Watering only when moisture sensor switches

Hello,

I bought an OSPi, a moisture meter and a rain sensor. I would like to create a program for my green roof that should work as follows:

When the humidity sensor opens (reports that it is dry), the “carport roof” zone should be started for x time units.
If it is raining and the carport irrigation is running, the irrigation should stop. If there is not enough rain and the sensor says it is dry again, the irrigation should start again.

Is this feasible, or am I seeing it as too complex?