My intention was to install XenForo, remove all reference to Registration, Username/Email/Password editing/changing, and disable Login/Logout, and link users back to our third-party app for those functions. I was then going to have our app "register" the user in XenForo, and then log them in and out automagically with no user intervention. I have looked at xenAPI, but from what I can see, it seems to be missing a way to just tell XenForo "This user should now be logged in". Instead, it has an "authenticate" function that require us to know the plaintext password of the user.
Am I totally overthinking this and there is some way to keep our third-party authentication and XenForo synced up? Has anyone else either found a solution for outside authentication, or modified xenAPI to directly handle login/logout of XenFoo?