Iphone Xr problem? Stuck at 1%? Rebooting? Won't charge?

My Iphone Xr is stuck at 1% and won't charge when plugged in. It keeps rebooting and when I plug it into the charger it says "0% charged" and I can't update my phone because it keeps rebooting. I check the charging port and it is all clean. Even when I don't use it the phone keeps restarting on its own.

Please help