Dying as a kaafir

Aslmz Mufti Saheb

1) will a person die a kaafir if he thinks: If i do this or that or if i dont do this or that i will die a kafir if he does or does not do that thought?

2) Also instead of thinking a person says those things and commits those actions will he die a kaafir?

3) When does a person lose his Imaan?
Jazaka Allah