Web app improvements

submodules/WebUI/Sources/WebAppController.swift

@@ -262,7 +262,7 @@ public final class WebAppController: ViewController, AttachmentContainable {
         }
                         
         func webView(_ webView: WKWebView, didCommit navigation: WKNavigation!) {
-            Queue.mainQueue().after(0.65, {
+            Queue.mainQueue().after(1.0, {
                 let transition = ContainedViewLayoutTransition.animated(duration: 0.2, curve: .linear)
                 transition.updateAlpha(layer: webView.layer, alpha: 1.0)
                 if let placeholderNode = self.placeholderNode {
@@ -283,9 +283,14 @@ public final class WebAppController: ViewController, AttachmentContainable {
             decisionHandler(.prompt)
         }
                 
+        private var targetContentOffset: CGPoint?
         func scrollViewDidScroll(_ scrollView: UIScrollView) {
             let contentOffset = scrollView.contentOffset.y
             self.controller?.navigationBar?.updateBackgroundAlpha(min(30.0, contentOffset) / 30.0, transition: .immediate)
+            
+            if let targetContentOffset = self.targetContentOffset, scrollView.contentOffset != targetContentOffset {
+                scrollView.contentOffset = targetContentOffset
+            }
         }
         
         private var validLayout: (ContainerViewLayout, CGFloat)?
@@ -298,8 +303,15 @@ public final class WebAppController: ViewController, AttachmentContainable {
                 let viewportFrame = CGRect(origin: CGPoint(x: layout.safeInsets.left, y: navigationBarHeight), size: CGSize(width: layout.size.width - layout.safeInsets.left - layout.safeInsets.right, height: max(1.0, layout.size.height - navigationBarHeight - layout.intrinsicInsets.bottom - layout.additionalInsets.bottom)))
                 
                 if previousLayout != nil && (previousLayout?.inputHeight ?? 0.0).isZero, let inputHeight = layout.inputHeight, inputHeight > 44.0, transition.isAnimated {
+                    webView.scrollToActiveElement(layout: layout, transition: transition)
                     Queue.mainQueue().after(0.4, {
+                        let contentOffset = webView.scrollView.contentOffset
                         transition.updateFrame(view: webView, frame: frame)
+                        webView.scrollView.contentOffset = contentOffset
+                        self.targetContentOffset = contentOffset                        
+                        Queue.mainQueue().after(0.1) {
+                            self.targetContentOffset = nil
+                        }
                     })
                 } else {
                     transition.updateFrame(view: webView, frame: frame)

submodules/WebUI/Sources/WebAppWebView.swift

@@ -4,6 +4,10 @@ import Display
 import WebKit
 import SwiftSignalKit
 
+private let findActiveElementY = """
+document.activeElement.getBoundingClientRect().y
+"""
+
 private class WeakGameScriptMessageHandler: NSObject, WKScriptMessageHandler {
     private let f: (WKScriptMessage) -> ()
     
@@ -104,6 +108,10 @@ final class WebAppWebView: WKWebView {
                 }
                 contentView?.removeInteraction(dragInteraction)
             })
+            
+            NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillChangeFrameNotification, object: nil)
+            NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillShowNotification, object: nil)
+            NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillHideNotification, object: nil)
         }
     }
     
@@ -122,6 +130,29 @@ final class WebAppWebView: WKWebView {
         self.didTouchOnce = true
     }
     
+    func scrollToActiveElement(layout: ContainerViewLayout, transition: ContainedViewLayoutTransition) {
+        self.evaluateJavaScript(findActiveElementY, completionHandler: { result, _ in
+            if let result = result as? CGFloat {
+                Queue.mainQueue().async {
+                    let convertedY = result - self.scrollView.contentOffset.y
+                    let viewportHeight = self.frame.height - (layout.inputHeight ?? 0.0)
+                    if convertedY < 0.0 || convertedY > viewportHeight {
+                        let targetOffset: CGFloat
+                        if convertedY < 0.0 {
+                            targetOffset = max(0.0, result - 36.0)
+                        } else {
+                            targetOffset = max(0.0, result + 60.0 - viewportHeight)
+                        }
+                        transition.animateView({
+                            self.scrollView.contentOffset = CGPoint(x: 0.0, y: targetOffset)
+                        })
+//                        transition.updateBounds(layer: self.scrollView.layer, bounds: CGRect(x: 0.0, y: targetOffset, width: self.scrollView.layer.bounds.width, height: self.scrollView.layer.bounds.height))
+                    }
+                }
+            }
+        })
+    }
+    
     override var inputAccessoryView: UIView? {
         return nil
     }