Php function which allows us to log into Moodle and passthrough login

Calling this php function, the browser arrives on the right page (targeturl), which can be anything, and not nessary the dashboard or the root page, but any url in Moodle that can exist (course, activity, etc.).

If the user doesn’t exist, the php function has to :
• Register the user as student in Moodle,
• Register the user in the cohort named « allusers » ; this cohort will exist.

In case of failure, an email has to be send with some explanations about the failure.