WKWebView+Rx.swift

//
//  WKWebView+Rx.swift
//  RxGround
//
//  Created by eyemac on 2017. 9. 2..
//  Copyright © 2017년 rollmind. All rights reserved.
//

import WebKit
import RxSwift
import RxCocoa

public class RxWKNavigationDelegateProxy
  : DelegateProxy
  , DelegateProxyType
, WKNavigationDelegate {
  /// For more information take a look at `DelegateProxyType`.
  public override class func createProxyForObject(_ object: AnyObject) -> AnyObject {
    guard let webView: WKWebView = object as? WKWebView else { fatalError() }
    return webView.createRxNavigationDelegateProxy()
  }

  /// For more information take a look at `DelegateProxyType`.
  public class func setCurrentDelegate(_ delegate: AnyObject?, toObject object: AnyObject) {
    guard let webView: WKWebView = object as? WKWebView else { fatalError() }
    webView.navigationDelegate = delegate as? WKNavigationDelegate
  }

  /// For more information take a look at `DelegateProxyType`.
  public class func currentDelegateFor(_ object: AnyObject) -> AnyObject? {
    guard let webView: WKWebView = object as? WKWebView else { fatalError() }
    return webView.navigationDelegate
  }

}

public class RxWKUIDelegateProxy
  : DelegateProxy
  , DelegateProxyType
, WKUIDelegate {
  /// For more information take a look at `DelegateProxyType`.
  public override class func createProxyForObject(_ object: AnyObject) -> AnyObject {
    guard let webView: WKWebView = object as? WKWebView else { fatalError() }
    return webView.createRxUIDelegateProxy()
  }

  /// For more information take a look at `DelegateProxyType`.
  public class func setCurrentDelegate(_ delegate: AnyObject?, toObject object: AnyObject) {
    guard let webView: WKWebView = object as? WKWebView else { fatalError() }
    webView.uiDelegate = delegate as? WKUIDelegate
  }

  /// For more information take a look at `DelegateProxyType`.
  public class func currentDelegateFor(_ object: AnyObject) -> AnyObject? {
    guard let webView: WKWebView = object as? WKWebView else { fatalError() }
    return webView.uiDelegate
  }
}

extension WKWebView {

  public func createRxNavigationDelegateProxy() -> RxWKNavigationDelegateProxy {
    return RxWKNavigationDelegateProxy(parentObject: self)
  }

  public func createRxUIDelegateProxy() -> RxWKUIDelegateProxy {
    return RxWKUIDelegateProxy(parentObject: self)
  }

}

extension Reactive where Base: WKWebView {

  public var navigationDelegate: RxWKNavigationDelegateProxy {
    return RxWKNavigationDelegateProxy.proxyForObject(base)
  }

  public var uiDelegate: RxWKUIDelegateProxy {
    return RxWKUIDelegateProxy.proxyForObject(base)
  }

  //MARK: - WKNavigationDelegate
  public var didStartProvisionalNavigation: Observable<Void> {
    return self.navigationDelegate
      .methodInvoked(#selector(WKNavigationDelegate.webView(_:didStartProvisionalNavigation:)))
      .map { _ in }
  }

  public var didFinish: Observable<Void> {
    return self.navigationDelegate
      .methodInvoked(#selector(WKNavigationDelegate.webView(_:didFinish:)))
      .map { _ in }
  }

  public var didFail: Observable<Void> {
    return self.navigationDelegate
      .methodInvoked(#selector(WKNavigationDelegate.webView(_:didFail:withError:)))
      .map { args in throw args[2] as! Error }
  }

  public var didFailProvisionalNavigation: Observable<Void> {
    return self.navigationDelegate
      .methodInvoked(#selector(WKNavigationDelegate.webView(_:didFailProvisionalNavigation:withError:)))
      .map { args in throw args[2] as! Error }
  }

  public var didTerminateWebContentProcess: Observable<Void> {
    return self.navigationDelegate
      .methodInvoked(#selector(WKNavigationDelegate.webViewWebContentProcessDidTerminate(_:)))
      .map { _ in }
  }

  public typealias ActionPolicyHandle = @convention(block) (WKNavigationActionPolicy) -> Void
  public var decideActionPolicy: Observable<(WKNavigationAction, ActionPolicyHandle)> {
    return self.navigationDelegate
      .methodInvoked(NSSelectorFromString("webView:decidePolicyForNavigationAction:decisionHandler:"))
      .map { args in
        return (self.cast(args[1]), self.castPointer(args[2])) }
  }

