# Some of these functions were taken from https://github.com/NixOS/nixpkgs/blob/master/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);
}