ImageLoader

ImageLoader.swift

import UIKit

struct ImageCache {
    
    
    private var cache : [URL : Data] = [:]
    static var worker : ImageCache = {
            return ImageCache()
    }()
    static func addToCache(url : URL, data : Data) {
            worker.cache[url] = data
    }
    
    
    static func fromCache(url : URL) -> Data? {
        return worker.cache[url]
    }
    
}


class CMImageView : UIImageView {
    
    var task : URLSessionTask?
    
    func assignImage(url : URL, completion : (() -> ())? = nil ) {
        
        self.image = nil
        
        if task != nil {
            task?.cancel()
            task = nil
        }
        
        if let data = ImageCache.fromCache(url: url) {
            self.image = UIImage(data: data)
            completion?()
            return
        }
        
        task = WS.worker.session.dataTask(with: url, completionHandler: { (data, response, error) in
            guard let data =  data else { return }
            ImageCache.addToCache(url: url, data: data)
            self.image = UIImage(data: data)
            completion?()
        })
        
        task?.resume()
    }
    
    
    func assignImage( videoURL : URL, completion: (() -> ())? = nil) {
        
        if let data = ImageCache.fromCache(url: videoURL) {
            self.image = UIImage(data: data)
            completion?()
            return
        } else {
            DispatchQueue.global().async {
                let asset = AVAsset(url: videoURL)
                let imageGenerator = AVAssetImageGenerator(asset: asset)
                let time = CMTimeMake(1, 1)
                if let imageRef = try? imageGenerator.copyCGImage(at: time, actualTime: nil) {
                    let thumbnail = UIImage(cgImage:imageRef)
                    if let data =  UIImagePNGRepresentation(thumbnail) {
                        ImageCache.addToCache(url: videoURL, data:data)
                    }
                    DispatchQueue.main.async {
                        self.image = thumbnail
                        completion?()
                    }
                    
                }else{
                    DispatchQueue.main.async {
                        completion?()
                    }

                }
               
            }
        }
        
        

    }
    
}