iOSGiphyCodeChallenge/LiveLikeGiphyChallenge/UIElements/ImageViews/LLAnimatableImageView.swift

//
//  LLAnimatableImageView.swift
//  LiveLikeGiphyChallenge
//
//  Created by Ljupco Nastevski on 30.1.22.
//

import UIKit

class LLAnimatableImageView: UIImageView {
    
    var cache = LLCache.shared
    
    private var url: URL?
    
    private var worker: DispatchWorkItem?
    
    private var activityIndicator: UIActivityIndicatorView = {
        let ai = UIActivityIndicatorView()
        ai.translatesAutoresizingMaskIntoConstraints = false
        ai.hidesWhenStopped = true
        return ai
    }()
    
    init() {
        super.init(frame: .zero)
        
        self.addSubview(activityIndicator)
        
        NSLayoutConstraint.activate([
            activityIndicator.centerXAnchor.constraint(equalTo: self.centerXAnchor),
            activityIndicator.centerYAnchor.constraint(equalTo: self.centerYAnchor)
        ])
        
        
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    
    func loadGifFromUrl(urlString: String) {
        
        guard let url = URL(string: urlString) else { return }
        self.url = url
        
        self.cancelAndClear()
        
        self.cache.retreiveDataFromUrl(url: url) {[weak self] gifImage in
            
            gifImage?.prepareForDisplay(completionHandler: { preparedImage in
                DispatchQueue.main.async {
                    self?.activityIndicator.stopAnimating()
                    self?.image = preparedImage
                }
                
            })

        }

    }

    /// Sets the current image to nil
    func cancelAndClear() {
        
        self.activityIndicator.startAnimating()
        self.image = nil
        cache.cancelTaskFor(url: url!)

    }
    
}