JXWebViewController.swift

//
//  JXWebViewController.swift
//  JXWebViewController
//
//  Created by swordray on 01/17/2018.
//  Copyright (c) 2018 swordray. All rights reserved.
//

import WebKit

open class JXWebViewController: UIViewController {

    open var webViewConfiguration: WKWebViewConfiguration
    open var webViewKeyValueObservations: [AnyKeyPath: NSKeyValueObservation]

    open var webView: WKWebView {
        loadViewIfNeeded()
        return view as? WKWebView ?? .init()
    }

    override public init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
        webViewConfiguration = WKWebViewConfiguration()
        webViewConfiguration.dataDetectorTypes = .phoneNumber

        webViewKeyValueObservations = [:]

        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)

        userActivity = NSUserActivity(activityType: NSUserActivityTypeBrowsingWeb)
    }

    @available(*, unavailable)
    public required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override open func loadView() {
        let webView = WKWebView(frame: .zero, configuration: webViewConfiguration)
        webView.allowsBackForwardNavigationGestures = true
        webView.navigationDelegate = self
        webView.scrollView.refreshControl = UIRefreshControl()
        webView.scrollView.refreshControl?.addTarget(webView, action: #selector(webView.reload), for: .valueChanged)
        webView.uiDelegate = self
        view = webView

        webViewKeyValueObservations[\WKWebView.title] = webView.observe(\.title, options: .new) { webView, _ in
            self.title = webView.title
        }

        webViewKeyValueObservations[\WKWebView.url] = webView.observe(\.url) { webView, _ in
            if let url = webView.url, ["http", "https"].contains(url.scheme) {
                self.userActivity?.webpageURL = url
                self.userActivity?.needsSave = true
            }
        }
    }

    override open func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        userActivity?.becomeCurrent()
    }

    override open func viewDidDisappear(_ animated: Bool) {
        super.viewDidDisappear(animated)

        userActivity?.invalidate()
    }
}

extension JXWebViewController: WKNavigationDelegate {

    open func webView(_ webView: WKWebView, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
        switch challenge.protectionSpace.authenticationMethod {
        case NSURLAuthenticationMethodHTTPBasic:
            let title = String.localizedStringWithFormat(JXLocalizedString("Log in to"), challenge.protectionSpace.host)
            let alertController = UIAlertController(title: title, message: nil, preferredStyle: .alert)
            alertController.addTextField { textField in
                textField.placeholder = JXLocalizedString("User Name")
                textField.text = challenge.proposedCredential?.user
            }
            alertController.addTextField { textField in
                textField.isSecureTextEntry = true
                textField.placeholder = JXLocalizedString("Password")
                textField.text = challenge.proposedCredential?.password
            }
            alertController.addAction(UIAlertAction(title: JXLocalizedString("Cancel"), style: .cancel) { _ in
                completionHandler(.cancelAuthenticationChallenge, nil)
            })
            alertController.addAction(UIAlertAction(title: JXLocalizedString("Log In"), style: .default) { _ in
                let user = alertController.textFields?.first?.text ?? ""
                let password = alertController.textFields?.last?.text ?? ""
                let credential = URLCredential(user: user, password: password, persistence: .forSession)
                completionHandler(.useCredential, credential)
            })
            alertController.preferredAction = alertController.actions.last
            present(alertController, animated: true)

        default:
            completionHandler(.performDefaultHandling, nil)
        }
    }

    open func webView(_ webView: WKWebView, didFail navigation: WKNavigation!, withError error: Error) {
        webView.scrollView.refreshControl?.endRefreshing()
    }

    open func webView(_ webView: WKWebView, didFailProvisionalNavigation navigation: WKNavigation!, withError error: Error) {
        webView.scrollView.refreshControl?.endRefreshing()
    }

    open func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
        webView.scrollView.refreshControl?.endRefreshing()
    }

    open func webViewWebContentProcessDidTerminate(_ webView: WKWebView) {
        webView.reload()
    }

    open func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
        if let url = navigationAction.request.url {
            if !WKWebView.handlesURLScheme(url.scheme ?? "") && UIApplication.shared.canOpenURL(url) {
                UIApplication.shared.open(url)
            }
        }
        decisionHandler(.allow)
    }
}

extension JXWebViewController: WKUIDelegate {

    open func webView(_ webView: WKWebView, createWebViewWith configuration: WKWebViewConfiguration, for navigationAction: WKNavigationAction, windowFeatures: WKWindowFeatures) -> WKWebView? {
        if !(navigationAction.targetFrame?.isMainFrame ?? false) {
            webView.load(navigationAction.request)
        }
        return nil
    }

    open func webView(_ webView: WKWebView, runJavaScriptAlertPanelWithMessage message: String, initiatedByFrame frame: WKFrameInfo, completionHandler: @escaping () -> Void) {
        let alertController = UIAlertController(title: message, message: nil, preferredStyle: .alert)
        alertController.addAction(UIAlertAction(title: JXLocalizedString("Close"), style: .default) { _ in
            completionHandler()
        })
        present(alertController, animated: true)
    }

    open func webView(_ webView: WKWebView, runJavaScriptConfirmPanelWithMessage message: String, initiatedByFrame frame: WKFrameInfo, completionHandler: @escaping (Bool) -> Void) {
        let alertController = UIAlertController(title: message, message: nil, preferredStyle: .alert)
        alertController.addAction(UIAlertAction(title: JXLocalizedString("Cancel"), style: .cancel) { _ in
            completionHandler(false)
        })
        alertController.addAction(UIAlertAction(title: JXLocalizedString("OK"), style: .default) { _ in
            completionHandler(true)
        })
        alertController.preferredAction = alertController.actions.last
        present(alertController, animated: true)
    }

    open func webView(_ webView: WKWebView, runJavaScriptTextInputPanelWithPrompt prompt: String, defaultText: String?, initiatedByFrame frame: WKFrameInfo, completionHandler: @escaping (String?) -> Void) {
        let alertController = UIAlertController(title: prompt, message: nil, preferredStyle: .alert)
        alertController.addTextField { textField in
            textField.text = defaultText
        }
        alertController.addAction(UIAlertAction(title: JXLocalizedString("Cancel"), style: .cancel) { _ in
            completionHandler(nil)
        })
        alertController.addAction(UIAlertAction(title: JXLocalizedString("OK"), style: .default) { _ in
            completionHandler(alertController.textFields?.first?.text)
        })
        alertController.preferredAction = alertController.actions.last
        present(alertController, animated: true)
    }

    open func webViewDidClose(_ webView: WKWebView) {
        guard let url = URL(string: "about:blank") else { return }
        webView.load(URLRequest(url: url))
    }
}