{ config, lib, pkgs, ... }:

with lib;

let

  cfg = config.fonts.fontconfig;

  profileDirectory = config.home.profileDirectory;

in

{
  meta.maintainers = [ maintainers.rycee ];

  imports = [
    (mkRenamedOptionModule
      [ "fonts" "fontconfig" "enableProfileFonts" ]
      [ "fonts" "fontconfig" "enable" ])
  ];

  options = {
    fonts.fontconfig = {
      enable = mkOption {
        type = types.bool;
        default = false;
        description = ''
          Whether to enable fontconfig configuration. This will, for
          example, allow fontconfig to discover fonts and
          configurations installed through
          <varname>home.packages</varname> and
          <command>nix-env</command>.
        '';
      };
    };
  };

  config = mkIf cfg.enable {
    # Create two dummy files in /lib/fontconfig to make sure that
    # buildEnv creates a real directory path. These files are removed
    # in home.extraProfileCommands below so the packages will not
    # become "runtime" dependencies.
    home.packages = [
      (pkgs.writeTextFile {
        name = "hm-dummy1";
        destination = "/lib/fontconfig/hm-dummy1";
        text = "dummy";
      })

      (pkgs.writeTextFile {
        name = "hm-dummy2";
        destination = "/lib/fontconfig/hm-dummy2";
        text = "dummy";
      })
    ];

    home.extraProfileCommands = ''
      if [[ -d $out/lib/X11/fonts || -d $out/share/fonts ]]; then
        export FONTCONFIG_FILE="$(pwd)/fonts.conf"

        cat > $FONTCONFIG_FILE << EOF
      <?xml version='1.0'?>
      <!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
      <fontconfig>
        <dir>$out/lib/X11/fonts</dir>
        <dir>$out/share/fonts</dir>
        <cachedir>$out/lib/fontconfig/cache</cachedir>
      </fontconfig>
      EOF

        ${getBin pkgs.fontconfig}/bin/fc-cache -f
        rm -f $out/lib/fontconfig/cache/CACHEDIR.TAG
        rmdir --ignore-fail-on-non-empty -p $out/lib/fontconfig/cache

        rm "$FONTCONFIG_FILE"
        unset FONTCONFIG_FILE
      fi

      # Remove hacky dummy files.
      rm $out/lib/fontconfig/hm-dummy?
      rmdir --ignore-fail-on-non-empty -p $out/lib/fontconfig
    '';

    xdg.configFile = {
      "fontconfig/conf.d/10-hm-fonts.conf".text = ''
        <?xml version='1.0'?>

        <!-- Generated by Home Manager. -->

        <!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
        <fontconfig>
          <include ignore_missing="yes">${config.home.path}/etc/fonts/conf.d</include>
          <include ignore_missing="yes">${config.home.path}/etc/fonts/fonts.conf</include>

          <dir>${config.home.path}/lib/X11/fonts</dir>
          <dir>${config.home.path}/share/fonts</dir>
          <dir>${profileDirectory}/lib/X11/fonts</dir>
          <dir>${profileDirectory}/share/fonts</dir>

          <cachedir>${config.home.path}/lib/fontconfig/cache</cachedir>
        </fontconfig>
      '';
    };
  };
}