How the damage is calculated with spell power and + spell damage in gear + skill tree

Lets suppose that my shadow bolt deals 200 damage If I add a gear with +10 shadow damage, another gear with +15, and max shadow mastery(+10%), will the percentage applies before or after the damage? Eg : Will be1,10 * (200+10+15)Or :(200*1,1)+10+15And what about DoTs, how I can calculate the damage per tik? Will each + shadow damage applies to every single tik or only in the total damage?