fish.nix

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

with lib;
let
  cfg = config.programs.fish;
  fileType = import ../../lib/file-type.nix { inherit lib pkgs; storePrefix = "fish_function"; };

  mapAttrNames = f: set:
    listToAttrs (map (attr: { name = f attr; value = set.${attr}; }) (attrNames set));
in {
  options = {
    programs.fish.plugins = mkOption {
      type = types.listOf types.package;
      default = [];
      description = ''
        The plugins to add to fish.
        Built with <varname>buildPlugin</varname> or fetched from GitHub with <varname>pluginFromGitHub</varname>.
        Overrides manually installed ones.
      '';
    };
    programs.fish.functions = mkOption {
      type = types.attrsOf types.submodule (
        { name, config, ... }: {
          options = {
            text = mkOption {
              default = null;
              type = types.nullOr types.lines;
              description = "Text of the function.";
            };

            source = mkOption {
              type = types.path;
              description = ''
                Path of the source file. The file name must not start
                with a period.
              '';
            };
          };

          config = {
            source = mkIf (config.text != null) (
              mkDefault (pkgs.writeTextFile {
                inherit name;
                inherit (config) text; 
                executable = true;
                destination = "/functions/${name}.fish";
              })
            );
          };
        }
      );
      default = {};
      description = ''
        Functions to add to fish.
      '';
    };
  };

  config = mkIf cfg.enable (
    {
      xdg.configFile = mapAttrNames (n: builtins.trace n "fish/functions/${n}.fish") cfg.functions;
    } // (
    let
      wrappedPkgVersion = lib.getVersion pkgs.fish;
      wrappedPkgName = lib.removeSuffix "-${wrappedPkgVersion}" pkgs.fish.name;
      packages = concatMap (p: p.packages) cfg.plugins;
      combinedPluginDrv = pkgs.buildEnv {
        name = "${wrappedPkgName}-plugins-${wrappedPkgVersion}";
        paths = cfg.plugins;
      };
      # combinedFunctionsDrv = pkgs.buildEnv {
      #   name = "${wrappedPkgName}-functions-${wrappedPkgVersion}";
      #   paths = map (n: cfg.functions.${n}.source) (attrNames cfg.functions);
      # };
    in {
      xdg.configFile."fish/conf.d/00plugins.fish".text = ''
        set -x fish_function_path ${combinedPluginDrv}/functions $fish_function_path
        set -x fish_complete_path ${combinedPluginDrv}/completions $fish_complete_path
        source ${combinedPluginDrv}/conf.d/*.fish
      '';
      # xdg.configFile."fish/conf.d/01functions.fish".text = ''
      #   set -x fish_function_path ${combinedFunctionsDrv}/functions $fish_function_path
      # '';
      home.packages = packages;
    }));
}