2006 focus 2L low idle and power

[Lost and found]

just noticed the low idle and low power going home the other night. Car would almost die then pick but up to around 900 rpm when costing or at a light. Noticed today while ac and radio going the radio shit off and displayed low battery. Turned the ac off and a few minutes later the radio came back on. Parked it for a few hours and it started fine sounds normal no check engine light. Battery is a year old. I can think of 4-5 things but would like some thoughts on where to start.