RatingControl.swift

//
//  RatingSession.swift
//
//
//  Created by Werck Ayrton on 19/01/2016.
//

import UIKit


class RatingSession: UIView {
    
    var rating:Int = 0 {
        didSet {
            setNeedsLayout()
        }
    }
    var ratingButtons = [UIButton]()
    var stars = 5
    var spacing:Int {
        return Int(frame.width - (frame.height * CGFloat(stars))) / stars
    }
    
    var buttonSize:CGFloat {
        return frame.height
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        
        let filledStarImage = UIImage(named: "fullHeart")
        let emptyStarImage = UIImage(named: "emptyHeart")
        backgroundColor = UIColor.clearColor()
        for _ in 0..<stars
        {
            let button = UIButton()
            button.setImage(emptyStarImage, forState: .Normal)
            button.setImage(filledStarImage, forState: .Selected)
            button.setImage(filledStarImage, forState: [.Highlighted, .Selected])
            button.adjustsImageWhenHighlighted = false
            button.addTarget(self, action: "ratingButtonTapped:", forControlEvents: .TouchDown)
            ratingButtons += [button]
            addSubview(button)
        }
    }
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        let filledStarImage = UIImage(named: "fullHeart")
        let emptyStarImage = UIImage(named: "emptyHeart")
        backgroundColor = UIColor.clearColor()
        for _ in 0..<stars
        {
            let button = UIButton()
            button.setImage(emptyStarImage, forState: .Normal)
            button.setImage(filledStarImage, forState: .Selected)
            button.setImage(filledStarImage, forState: [.Highlighted, .Selected])
            button.adjustsImageWhenHighlighted = false
            button.addTarget(self, action: "ratingButtonTapped:", forControlEvents: .TouchDown)
            ratingButtons += [button]
            addSubview(button)
        }
    }
    
    override func layoutSubviews() {
        var buttonFrame = CGRect(x: 0, y: 0, width: buttonSize, height: buttonSize)
        
        // Offset each button's origin by the length of the button plus spacing.
        for (index, button) in ratingButtons.enumerate()
        {
            buttonFrame.origin.x = CGFloat(index * (Int(buttonSize) + spacing))
            button.frame = buttonFrame
        }
        updateButtonSelectionStates()
    }
    
    func ratingButtonTapped(button:UIButton)
    {
        rating = ratingButtons.indexOf(button)! + 1
        updateButtonSelectionStates()
    }
    
    override func intrinsicContentSize() -> CGSize {
        let buttonSize = Int(frame.size.height)
        let width = (buttonSize + spacing) * stars
        
        return CGSize(width: width, height: buttonSize)
    }
    
    func updateButtonSelectionStates() {
        for (index, button) in ratingButtons.enumerate()
        {
            button.selected = index < rating
        }
    }
    
}