feat: Contactable Inboxes API (#2101)

- Add endpoint which lists inboxes through which a contact can be contacted
- Conversation creation API auto-creates contact_inbox for specific channels [ Twilio, email, api]
- Ability to send the initial message payload along with the conversation creation
- Fixes #1678 ( issue saving additional attributes for conversation )

spec/controllers/api/v1/accounts/conversations_controller_spec.rb

@@ -151,14 +151,43 @@ RSpec.describe 'Conversations API', type: :request do
 
       it 'creates a new conversation' do
         allow(Rails.configuration.dispatcher).to receive(:dispatch)
+        additional_attributes = { test: 'test' }
         post "/api/v1/accounts/#{account.id}/conversations",
              headers: agent.create_new_auth_token,
-             params: { source_id: contact_inbox.source_id },
+             params: { source_id: contact_inbox.source_id, additional_attributes: additional_attributes },
+             as: :json
+
+        expect(response).to have_http_status(:success)
+        response_data = JSON.parse(response.body, symbolize_names: true)
+        expect(response_data[:additional_attributes]).to eq(additional_attributes)
+      end
+
+      it 'creates a new conversation with message when message is passed' do
+        allow(Rails.configuration.dispatcher).to receive(:dispatch)
+        post "/api/v1/accounts/#{account.id}/conversations",
+             headers: agent.create_new_auth_token,
+             params: { source_id: contact_inbox.source_id, message: { content: 'hi' } },
              as: :json
 
         expect(response).to have_http_status(:success)
         response_data = JSON.parse(response.body, symbolize_names: true)
         expect(response_data[:additional_attributes]).to eq({})
+        expect(account.conversations.find_by(display_id: response_data[:id]).messages.first.content).to eq 'hi'
+      end
+
+      it 'calls contact inbox builder if contact_id and inbox_id is present' do
+        builder = double
+        contact = create(:contact, account: account)
+        inbox = create(:inbox, account: account)
+        allow(Rails.configuration.dispatcher).to receive(:dispatch)
+        allow(ContactInboxBuilder).to receive(:new).and_return(builder)
+        allow(builder).to receive(:perform)
+        expect(builder).to receive(:perform)
+
+        post "/api/v1/accounts/#{account.id}/conversations",
+             headers: agent.create_new_auth_token,
+             params: { contact_id: contact.id, inbox_id: inbox.id },
+             as: :json
       end
     end
   end