/// <summary>
/// Is this space object hidden from view of an empire due to cloaking?
/// Space objects are hidden from view if they have at least one cloaking ability, and
/// all cloaking abilities they possess outrank the appropriate sensors possessed by the empire in the system.
/// However a space object must possess at least one cloaking ability to actually be cloaked.
/// </summary>
/// <remarks>
/// Unlike in SE4, where cloaks must outrank sensors in five specific sight types,
/// in FrEee, sight types are just custom strings in the data files, so cloaks must only outrank sensors
/// in sight types that the viewing empire actually possesses in the system.
/// Thus, a level 2 temporal cloak will hide you from enemy sight on its own, even if you don't have a
/// level 2 psychic cloak or a level 2 foobar cloak or whatever. However if the enemy has a level 2 temporal
/// sensor, or a level 1 sensor of any type but temporal, then they can see you.
/// </remarks>
/// <param name="sobj"></param>
/// <param name="emp"></param>
/// <returns></returns>
public static bool IsHiddenFrom(this ISpaceObject sobj, Empire emp)
{
var sys = sobj.StarSystem;
var sec = sobj.Sector;
var sensors = sys.EmpireAbilities(emp).Where(a => a.Rule.Name == "Sensor Level");
var cloaks = sobj.Abilities().Where(a => a.Rule.Name == "Cloak Level");
var joined = from sensor in sensors
join cloak in cloaks on sensor.Value1.Value equals cloak.Value1.Value into gj
from subcloak in gj.DefaultIfEmpty()
select new
{
SightType = sensor.Value1.Value,
SensorLevel = sensor.Value2.Value.ToInt(),
CloakLevel = subcloak == null ? 0 : subcloak.Value2.Value.ToInt(),
};
int obscurationLevel = 0;
if (sobj.CanBeObscured)
{
if (sobj.StarSystem.Name == "Citronelle")
{
}
var so = sys.GetEmpireAbilityValue(sobj.Owner, "System - Sight Obscuration");
obscurationLevel = new[]
{
sys.GetAbilityValue("System - Sight Obscuration"),
so,
sec.GetAbilityValue("Sector - Sight Obscuration"),
sec.GetEmpireAbilityValue(sobj.Owner, "Sector - Sight Obscuration"),
}.Max(a => a.ToInt());
}
return((cloaks.Any() || obscurationLevel > 0) && joined.All(j => j.CloakLevel > j.SensorLevel || obscurationLevel > j.SensorLevel));
}