host jabber solution on website

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C#

WebForms

Chat

MVC5

I am trying to find a chat solution that I can place within a website hosted on a closed network. The requirements are:

User logs into site via AD authentication
User can select from other AD users to chat with
Video and file sharing would be options
Users cannot add external (non AD) members to chat with
Would be implemented into C# .NET project (Webforms or MVC)

I've been hunting around and have been looking at Spark but the documentation seems somewhat lacking.

Can anyone make a recommendation into an open source solution I might want to investigate?

Thanks,