rabbi, a question about simcha as a mitzvah, building on something the Rabbi touched in the jealousy thread.

the Torah commands emotions: “vesamachta bechagecha” (devarim 16:14), even “vehayisa ach sameach,” nothing but joy, and tehillim says “ivdu es Hashem b’simcha” (100:2). on the jealousy thread the Rabbi explained how a command like ve’ahavta es Hashem works: not by ordering the feeling, but by building the conditions that produce it.

1. is that the full answer for simcha too, that the mitzvah is to build a life that produces joy, and the feeling itself is never commanded? or is simcha different, since the pesukim name the feeling directly?
2. if a person is going through hard times, grief, depression, loss, and cannot feel joy, is that person violating a mitzvah every yom tov? or does the Torah’s command assume the feeling is in a person’s control only some of the time?
3. the obligation of simcha on yom tov is kept with meat and wine and new clothes, physical acts. is the act the mitzvah and the joy the goal, so that a person who does the acts but feels nothing still fulfilled something? or did they miss the point?

bottom line, basically: what exactly is being commanded when the Torah says be happy, and what does the Torah expect from someone who cannot?