mehmetdelikaya · September 21, 2022 15:47
diff --git a/EmbedsViewController.swift b/EmbedsViewController.swift
 //
 //  EmbedsViewController.swift
 //
 //  Created by Evan Sobkowicz.
 //  Copyright © 2019 Twitter. All rights reserved.
 //

 import UIKit
 import WebKit
 import SafariServices

 let DefaultCellHeight: CGFloat = 1000
 let TweetPadding: CGFloat = 20

 let HtmlTemplate = "<html><head><meta name='viewport' content='width=device-width, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0, user-scalable=no'></head><body><div id='wrapper'></div></body></html>"

 let TweetIds = ["1190287688685047808", "1190058389134610433", "1189695999633186816", "1189200245827211264", "1188969975454879747", "1187520413661892608", "1187158033077620736", "1184489710409961473", "1184260182924283906", "1182314890419146752", "1180500441764962304", "1178317279366434818", "1177241651552632833", "1176286416181108736", "1172661285877628931", "1171576431677267969"]


 let HeightCallback = "heightCallback"
 let ClickCallback = "clickCallback"

 class EmbedsViewController: UITableViewController, UITableViewDataSource, UITableViewDelegate {
    
    let Tweets = TweetsManager.shared
    let WidgetsJs = WidgetsJsManager.shared
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        title = "Embeds"
        
        // Set up tableview
        tableView.datasource = self
        tableView.delegate = self
        tableView.allowsSelection = false
        tableView.estimatedRowHeight = DefaultCellHeight
        tableView.separatorStyle = .none
        tableView.register(UITableViewCell.self, forCellReuseIdentifier: "WebCell")
        
        self.initializeView(TweetIds)
    }
    
    func initializeView(_ tweetIds: [String]) {
        Tweets.initializeWithTweetIds(tweetIds)
        
        // Load widgets.js globally
        WidgetsJs.load()
        
        // Preload WebViews before they are rendered
        preloadWebviews()
        
        tableView.reloadData()
    }
    
    // WebView Management
    
    func preloadWebviews() {
        Tweets.all().forEach { tweet in
            tweet.setWebView(createWebView(idx: tweet.idx))
        }
    }
    
    func createWebView(idx: Int) -> WKWebView {
        let webView = WKWebView()
        
        // Set delegates
        webView.navigationDelegate = self
        webView.uiDelegate = self
        
        // Register callbacks
        webView.configuration.userContentController.add(self, name: ClickCallback)
        webView.configuration.userContentController.add(self, name: HeightCallback)
        
        // Set index as tag
        webView.tag = idx
        
        // Set initial frame
        webView.frame = CGRect(x: 0, y: 0, width: view.bounds.width, height: CGFloat(DefaultCellHeight))
        
        // Prevent scrolling
        webView.scrollView.isScrollEnabled = false
        
        // Load HTML template and set your domain
        webView.loadHTMLString(HtmlTemplate, baseURL: URL(string: "https://your-apps-website.com")!)
        
        return webView
    }
    
    // UITableViewController
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return Tweets.count()
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "WebCell", for: indexPath)
        cell.contentView.subviews.forEach { (view) in
            view.removeFromSuperview()
        }
        if let tweet = Tweets.getByIdx(indexPath.row), let webView = tweet.webView {
            cell.contentView.addSubview(webView)
        }
        return cell
    }
    
    func tableView(_ tableView: UITableView, didEndDisplaying cell: UITableViewCell, forRowAt indexPath: IndexPath) {
        
    }
    
    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        if let tweet = Tweets.getByIdx(indexPath.row) {
            return tweet.height
        }
        return DefaultCellHeight
    }
    
    // Helpers
    
    func updateHeight(idx: Int, height: String) {
        if let tweet = Tweets.getByIdx(idx) {
            if (tweet.height == DefaultCellHeight) {
                // Store the height to display the UITableViewCell at the correct height
                tweet.setHeight(stringToCGFloat(height) + TweetPadding)
                
