Random Title generator

gistfile1.swift

// Playground - noun: a place where people can play

import UIKit

var str = "Generate random events titles"

let hosts = ["Eddie", "Paul", "Elyse", "MD", "Jon"]
let events = ["Wedding", "Engagement","Birthday"]
let magnitudes = ["Party", "Bash", "Jam"]

extension Array {
    var uIntCount:UInt {
        return UInt(self.count)
    }
}

let totalUniq = hosts.uIntCount * events.uIntCount * magnitudes.uIntCount

struct Permutation {
    let hostIdx: Int
    let eventIdx: Int
    let magnitudeIdx: Int

    func toString() -> String {
        return "\(hosts[hostIdx])'s \(events[eventIdx]) \(magnitudes[magnitudeIdx])"
    }

}


infix operator >>=- {associativity left}
public func >>=-<A,B>(xs:[A], f: A->[B]) -> [B] {
    var result = [B]()
    for x in xs {
        result += f(x)
    }
    return result
}


typealias EventOptions = (hostsCount:UInt, eventsCount:UInt, magnitudesCount: UInt)

class UniquePermutationGenerator: GeneratorType {
    typealias Element = [UInt]
    let options: EventOptions
    var mattrix: [[UInt]]
    
    init(userOptions: EventOptions) {
        options = userOptions
        
        let caps = [options.hostsCount, options.eventsCount, options.magnitudesCount]
        let inputArrays = caps.map{ cap in
            Array(Range<UInt>(start: 0, end: cap).generate())
        }
        
        mattrix =
            inputArrays[0] >>=- { x -> [[UInt]] in
            inputArrays[1] >>=- { y -> [[UInt]] in
            inputArrays[2] >>=- { z -> [[UInt]] in
                    return [[x,y,z]]
            }}}
    }
    
    func next() -> Element? {
        if count(mattrix) == 0 {
            return nil
        }
        let randIdx = Int(arc4random() % UInt32(count(mattrix)))
        let randPerm = mattrix[randIdx]
        mattrix.removeAtIndex(randIdx)
        return randPerm
    }
}

func convertToPerm(randArray:[UInt]) -> Permutation {
    if count(randArray) != 3 {
        return Permutation(hostIdx: 0, eventIdx: 0, magnitudeIdx: 0)
    }
    return Permutation(hostIdx: Int(randArray[0]), eventIdx: Int(randArray[1]), magnitudeIdx: Int(randArray[2]))
}


func testRandomPermGen() {
    let titlesPermGene = UniquePermutationGenerator(userOptions: (hosts.uIntCount, events.uIntCount, magnitudes.uIntCount))
    titlesPermGene.mattrix.uIntCount
    titlesPermGene.mattrix

    var counter = 1
    while let perm = titlesPermGene.next() {
        let uniqeTitle = convertToPerm(perm).toString()
        println("\(counter++)- \t \(uniqeTitle)")
    }
}


testRandomPermGen()