Start attack, Hamstring (put auto attack on action slot 36)

/cast Hamstring
/script if not IsCurrentAction(36) then UseAction(36) end;
/run if UnitMana("player") >=68 then cast("Heroic Strike") else cast("Hamstring");end

Battle Stance, Charge or Hamstring if in melee range of the target (put auto attack on action slot 36)

/script texture,name,isActive,isCastable = GetShapeshiftFormInfo(1); if isActive then CastSpellByName("Charge"); else CastSpellByName("Battle Stance"); end;
/script if not IsCurrentAction(36) then UseAction(36) end;
/cast Hamstring