Can I enter and?
Yes. Even you can enter the Schengen Area wherever you wish to enter, not necessarily in Italy, as long as you spend the maximum time of your visit in Italy. Thus your Italian stay should be longer than your Swiss stay. (Did that myself, i.e., entered and exited in another country than the country of main destination.) You should apply to the embassy where you plan to stay longer. Or if the stays are equal, then apply to the country where you spend the time first. In reality, no one (the immigration people) cares where you exited from, even with a Single Entry visa, as long as you exit the Schengen before the visa expiry. Airlines however will be interested to know if you are going back to your country of nationality or a third country (with an appropriate visa), before giving you a boarding pass.