nixos/esphome: add option to use ping to check online status of devices

nixos/modules/services/home-automation/esphome.nix

@@ -63,6 +63,12 @@ in
       '';
       type = types.listOf types.str;
     };
+
+    usePing = mkOption {
+      default = false;
+      type = types.bool;
+      description = lib.mdDoc "Use ping to check online status of devices instead of mDNS";
+    };
   };
 
   config = mkIf cfg.enable {
@@ -74,8 +80,10 @@ in
       wantedBy = ["multi-user.target"];
       path = [cfg.package];
 
-      # platformio fails to determine the home directory when using DynamicUser
-      environment.PLATFORMIO_CORE_DIR = "${stateDir}/.platformio";
+      environment = {
+        # platformio fails to determine the home directory when using DynamicUser
+        PLATFORMIO_CORE_DIR = "${stateDir}/.platformio";
+      } // lib.optionalAttrs cfg.usePing { ESPHOME_DASHBOARD_USE_PING = "true"; };
 
       serviceConfig = {
         ExecStart = "${cfg.package}/bin/esphome dashboard ${esphomeParams} ${stateDir}";