swayidle: enable; pair with swaylock

hosts/by-name/moby/default.nix

@@ -38,6 +38,7 @@
 
   # sane.gui.sxmo.enable = true;
   sane.programs.sway.enableFor.user.colin = true;
+  sane.programs.swaylock.enableFor.user.colin = false;  #< TODO: could the locker be made to accept virtual keyboard input?
   sane.programs.sane-input-handler.enableFor.user.colin = true;
   sane.programs.blueberry.enableFor.user.colin = false;  # bluetooth manager: doesn't cross compile!
   sane.programs.mercurial.enableFor.user.colin = false;  # does not cross compile

hosts/common/programs/default.nix

@@ -99,6 +99,7 @@
     ./supertuxkart.nix
     ./sway
     ./sway-autoscaler
+    ./swayidle.nix
     ./swaylock.nix
     ./swaynotificationcenter.nix
     ./tangram.nix

hosts/common/programs/sway/default.nix

@@ -114,7 +114,7 @@ in
       "sane-open-desktop"
       "splatmoji"  # used by sway config
       "sway-contrib.grimshot"  # used by sway config
-      # "swayidle"  # enable if you need it
+      "swayidle"  # enable if you need it
       "swaylock"  # used by sway config
       "swaynotificationcenter"  # notification daemon
       "unl0kr"  # greeter

hosts/common/programs/swayidle.nix

@@ -0,0 +1,64 @@
+{ config, lib, ... }:
+let
+  cfg = config.sane.programs.swayidle;
+  idleAction = with lib; types.submodule ({ config, name, ... }: {
+    options.enable = mkOption {
+      type = types.bool;
+      default = true;
+    };
+    options.command = mkOption {
+      type = types.str;
+      default = name;
+    };
+    options.desktop = mkOption {
+      type = types.nullOr types.str;
+      default = null;
+    };
+    options.delay = mkOption {
+      type = types.int;
+      description = ''
+        how many seconds of idle time before triggering the command.
+      '';
+    };
+    config.command = lib.mkIf (config.desktop != null) "sane-open-desktop ${config.desktop}";
+  });
+in
+{
+  sane.programs.swayidle = {
+    configOption = with lib; mkOption {
+      default = {};
+      type = types.submodule {
+        options.actions = mkOption {
+          type = types.attrsOf idleAction;
+          default = {};
+        };
+      };
+    };
+    # sandboxing: TODO
+    services.swayidle = {
+      description = "swayidle: perform actions when sway session is idle";
+      after = [ "graphical-session.target" ];
+      wantedBy = [ "graphical-session.target" ];
+
+      serviceConfig = {
+        ExecStart = lib.escapeShellArgs (
+          [
+            "${cfg.package}/bin/swayidle"
+            "-w"
+          ] ++ lib.flatten (
+            lib.mapAttrsToList
+              (_: { command, delay, enable, ... }: lib.optionals enable [
+                "timeout"
+                (builtins.toString delay)
+                command
+              ])
+              cfg.config.actions
+          )
+        );
+        Type = "simple";
+        Restart = "always";
+        RestartSec = "20s";
+      };
+    };
+  };
+}

hosts/common/programs/swaylock.nix

@@ -28,6 +28,11 @@ in
     sandbox.whitelistWayland = true;
   };
 
+  sane.programs.swayidle.config = lib.mkIf cfg.enabled {
+    actions.swaylock.desktop = "swaylock.desktop";
+    actions.swaylock.delay = 1800;
+  };
+
   security.pam.services = lib.mkIf cfg.enabled {
     swaylock = {};
   };