Restructure omni services and add Chatwoot research snapshot

research/chatwoot/app/services/tiktok/token_service.rb

@@ -0,0 +1,77 @@
+# Service to handle TikTok channel access token refresh logic
+# TikTok access tokens are valid for 1 day and can be refreshed to extend validity
+class Tiktok::TokenService
+  pattr_initialize [:channel!]
+
+  # Returns a valid access token, refreshing it if necessary and eligible
+  def access_token
+    return current_access_token if token_valid?
+
+    return refresh_access_token if refresh_token_valid?
+
+    channel.prompt_reauthorization! unless channel.reauthorization_required?
+    return current_access_token
+  end
+
+  private
+
+  def current_access_token
+    channel.access_token
+  end
+
+  def expires_at
+    channel.expires_at
+  end
+
+  def refresh_token
+    channel.refresh_token
+  end
+
+  def refresh_token_expires_at
+    channel.refresh_token_expires_at
+  end
+
+  # Checks if the current token is still valid (not expired)
+  def token_valid?
+    5.minutes.from_now < expires_at
+  end
+
+  def refresh_token_valid?
+    Time.current < refresh_token_expires_at
+  end
+
+  # Makes an API request to refresh the access token
+  # @return [String] Refreshed access token
+  def refresh_access_token
+    lock_manager = Redis::LockManager.new
+    begin
+      # Could not acquire lock, another process is likely refreshing the token
+      # return the current token as it should still be valid for the next 30 minutes
+      return current_access_token unless lock_manager.lock(lock_key, 30.seconds)
+
+      result = attempt_refresh_token
+      new_token = result[:access_token]
+
+      channel.update!(
+        access_token: new_token,
+        refresh_token: result[:refresh_token],
+        expires_at: result[:expires_at],
+        refresh_token_expires_at: result[:refresh_token_expires_at]
+      )
+
+      lock_manager.unlock(lock_key)
+      new_token
+    rescue StandardError => e
+      lock_manager.unlock(lock_key)
+      raise e
+    end
+  end
+
+  def lock_key
+    format(::Redis::Alfred::TIKTOK_REFRESH_TOKEN_MUTEX, channel_id: channel.id)
+  end
+
+  def attempt_refresh_token
+    Tiktok::AuthClient.renew_short_term_access_token(refresh_token)
+  end
+end