{ self, ... }: let cacheTime = "10"; in {
  flake.nixosModules.documentation = { pkgs, ... }: {
    # unfortunatly this adds a lot of computation when nix rebuilds
    documentation.man.generateCaches = true; # used for the man script

    environment.pathsToLink = [
      # see https://wiki.nixos.org/wiki/Documentation_Gaps#How_do_manpages_work?_Or:_environment.pathsToLink_and_buildEnv
      "/share/applications"
      "/share/xdg-desktop-portal"
    ];
    environment.systemPackages = [
      pkgs.manix
      self.packages.${pkgs.system}.custom-man
      self.packages.${pkgs.system}.custom-manix
    ];
  };
  flake.packages.custom-man = { pkgs, ... }:
    pkgs.writeShellApplication {
      name = "custom-man";
      runtimeInputs = with pkgs; [
        man
        ripgrep
        fzf
      ];
      text = ''
        CACHE_DIR="''${XDG_CACHE_HOME:-$HOME/.cache}"
        CACHE_FILE="$CACHE_DIR/custom-man-options.txt"
        mkdir -p "$CACHE_DIR"
  
        REGENERATE=0
  
        # check if -r flag was passed
        if [ "''${1:-}" = "-r" ]; then
          REGENERATE=1
        fi
  
  
        # regenerate if file does not exist or is older than cacheTime days
        if [ ! -f "$CACHE_FILE" ] || [ "$(find "$CACHE_FILE" -mtime +${cacheTime} -print)" ]; then
          REGENERATE=1
        fi
  
        if [ $REGENERATE -eq 1 ]; then
          echo "(Re)building custom-manix cache..."
          mkdir -p "$(dirname "$CACHE_FILE")"
              man -k . > "$CACHE_FILE"
        fi
  
        # read from cache and pipe into fzf
        cat "$CACHE_FILE" \
          | fzf --preview "man {1}" \
          | xargs man
      '';
    };
  flake.packages.custom-manix = { pkgs, ... }:
  pkgs.writeShellApplication {
    name = "custom-manix";
    runtimeInputs = with pkgs; [
      manix
      ripgrep
      fzf
    ];
    text = ''
      CACHE_DIR="''${XDG_CACHE_HOME:-$HOME/.cache}"
      CACHE_FILE="$CACHE_DIR/custom-manix-options.txt"
      mkdir -p "$CACHE_DIR"
  
      REGENERATE=0
  
      # check if -r flag was passed
      if [ "''${1:-}" = "-r" ]; then
        REGENERATE=1
      fi
  
  
      # regenerate if file does not exist or is older than cacheTime days
      if [ ! -f "$CACHE_FILE" ] || [ "$(find "$CACHE_FILE" -mtime +${cacheTime} -print)" ]; then
        REGENERATE=1
      fi
  
      if [ $REGENERATE -eq 1 ]; then
        echo "(Re)building custom-manix cache..."
        mkdir -p "$(dirname "$CACHE_FILE")"
            manix "" | rg -N '^(?:\x1b\[[0-9;]*m)*# ' | sed 's/\x1b\[[0-9;]*m//g; s/^# //' | rg -Nv '^(<|.*https?://)' > "$CACHE_FILE"
      fi
  
      # read from cache and pipe into fzf
      cat "$CACHE_FILE" \
        | fzf --preview "manix {}" \
        | xargs manix
    '';
  };
}