Web app improvements

submodules/WebUI/Sources/WebAppWebView.swift

@@ -0,0 +1,135 @@
+import Foundation
+import UIKit
+import Display
+import WebKit
+import SwiftSignalKit
+
+private let findFixedPositionClasses = """
+function findFixedPositionClasses() {
+    var elems = document.body.getElementsByTagName("*");
+    var len = elems.length
+
+    var result = []
+    var j = 0;
+    for (var i = 0; i < len; i++) {
+        if ((window.getComputedStyle(elems[i],null).getPropertyValue('position') == 'fixed') && (window.getComputedStyle(elems[i],null).getPropertyValue('bottom') == '0px')) {
+            result[j] = elems[i].className;
+            j++;
+        }
+    }
+    return result;
+}
+findFixedPositionClasses();
+"""
+
+private func findFixedPositionViews(webView: WKWebView, classes: [String]) -> [(String, UIView)] {
+    if let contentView = webView.scrollView.subviews.first {
+        func recursiveSearch(_ view: UIView) -> [(String, UIView)] {
+            var result: [(String, UIView)] = []
+            
+            let description = view.description
+            if description.contains("class='") {
+                for className in classes {
+                    if description.contains(className) {
+                        result.append((className, view))
+                        break
+                    }
+                }
+            }
+            
+            for subview in view.subviews {
+                result.append(contentsOf: recursiveSearch(subview))
+            }
+            
+            return result
+        }
+        
+        return recursiveSearch(contentView)
+    } else {
+        return []
+    }
+}
+
+final class WebAppWebView: WKWebView {
+    private var fixedPositionClasses: [String] = []
+    private var currentFixedViews: [(String, UIView, UIView)] = []
+    
+    private var timer: SwiftSignalKit.Timer?
+    
+    deinit {
+        self.timer?.invalidate()
+    }
+    
+    override func didMoveToSuperview() {
+        super.didMoveToSuperview()
+        
+        if self.timer == nil {
+            let timer = SwiftSignalKit.Timer(timeout: 1.0, repeat: true, completion: { [weak self] in
+                guard let strongSelf = self else {
+                    return
+                }
+                
+                strongSelf.evaluateJavaScript(findFixedPositionClasses, completionHandler: { [weak self] result, _ in
+                    if let result = result {
+                        Queue.mainQueue().async {
+                            self?.fixedPositionClasses = (result as? [String]) ?? []
+                        }
+                    }
+                })
+            }, queue: Queue.mainQueue())
+            timer.start()
+            self.timer = timer
+        }
+    }
+    
+    
+    
+    func updateFrame(frame: CGRect, panning: Bool, transition: ContainedViewLayoutTransition) {
+        if panning {
+            let fixedPositionViews = findFixedPositionViews(webView: self, classes: self.fixedPositionClasses)
+            if fixedPositionViews.count != self.currentFixedViews.count {
+                for (_, view, snapshotView) in self.currentFixedViews {
+                    view.alpha = 1.0
+                    snapshotView.removeFromSuperview()
+                }
+                self.currentFixedViews = []
+                
+                var updatedFixedViews: [(String, UIView, UIView)] = []
+                for (className, view) in fixedPositionViews {
+                    if let snapshotView = view.snapshotView(afterScreenUpdates: false) {
+                        updatedFixedViews.append((className, view, snapshotView))
+                        self.addSubview(snapshotView)
+                    }
+                }
+                self.currentFixedViews = updatedFixedViews
+            }
+            
+            transition.updateFrame(view: self, frame: frame)
+            
+            for (_, view, snapshotView) in self.currentFixedViews {
+                view.alpha = 0.0
+                
+                var snapshotFrame = view.frame
+                snapshotFrame.origin.y = frame.height - snapshotFrame.height
+                transition.updateFrame(view: snapshotView, frame: snapshotFrame)
+            }
+        } else {
+            for (_, view, snapshotView) in self.currentFixedViews {
+                view.alpha = 0.0
+                
+                var snapshotFrame = view.frame
+                snapshotFrame.origin.y = frame.height - snapshotFrame.height
+                transition.updateFrame(view: snapshotView, frame: snapshotFrame)
+            }
+            
+            transition.updateFrame(view: self, frame: frame, completion: { _ in
+                for (_, view, snapshotView) in self.currentFixedViews {
+                    view.alpha = 1.0
+                    snapshotView.removeFromSuperview()
+                }
+                self.currentFixedViews = []
+            })
+        }
+        
+    }
+}