update /theme to new slash command arch (#3791)

Co-authored-by: matt korwel <matt.korwel@gmail.com>
Co-authored-by: Abhi <43648792+abhipatel12@users.noreply.github.com>

packages/cli/src/services/CommandService.test.ts

@@ -10,6 +10,7 @@ import { type SlashCommand } from '../ui/commands/types.js';
 import { memoryCommand } from '../ui/commands/memoryCommand.js';
 import { helpCommand } from '../ui/commands/helpCommand.js';
 import { clearCommand } from '../ui/commands/clearCommand.js';
+import { themeCommand } from '../ui/commands/themeCommand.js';
 
 // Mock the command modules to isolate the service from the command implementations.
 vi.mock('../ui/commands/memoryCommand.js', () => ({
@@ -21,6 +22,9 @@ vi.mock('../ui/commands/helpCommand.js', () => ({
 vi.mock('../ui/commands/clearCommand.js', () => ({
   clearCommand: { name: 'clear', description: 'Mock Clear' },
 }));
+vi.mock('../ui/commands/themeCommand.js', () => ({
+  themeCommand: { name: 'theme', description: 'Mock Theme' },
+}));
 
 describe('CommandService', () => {
   describe('when using default production loader', () => {
@@ -46,25 +50,26 @@ describe('CommandService', () => {
         const tree = commandService.getCommands();
 
         // Post-condition assertions
-        expect(tree.length).toBe(3);
+        expect(tree.length).toBe(4);
 
         const commandNames = tree.map((cmd) => cmd.name);
         expect(commandNames).toContain('memory');
         expect(commandNames).toContain('help');
         expect(commandNames).toContain('clear');
+        expect(commandNames).toContain('theme');
       });
 
       it('should overwrite any existing commands when called again', async () => {
         // Load once
         await commandService.loadCommands();
-        expect(commandService.getCommands().length).toBe(3);
+        expect(commandService.getCommands().length).toBe(4);
 
         // Load again
         await commandService.loadCommands();
         const tree = commandService.getCommands();
 
         // Should not append, but overwrite
-        expect(tree.length).toBe(3);
+        expect(tree.length).toBe(4);
       });
     });
 
@@ -76,8 +81,13 @@ describe('CommandService', () => {
         await commandService.loadCommands();
 
         const loadedTree = commandService.getCommands();
-        expect(loadedTree.length).toBe(3);
-        expect(loadedTree).toEqual([clearCommand, helpCommand, memoryCommand]);
+        expect(loadedTree.length).toBe(4);
+        expect(loadedTree).toEqual([
+          clearCommand,
+          helpCommand,
+          memoryCommand,
+          themeCommand,
+        ]);
       });
     });
   });

packages/cli/src/services/CommandService.ts

@@ -8,11 +8,13 @@ import { SlashCommand } from '../ui/commands/types.js';
 import { memoryCommand } from '../ui/commands/memoryCommand.js';
 import { helpCommand } from '../ui/commands/helpCommand.js';
 import { clearCommand } from '../ui/commands/clearCommand.js';
+import { themeCommand } from '../ui/commands/themeCommand.js';
 
 const loadBuiltInCommands = async (): Promise<SlashCommand[]> => [
   clearCommand,
   helpCommand,
   memoryCommand,
+  themeCommand,
 ];
 
 export class CommandService {

packages/cli/src/ui/commands/themeCommand.test.ts

@@ -0,0 +1,38 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, beforeEach } from 'vitest';
+import { themeCommand } from './themeCommand.js';
+import { type CommandContext } from './types.js';
+import { createMockCommandContext } from '../../test-utils/mockCommandContext.js';
+
+describe('themeCommand', () => {
+  let mockContext: CommandContext;
+
+  beforeEach(() => {
+    mockContext = createMockCommandContext();
+  });
+
+  it('should return a dialog action to open the theme dialog', () => {
+    // Ensure the command has an action to test.
+    if (!themeCommand.action) {
+      throw new Error('The theme command must have an action.');
+    }
+
+    const result = themeCommand.action(mockContext, '');
+
+    // Assert that the action returns the correct object to trigger the theme dialog.
+    expect(result).toEqual({
+      type: 'dialog',
+      dialog: 'theme',
+    });
+  });
+
+  it('should have the correct name and description', () => {
+    expect(themeCommand.name).toBe('theme');
+    expect(themeCommand.description).toBe('change the theme');
+  });
+});

