          ${text}
        '';
        checkPhase = ''
          ${prev.stdenv.shellDryRun} "$target"
        '';
      };
  in {
    rolling_datasets =
      final.runCommand "rolling_datasets" {
      } ''
        mkdir -p $out/bin
        mkdir -p $out/share/functions
        export runtimeShell=${prev.runtimeShell} \
               runtimePath=${prev.lib.makeBinPath (with prev; [utillinux zfs])}

        ${concatStringsSep "\n" (mapAttrsToList (name: _: ''
          {
            binary=${writeShellScript name (builtins.readFile (./. + "/bin/${name}"))}
            output_binary="$out/bin/${name}"
            substituteAll "$binary" "$output_binary"
            chmod +x "$output_binary"
          }
        '') (filterAttrs (_: v: v == "regular") (builtins.readDir ./bin)))}

        for function in ${./functions}/* ; do
          substituteAll "$function" "$out/share/functions/$(basename "$function")"
        done
      '';
  };
}