basic scrollview on the native side

modules/bottom-sheet/ios/BottomSheetScrollView.swift

@@ -6,30 +6,97 @@
 //
 
 class BottomSheetScrollView: UIScrollView, UIScrollViewDelegate {
+  private let sheetView: SheetView
   private var previousHeight: CGFloat?
+  private var beganDraggingY: CGFloat?
   
-  init() {
+  init(sheetView: SheetView) {
+    self.sheetView = sheetView
     super.init(frame: .zero)
     if let window = Util.getWindow() {
       self.frame = window.bounds
-      self.contentInset = UIEdgeInsets(top: 0,
-                                       left: 0,
-                                       bottom: window.safeAreaInsets.bottom,
-                                       right: 0)
+      let offset = window.safeAreaInsets.bottom * 3
+      self.contentInset.bottom = offset
+      self.verticalScrollIndicatorInsets.top = 20
+      self.verticalScrollIndicatorInsets.bottom = offset
     }
+    
+    self.delegate = self
+    
+    NotificationCenter.default.addObserver(self,
+                                           selector: #selector(keyboardWillShow(notification:)),
+                                           name: UIResponder.keyboardWillShowNotification,
+                                           object: nil)
+    NotificationCenter.default.addObserver(self,
+                                           selector: #selector(keyboardWillHide(notification:)),
+                                           name: UIResponder.keyboardWillHideNotification,
+                                           object: nil)
   }
   
   required init?(coder: NSCoder) {
     fatalError("init(coder:) has not been implemented")
   }
   
+  deinit {
+    NotificationCenter.default.removeObserver(self)
+  }
+  
   override func layoutSubviews() {
     super.layoutSubviews()
     
     if let height = self.subviews.first?.frame.size.height,
        self.previousHeight != height,
        let window = self.window {
-      self.contentSize = CGSize(width: window.bounds.width, height: height + window.safeAreaInsets.bottom)
+      let newDetent = self.sheetView.sheetVc.updateDetents(contentHeight: self.sheetView.clampHeight(height),
+                                           preventExpansion: self.sheetView.preventExpansion)
+      self.sheetView.selectedDetentIdentifier = newDetent
+      self.contentSize = CGSize(width: window.bounds.width, height: height)
+      self.previousHeight = height
+    }
+  }
+
+  @objc func keyboardWillShow(notification: Notification) {
+    if let keyboardFrame = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect {
+      let keyboardHeight = keyboardFrame.height
+      let newOffset = self.contentInset.bottom + keyboardHeight
+      
+      // We purposefully add keyboard height to content inset and only update
+      // the scroll indicator inset
+      self.contentInset.bottom = newOffset
+      self.verticalScrollIndicatorInsets.bottom = keyboardHeight
+      
+      if let firstResponder = self.findFirstResponder(),
+         let window = self.window {
+        let position = firstResponder.convert(firstResponder.bounds,
+                                                    to: window)
+        
+        if position.minY > window.bounds.height - keyboardHeight {
+          self.setContentOffset(CGPoint(x: 0, y: self.contentOffset.y + keyboardHeight),
+                                animated: true)
+        }
+      }
+    }
+  }
+
+  @objc func keyboardWillHide(notification: Notification) {
+    if let window = Util.getWindow() {
+      let offset = window.safeAreaInsets.bottom * 3
+      self.contentInset.bottom = offset
+      self.verticalScrollIndicatorInsets.bottom = offset
+    }
+  }
+  
+  func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
+    self.beganDraggingY = self.contentOffset.y
+  }
+  
+  func scrollViewDidScroll(_ scrollView: UIScrollView) {
+    if let beganDraggingY = self.beganDraggingY,
+       self.contentOffset.y < beganDraggingY {
+      if let firstResponder = self.findFirstResponder() {
+        firstResponder.resignFirstResponder()
+      }
+      self.beganDraggingY = nil
     }
   }
 }