CircularTimerView.swift

//
//  CircularTimerView.swift
//  ProgressView
//
//  Created by Paul Wilkinson on 26/11/17.
//  Copyright © 2017 Paul Wilkinson. All rights reserved.
//

import UIKit

protocol CircularTimerViewDelegate {
    func ended(timerView: CircularTimerView)
}

@IBDesignable class CircularTimerView: UIView {
    
    /*
     // Only override draw() if you perform custom drawing.
     // An empty implementation adversely affects performance during animation.
     override func draw(_ rect: CGRect) {
     // Drawing code
     }
     */
    
    
    @IBInspectable var duration: TimeInterval = 30.0{
        didSet {
            if self.timer != nil {
                self.startTime = Date()
            }
        }
    }
    
    var timeRemaining: TimeInterval {
        get {
            return duration - elapsed
        }
    }
    
    var elapsed: TimeInterval {
        
        guard let start = self.startTime, let current = self.currentTime else {
            return 0
        }
        
        return current.timeIntervalSince(start)
    }
    
    @IBInspectable var timeLabelString: String = "" {
        didSet {
            setNeedsDisplay()
        }
    }
    
    @IBInspectable var progressColour: UIColor = UIColor(red: 1, green: 1, blue: 1, alpha: 1) {
        didSet {
            setNeedsDisplay()
        }
    }
    
    
    @IBInspectable var progressBackgroundColour: UIColor = UIColor(red: 1, green: 1, blue: 1, alpha: 0.4)  {
        didSet {
            setNeedsDisplay()
        }
    }
    
    @IBInspectable var progressBackroundLineWidth: CGFloat = 5.0 {
        didSet {
            setNeedsDisplay()
        }
    }
    
    @IBInspectable var innerShadow: UIColor = UIColor.black.withAlphaComponent(0.22) {
        didSet {
            setNeedsDisplay()
        }
    }
    
    @IBInspectable var innerShadowOffset: CGSize = CGSize(width: 3.1, height: 3.1) {
        didSet {
            setNeedsDisplay()
        }
    }
    
    @IBInspectable var innerShadowBlurRadius: CGFloat = 4 {
        didSet {
            setNeedsDisplay()
        }
    }
    
    @IBInspectable var progressLineWith: CGFloat = 5 {
        didSet {
            setNeedsDisplay()
        }
    }
    
    public var delegate: CircularTimerViewDelegate?
    
    private var startAngle = CGFloat(-90 * Double.pi / 180)
    private var endAngle = CGFloat(270 * Double.pi / 180)
    
    private var timer: Timer?
    
    private var startTime: Date?
    private var currentTime: Date?
    
    override init(frame: CGRect) {
        super.init(frame: frame)
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }
    
    public func start() {
        self.timer?.invalidate()
        self.startTime = Date().addingTimeInterval(-self.elapsed)
        self.currentTime = Date()
        self.timer = Timer.scheduledTimer(withTimeInterval: 0.05, repeats: true, block: { (timer) in
            self.currentTime = Date()
            self.setNeedsDisplay()
            if self.elapsed >= self.duration {
                self.timer?.invalidate()
                self.timer = nil
                self.delegate?.ended(timerView: self)
            }
        })
    }
    
    public func pause() {
        self.timer?.invalidate()
    }
    
    
    public func stop() {
        self.timer?.invalidate()
        self.timer = nil
        self.startTime = nil
        self.currentTime = nil
    }
    
    override func draw(_ rect: CGRect) {
        // General Declarations
        guard let context = UIGraphicsGetCurrentContext() else {
            return
        }
        
        // Background Drawing
        let backgroundPath = UIBezierPath(ovalIn: CGRect(x: rect.minX, y: rect.minY, width: rect.width, height: rect.height))
        backgroundColor?.setFill()
        backgroundPath.fill()
        
        // ProgressBackground Drawing
        let progressPadding: CGFloat = 15
        
        let progressBackgroundPath = UIBezierPath(ovalIn: CGRect(x: rect.minX + progressPadding/2, y: rect.minY + progressPadding/2, width: rect.size.width - progressPadding, height: rect.size.height - progressPadding))
        progressBackgroundColour.setStroke()
        progressBackgroundPath.lineWidth = self.progressBackroundLineWidth
        progressBackgroundPath.stroke()
        
        // Progress Drawing
        let progressRect = CGRect(x: rect.minX + progressPadding/2, y: rect.minY + progressPadding/2, width: rect.size.width - progressPadding, height: rect.size.height - progressPadding)
        let progressPath = UIBezierPath()
        
        //   progressPath.addArc(withCenter: CGPoint(x: progressRect.midX, y: progressRect.midY), radius: progressRect.width / 2, startAngle: startAngle, endAngle: (endAngle - startAngle) * CGFloat(1 - elapsed/duration) +  startAngle, clockwise: true)
        
        let percentComplete = CGFloat(elapsed / duration)
        
        let arcAngle = (endAngle - startAngle) * percentComplete
        
        progressPath.addArc(withCenter: CGPoint(x: progressRect.midX, y: progressRect.midY), radius: progressRect.width / 2, startAngle: startAngle, endAngle: startAngle+arcAngle, clockwise: true)
        progressColour.setStroke()
        progressPath.lineWidth = self.progressLineWith
        progressPath.lineCapStyle = CGLineCap.round
        progressPath.stroke()
        
        // Text Drawing
        let textRect = CGRect(x: rect.minX, y: rect.minY, width: rect.size.width, height: rect.size.height)
        let textContent = NSString(string: timeLabelString)
        let textStyle = NSMutableParagraphStyle.default.mutableCopy() as! NSMutableParagraphStyle
        textStyle.alignment = .center
        
        let textFontAttributes = [
            NSAttributedStringKey.font: UIFont(name: "Helvetica", size: rect.width / 12)!, // 3, HelveticaNeue-Light
            NSAttributedStringKey.foregroundColor: UIColor.black, // NSAttributedStringKey.foregroundColor: titleColor,
            NSAttributedStringKey.paragraphStyle: textStyle]
        
        let textHeight = textContent.boundingRect(with: CGSize(width: textRect.width, height: textRect.height), options: .usesLineFragmentOrigin, attributes: textFontAttributes, context: nil).height
        
        context.saveGState()
        context.clip(to: textRect)
        textContent.draw(in: CGRect(x: textRect.minX, y: textRect.minY + (textRect.height - textHeight) / 2, width: textRect.width, height: textHeight), withAttributes: textFontAttributes)
        context.restoreGState();
    }
    
    override func prepareForInterfaceBuilder() {
        self.currentTime = Date()
        self.startTime = self.currentTime?.addingTimeInterval(-self.duration/3)
    }
    
}