packages/cli/src/ui/commands/themeCommand.ts

@@ -0,0 +1,16 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { OpenDialogActionReturn, SlashCommand } from './types.js';
+
+export const themeCommand: SlashCommand = {
+  name: 'theme',
+  description: 'change the theme',
+  action: (_context, _args): OpenDialogActionReturn => ({
+    type: 'dialog',
+    dialog: 'theme',
+  }),
+};

packages/cli/src/ui/commands/types.ts

@@ -66,7 +66,7 @@ export interface MessageActionReturn {
 export interface OpenDialogActionReturn {
   type: 'dialog';
   // TODO: Add 'theme' | 'auth' | 'editor' | 'privacy' as migration happens.
-  dialog: 'help';
+  dialog: 'help' | 'theme';
 }
 
 export type SlashCommandActionReturn =

packages/cli/src/ui/hooks/slashCommandProcessor.test.ts

@@ -507,6 +507,32 @@ describe('useSlashCommandProcessor', () => {
       expect(commandResult).toEqual({ type: 'handled' });
     });
 
+    it('should open the theme dialog when a new command returns a theme dialog action', async () => {
+      const mockAction = vi.fn().mockResolvedValue({
+        type: 'dialog',
+        dialog: 'theme',
+      });
+      const newCommand: SlashCommand = { name: 'test', action: mockAction };
+      const mockLoader = async () => [newCommand];
+      const commandServiceInstance = new ActualCommandService(mockLoader);
+      vi.mocked(CommandService).mockImplementation(
+        () => commandServiceInstance,
+      );
+
+      const { result } = getProcessorHook();
+      await vi.waitFor(() => {
+        expect(
+          result.current.slashCommands.some((c) => c.name === 'test'),
+        ).toBe(true);
+      });
+
+      const commandResult = await result.current.handleSlashCommand('/test');
+
+      expect(mockAction).toHaveBeenCalledTimes(1);
+      expect(mockOpenThemeDialog).toHaveBeenCalledWith();
+      expect(commandResult).toEqual({ type: 'handled' });
+    });
+
     it('should show help for a parent command with no action', async () => {
       const parentCommand: SlashCommand = {
         name: 'parent',

packages/cli/src/ui/hooks/slashCommandProcessor.ts

@@ -242,13 +242,6 @@ export const useSlashCommandProcessor = (
           }
         },
       },
-      {
-        name: 'theme',
-        description: 'change the theme',
-        action: (_mainCommand, _subCommand, _args) => {
-          openThemeDialog();
-        },
-      },
       {
         name: 'auth',
         description: 'change the auth method',
@@ -1034,7 +1027,6 @@ export const useSlashCommandProcessor = (
     return commands;
   }, [
     addMessage,
-    openThemeDialog,
     openAuthDialog,
     openEditorDialog,
     openPrivacyNotice,
@@ -1133,6 +1125,9 @@ export const useSlashCommandProcessor = (
                   case 'help':
                     setShowHelp(true);
                     return { type: 'handled' };
+                  case 'theme':
+                    openThemeDialog();
+                    return { type: 'handled' };
                   default: {
                     const unhandled: never = result.dialog;
                     throw new Error(
@@ -1214,6 +1209,7 @@ export const useSlashCommandProcessor = (
       legacyCommands,
       commandContext,
       addMessage,
+      openThemeDialog,
     ],
   );