                // Prevent UITableViewCells from jumping around and changing
                //   the scroll position as they resize
                //tableView.reloadRowWithoutAnimation(IndexPath(row: idx, section: 0))
                tableView.reloadData()
            }
        }
    }
    
    func openTweet(_ id: String) {
        if let url = URL(string: "https://twitter.com/i/status/\(id)") {
            openInSafarViewController(url)
        }
    }
    
    func openInSafarViewController(_ url: URL) {
        let vc = SFSafariViewController(url: url)
        self.showDetailViewController(vc, sender: self)
    }
    
    func stringToCGFloat (_ s: String) -> CGFloat {
        if let intHeight = Int(s) {
            return CGFloat(integerLiteral: intHeight)
        }
        return DefaultCellHeight
    }

 }

 extension EmbedsViewController: WKNavigationDelegate {
    func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
        if let url = navigationAction.request.url, navigationAction.navigationType == .linkActivated {
            openInSafarViewController(url)
            decisionHandler(.cancel)
        } else {
            decisionHandler(.allow)
        }
    }
    
    func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
        loadTweetInWebView(webView)
    }
    
    // Tweet Loader
    func loadTweetInWebView(_ webView: WKWebView) {
        if let widgetsJsScript = WidgetsJs.getScriptContent(), let tweet = Tweets.getByIdx(webView.tag) {
            webView.evaluateJavaScript(widgetsJsScript)
            webView.evaluateJavaScript("twttr.widgets.load();")
            
            // Documentation:
            // https://developer.twitter.com/en/docs/twitter-for-websites/embedded-tweets/guides/embedded-tweet-javascript-factory-function
            webView.evaluateJavaScript("""
                twttr.widgets.createTweet(
                    '\(tweet.id)',
                    document.getElementById('wrapper'),
                    { align: 'center' }
                ).then(el => {
                    window.webkit.messageHandlers.heightCallback.postMessage(el.offsetHeight.toString())
                });
            """)
        }
    }
 }

 extension EmbedsViewController: WKUIDelegate {
    func webView(_ webView: WKWebView, createWebViewWith configuration: WKWebViewConfiguration, for navigationAction: WKNavigationAction, windowFeatures: WKWindowFeatures) -> WKWebView? {
        
        // Allow links with target="_blank" to open in SafariViewController
        //   (includes clicks on the background of Embedded Tweets
        if let url = navigationAction.request.url, navigationAction.targetFrame == nil {
            openInSafarViewController(url)
        }
        
        return nil
    }
 }

 extension EmbedsViewController: WKScriptMessageHandler {
    
    func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
        switch message.name {
        case HeightCallback:
            updateHeight(idx: message.webView!.tag, height: message.body as! String)
        default:
            print("Unhandled callback")
        }
    }
    
 }

 extension UITableView {
    func reloadRowWithoutAnimation(_ indexPath: IndexPath) {
        let lastScrollOffset = contentOffset
        UIView.performWithoutAnimation {
            reloadRows(at: [indexPath], with: .none)
        }
        setContentOffset(lastScrollOffset, animated: false)
    }
 }

 class TweetsManager {
    static let shared = TweetsManager()
    
    var tweets: [Tweet] = []
    
    func initializeWithTweetIds(_ tweetIds: [String]) {
        tweets = buildIndexedTweets(tweetIds)
    }
    
    func count() -> Int {
        return tweets.count
    }
    
    func all() -> [Tweet] {
        return tweets
    }
    
    func getByIdx(_ idx: Int) -> Tweet? {
        return tweets.first { $0.idx == idx }
    }
    
    private func buildIndexedTweets(_ tweetIds: [String]) -> [Tweet] {
         return tweetIds.enumerated().map { (idx, id) in
            return Tweet(id: id, idx: idx)
        }
    }
 }

 class Tweet {
    // The Tweet ID
    var id: String
    
    // An index value we'll use to map Tweets to the WKWebView tag property and the UITableView row
    var idx: Int
    
    // The height of the WKWebView
    var height: CGFloat
    
    // The WKWebView we'll use to display the Tweet
    var webView: WKWebView?
    
    init(id: String, idx: Int) {
        self.id = id
        self.idx = idx
        self.height = DefaultCellHeight
    }
    
    func setHeight(_ value: CGFloat) {
        height = value
    }
    
    func setWebView(_ value: WKWebView) {
        webView = value
    }
 }

 class WidgetsJsManager {
    static let shared = WidgetsJsManager()
    
    // The contents of https://platform.twitter.com/widgets.js
    var content: String?
    
