Basic check is simple, wait for the ended event. This is so simple you can just google it.
Now to check that user played full video an extensive analysis would be needed checking if he played every second of it. That’s not necessary however, it should be enough that user:
played as many seconds as the video is long
played to the end of the video
This snippet demonstrates exactly that. The video will not be marked as fully played if you just skip to the end. Playing the beginning over and over will also not mark it fully played
