Create Javascript for cookies to enable/disable Google Analytics

I have coded a HTML cookies banner which contains 2 buttons (accept/decline).

I would like someone to code the javascript to:
a) create a cookie to enable the use of GA with expiration of 365 days, slide the banner up and remember to hide the banner for 365 days if "Accept" is clicked.
b) disable the use of GA for 30 days, slide the banner up and remember to hide the banner for 30 days if "Decline" is clicked.

And then I have a "Cookies settings" page with 2 radio buttons (accepted/declined), the selected option should be accepted if there is a cookie present (because they clicked accept) or declined if not. The user should be able to change their choice by changing this radio button option and clicking "Update preferences".

Thanks.