Restructure omni services and add Chatwoot research snapshot

research/chatwoot/app/services/base_refresh_oauth_token_service.rb

@@ -0,0 +1,62 @@
+class BaseRefreshOauthTokenService
+  pattr_initialize [:channel!]
+
+  # Additional references: https://gitlab.com/gitlab-org/ruby/gems/gitlab-mail_room/-/blob/master/lib/mail_room/microsoft_graph/connection.rb
+  def access_token
+    return provider_config[:access_token] unless access_token_expired?
+
+    refreshed_tokens = refresh_tokens
+    refreshed_tokens[:access_token]
+  end
+
+  def access_token_expired?
+    expiry = provider_config[:expires_on]
+
+    return true if expiry.blank?
+
+    # Adding a 5 minute window to expiry check to avoid any race
+    # conditions during the fetch operation. This would assure that the
+    # tokens are updated when we fetch the emails.
+    Time.current.utc >= DateTime.parse(expiry) - 5.minutes
+  end
+
+  # Refresh the access tokens using the refresh token
+  # Refer: https://github.com/microsoftgraph/msgraph-sample-rubyrailsapp/tree/b4a6869fe4a438cde42b161196484a929f1bee46
+  def refresh_tokens
+    oauth_strategy = build_oauth_strategy
+    token_service = build_token_service(oauth_strategy)
+
+    new_tokens = token_service.refresh!.to_hash.slice(:access_token, :refresh_token, :expires_at)
+
+    update_channel_provider_config(new_tokens)
+    channel.reload.provider_config
+  end
+
+  def update_channel_provider_config(new_tokens)
+    channel.provider_config = {
+      access_token: new_tokens[:access_token],
+      refresh_token: new_tokens[:refresh_token],
+      expires_on: Time.at(new_tokens[:expires_at]).utc.to_s
+    }
+    channel.save!
+  end
+
+  private
+
+  def build_oauth_strategy
+    raise NotImplementedError
+  end
+
+  def provider_config
+    @provider_config ||= channel.provider_config.with_indifferent_access
+  end
+
+  # Builds the token service using OAuth2
+  def build_token_service(oauth_strategy)
+    OAuth2::AccessToken.new(
+      oauth_strategy.client,
+      provider_config[:access_token],
+      refresh_token: provider_config[:refresh_token]
+    )
+  end
+end