DataManager

DataManager

class DataManager {
    private let queueManager: QueueManager
    init(withQueueManager queueManager: QueueManager = QueueManager.sharedInstance) {
        self.queueManager = queueManager
    }
    
    func retrieveUserList(completionBlock: @escaping (ListUsersModel?) -> Void) {
        guard let url = URL(string: Constants.baseURL + "?page=2") else {return}
        let fetch = UserListRetrievalOperation(url: url, httpManager: HTTPManager(session: URLSession.shared))
        let parse = UserListDecodeOperation()

        // use an adapter to pass the data from fetch to parse
        let adapter = BlockOperation() { [unowned fetch, unowned parse] in
            parse.dataFetched = fetch.dataFetched
            parse.error = fetch.error
        }
        
        adapter.addDependency(fetch)
        parse.addDependency(adapter)
                
        parse.completionHandler = {data in
            completionBlock(data)
        }
        queueManager.addOperations([fetch, parse, adapter])
    }
}