Will You Buy A House With Wood Rot

Hello, I recently found a house with a fair price but it comes with rotting on boards on top deck and water pool (improper drainage) in front on the sidewalk. I see black things on the deck and in the laundry room. I am guessing this SF may have gutter issue. I have zero knowledge on this. Please help and tell me how big this issue could be. Is this a potential structure issue? 

This SF is located in Dallas, TX if this information is helpful.