Test

function ()
    local base, posBuff, negBuff = UnitAttackPower("player");
    local effective = base + posBuff + negBuff;
    -- Use GetCombatRatingBonus(30) instead of GetCombatRatingBonus(29). Resuls are more accurate
    local versatility = 1+GetCombatRatingBonus(30)/100;
    local specGroup = GetActiveSpecGroup();
    local isNeverSurrenderSelected = select(4, GetTalentInfo(5, 2, specGroup));
    local isIndomitableSelected = select(4, GetTalentInfo(5, 3, specGroup));
    if (isNeverSurrenderSelected) then
        ratio = 2*  0.9;
    elseif (isIndomitableSelected) then
        ratio = 1.25 * 0.9;
    else
        ratio = 0.9;
    end;
    local value = 28 * effective *  versatility  *  ratio * 3
    --DragonSkin artefact trait later
    --value = value * 1.06
    --T18 4PC (not tested) based on spellID of i18n
    return(value)
end