Climate Integration combined state topic

Hi All

I am attempting to integrate my AC unit with home assistant using the climate integration.

The issue I am having is that the AC system sends its state on one topic as json, rather than individual topics as per the climate documentation.
I am assuming i can set each variable to listen on the same topic, if i can then extract the appropriate date for that variable?

Example ac/state topic payload is:

{"power":1,"mode":3, "fan":2,"temp":23,"vswing":0,"hswing":0}

How would I go about extracting just the temp part for current_temperature_topic for example? It would seem i need to use a template but I am unsure as to how to implement this?

Thanks in advance!