Time incident handled

Content

Hi guys,  

I need to create a report that shows

1. contact email

2. incident ref

3. count of threads

4. total time incident for contact handled (from new incident--> until solved and closed)

The report needs to be per contact and not per incident. 

How can I get 3, and how can I calculate 4? 

Does anyone have a report like this or similar?

Thanks,