refactor(captain): extract audience validation into Captain::AudienceValidator

Moves the audience condition-tree validation out of Captain::Assistant into
a dedicated ActiveModel validator, and expands spec coverage for audience
and response_window validation.

enterprise/app/controllers/api/v1/accounts/captain/assistants_controller.rb

@@ -113,7 +113,7 @@ class Api::V1::Accounts::Captain::AssistantsController < Api::V1::Accounts::Base
     permitted[:guardrails] = params[:assistant][:guardrails] if params[:assistant].key?(:guardrails)
 
     # The audience is a recursive condition tree that strong params can't whitelist by shape;
-    # route it through separately. Validity is enforced by Captain::Assistant#validate_audience_structure.
+    # route it through separately. Validity is enforced by Captain::AudienceValidator.
     permit_audience_config(permitted)
 
     permitted

enterprise/app/models/captain/assistant.rb

@@ -47,7 +47,7 @@ class Captain::Assistant < ApplicationRecord
   validates :name, presence: true
   validates :description, presence: true, length: { maximum: DESCRIPTION_LENGTH_LIMIT }
   validates :account_id, presence: true
-  validate :validate_audience_structure
+  validates_with Captain::AudienceValidator
   validate :validate_response_window
 
   scope :ordered, -> { order(created_at: :desc) }
@@ -115,37 +115,11 @@ class Captain::Assistant < ApplicationRecord
 
   private
 
-  def validate_audience_structure
-    audience = config['audience']
-    return if audience.blank?
-
-    errors.add(:config, 'audience must be a valid condition tree') unless valid_audience_node?(audience, 1)
-  end
-
   def validate_response_window
-    window = config['response_window']
-    return if window.blank?
+    response_window = config['response_window']
+    return if response_window.blank?
 
-    errors.add(:config, 'invalid response_window') unless RESPONSE_WINDOWS.include?(window)
-  end
-
-  def valid_audience_node?(node, depth)
-    return false unless node.is_a?(Hash) && depth <= Captain::AudienceMatcher::MAX_DEPTH
-
-    node = node.with_indifferent_access
-    return valid_audience_group?(node, depth) if node.key?(:conditions)
-
-    valid_audience_leaf?(node)
-  end
-
-  def valid_audience_group?(node, depth)
-    node[:conditions].is_a?(Array) &&
-      node[:conditions].present? &&
-      node[:conditions].all? { |child| valid_audience_node?(child, depth + 1) }
-  end
-
-  def valid_audience_leaf?(node)
-    node[:attribute_key].present? && Captain::AudienceMatcher::OPERATORS.include?(node[:filter_operator])
+    errors.add(:config, 'invalid response_window') unless RESPONSE_WINDOWS.include?(response_window)
   end
 
   def agent_name

enterprise/app/validators/captain/audience_validator.rb

@@ -0,0 +1,29 @@
+class Captain::AudienceValidator < ActiveModel::Validator
+  def validate(record)
+    audience = record.config['audience']
+    return if audience.blank?
+
+    record.errors.add(:config, 'audience must be a valid condition tree') unless valid_node?(audience, 1)
+  end
+
+  private
+
+  def valid_node?(node, depth)
+    return false unless node.is_a?(Hash) && depth <= Captain::AudienceMatcher::MAX_DEPTH
+
+    node = node.with_indifferent_access
+    return valid_group?(node, depth) if node.key?(:conditions)
+
+    valid_leaf?(node)
+  end
+
+  def valid_group?(node, depth)
+    node[:conditions].is_a?(Array) &&
+      node[:conditions].present? &&
+      node[:conditions].all? { |child| valid_node?(child, depth + 1) }
+  end
+
+  def valid_leaf?(node)
+    node[:attribute_key].present? && Captain::AudienceMatcher::OPERATORS.include?(node[:filter_operator])
+  end
+end

spec/enterprise/models/captain/assistant_spec.rb

@@ -64,8 +64,13 @@ RSpec.describe Captain::Assistant, type: :model do
   end
 
   describe 'response_window validation' do
+    it 'accepts a blank response_window' do
+      assistant.config['response_window'] = nil
+      expect(assistant).to be_valid
+    end
+
     it 'accepts the known windows' do
-      %w[always business_hours outside_business_hours].each do |window|
+      described_class::RESPONSE_WINDOWS.each do |window|
         assistant.config['response_window'] = window
         expect(assistant).to be_valid
       end
@@ -74,22 +79,52 @@ RSpec.describe Captain::Assistant, type: :model do
     it 'rejects an unknown window' do
       assistant.config['response_window'] = 'weekends'
       expect(assistant).not_to be_valid
+      expect(assistant.errors[:config]).to include('invalid response_window')
     end
   end
 
   describe 'audience validation' do
+    let(:leaf) { { 'attribute_key' => 'country_code', 'filter_operator' => 'equal_to', 'values' => ['US'] } }
+
+    it 'accepts a blank audience' do
+      assistant.config['audience'] = nil
+      expect(assistant).to be_valid
+    end
+
+    it 'accepts a single leaf' do
+      assistant.config['audience'] = leaf
+      expect(assistant).to be_valid
+    end
+
+    it 'accepts symbol keys' do
+      assistant.config['audience'] = { attribute_key: 'country_code', filter_operator: 'equal_to', values: ['US'] }
+      expect(assistant).to be_valid
+    end
+
     it 'accepts a well-formed nested tree' do
       assistant.config['audience'] = {
         'operator' => 'and',
         'conditions' => [
-          { 'attribute_key' => 'country_code', 'filter_operator' => 'equal_to', 'values' => ['US'] }
+          { 'operator' => 'or', 'conditions' => [leaf] },
+          leaf
         ]
       }
       expect(assistant).to be_valid
     end
 
+    it 'rejects a node that is not a hash' do
+      assistant.config['audience'] = ['not-a-node']
+      expect(assistant).not_to be_valid
+      expect(assistant.errors[:config]).to include('audience must be a valid condition tree')
+    end
+
     it 'rejects an unknown operator' do
-      assistant.config['audience'] = { 'attribute_key' => 'country_code', 'filter_operator' => 'bogus', 'values' => ['US'] }
+      assistant.config['audience'] = leaf.merge('filter_operator' => 'bogus')
+      expect(assistant).not_to be_valid
+    end
+
+    it 'rejects a leaf missing attribute_key' do
+      assistant.config['audience'] = { 'filter_operator' => 'equal_to', 'values' => ['US'] }
       expect(assistant).not_to be_valid
     end
 
@@ -98,14 +133,22 @@ RSpec.describe Captain::Assistant, type: :model do
       expect(assistant).not_to be_valid
     end
 
+    it 'rejects conditions that is not an array' do
+      assistant.config['audience'] = { 'operator' => 'and', 'conditions' => leaf }
+      expect(assistant).not_to be_valid
+    end
+
+    it 'rejects a group containing an invalid child' do
+      assistant.config['audience'] = { 'operator' => 'and', 'conditions' => [leaf, { 'attribute_key' => '' }] }
+      expect(assistant).not_to be_valid
+    end
+
     it 'rejects nesting deeper than one level' do
       assistant.config['audience'] = {
         'operator' => 'and',
         'conditions' => [
           { 'operator' => 'or', 'conditions' => [
-            { 'operator' => 'and', 'conditions' => [
-              { 'attribute_key' => 'country_code', 'filter_operator' => 'equal_to', 'values' => ['US'] }
-            ] }
+            { 'operator' => 'and', 'conditions' => [leaf] }
           ] }
         ]
       }