  public typealias ResponsePolicyHandle = @convention(block) (WKNavigationResponsePolicy) -> Void
  public var decideResponsePolicy: Observable<(WKNavigationResponse, ResponsePolicyHandle)> {
    return self.navigationDelegate
      .methodInvoked(NSSelectorFromString("webView:decidePolicyForNavigationResponse:decisionHandler:"))
      .map { args in
        return (self.cast(args[1]), self.castPointer(args[2]))
      }
  }

  public var didCommit: Observable<Void> {
    return self.navigationDelegate
      .methodInvoked(#selector(WKNavigationDelegate.webView(_:didCommit:)))
      .map { _ in }
  }

  public var didReceiveServerRedirectForProvisionalNavigation: Observable<Void> {
    return self.navigationDelegate
      .methodInvoked(#selector(WKNavigationDelegate.webView(_:didReceiveServerRedirectForProvisionalNavigation:)))
      .map { _ in }
  }

  public typealias AuthChallengeCompletionHandler = @convention(block) (URLSession.AuthChallengeDisposition, URLCredential?) -> Void
  public var didReceive: Observable<(URLAuthenticationChallenge, AuthChallengeCompletionHandler)> {
    return self.navigationDelegate
      .methodInvoked(#selector(WKNavigationDelegate.webView(_:didReceive:completionHandler:)))
      .map { args in
        return (self.cast(args[1]), self.castPointer(args[2]))
    }
  }

  //MARK: - WKUIDelegate
//  public var createWebView: Observable<WKWebView> {
//    return self.uiDelegate
//      .methodInvoked(#selector(WKUIDelegate.webView(_:createWebViewWith:for:windowFeatures:)))
//      .map { args in
//        guard let configuration: WKWebViewConfiguration = args[1] as? WKWebViewConfiguration else { fatalError() }
//        guard let action: WKNavigationAction = args[2] as? WKNavigationAction else { fatalError() }
//        let webView = WKWebView(frame: .zero, configuration: configuration)
//        webView.load(action.request)
//        return webView
//      }
//  }

//  public var closeWebView: Observable<WKWebView> {
//    return self.uiDelegate
//      .methodInvoked(#selector(WKUIDelegate.webViewDidClose(_:)))
//      .map { args in self.cast(args[1]) }
//  }

//  public typealias CompletionHandlerWithNoArguments = () -> Void
//  public typealias JavaScriptAlertPanelValues = (message: String, frame: WKFrameInfo, completionHandler: CompletionHandlerWithNoArguments)
//  public var runJavaScriptAlertPanel: Observable<JavaScriptAlertPanelValues> {
//    return self.uiDelegate
//      .methodInvoked(#selector(WKUIDelegate.webView(_:runJavaScriptAlertPanelWithMessage:initiatedByFrame:completionHandler:)))
//      .map { args in JavaScriptAlertPanelValues(self.cast(args[1]), self.cast(args[2]), self.castPointer(args[3])) }
//  }
//
//  public var addWebView: UIBindingObserver<Base, WKWebView> {
//    return UIBindingObserver(UIElement: base, binding: { (base, newWebView) in
//      newWebView.frame = base.bounds
//      newWebView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
//      base.addSubview(newWebView)
//    })
//  }
//
//  public var removeWebView: UIBindingObserver<Base, WKWebView> {
//    return UIBindingObserver(UIElement: base, binding: { (_, newWebView) in
//      if newWebView.superview != nil {
//        newWebView.removeFromSuperview()
//      }
//    })
//  }

}

extension WKNavigationType: CustomStringConvertible {

  public var description: String {
    switch self {
    case .backForward: return "backForward"
    case .formResubmitted: return "formResubmitted"
    case .formSubmitted: return "formSubmitted"
    case .linkActivated: return "linkActivated"
    case .other: return "other"
    case .reload: return "reload"
    }
  }

}

extension Reactive {

  public func castPointer<T>(_ any: Any) -> T {
    let block = any as AnyObject
    let ptr = UnsafeRawPointer(Unmanaged<AnyObject>.passUnretained(block).toOpaque())
    let casted = unsafeBitCast(ptr, to: T.self)
    return casted
  }

  public func cast<T>(_ any: Any) -> T {
    guard let casted: T = any as? T else { fatalError() }
    return casted
  }
}