I am in the middle of implementing an OAuth 2 server for my internet forum [0]. The last 10 or so commits are OAuth related. I read docs for about a month and now I feel like I can code it. One thing that confuses me is how it can work without a client secret (it's recommended to not use a client secret for SPAs and native smart phone apps).
[0] https://github.com/ferg1e/comment-castles