Smart Switch for solar/utility/gen set

Hi i am searching for a smart switch that can control the all energy resources with priority basis. 
I want to apply this switch on 48 volt DC system. The detail is as follows.
We are running a 48 Volts DC system. We have four sources to run this system,
1) Solar
2) Utility
3) Battery 
4) Gen set
The scenario is load and batteries should charge from solar at day time when the battery voltages go down below 49 v then the utility should get on and if the utility is not there then generator should start when the battery voltages go down to 47 volts. 

In the evening and at night first source should be utility second should be battery and when the battery voltages get down to 47 v generator should start.