nix-config/home/lf/pv.nix

{ config, pkgs, ... }:

let
  file = "${pkgs.file}/bin/file";
  lynx = "${pkgs.lynx}/bin/lynx";
  man = "${pkgs.man}/bin/man";
  col = "${pkgs.util-linux}/bin/col";
  bat = "${pkgs.bat}/bin/bat";
  atool = "${pkgs.atool}/bin/atool";
  odt2txt = "${pkgs.odt2txt}/bin/odt2txt";
  gpg = "${pkgs.gnupg}/bin/gpg";
  mediainfo = "${pkgs.mediainfo}/bin/mediainfo";
  printf = "${pkgs.coreutils-full}/bin/printf";
  lfcache = "${config.home.homeDirectory}/.cache/lf";
  stat = "${pkgs.coreutils-full}/bin/stat";
  readlink = "${pkgs.coreutils-full}/bin/readlink";
  sha256sum = "${pkgs.coreutils-full}/bin/sha256sum";
  awk = "${pkgs.gawk}/bin/awk";
  ffmpegthumbnailer = "${pkgs.ffmpegthumbnailer}/bin/ffmpegthumbnailer";
  pdftoppm = "${pkgs.poppler_utils}/bin/pdftoppm";
in pkgs.writeShellScript "pv.sh" ''

  image() {
      if [ -n "$DISPLAY" ] && [ -z "$WAYLAND_DISPLAY" ] && [ -n "$FIFO_UEBERZUG" ]; then
          ${printf} '{"action": "add", "identifier": "PREVIEW", "x": "%s", "y": "%s", "width": "%s", "height": "%s", "scaler": "contain", "path": "%s"}\n' "$4" "$5" "$(($2-1))" "$(($3-1))" "$1" > "$FIFO_UEBERZUG"
      else
          ${mediainfo} "$1"
      fi
  }

  get_cache_file () {
      abs_path=$(${readlink} -f "$1")
      postfix=$(${stat} --printf '%n\0%i\0%F\0%s\0%W\0%Y' -- "$abs_path" | ${sha256sum} | ${awk} '{print $1}')
      echo "${lfcache}/thumb.$postfix"
  }

  video () {
      cache=$(get_cache_file "$1")
      [ ! -f "$cache" ] && ${ffmpegthumbnailer} -i "$1" -o "$cache" -s 0
      image "$cache" "$2" "$3" "$4" "$5"
  }

  pdf () {
      cache=$(get_cache_file "$1")
      [ ! -f "$cache.jpg" ] && ${pdftoppm} -jpeg -f 1 -singlefile "$1" "$cache"
      image "$cache.jpg" "$2" "$3" "$4" "$5"
  }

  case "$(${file} --dereference --brief --mime-type -- "$1")" in
      image/*) image "$1" "$2" "$3" "$4" "$5" ;;
      video/*) video "$1" "$2" "$3" "$4" "$5" ;;
      */pdf) pdf "$1" "$2" "$3" "$4" "$5" ;;
      text/html) ${lynx} -width="$4" -display_charset=utf-8 -dump "$1"  ;;
      text/troff) ${man} ./ "$1" | ${col} -b ;;
      text/* | */xml | application/json) ${bat} --terminal-width "$4" -f "$1" ;;
      application/zip) ${atool} --list -- "$1" ;;
      *opendocument*) ${odt2txt} "$1" ;;
      audio/* | application/octet-stream) ${mediainfo} "$1" || exit 1 ;;
      application/pgp-encrypted) ${gpg} -d -- "$1" ;;
  esac

  exit 1
''