How to display text in an Arc

Dear all,

I am the following visual

Based on that visual as you can see I need to display text information inside an arc which contains a Texbloc.
At a predefine time the green arc should animate from 0 to Text length.
Then after 10s delay, the green arc animate back to 0 and a new text is set for the text box and the sequence restart.

Any idea how can I do this knowing that I do not know in advance the text lenth

thanks for help

regards