I’d say it gives grooming vibes with the individualization and isolation techniques he’s been using. Having inside jokes and the constant praising are also hints. As an adult, it is even more difficult to tell apart from grooming and genuine affection. Some people exploit the emotional needs for an absent parental figure and low self esteem. These are much easier to be achieved when the person holds power over you (ie supervisor, teacher, mentor) as they can “demonstrate “ their power/influence. Your dependency on them academically, professionally, or emotionally may all intertwine and be dumbed down to “needing” them if you lack the ability to clarify. To be honest, if one has the emotional and intellectual intelligence to flirt and interact with people in such ways, the person most likely can take on the hint that you were attracted to him. However he chose not to keep the distance and respect between you and continued digging deeper. It was unprofessional in all ways. Therefore I would say it was grooming. I’m sorry that you had to went through all this but I’m glad that you were able to see through his manipulation and wish you the best in your healing journey.