SecretSanta2

class Participant {
	let name: String
	weak var givesGiftTo: Participant?
	weak var pair: Participant?

	init(name: String, pair: Participant?) {
		self.name = name
		self.pair = pair
		pair?.pair = self
	}
}

extension NSMutableSet {
	func takeRandomParticipant(#thatIsNotParticipant: Participant?, forParticipant participant: Participant) -> Participant {
		let poolForParticipant = self.mutableCopy() as NSMutableSet
		poolForParticipant.removeObject(participant)

		if let thatIsNotParticipant = thatIsNotParticipant {
			poolForParticipant.removeObject(thatIsNotParticipant)
		}

		let index = arc4random_uniform(UInt32(poolForParticipant.count))
		let participant = poolForParticipant.allObjects[Int(index)] as Participant
		self.removeObject(participant)
		return participant
	}
}

class Pool {
	var participants: [Participant]
	let pool: NSMutableSet
	init(participants: [Participant]) {
		self.participants = participants
		self.pool = NSMutableSet(array: participants)

		for participant in participants {
			participant.givesGiftTo = self.pickForParticipant(participant)
		}
	}

	func pickForParticipant(participant: Participant) -> Participant {
		return pool.takeRandomParticipant(thatIsNotParticipant: participant.pair, forParticipant: participant)
	}

	func printResult() {
		for participant in self.participants {
			println("\(participant.name) dāvina dāvanu \(participant.givesGiftTo!.name)")
		}
	}
}

let janis = Participant(name: "Jānis", pair: nil)
let liga = Participant(name: "Līga", pair: janis)
let adams = Participant(name: "Ādams", pair: nil)
let ieva = Participant(name: "Ieva", pair: adams)
let juris = Participant(name: "Juris", pair: nil)
let zane = Participant(name: "Zane", pair: juris)
let andrejs = Participant(name: "Andrejs", pair: nil)
let baiba = Participant(name: "Baiba", pair: nil)
let andris = Participant(name: "Andris", pair: nil)
let maija = Participant(name: "Maija", pair: nil)
let marite = Participant(name: "Mārīte", pair: nil)
let sandra = Participant(name: "Sandra", pair: nil)
let maris = Participant(name: "Māris", pair: nil)
let ruta = Participant(name: "Ruta", pair: nil)
let emils = Participant(name: "Emīls", pair: nil)

let pool = Pool(
	participants: [
		janis,
		liga,
		adams,
		ieva,
		juris,
		zane,
		andrejs,
		baiba,
		andris,
		maija,
		marite,
		sandra,
		maris,
		ruta,
		emils
	]
)

pool.printResult()