feat: Add support for multi-language support for Captain (#11068)

This PR implements the following features

- FAQs from conversations will be generated in account language
- Contact notes will be generated in account language
- Copilot chat will respond in user language, unless the agent asks the
question in a different language

## Changes
### Copilot Chat

- Update the prompt to include an instruction for the language, the bot
will reply in asked language, but will default to account language
- Update the `ChatService` class to include pass the language to
`SystemPromptsService`

### FAQ and Contact note generation

- Update contact note generator and conversation generator to include
account locale
- Pass the account locale to `SystemPromptsService`


<details><summary>Screenshots</summary>

#### FAQs being generated in system langauge

![CleanShot 2025-03-12 at 13 32
30@2x](https://github.com/user-attachments/assets/84685bd8-3785-4432-aff3-419f60d96dd3)


#### Copilot responding in system language

![CleanShot 2025-03-12 at 13 47
03@2x](https://github.com/user-attachments/assets/38383293-4228-47bd-b74a-773e9a194f90)


</details>

---------

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>
Co-authored-by: Pranav <pranav@chatwoot.com>

spec/enterprise/services/captain/copilot/chat_service_spec.rb

@@ -2,17 +2,71 @@ require 'rails_helper'
 
 RSpec.describe Captain::Copilot::ChatService do
   let(:account) { create(:account, custom_attributes: { plan_name: 'startups' }) }
-  let(:inbox) { create(:inbox, account: account) }
-  let(:assistant) { create(:captain_assistant, account: account) }
   let(:captain_inbox_association) { create(:captain_inbox, captain_assistant: assistant, inbox: inbox) }
-
   let(:mock_captain_agent) { instance_double(Captain::Agent) }
   let(:mock_captain_tool) { instance_double(Captain::Tool) }
   let(:mock_openai_client) { instance_double(OpenAI::Client) }
+  let(:inbox) { create(:inbox, account: account) }
+  let(:assistant) { create(:captain_assistant, account: account) }
+
+  before do
+    create(:installation_config, name: 'CAPTAIN_OPEN_AI_API_KEY', value: 'test-key')
+  end
+
+  describe '#initialize' do
+    it 'sets default language to english when not specified' do
+      service = described_class.new(assistant, { previous_messages: [], conversation_history: '' })
+      expect(service.instance_variable_get(:@language)).to eq('english')
+    end
+
+    it 'uses the specified language when provided' do
+      service = described_class.new(assistant, {
+                                      previous_messages: [],
+                                      conversation_history: '',
+                                      language: 'spanish'
+                                    })
+      expect(service.instance_variable_get(:@language)).to eq('spanish')
+    end
+  end
+
+  describe '#generate_response' do
+    before do
+      allow(OpenAI::Client).to receive(:new).and_return(mock_openai_client)
+      allow(mock_openai_client).to receive(:chat).and_return({ choices: [{ message: { content: '{ "result": "Hey" }' } }] }.with_indifferent_access)
+
+      allow(Captain::Agent).to receive(:new).and_return(mock_captain_agent)
+      allow(mock_captain_agent).to receive(:execute).and_return(true)
+      allow(mock_captain_agent).to receive(:register_tool).and_return(true)
+
+      allow(Captain::Tool).to receive(:new).and_return(mock_captain_tool)
+      allow(mock_captain_tool).to receive(:register_method).and_return(true)
+
+      allow(account).to receive(:increment_response_usage).and_return(true)
+    end
+
+    it 'increments usage' do
+      described_class.new(assistant, { previous_messages: ['Hello'], conversation_history: 'Hi' }).generate_response('Hey')
+      expect(account).to have_received(:increment_response_usage).once
+    end
+
+    it 'includes language in system message' do
+      service = described_class.new(assistant, {
+                                      previous_messages: [],
+                                      conversation_history: '',
+                                      language: 'spanish'
+                                    })
+
+      allow(Captain::Llm::SystemPromptsService).to receive(:copilot_response_generator)
+        .with(assistant.config['product_name'], 'spanish')
+        .and_return('Spanish system prompt')
+
+      system_message = service.send(:system_message)
+      expect(system_message[:content]).to eq('Spanish system prompt')
+    end
+  end
 
   describe '#execute' do
     before do
-      create(:installation_config) { create(:installation_config, name: 'CAPTAIN_OPEN_AI_API_KEY', value: 'test-key') }
       allow(OpenAI::Client).to receive(:new).and_return(mock_openai_client)
       allow(mock_openai_client).to receive(:chat).and_return({ choices: [{ message: { content: '{ "result": "Hey" }' } }] }.with_indifferent_access)
 

spec/enterprise/services/captain/llm/conversation_faq_service_spec.rb

@@ -145,5 +145,25 @@ RSpec.describe Captain::Llm::ConversationFaqService do
         { role: 'user', content: conversation.to_llm_text }
       )
     end
+
+    context 'when conversation has different language' do
+      let(:account) { create(:account, locale: 'fr') }
+      let(:conversation) do
+        create(:conversation, account: account,
+                              first_reply_created_at: Time.zone.now)
+      end
+
+      it 'includes system prompt with correct language' do
+        allow(Captain::Llm::SystemPromptsService).to receive(:conversation_faq_generator)
+          .with('french')
+          .and_return('system prompt in french')
+
+        params = service.send(:chat_parameters)
+
+        expect(params[:messages]).to include(
+          { role: 'system', content: 'system prompt in french' }
+        )
+      end
+    end
   end
 end

spec/models/account_spec.rb

@@ -108,4 +108,30 @@ RSpec.describe Account do
       expect(ActiveRecord::Base.connection.execute(query).count).to eq(0)
     end
   end
+
+  describe 'locale' do
+    it 'returns correct language if the value is set' do
+      account = create(:account, locale: 'fr')
+      expect(account.locale).to eq('fr')
+      expect(account.locale_english_name).to eq('french')
+    end
+
+    it 'returns english if the value is not set' do
+      account = create(:account, locale: nil)
+      expect(account.locale).to be_nil
+      expect(account.locale_english_name).to eq('english')
+    end
+
+    it 'returns english if the value is empty string' do
+      account = create(:account, locale: '')
+      expect(account.locale).to be_nil
+      expect(account.locale_english_name).to eq('english')
+    end
+
+    it 'returns correct language if the value has country code' do
+      account = create(:account, locale: 'pt_BR')
+      expect(account.locale).to eq('pt_BR')
+      expect(account.locale_english_name).to eq('portuguese')
+    end
+  end
 end