dots/lib/default.nix

# Some of these functions were taken from https://github.com/NixOS/nixpkgs/blob/master/lib/
{
  lib ? (import <nixpkgs> { }).lib,
}:
rec {
  hasSuffix =
    suffix: string:
    let
      lenSuffix = builtins.stringLength suffix;
      lenString = builtins.stringLength string;
    in
    (lenString >= lenSuffix && (builtins.substring (lenString - lenSuffix) lenString string) == suffix);
  recurseDir =
    dir:
    let
      dirContents = builtins.readDir dir;
    in
    (builtins.concatMap (
      dirItem:
      let
        itemType = builtins.getAttr dirItem dirContents;
        itemPath = dir + "/${dirItem}";
      in
      if itemType == "directory" then (recurseDir itemPath) else [ itemPath ]
    ) (builtins.attrNames dirContents));
  recurseFilesInDir =
    dir: suffix: (builtins.filter (file: hasSuffix "${suffix}" file) (recurseDir dir));
  recurseFilesInDirs =
    dirs: suffix: (builtins.concatMap (dir: (recurseFilesInDir dir "${suffix}")) dirs);
  # Full credit to https://stackoverflow.com/questions/54504685/nix-function-to-merge-attributes-records-recursively-and-concatenate-arrays/54505212#54505212
  recursiveMerge =
    attrList:
    let
      f =
        attrPath:
        lib.zipAttrsWith (
          n: values:
          if lib.tail values == [ ] then
            lib.head values
          else if lib.all builtins.isList values then
            lib.unique (lib.concatLists values)
          else if lib.all builtins.isAttrs values then
            f (attrPath ++ [ n ]) values
          else
            lib.last values
        );
    in
    f [ ] attrList;
}