Swiftgram/submodules/TelegramBaseController/Sources/LocationBroadcastPanelWavesNode.swift

import Foundation
import UIKit
import Display
import AsyncDisplayKit

import LegacyComponents

private final class LocationBroadcastPanelWavesNodeParams: NSObject {
    let color: UIColor
    let progress: CGFloat
    
    init(color: UIColor, progress: CGFloat) {
        self.color = color
        self.progress = progress
        
        super.init()
    }
}

private func degToRad(_ degrees: CGFloat) -> CGFloat {
    return degrees * CGFloat.pi / 180.0
}

final class LocationBroadcastPanelWavesNode: ASDisplayNode {
    var color: UIColor {
        didSet {
            self.setNeedsDisplay()
        }
    }
    
    private var effectiveProgress: CGFloat = 0.0 {
        didSet {
            self.setNeedsDisplay()
        }
    }
    
    init(color: UIColor) {
        self.color = color
        
        super.init()
        
        self.isLayerBacked = true
        self.isOpaque = false
    }
    
    override func willEnterHierarchy() {
        super.willEnterHierarchy()
        
        self.pop_removeAnimation(forKey: "indefiniteProgress")
        
        let animation = POPBasicAnimation()
        animation.property = (POPAnimatableProperty.property(withName: "progress", initializer: { property in
            property?.readBlock = { node, values in
                values?.pointee = (node as! LocationBroadcastPanelWavesNode).effectiveProgress
            }
            property?.writeBlock = { node, values in
                (node as! LocationBroadcastPanelWavesNode).effectiveProgress = values!.pointee
            }
            property?.threshold = 0.01
        }) as! POPAnimatableProperty)
        animation.fromValue = CGFloat(0.0) as NSNumber
        animation.toValue = CGFloat(1.0) as NSNumber
        animation.timingFunction = CAMediaTimingFunction(name: CAMediaTimingFunctionName.linear)
        animation.duration = 2.5
        animation.repeatForever = true
        self.pop_add(animation, forKey: "indefiniteProgress")
    }
    
    override func didExitHierarchy() {
        super.didExitHierarchy()
        
        self.pop_removeAnimation(forKey: "indefiniteProgress")
    }
    
    override func drawParameters(forAsyncLayer layer: _ASDisplayLayer) -> NSObjectProtocol? {
        let t = CACurrentMediaTime()
        let value: CGFloat = CGFloat(t.truncatingRemainder(dividingBy: 2.0)) / 2.0
        return LocationBroadcastPanelWavesNodeParams(color: self.color, progress: value)
    }
    
    @objc override class func draw(_ bounds: CGRect, withParameters parameters: Any?, isCancelled: () -> Bool, isRasterizing: Bool) {
        let context = UIGraphicsGetCurrentContext()!
        
        if !isRasterizing {
            context.setBlendMode(.copy)
            context.setFillColor(UIColor.clear.cgColor)
            context.fill(bounds)
        }
        
        if let parameters = parameters as? LocationBroadcastPanelWavesNodeParams {
            let center = CGPoint(x: bounds.width / 2.0, y: bounds.height / 2.0)
            let length: CGFloat = 9.0
            
            context.setFillColor(parameters.color.cgColor)
            
            let draw: (CGContext, CGFloat, Bool) -> Void = { context, pos, right in
                let path = CGMutablePath()
                
                path.addArc(center: center, radius: length * pos + 7.0, startAngle: right ? degToRad(-26.0) : degToRad(154.0), endAngle: right ? degToRad(26.0) : degToRad(206.0), clockwise: false)
                
                let strokedArc = path.copy(strokingWithWidth: 1.65, lineCap: .round, lineJoin: .miter, miterLimit: 10.0)
                
                context.addPath(strokedArc)
                
                context.fillPath()
            }
            
            let position = parameters.progress
            var alpha = position / 0.5
            if alpha > 1.0 {
                alpha = 2.0 - alpha
            }
            context.setAlpha(alpha * 0.7)
            
            draw(context, position, false)
            draw(context, position, true)
            
            var progress = parameters.progress + 0.5
            if progress > 1.0 {
                progress = progress - 1.0
            }
            
            let largerPos = progress
            var largerAlpha = largerPos / 0.5
            if largerAlpha > 1.0 {
                largerAlpha = 2.0 - largerAlpha
            }
            context.setAlpha(largerAlpha * 0.7)
            
            draw(context, largerPos, false)
            draw(context, largerPos, true)
        }
    }
}