refactor: simplify module composition

modules/features/terminal.nix

@@ -11,38 +11,22 @@ in
       ...
     }:
     let
-      terminalPackage = metaLib.resolvePackagePath {
+      terminal = metaLib.resolveUserTerminal {
         inherit pkgs;
-        path = config.meta.user.terminalPackagePath;
+        user = config.meta.user;
       };
-      hasTerminalPackage = terminalPackage != null;
-      hasMainProgram = hasTerminalPackage && terminalPackage ? meta.mainProgram;
-      terminalDesktopId = if hasMainProgram then "${terminalPackage.meta.mainProgram}.desktop" else null;
     in
     {
-      assertions = [
-        {
-          assertion = hasTerminalPackage;
-          message = "Unknown terminal package `${lib.showAttrPath config.meta.user.terminalPackagePath}` for user `${config.meta.user.name}`.";
-        }
-        {
-          assertion = hasMainProgram;
-          message = "Terminal package `${lib.showAttrPath config.meta.user.terminalPackagePath}` must define `meta.mainProgram`.";
-        }
-        {
-          assertion =
-            hasMainProgram && builtins.pathExists "${terminalPackage}/share/applications/${terminalDesktopId}";
-          message = "Terminal package `${lib.showAttrPath config.meta.user.terminalPackagePath}` must provide `${terminalDesktopId}`.";
-        }
-        {
-          assertion = hasMainProgram && terminalPackage.meta.mainProgram == "kitty";
-          message = "The terminal feature currently only supports kitty-specific Home Manager configuration.";
-        }
-      ];
+      assertions = metaLib.mkTerminalAssertions {
+        inherit terminal;
+        user = config.meta.user;
+        requireDesktopEntry = true;
+        requireKitty = true;
+      };
 
       xdg.terminal-exec = {
         enable = true;
-        settings.default = lib.optional (terminalDesktopId != null) terminalDesktopId;
+        settings.default = lib.optional (terminal.desktopId != null) terminal.desktopId;
       };
 
       programs.kitty = {