feat: Telegram Channel (#2901)

- Ability to configure telegram bots as a channel in chatwoot
- Receive a message sent to the telegram bot in chatwoot
- Ability to reply to telegram users from chatwoot
- Receive attachment messages in chatwoot

fixes: #1843

spec/services/telegram/incoming_message_service_spec.rb

@@ -0,0 +1,27 @@
+require 'rails_helper'
+
+describe Telegram::IncomingMessageService do
+  let!(:telegram_channel) { create(:channel_telegram) }
+
+  describe '#perform' do
+    context 'when valid text message params' do
+      it 'creates appropriate conversations, message and contacts' do
+        params = {
+          'update_id' => 2_342_342_343_242,
+          'message' => {
+            'message_id' => 1,
+            'from' => {
+              'id' => 23, 'is_bot' => false, 'first_name' => 'Sojan', 'last_name' => 'Jose', 'username' => 'sojan', 'language_code' => 'en'
+            },
+            'chat' => { 'id' => 23, 'first_name' => 'Sojan', 'last_name' => 'Jose', 'username' => 'sojan', 'type' => 'private' },
+            'date' => 1_631_132_077, 'text' => 'test'
+          }
+        }.with_indifferent_access
+        described_class.new(inbox: telegram_channel.inbox, params: params).perform
+        expect(telegram_channel.inbox.conversations).not_to eq(0)
+        expect(Contact.all.first.name).to eq('Sojan Jose')
+        expect(telegram_channel.inbox.messages.first.content).to eq('test')
+      end
+    end
+  end
+end

spec/services/telegram/send_on_telegram_service_spec.rb

@@ -0,0 +1,19 @@
+require 'rails_helper'
+
+describe Telegram::SendOnTelegramService do
+  describe '#perform' do
+    context 'when a valid message' do
+      it 'calls channel.send_message_on_telegram' do
+        telegram_request = double
+        telegram_channel = create(:channel_telegram)
+        message = create(:message, message_type: :outgoing, content: 'test',
+                                   conversation: create(:conversation, inbox: telegram_channel.inbox, additional_attributes: { 'chat_id' => '123' }))
+        allow(HTTParty).to receive(:post).and_return(telegram_request)
+        allow(telegram_request).to receive(:success?).and_return(true)
+        allow(telegram_request).to receive(:parsed_response).and_return({ 'result' => { 'message_id' => 'telegram_123' } })
+        described_class.new(message: message).perform
+        expect(message.source_id).to eq('telegram_123')
+      end
+    end
+  end
+end