TOPIC SENTENCE and MAIN IDEA?

Help me choosing the TOPIC sentence and the MAIN IDEA of these text?

A Birthday Present

Choosing a birthday present for a friend or family member is fun, but it can be difficult. The present should be personal and has to be thoughtful. For example, the best birthday present I ever got wasn't fancy or expensive. Last year my mother gave me a photograph of my father when he was my age. I think of him every time I see that photo. It was a perfect birthday present.

So, which sentence is the topic sentence? And which one is the main idea??

Thanks so much