RxNetworkExample.swift

//
//  ViewController.swift
//  NetworkChaining
//
//  Created by JungMin Ahn on 2016. 5. 15..
//  Copyright © 2016년 SmartStudy. All rights reserved.
//

import UIKit
import RxSwift
import RxCocoa

extension Dictionary where Key:StringLiteralConvertible, Value: StringLiteralConvertible {
    func toParameterString() -> String {
        guard let _self = (self as? AnyObject) as? Dictionary<String, String> else {
            return ""
        }
        if _self.count < 10 {
            return (1..._self.count+1).map { "\($0)=\($0)" }.joinWithSeparator("&")
        }
        return (1..._self.count).map { "\($0)=\($0)" }.joinWithSeparator("&")
    }
}

protocol HTTPBinAPI {
    func get(parameter: String) -> Observable<[String:String]>
}

class HTTPBinDefaultAPI: HTTPBinAPI {
    let url = "http://httpbin.org/"

    static let sharedAPI = HTTPBinDefaultAPI()

    func get(parameter: String) -> Observable<[String : String]> {
        let requestURL = NSURL(string: url + "get?" + parameter)!

        return Observable.create { observer -> Disposable in
            let s = NSURLSession.sharedSession().dataTaskWithURL(requestURL) {
                (data, response, error) in
                if let error = error {
                    observer.onError(error)
                }
                guard let
                    data = data,
                    json = try? NSJSONSerialization.JSONObjectWithData(data, options: []),
                    args = json["args"] as? [String:String]
                    else {
                        observer.onError(NSError(domain: "Error", code: 1, userInfo: nil))
                        return
                }
                observer.onNext(args)
            }
            s.resume()
            return NopDisposable.instance
        }
    }
}

class ViewController: UIViewController {

    var label: UILabel!
    var disposeBag = DisposeBag()
    let backgroundScheduler = SerialDispatchQueueScheduler(globalConcurrentQueueQOS: .Background)

    override func viewDidLoad() {
        super.viewDidLoad()

        let btn1 = UIButton(frame: CGRectMake(100,100,100,100))
        btn1.backgroundColor = .redColor()
        self.view.addSubview(btn1)

        let btn2 = UIButton(frame: CGRectMake(250,100,100,100))
        btn2.backgroundColor = .greenColor()
        self.view.addSubview(btn2)

        label = UILabel(frame: CGRectMake(100, 200, 300, 100))
        label.backgroundColor = .whiteColor()
        label.font = UIFont.systemFontOfSize(15)
        self.view.addSubview(label)

        btn1
            .rx_tap
            .subscribeOn(MainScheduler.instance)
            .map { [String:String]() }
            .debug()
            .doOnNext { [unowned self] _ in
                UIApplication.sharedApplication().networkActivityIndicatorVisible = true
                self.label.text = "Loading..."
            }
            .debug()
            .observeOn(backgroundScheduler)

            .flatMapLatest { p in
                HTTPBinDefaultAPI.sharedAPI.get(p.toParameterString()).retry(2)
                    .observeOn(MainScheduler.instance).doOnNext { [unowned self] p in self.label.text = p.description
                }
            }
            .debug()
            .flatMapLatest { p in
                HTTPBinDefaultAPI.sharedAPI.get(p.toParameterString()).retry(2)
                    .observeOn(MainScheduler.instance).doOnNext { [unowned self] p in self.label.text = p.description
                }
            }
            .debug()
            .flatMapLatest { p in
                HTTPBinDefaultAPI.sharedAPI.get(p.toParameterString()).retry(2)
                    .observeOn(MainScheduler.instance).doOnNext { [unowned self] p in self.label.text = p.description
                }
            }
            .debug()
            .flatMapLatest { p in
                HTTPBinDefaultAPI.sharedAPI.get(p.toParameterString()).retry(2)
                    .observeOn(MainScheduler.instance).doOnNext { [unowned self] p in self.label.text = p.description
                }
            }
            .debug()
            .flatMapLatest { p in
                HTTPBinDefaultAPI.sharedAPI.get(p.toParameterString()).retry(2)
                    .observeOn(MainScheduler.instance).doOnNext { [unowned self] p in self.label.text = p.description
                }
            }
            .flatMapLatest { p in
                HTTPBinDefaultAPI.sharedAPI.get(p.toParameterString()).retry(2)
                    .observeOn(MainScheduler.instance).doOnNext { [unowned self] p in self.label.text = p.description
                }
            }
            .flatMapLatest { p in
                HTTPBinDefaultAPI.sharedAPI.get(p.toParameterString()).retry(2)
                    .observeOn(MainScheduler.instance).doOnNext { [unowned self] p in self.label.text = p.description
                }
            }
            .debug()
            .flatMapLatest { p in
                HTTPBinDefaultAPI.sharedAPI.get(p.toParameterString()).retry(2)
                    .observeOn(MainScheduler.instance)
                    .doOnNext { [unowned self] p in
                        self.label.text = p.description
                }
            }
            .debug()
            .observeOn(MainScheduler.instance)
            .subscribe { [unowned self] s in
                guard let e = s.element else {
                    self.label.text = ""
                    return
                }
                self.label.text = "Done"
            }
            .addDisposableTo(disposeBag)

        btn2
            .rx_tap
            .debug()
            .subscribe { [unowned self] _ in
                print(self.label.text)
                self.label.text = ""
            }
            .addDisposableTo(disposeBag)
    }
}