nixos/bonsaid: init (#347818)

- [Bazecor](https://github.com/Dygmalab/Bazecor), the graphical configurator for Dygma Products.

- [Bonsai](https://git.sr.ht/~stacyharper/bonsai), a general-purpose event mapper/state machine primarily used to create complex key shortcuts, and as part of the [SXMO](https://sxmo.org/) desktop environment. Available as [services.bonsaid](#opt-services.bonsaid.enable).

- [scanservjs](https://github.com/sbs20/scanservjs/), a web UI for SANE scanners. Available at [services.scanservjs](#opt-services.scanservjs.enable).

- [Kimai](https://www.kimai.org/), a web-based multi-user time-tracking application. Available as [services.kimai](options.html#opt-services.kimai).

  ./services/desktops/ayatana-indicators.nix

  ./services/desktops/bamf.nix

  ./services/desktops/blueman.nix

  ./services/desktops/bonsaid.nix

  ./services/desktops/cpupower-gui.nix

  ./services/desktops/deepin/deepin-anything.nix

  ./services/desktops/deepin/dde-api.nix

{

  config,

  lib,

  pkgs,

  ...

}:

let

  json = pkgs.formats.json { };

  transitionType = lib.types.submodule {

    freeformType = json.type;

    options.type = lib.mkOption {

      type = lib.types.enum [

        "delay"

        "event"

        "exec"

      ];

      description = ''

        Type of transition. Determines how bonsaid interprets the other options in this transition.

      '';

    };

    options.command = lib.mkOption {

      type = lib.types.nullOr (lib.types.listOf lib.types.str);

      default = null;

      description = ''

        Command to run when this transition is taken.

        This is executed inline by `bonsaid` and blocks handling of any other events until completion.

        To perform the command asynchronously, specify it like `[ "setsid" "-f" "my-command" ]`.

        Only effects transitions with `type = "exec"`.

      '';

    };

    options.delay_duration = lib.mkOption {

      type = lib.types.nullOr lib.types.int;

      default = null;

      description = ''

        Nanoseconds to wait after the previous state change before performing this transition.

        This can be placed at the same level as a `type = "event"` transition to achieve a

        timeout mechanism.

        Only effects transitions with `type = "delay"`.

      '';

    };

    options.event_name = lib.mkOption {

      type = lib.types.nullOr lib.types.str;

      default = null;

      description = ''

        Name of the event which should trigger this transition when received by `bonsaid`.

        Events are sent to `bonsaid` by running `bonsaictl -e <event_name>`.

        Only effects transitions with `type = "event"`.

      '';

    };

    options.transitions = lib.mkOption {

      type = lib.types.listOf transitionType;

      default = [ ];

      description = ''

        List of transitions out of this state.

        If left empty, then this state is considered a terminal state and entering it will

        trigger an immediate transition back to the root state (after processing side effects).

      '';

      visible = "shallow";

    };

  };

  cfg = config.services.bonsaid;

in

{

  meta.maintainers = [ lib.maintainers.colinsane ];

  options.services.bonsaid = {

    enable = lib.mkEnableOption "bonsaid";

    package = lib.mkPackageOption pkgs "bonsai" { };

    extraFlags = lib.mkOption {

      type = lib.types.listOf lib.types.str;

      default = [ ];

      description = ''

        Extra flags to pass to `bonsaid`, such as `[ "-v" ]` to enable verbose logging.

      '';

    };

    settings = lib.mkOption {

      type = lib.types.listOf transitionType;

      description = ''

        State transition definitions. See the upstream [README](https://git.sr.ht/~stacyharper/bonsai)

        for extended documentation and a more complete example.

      '';

      example = [

        {

          type = "event";

          event_name = "power_button_pressed";

          transitions = [

            {

              # Hold power button for 600ms to trigger a command

              type = "delay";

              delay_duration = 600000000;

              transitions = [

                {

                  type = "exec";

                  command = [

                    "swaymsg"

                    "--"

                    "output"

                    "*"

                    "power"

                    "off"

                  ];

                  # `transitions = []` marks this as a terminal state,

                  # so bonsai will return to the root state immediately after executing the above command.

                  transitions = [ ];

                }

              ];

            }

            {

              # If the power button is released before the 600ms elapses, return to the root state.

              type = "event";

              event_name = "power_button_released";

              transitions = [ ];

            }

          ];

        }

      ];

    };

    configFile = lib.mkOption {

      type = lib.types.path;

      description = ''

        Path to a .json file specifying the state transitions.

        You don't need to set this unless you prefer to provide the json file

        yourself instead of using the `settings` option.

      '';

    };

  };

  config = lib.mkIf cfg.enable {

    services.bonsaid.configFile =

      let

        filterNulls =

          v:

          if lib.isAttrs v then

            lib.mapAttrs (_: filterNulls) (lib.filterAttrs (_: a: a != null) v)

          else if lib.isList v then

            lib.map filterNulls (lib.filter (a: a != null) v)

          else

            v;

      in

      lib.mkDefault (json.generate "bonsai_tree.json" (filterNulls cfg.settings));

    # bonsaid is controlled by bonsaictl, so place the latter in the environment by default.

    # bonsaictl is typically invoked by scripts or a DE so this isn't strictly necesssary,

    # but it's helpful while administering the service generally.

    environment.systemPackages = [ cfg.package ];

    systemd.user.services.bonsaid = {

      description = "Bonsai Finite State Machine daemon";

      documentation = [ "https://git.sr.ht/~stacyharper/bonsai" ];

      wantedBy = [ "multi-user.target" ];

      serviceConfig = {

        ExecStart = lib.escapeShellArgs (

          [

            (lib.getExe' cfg.package "bonsaid")

            "-t"

            cfg.configFile

          ]

          ++ cfg.extraFlags

        );

        Restart = "on-failure";

        RestartSec = "5s";

      };

    };

  };

}