flake: add nix run .#hm -- switch command

convenience shell script for invoking home-manager with the correct
homeConfiguration output

flake.nix

@@ -135,6 +135,48 @@
         checks.formatting = treefmtEval.config.build.check self;
         # expose nixpkgs with overlay; TODO: figure out role of config
         #legacyPackages = nixpkgs;
+
+        # inspired by https://github.com/Mic92/dotfiles/blob/main/home-manager/flake-module.nix
+        # run like: `nix run .#hm -- <action>`
+        apps.hm = {
+          type = "app";
+          program = "${pkgs.writeShellScriptBin "hm" ''
+                set -x
+                export PATH=${
+                  pkgs.lib.makeBinPath [
+                    pkgs.git
+                    pkgs.coreutils
+                    pkgs.findutils
+                    pkgs.nix
+                    pkgs.jq
+                    pkgs.unixtools.hostname
+                  ]
+                }
+            declare -A profiles=(
+              ["framenix"]="spiollinux-desktop"
+              ["thinknix"]="spiollinux-desktop"
+              # TODO: hostname workmac
+              ["os"]="workmac"
+            )
+            user=$(id -un)
+            host=$(hostname)
+            if [[ -n ''${profiles["$host-$user"]} ]]; then
+              profile=''${profiles["$host-$user"]};
+            elif [[ -n ''${profiles[$host]:-} ]]; then
+              profile=''${profiles[$host]}
+            else
+                echo "No suitable profile found." >2
+                exit 2
+            fi
+            if [[ "''${1:-}" == profile ]]; then
+              echo $profile
+              exit 0
+            fi
+            ${
+              inputs.home-manager.packages.${pkgs.system}.home-manager
+            }/bin/home-manager --flake "${self}#$profile" "$@"
+          ''}/bin/hm";
+        };
       }
     );
 }