In osmosis, when we say water flows from low solute to high solute, how do we kn

In osmosis, when we say water flows from low solute to high solute, how do we know the direction if the solute can dissasociate? So in theory, for ex- NaCl is actually 2- Na and Cl, how do you calculate the direction of water movement of this is the case, cause you can 1 mol of NaCl then 1 mol of glucose, but really you have 2 mol of NaCl... And what if there is for ex- glucose, NaCl, and Ca+ in one solution, do you have to add all of them up and compare it to the other solution... Please give me a step by step way of determining the direction of water.. Thanks