    func load() {
       do {
           content = try String(contentsOf: URL(string: "https://platform.twitter.com/widgets.js")!)
       } catch {
           print("Could not load widgets.js script")
       }
    }
    
    func getScriptContent() -> String? {
        return content
    }
 }
	//
	// EmbedsViewController.swift
	//
	// Created by Evan Sobkowicz.
	// Copyright © 2019 Twitter. All rights reserved.
	//

	import UIKit
	import WebKit
	import SafariServices

	let DefaultCellHeight: CGFloat = 1000
	let TweetPadding: CGFloat = 20

	let HtmlTemplate = "<html><head><meta name='viewport' content='width=device-width, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0, user-scalable=no'></head><body><div id='wrapper'></div></body></html>"

	let TweetIds = ["1190287688685047808", "1190058389134610433", "1189695999633186816", "1189200245827211264", "1188969975454879747", "1187520413661892608", "1187158033077620736", "1184489710409961473", "1184260182924283906", "1182314890419146752", "1180500441764962304", "1178317279366434818", "1177241651552632833", "1176286416181108736", "1172661285877628931", "1171576431677267969"]


	let HeightCallback = "heightCallback"
	let ClickCallback = "clickCallback"

	class EmbedsViewController: UITableViewController, UITableViewDataSource, UITableViewDelegate {

	let Tweets = TweetsManager.shared
	let WidgetsJs = WidgetsJsManager.shared

	override func viewDidLoad() {
	super.viewDidLoad()

	title = "Embeds"

	// Set up tableview
	tableView.datasource = self
	tableView.delegate = self
	tableView.allowsSelection = false
	tableView.estimatedRowHeight = DefaultCellHeight
	tableView.separatorStyle = .none
	tableView.register(UITableViewCell.self, forCellReuseIdentifier: "WebCell")

	self.initializeView(TweetIds)
	}

	func initializeView(_ tweetIds: [String]) {
	Tweets.initializeWithTweetIds(tweetIds)

	// Load widgets.js globally
	WidgetsJs.load()

	// Preload WebViews before they are rendered
	preloadWebviews()

	tableView.reloadData()
	}

	// WebView Management

	func preloadWebviews() {
	Tweets.all().forEach { tweet in
	tweet.setWebView(createWebView(idx: tweet.idx))
	}
	}

	func createWebView(idx: Int) -> WKWebView {
	let webView = WKWebView()

	// Set delegates
	webView.navigationDelegate = self
	webView.uiDelegate = self

	// Register callbacks
	webView.configuration.userContentController.add(self, name: ClickCallback)
	webView.configuration.userContentController.add(self, name: HeightCallback)

	// Set index as tag
	webView.tag = idx

	// Set initial frame
	webView.frame = CGRect(x: 0, y: 0, width: view.bounds.width, height: CGFloat(DefaultCellHeight))

	// Prevent scrolling
	webView.scrollView.isScrollEnabled = false

	// Load HTML template and set your domain
	webView.loadHTMLString(HtmlTemplate, baseURL: URL(string: "https://your-apps-website.com")!)

	return webView
	}

	// UITableViewController

	func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
	return Tweets.count()
	}

	func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
	let cell = tableView.dequeueReusableCell(withIdentifier: "WebCell", for: indexPath)
	cell.contentView.subviews.forEach { (view) in
	view.removeFromSuperview()
	}
	if let tweet = Tweets.getByIdx(indexPath.row), let webView = tweet.webView {
	cell.contentView.addSubview(webView)
	}
	return cell
	}

	func tableView(_ tableView: UITableView, didEndDisplaying cell: UITableViewCell, forRowAt indexPath: IndexPath) {

	}

	func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
	if let tweet = Tweets.getByIdx(indexPath.row) {
	return tweet.height
	}
	return DefaultCellHeight
	}

	// Helpers

	func updateHeight(idx: Int, height: String) {
	if let tweet = Tweets.getByIdx(idx) {
	if (tweet.height == DefaultCellHeight) {
	// Store the height to display the UITableViewCell at the correct height
	tweet.setHeight(stringToCGFloat(height) + TweetPadding)

