Convert iOS to use Javascript rendering

iOS/AppDelegate.swift

@@ -53,6 +53,9 @@ class AppDelegate: UIResponder, UIApplicationDelegate, UISplitViewControllerDele
 		super.init()
 		appDelegate = self
 
+		// Force lazy initialization of the web view provider so that it can warm up the queue of prepared web views
+		let _ = DetailViewControllerWebViewProvider.shared
+
 		AccountManager.shared = AccountManager(accountsFolder: RSDataSubfolder(nil, "Accounts")!)
 		
 		registerBackgroundTasks()

iOS/ArticleActivityItemSource.swift

@@ -0,0 +1,33 @@
+//
+//  ArticleActivityItemSource.swift
+//  NetNewsWire-iOS
+//
+//  Created by Maurice Parker on 9/20/19.
+//  Copyright © 2019 Ranchero Software. All rights reserved.
+//
+
+import UIKit
+
+class ArticleActivityItemSource: NSObject, UIActivityItemSource {
+	
+	private let url: URL
+	private let subject: String?
+	
+	init(url: URL, subject: String?) {
+		self.url = url
+		self.subject = subject
+	}
+	
+	func activityViewControllerPlaceholderItem(_ : UIActivityViewController) -> Any {
+		return url
+	}
+	
+	func activityViewController(_ activityViewController: UIActivityViewController, itemForActivityType activityType: UIActivity.ActivityType?) -> Any? {
+		return url
+	}
+	
+	func activityViewController(_ activityViewController: UIActivityViewController, subjectForActivityType activityType: UIActivity.ActivityType?) -> String {
+		return subject ?? ""
+	}
+	
+}

iOS/Detail/DetailViewController.swift

@@ -99,14 +99,23 @@ class DetailViewController: UIViewController {
 	}
 	
 	func reloadHTML() {
-		
 		guard let article = coordinator.currentArticle, let webView = webView else {
 			return
 		}
-		let style = ArticleStylesManager.shared.currentStyle
-		let (styleSheet, html) = ArticleRenderer.articleHTML(article: article, style: style)
-		webView.loadHTMLString(html, baseURL: nil)
 		
+		let style = ArticleStylesManager.shared.currentStyle
+		let rendering = ArticleRenderer.articleHTML(article: article, style: style)
+		
+		let templateData = TemplateData(style: rendering.style, body: rendering.html)
+		
+		let encoder = JSONEncoder()
+		var render = "error();"
+		if let data = try? encoder.encode(templateData) {
+			let json = String(data: data, encoding: .utf8)!
+			render = "render(\(json));"
+		}
+
+		webView.evaluateJavaScript(render)
 	}
 	
 	// MARK: Notifications
@@ -205,31 +214,8 @@ class DetailViewController: UIViewController {
 	}
 	
 }
-//print("\(candidateY) : \(webView.scrollView.contentSize.height)")
 
-class ArticleActivityItemSource: NSObject, UIActivityItemSource {
-	
-	private let url: URL
-	private let subject: String?
-	
-	init(url: URL, subject: String?) {
-		self.url = url
-		self.subject = subject
-	}
-	
-	func activityViewControllerPlaceholderItem(_ : UIActivityViewController) -> Any {
-		return url
-	}
-	
-	func activityViewController(_ activityViewController: UIActivityViewController, itemForActivityType activityType: UIActivity.ActivityType?) -> Any? {
-		return url
-	}
-	
-	func activityViewController(_ activityViewController: UIActivityViewController, subjectForActivityType activityType: UIActivity.ActivityType?) -> String {
-		return subject ?? ""
-	}
-	
-}
+// MARK: WKNavigationDelegate
 
 extension DetailViewController: WKNavigationDelegate {
 	func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
@@ -259,6 +245,8 @@ extension DetailViewController: WKNavigationDelegate {
 	}
 }
 
+// MARK: Private
+
 private extension DetailViewController {
 	
 	func updateProgressIndicatorIfNeeded() {
@@ -269,13 +257,26 @@ private extension DetailViewController {
 	
 }
 
+private struct TemplateData: Codable {
+	let style: String
+	let body: String
+}
+
+
 // MARK: -
 
 /// WKWebView has an awful behavior of a flash to white on first load when in dark mode.
 /// Keep a queue of WebViews where we've already done a trivial load so that by the time we need them in the UI, they're past the flash-to-shite part of their lifecycle.
 class DetailViewControllerWebViewProvider {
+	
 	static var shared = DetailViewControllerWebViewProvider()
 	
+	static let template: String = {
+		let path = Bundle.main.path(forResource: "page", ofType: "html")!
+		let s = try! NSString(contentsOfFile: path, encoding: String.Encoding.utf8.rawValue)
+		return s as String
+	}()
+	
 	func dequeueWebView() -> WKWebView {
 		if let webView = queue.popLast() {
 			replenishQueueIfNeeded()
@@ -295,8 +296,7 @@ class DetailViewControllerWebViewProvider {
 		webView.uiDelegate = nil
 		webView.navigationDelegate = nil
 
-		let html = ArticleRenderer.noContentHTML(style: .defaultStyle)
-		webView.loadHTMLString(html, baseURL: nil)
+		webView.loadHTMLString(DetailViewControllerWebViewProvider.template, baseURL: nil)
 
 		queue.insert(webView, at: 0)
 	}

iOS/Resources/page.html

@@ -0,0 +1,34 @@
+<html>
+    <head>
+		<meta name="viewport" content="width=device-width">
+        <style>
+			:root {
+				color-scheme: light dark;
+			}
+        </style>
+        <script>
+            function mouseDidEnterLink(anchor) {
+                window.webkit.messageHandlers.mouseDidEnter.postMessage(anchor.href);
+            }
+
+            function mouseDidExitLink(anchor) {
+                window.webkit.messageHandlers.mouseDidExit.postMessage(anchor.href);
+            }
+
+            function render(data) {
+				document.getElementsByTagName("style")[0].innerHTML = data.style;
+                document.body.innerHTML = data.body;
+                window.scrollTo(0, 0);
+                document.getElementsByTagName("body")[0].querySelectorAll("style, link[rel=stylesheet]").forEach(element => element.remove());
+                document.getElementsByTagName("body")[0].querySelectorAll("[style]").forEach(element => element.removeAttribute("style"));
+            }
+
+            function error() {
+                document.body.innerHTML = "error";
+            }
+        </script>
+    </head>
+    <body>
+    </body>
+</html>
+

iOS/SceneCoordinator.swift

@@ -269,8 +269,6 @@ class SceneCoordinator: NSObject, UndoableCommandRunner, UnreadCountProvider {
 		NotificationCenter.default.addObserver(self, selector: #selector(userDefaultsDidChange(_:)), name: UserDefaults.didChangeNotification, object: nil)
 		NotificationCenter.default.addObserver(self, selector: #selector(accountDidDownloadArticles(_:)), name: .AccountDidDownloadArticles, object: nil)
 		
-		// Force lazy initialization of the web view provider so that it can warm up the queue of prepared web views
-		let _ = DetailViewControllerWebViewProvider.shared
 	}
 	
 	func start(for size: CGSize) -> UIViewController {