weaver_tutorial_6.swift

final class MovieManager {
    
    func getDiscoverMovies(_ completion: @escaping (Page<Movie>?) -> Void) {
        
        let completionOnMainThread = { result in
            DispatchQueue.main.async {
                completion(result)
            }
        }
        
        guard let url = URL(string: "https://api.themoviedb.org/3/discover/movie?api_key=1a6eb1225335bbb37278527537d28a5d") else {
            completion(nil)
            return
        }
        
        let task = URLSession.shared.dataTask(with: url) { (data, response, error) in
            
            if error != nil {
                completionOnMainThread(nil)
                return
            }
            
            guard let response = response as? HTTPURLResponse else {
                completionOnMainThread(nil)
                return
            }
            
            guard response.statusCode == 200 || response.statusCode == 304 else {
                completionOnMainThread(nil)
                return
            }
            
            guard let data = data else {
                completionOnMainThread(nil)
                return
            }
            
            do {
                let model = try JSONDecoder().decode(Page<Movie>.self, from: data)
                completionOnMainThread(model)
            } catch {
                completionOnMainThread(nil)
            }
        }
        
        task.resume()
    }
}