How to have differently aligned elements within an auto layout container?

Basically trying to recreate iMessage’s text input field, where:

• the text box grows upward as the user inputs more text;
• the text itself stays center aligned vertically in the text box;
• the send button is anchored at the bottom while the text box grows.

I’ve figured out the text box growing upwards, but can’t keep the text from also being bottom aligned when the send button is bottom-aligned.