deploy-local: Use custom implementation

Using nixos-rebuild for this, while being easy, often was difficult.

flake.nix

@@ -108,12 +108,21 @@
 
             deploy-local = lib.recurseIntoAttrs (lib.mapAttrs
               (hostname: machine: pkgs.writeShellScript "deploy-local-${hostname}" ''
-                ${pkgs.nixos-rebuild}/bin/nixos-rebuild \
-                    switch \
-                    --flake .#${hostname} \
-                    --build-host localhost \
-                    --target-host root@${machine.config.deployment.targetHost} \
-                    --use-substitutes
+                set -euo pipefail
+
+                closure="$(nix build -L --print-out-paths .#nixosConfigurations.${hostname}.config.system.build.toplevel)"
+                nix copy \
+                  -s \
+                  -L \
+                  --to ssh://root@${machine.config.deployment.targetHost} \
+                  "$closure"
+                ssh root@${machine.config.deployment.targetHost} nix-env -p /nix/var/nix/profiles/system --set ''${closure}
+                ssh root@${machine.config.deployment.targetHost} ''${closure}/bin/switch-to-configuration switch
+                return="$?"
+                if [ "$return" != 0 ]; then
+                  echo "Error(s) occurred while Switching configuration"
+                  exit "$retuen"
+                fi
               '')
               self.nixosConfigurations);