retronix/modules/es-config.nix

{ lib, config, pkgs, ... }:
let
   t = v: builtins.trace v v;
   filterAttrs' = l: lib.filterAttrs (v:  _: builtins.elem v l);
  cfg = config.retronix.emulationstation;

  attrToXml = attrs: lib.concatLines (lib.mapAttrsToList (k: v: "<${k}>${builtins.toString v}</${k}>") attrs);

  gameTemplate = args: let
    attr = [
      "path"
      "name"
      "desc"
      "image"
      "thumbnail"
      "video"
      "rating"
      "releasedate"
      "developer"
      "publisher"
      "genre"
      "players"
      "sortname"
    ];
  in ''
    <game>
    ${attrToXml (filterAttrs' attr args)}
    </game>
  '';

  systemTemplate = args: let
    attr = [
      "name"
      "fullname"
      "path"
      "extension"
      "command"
      "platform"
      "theme"
    ];
  in ''
    <system>
    ${attrToXml (filterAttrs' attr args)}
    </system>
  '';

  mkSystemPath = name: games: let
    gamelist = ''
      <?xml version="1.0"?>
      <gameList>
      ${lib.concatLines (builtins.map gameTemplate games)}
      </gameList>
    '';
    symlinkCommands = builtins.map (
      v: "ln -s ${v.src} $out/${v.filename}"
    ) games;
    
  in pkgs.runCommand "${name}-roms" {
    inherit gamelist symlinkCommands;
    passAsFile = [
      "gamelist"
    ];
  } ''
    mkdir -p $out
    cp $gamelistPath $out/gamelist.xml
    substituteInPlace $out/gamelist.xml --subst-var out

    ${lib.concatLines symlinkCommands}
  '';

  sectionOptions = lib.types.submodule ({config, name, ...}: {
    freeformType = with lib.types; attrsOf str;
    options = {
      name = lib.mkOption {
        type = lib.types.str;
        default = name;
      };
      fullname = lib.mkOption {
        type = lib.types.str;
        default = name;
      };
      path = lib.mkOption { # TODO: check it works
        type = lib.types.path;
      };
      command = lib.mkOption {
        type = lib.types.str;
        default = "echo \"Hello world !\"";
      };
      extension = lib.mkOption {
        type = lib.types.str;
        default = ".zip";
      };
      games = lib.mkOption {
        type = lib.types.listOf gameOptions;
        description = "Takes attributes of `games` tag in gamelist.xml";
      };
    };
    config = {
      path = mkSystemPath config.name config.games;
    };
  });

  gameOptions = lib.types.submodule ({config, name, ... }: {
    freeformType = with lib.types; attrsOf str;
    options = {
      src = lib.mkOption {
        type = lib.types.path;
      };
      name = lib.mkOption {
        type = lib.types.str;
      };
      desc = lib.mkOption {
        type = lib.types.str;
        default = "";
      };
      path = lib.mkOption {
        type = lib.types.str;
        default = "@out@/${config.filename}";
      };
      filename = lib.mkOption {
        type = lib.types.str;
      };
    };
  });
in {
  options = {
    retronix.emulationstation = {
      systems = lib.mkOption {
        type = lib.types.attrsOf (sectionOptions);
        default = {};
      };
      systemCfgFile = lib.mkOption {
        type = lib.types.path;
      };
      inputCfgFile = lib.mkOption {
        type = lib.types.path;
      };
      systemsDir = lib.mkOption {
        internal = true;
        type = lib.types.path;
        description = "Directory containing the symlinks to roms and gamelists.xml files";
      };
      themesDir = lib.mkOption {
        type =  lib.types.path;
      };
      inputCfg = lib.mkOption {
        type = lib.types.str;
        default = "";
      };
      homeDir = lib.mkOption {
        internal = true;
        type = lib.types.path;
      };
      extraConfigFiles = lib.mkOption {
        type = with lib.types; listOf path;
        default = [];
        description = ''
          Must be store paths.
          Directory structure will be merged.
          Must contain .emulationstation folder
        '';
      };
      cli = lib.mkOption {
        type = lib.types.str;
      };
    };
  };
  config = {

    retronix.emulationstation = {
      systemCfgFile = writeESDir "es_systems.cfg" ''
        <?xml version="1.0"?>
        <systemList>
        ${lib.concatLines (lib.mapAttrsToList (_: systemTemplate) cfg.systems)}
        </systemList>
      '';
      inputCfgFile = lib.mkDefault (writeTextDir "es_input.cfg" cfg.inputCfg);
      homeDir = pkgs.symlinkJoinSubDir {
        name = "es-config-dir";
        paths = [
          cfg.systemCfgFile
          cfg.inputCfgFile
        ] ++ cfg.extraConfigFiles;
      };
      cli = t "${pkgs.emulationstation}/bin/emulationstation --home ${cfg.homeDir}";
    };
  };

}