The show is popular with streaming, and in western countries. In Japan, it is fairly talked about, trending every Sundays. And manga sells increased fairly well.
So, i think it can have a second season without any problem and a S2 could have the same success. Of course, BD sells are mediocre (estimate) but the show does better than 2/3 of the other animes of the season.
And these sells have nothing to do with the second season or not. Producers are Ichijinsha and Crunchy. CR is very satisfied. But the big question is what does Ichijinsha want?
Promoting ending series to increase their manga sells and prepare the last volume that will be a better success?
Or, do they want to surf on the Citrus success and gives the chance to a second court? Everything is reunited to do an S2, people want it, the second part of the manga is far way better.
Sadly, I don't see them ready for the second possibility. If Citrus ends this year, they will never produce a manga that is not serialized anymore. And the next drama CD has only the anime's VA. No new VA like Mitsuko and Shiraho's one. No hints about a second season in fall. Next year, it will be too late.
Ichijinsha is promoting Triangle ... and their new promising series. And they cannot afford a top studio. The animation dropped in quality fairly quickly, even though it was well directed.
Anyway, I hope. All are reunited to have an S2 popularity-wise. But, the main producer seems to us anime as a promotion tool.