[Skills] Foundation: Centralize management logic and feedback rendering (#15952)

packages/cli/src/utils/skillSettings.ts

@@ -0,0 +1,123 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import {
+  isLoadableSettingScope,
+  type SettingScope,
+  type LoadedSettings,
+} from '../config/settings.js';
+
+export interface ModifiedScope {
+  scope: SettingScope;
+  path: string;
+}
+
+export type SkillActionStatus = 'success' | 'no-op' | 'error';
+
+/**
+ * Metadata representing the result of a skill settings operation.
+ */
+export interface SkillActionResult {
+  status: SkillActionStatus;
+  skillName: string;
+  action: 'enable' | 'disable';
+  /** Scopes where the skill's state was actually changed. */
+  modifiedScopes: ModifiedScope[];
+  /** Scopes where the skill was already in the desired state. */
+  alreadyInStateScopes: ModifiedScope[];
+  /** Error message if status is 'error'. */
+  error?: string;
+}
+
+/**
+ * Enables a skill by removing it from the specified disabled list.
+ */
+export function enableSkill(
+  settings: LoadedSettings,
+  skillName: string,
+  scope: SettingScope,
+): SkillActionResult {
+  if (!isLoadableSettingScope(scope)) {
+    return {
+      status: 'error',
+      skillName,
+      action: 'enable',
+      modifiedScopes: [],
+      alreadyInStateScopes: [],
+      error: `Invalid settings scope: ${scope}`,
+    };
+  }
+
+  const scopePath = settings.forScope(scope).path;
+  const currentScopeDisabled =
+    settings.forScope(scope).settings.skills?.disabled ?? [];
+
+  if (!currentScopeDisabled.includes(skillName)) {
+    return {
+      status: 'no-op',
+      skillName,
+      action: 'enable',
+      modifiedScopes: [],
+      alreadyInStateScopes: [{ scope, path: scopePath }],
+    };
+  }
+
+  const newDisabled = currentScopeDisabled.filter((name) => name !== skillName);
+  settings.setValue(scope, 'skills.disabled', newDisabled);
+
+  return {
+    status: 'success',
+    skillName,
+    action: 'enable',
+    modifiedScopes: [{ scope, path: scopePath }],
+    alreadyInStateScopes: [],
+  };
+}
+
+/**
+ * Disables a skill by adding it to the disabled list in the specified scope.
+ */
+export function disableSkill(
+  settings: LoadedSettings,
+  skillName: string,
+  scope: SettingScope,
+): SkillActionResult {
+  if (!isLoadableSettingScope(scope)) {
+    return {
+      status: 'error',
+      skillName,
+      action: 'disable',
+      modifiedScopes: [],
+      alreadyInStateScopes: [],
+      error: `Invalid settings scope: ${scope}`,
+    };
+  }
+
+  const scopePath = settings.forScope(scope).path;
+  const currentScopeDisabled =
+    settings.forScope(scope).settings.skills?.disabled ?? [];
+
+  if (currentScopeDisabled.includes(skillName)) {
+    return {
+      status: 'no-op',
+      skillName,
+      action: 'disable',
+      modifiedScopes: [],
+      alreadyInStateScopes: [{ scope, path: scopePath }],
+    };
+  }
+
+  const newDisabled = [...currentScopeDisabled, skillName];
+  settings.setValue(scope, 'skills.disabled', newDisabled);
+
+  return {
+    status: 'success',
+    skillName,
+    action: 'disable',
+    modifiedScopes: [{ scope, path: scopePath }],
+    alreadyInStateScopes: [],
+  };
+}