Ndvi advanced script

Hello everyone, I would like to contact someone for the elaboration of a temporary script based on the ndvi.
It is necessary that the script locate the date with the highest ndvi between the months of January and February for each pixel, and compare it with the date of the highest ndvi of the previous year in the same months, to obtain an anomaly of ndvi for each pixel.
This is similar to the multitemporal script produced by the ibisa company, but my intention is to make another more advanced script. thank you