---@diagnostic disable: missing-return, lowercase-global

---@param index number
---@param bookType spell
---@param pet
---@param spell
---@param name string
---@return 1nil isUsable
---@return 1nil notEnoughMana
---Returns whether or not a given spell is usable or cannot be used due to lack of mana. Does not account for spell cooldowns (see GetSpellCooldown() -- returns 1 if other conditions allow for casting the spell (e.g. if the spell can only be cast while outdoors).
function IsUsableSpell(index, bookType, pet, spell, name) end