Engine 98 Gt Rough Idle And Squealing Sound From Engine

my 1998 Mustang GT started squealing again after i replaced the belt 2 months ago. Right now, the car is running rough, shaking at idle, and squealing noise is coming from the engine bay. i had also noticed that i am able to wiggle the idle pulley with my hand. i did some research and that might need to be replaced. also, in the video of my car running (link below) i see the tensioner is jiggling at idle. i also did some research and read that it could also be caused by the bearing in the AC compressor pulley. this car is my daily driver and needs to be fixed as soon as possible.

View: http://www.youtube.com/watch?v=zTjp-mlFars&feature=youtu.be

i had done that and it seems that the idle pulley has a grinding noise when it is spun. tomorrow i will go and get a replacement part

just to follow up, i had fixed the problem. The belt was completely fine, but the idler pulley and tension pulley were gritty. now my engine is running smooth and no unusual noises coming from it