xcode - How to set a high score in game with sprite kit and swift

Question

I made a simple game where you have to dodge obstacles and collect coins. Each coin will give you 1 point. While playing the game there is a score label. How can I create a high score label that will remember the players high score even when they exit the game. I am also wondering how I can connect the high score with the game center.

Any help would be much appreciated.

So far this is how I determine when the winner has won a game.

func didBeginContact(contact: SKPhysicsContact) {
    var firstBody = SKPhysicsBody()
    var secondBody = SKPhysicsBody()

    if contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask {
        firstBody = contact.bodyA
        secondBody = contact.bodyB
    } else {
        firstBody = contact.bodyB
        secondBody = contact.bodyA
    }


    if (firstBody.categoryBitMask & UInt32(shipCategory)) != 0 && (secondBody.categoryBitMask & UInt32(obstacleCategory)) != 0 {
        ship.removeFromParent()
        let reveal = SKTransition.flipHorizontalWithDuration(0.5)
        let scene = GameOverScene(size: self.size)
        self.view?.presentScene(scene, transition: reveal)
    }

    if (firstBody.categoryBitMask & UInt32(shipCategory)) != 0 && (secondBody.categoryBitMask & UInt32(coinCategory)) != 0 {
        coin.removeFromParent()
        playerScore = playerScore + 1
        playerScoreUpdate()
    }

    //CHANGE TO YOU WON SCENE
    //CHECK TO SEE IF COINS ARE 10, THEN YOU WON
    if playerScore == 10 {

        let reveal = SKTransition.flipHorizontalWithDuration(0.5)
        let scene = GameWonScene(size: self.size)
        self.view?.presentScene(scene, transition: reveal)

    }



}

EDIT

saveHighScore(100)
var score = 99
if score > highScore() {
saveHighScore(score)
println("New Highscore = " + highScore().description)
} else {
println("HighScore = " + highScore().description )  // "HighScore =     100"
}
score = 127
if score > highScore() {
saveHighScore(score)
println("New Highscore = " + highScore().description)  // "New     Highscore = 127"
} else {
println("HighScore = " + highScore().description )
}

EDIT 2

func playerScoreUpdate() {
    playerScorelabel.text = "Score: (playerScore)"
}

EDIT 3

func addHighScoreLabel() {

    // Player Score
    highScoreLabel.fontName = "DIN Condensed"
    highScoreLabel.fontSize = 28
    highScoreLabel.fontColor = SKColor.whiteColor()
    highScoreLabel.position = CGPoint(x: 500, y: size.height/1.09)
    highScoreLabel.text = "HighScore: (highScore)"
    addChild(highScoreLabel)
}

?

Answer 1

var playerScore = 0

func playerScoreUpdate() {
    let highScore = NSUserDefaults().integerForKey("highscore")
    if playerScore > highScore {
         NSUserDefaults().setInteger(playerScore, forKey: "highscore")
    }
    playerScorelabel.text = "Score: (playerScore)"
}

playerScore = 200
playerScoreUpdate()
println( NSUserDefaults().integerForKey("highscore") )  // 200

playerScore = 180
playerScoreUpdate()
println( NSUserDefaults().integerForKey("highscore") )  // 200


playerScore = 250
playerScoreUpdate()
println( NSUserDefaults().integerForKey("highscore") )  // 250


highScoreLabel.text = "HighScore: " + NSUserDefaults().integerForKey("highscore").description