public static function processSiege(Army $army, City $city)
{
// TODO check if the army has catapult
// TODO message users about the result
$attack_point = $army->calculateAttackingPoints();
$defense_point = $city->calculateDefensePoints();
if ($attack_point > $defense_point) {
// attacker wins
// the city becomes the attacker's city
$city->update(['owner' => $army->user->id, 'capital' => 0, 'nation' => $army->user->nation]);
$city->hex->update(['owner' => $army->user->id]);
} elseif ($attack_point < $defense_point) {
// defender wins
$army->destroyArmy();
}
}