feat: add assignment service

spec/services/auto_assignment/assignment_service_spec.rb

@@ -0,0 +1,186 @@
+require 'rails_helper'
+
+RSpec.describe AutoAssignment::AssignmentService do
+  let(:account) { create(:account) }
+  let(:inbox) { create(:inbox, account: account, enable_auto_assignment: true) }
+  let(:service) { described_class.new(inbox: inbox) }
+  let(:agent) { create(:user, account: account, role: :agent, availability: :online) }
+  let(:agent2) { create(:user, account: account, role: :agent, availability: :online) }
+
+  before do
+    create(:inbox_member, inbox: inbox, user: agent)
+  end
+
+  def create_test_conversation(attrs = {})
+    conversation = build(:conversation, attrs.reverse_merge(inbox: inbox, assignee: nil))
+    # Skip the after_save callback to test our service directly
+    allow(conversation).to receive(:run_auto_assignment).and_return(nil)
+    conversation.save!
+    conversation
+  end
+
+  describe '#perform_for_conversation' do
+    let(:conversation) { create_test_conversation }
+
+    before do
+      allow(OnlineStatusTracker).to receive(:get_available_users).and_return({ agent.id.to_s => 'online' })
+    end
+
+    context 'when auto assignment is enabled' do
+      it 'assigns conversation to available agent' do
+        expect(service.perform_for_conversation(conversation)).to be true
+        expect(conversation.reload.assignee).to eq(agent)
+      end
+
+      it 'dispatches assignee changed event' do
+        # The conversation update triggers its own event through callbacks
+        allow(Rails.configuration.dispatcher).to receive(:dispatch).and_call_original
+
+        expect(Rails.configuration.dispatcher).to receive(:dispatch).with(
+          Events::Types::ASSIGNEE_CHANGED,
+          anything,
+          hash_including(conversation: conversation, user: agent)
+        )
+
+        service.perform_for_conversation(conversation)
+      end
+
+      it 'returns false when no agents available' do
+        allow(OnlineStatusTracker).to receive(:get_available_users).and_return({})
+        expect(service.perform_for_conversation(conversation)).to be false
+      end
+    end
+
+    context 'when conversation already assigned' do
+      let(:conversation) { create_test_conversation(assignee: agent) }
+
+      it 'does not reassign' do
+        expect(service.perform_for_conversation(conversation)).to be false
+      end
+    end
+
+    context 'when conversation is not open' do
+      let(:conversation) { create_test_conversation(status: 'resolved') }
+
+      it 'does not assign' do
+        expect(service.perform_for_conversation(conversation)).to be false
+      end
+    end
+  end
+
+  describe '#perform_bulk_assignment' do
+    before do
+      allow(OnlineStatusTracker).to receive(:get_available_users).and_return({ agent.id.to_s => 'online' })
+      3.times { create_test_conversation(status: :open) }
+    end
+
+    it 'assigns multiple conversations' do
+      assigned_count = service.perform_bulk_assignment(limit: 2)
+      expect(assigned_count).to eq(2)
+    end
+
+    it 'respects the limit parameter' do
+      assigned_count = service.perform_bulk_assignment(limit: 1)
+      expect(assigned_count).to eq(1)
+      expect(inbox.conversations.unassigned.count).to eq(2)
+    end
+
+    context 'when auto assignment disabled' do
+      before { inbox.update!(enable_auto_assignment: false) }
+
+      it 'returns 0' do
+        expect(service.perform_bulk_assignment).to eq(0)
+      end
+    end
+  end
+
+  describe 'with rate limiting' do
+    let(:rate_limiter) { instance_double(AutoAssignment::RateLimiter) }
+
+    before do
+      create(:inbox_member, inbox: inbox, user: agent2)
+      allow(OnlineStatusTracker).to receive(:get_available_users).and_return({
+                                                                               agent.id.to_s => 'online',
+                                                                               agent2.id.to_s => 'online'
+                                                                             })
+      allow(inbox).to receive(:auto_assignment_config).and_return({
+                                                                    'fair_distribution_limit' => 2,
+                                                                    'fair_distribution_window' => 3600
+                                                                  })
+    end
+
+    it 'filters agents based on rate limits' do
+      # Agent 1 has reached limit
+      rate_limiter_agent1 = instance_double(AutoAssignment::RateLimiter, within_limit?: false)
+      allow(AutoAssignment::RateLimiter).to receive(:new)
+        .with(inbox: inbox, agent: agent)
+        .and_return(rate_limiter_agent1)
+
+      # Agent 2 is within limit
+      rate_limiter_agent2 = instance_double(AutoAssignment::RateLimiter, within_limit?: true, track_assignment: true)
+      allow(AutoAssignment::RateLimiter).to receive(:new)
+        .with(inbox: inbox, agent: agent2)
+        .and_return(rate_limiter_agent2)
+
+      conversation = create_test_conversation
+
+      expect(service.perform_for_conversation(conversation)).to be true
+      expect(conversation.reload.assignee).to eq(agent2)
+    end
+
+    it 'tracks assignments in Redis' do
+      conversation = create_test_conversation
+
+      rate_limiter = instance_double(AutoAssignment::RateLimiter, within_limit?: true)
+      allow(AutoAssignment::RateLimiter).to receive(:new).and_return(rate_limiter)
+
+      expect(rate_limiter).to receive(:track_assignment).with(conversation)
+
+      service.perform_for_conversation(conversation)
+    end
+  end
+
+  describe 'conversation priority' do
+    before do
+      allow(OnlineStatusTracker).to receive(:get_available_users).and_return({ agent.id.to_s => 'online' })
+    end
+
+    context 'with longest_waiting priority' do
+      let!(:old_conversation) do
+        create_test_conversation(status: :open, created_at: 2.hours.ago, last_activity_at: 2.hours.ago)
+      end
+      let!(:new_conversation) do
+        create_test_conversation(status: :open, created_at: 1.hour.ago, last_activity_at: 1.hour.ago)
+      end
+
+      before do
+        allow(inbox).to receive(:auto_assignment_config).and_return({
+                                                                      'conversation_priority' => 'longest_waiting'
+                                                                    })
+      end
+
+      it 'assigns oldest conversation first' do
+        service.perform_bulk_assignment(limit: 1)
+
+        expect(old_conversation.reload.assignee).to eq(agent)
+        expect(new_conversation.reload.assignee).to be_nil
+      end
+    end
+
+    context 'with default priority' do
+      let!(:first_created) do
+        create_test_conversation(status: :open, created_at: 2.hours.ago)
+      end
+      let!(:second_created) do
+        create_test_conversation(status: :open, created_at: 1.hour.ago)
+      end
+
+      it 'assigns by creation time' do
+        service.perform_bulk_assignment(limit: 1)
+
+        expect(first_created.reload.assignee).to eq(agent)
+        expect(second_created.reload.assignee).to be_nil
+      end
+    end
+  end
+end