	// Prevent UITableViewCells from jumping around and changing
	// the scroll position as they resize
	//tableView.reloadRowWithoutAnimation(IndexPath(row: idx, section: 0))
	tableView.reloadData()
	}
	}
	}

	func openTweet(_ id: String) {
	if let url = URL(string: "https://twitter.com/i/status/\(id)") {
	openInSafarViewController(url)
	}
	}

	func openInSafarViewController(_ url: URL) {
	let vc = SFSafariViewController(url: url)
	self.showDetailViewController(vc, sender: self)
	}

	func stringToCGFloat (_ s: String) -> CGFloat {
	if let intHeight = Int(s) {
	return CGFloat(integerLiteral: intHeight)
	}
	return DefaultCellHeight
	}

	}

	extension EmbedsViewController: WKNavigationDelegate {
	func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
	if let url = navigationAction.request.url, navigationAction.navigationType == .linkActivated {
	openInSafarViewController(url)
	decisionHandler(.cancel)
	} else {
	decisionHandler(.allow)
	}
	}

	func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
	loadTweetInWebView(webView)
	}

	// Tweet Loader
	func loadTweetInWebView(_ webView: WKWebView) {
	if let widgetsJsScript = WidgetsJs.getScriptContent(), let tweet = Tweets.getByIdx(webView.tag) {
	webView.evaluateJavaScript(widgetsJsScript)
	webView.evaluateJavaScript("twttr.widgets.load();")

	// Documentation:
	// https://developer.twitter.com/en/docs/twitter-for-websites/embedded-tweets/guides/embedded-tweet-javascript-factory-function
	webView.evaluateJavaScript("""
	twttr.widgets.createTweet(
	'\(tweet.id)',
	document.getElementById('wrapper'),
	{ align: 'center' }
	).then(el => {
	window.webkit.messageHandlers.heightCallback.postMessage(el.offsetHeight.toString())
	});
	""")
	}
	}
	}

	extension EmbedsViewController: WKUIDelegate {
	func webView(_ webView: WKWebView, createWebViewWith configuration: WKWebViewConfiguration, for navigationAction: WKNavigationAction, windowFeatures: WKWindowFeatures) -> WKWebView? {

	// Allow links with target="_blank" to open in SafariViewController
	// (includes clicks on the background of Embedded Tweets
	if let url = navigationAction.request.url, navigationAction.targetFrame == nil {
	openInSafarViewController(url)
	}

	return nil
	}
	}

	extension EmbedsViewController: WKScriptMessageHandler {

	func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
	switch message.name {
	case HeightCallback:
	updateHeight(idx: message.webView!.tag, height: message.body as! String)
	default:
	print("Unhandled callback")
	}
	}

	}

	extension UITableView {
	func reloadRowWithoutAnimation(_ indexPath: IndexPath) {
	let lastScrollOffset = contentOffset
	UIView.performWithoutAnimation {
	reloadRows(at: [indexPath], with: .none)
	}
	setContentOffset(lastScrollOffset, animated: false)
	}
	}

	class TweetsManager {
	static let shared = TweetsManager()

	var tweets: [Tweet] = []

	func initializeWithTweetIds(_ tweetIds: [String]) {
	tweets = buildIndexedTweets(tweetIds)
	}

	func count() -> Int {
	return tweets.count
	}

	func all() -> [Tweet] {
	return tweets
	}

	func getByIdx(_ idx: Int) -> Tweet? {
	return tweets.first { $0.idx == idx }
	}

	private func buildIndexedTweets(_ tweetIds: [String]) -> [Tweet] {
	return tweetIds.enumerated().map { (idx, id) in
	return Tweet(id: id, idx: idx)
	}
	}
	}

	class Tweet {
	// The Tweet ID
	var id: String

	// An index value we'll use to map Tweets to the WKWebView tag property and the UITableView row
	var idx: Int

	// The height of the WKWebView
	var height: CGFloat

	// The WKWebView we'll use to display the Tweet
	var webView: WKWebView?

	init(id: String, idx: Int) {
	self.id = id
	self.idx = idx
	self.height = DefaultCellHeight
	}

	func setHeight(_ value: CGFloat) {
	height = value
	}

	func setWebView(_ value: WKWebView) {
	webView = value
	}
	}

	class WidgetsJsManager {
	static let shared = WidgetsJsManager()

	// The contents of https://platform.twitter.com/widgets.js
	var content: String?

	func load() {
	do {
	content = try String(contentsOf: URL(string: "https://platform.twitter.com/widgets.js")!)
	} catch {
	print("Could not load widgets.js script")
	}
	}

	func getScriptContent() -> String? {
	return content
	}
	}