[Sheets] [Pt. 1] Root PR (#5557)

Co-authored-by: Samuel Newman <mozzius@protonmail.com>
Co-authored-by: Eric Bailey <git@esb.lol>
Co-authored-by: dan <dan.abramov@gmail.com>
Co-authored-by: Hailey <me@haileyok.com>

1 files changed, 189 insertions, 0 deletions

diff --git a/modules/bottom-sheet/ios/SheetView.swift b/modules/bottom-sheet/ios/SheetView.swift
new file mode 100644
index 000000000..cf2019c6a
--- /dev/null
+++ b/modules/bottom-sheet/ios/SheetView.swift
@@ -0,0 +1,189 @@
+import ExpoModulesCore
+import UIKit
+
+class SheetView: ExpoView, UISheetPresentationControllerDelegate {
+  // Views
+  private var sheetVc: SheetViewController?
+  private var innerView: UIView?
+  private var touchHandler: RCTTouchHandler?
+
+  // Events
+  private let onAttemptDismiss = EventDispatcher()
+  private let onSnapPointChange = EventDispatcher()
+  private let onStateChange = EventDispatcher()
+
+  // Open event firing
+  private var isOpen: Bool = false {
+    didSet {
+      onStateChange([
+        "state": isOpen ? "open" : "closed"
+      ])
+    }
+  }
+
+  // React view props
+  var preventDismiss = false
+  var preventExpansion = false
+  var cornerRadius: CGFloat?
+  var minHeight = 0.0
+  var maxHeight: CGFloat! {
+    didSet {
+      let screenHeight = Util.getScreenHeight() ?? 0
+      if maxHeight > screenHeight {
+        maxHeight = screenHeight
+      }
+    }
+  }
+
+  private var isOpening = false {
+    didSet {
+      if isOpening {
+        onStateChange([
+          "state": "opening"
+        ])
+      }
+    }
+  }
+  private var isClosing = false {
+    didSet {
+      if isClosing {
+        onStateChange([
+          "state": "closing"
+        ])
+      }
+    }
+  }
+  private var selectedDetentIdentifier: UISheetPresentationController.Detent.Identifier? {
+    didSet {
+      if selectedDetentIdentifier == .large {
+        onSnapPointChange([
+          "snapPoint": 2
+        ])
+      } else {
+        onSnapPointChange([
+          "snapPoint": 1
+        ])
+      }
+    }
+  }
+
+  // MARK: - Lifecycle
+
+  required init (appContext: AppContext? = nil) {
+    super.init(appContext: appContext)
+    self.maxHeight = Util.getScreenHeight()
+    self.touchHandler = RCTTouchHandler(bridge: appContext?.reactBridge)
+    SheetManager.shared.add(self)
+  }
+
+  deinit {
+    self.destroy()
+  }
+
+  // We don't want this view to actually get added to the tree, so we'll simply store it for adding
+  // to the SheetViewController
+  override func insertReactSubview(_ subview: UIView!, at atIndex: Int) {
+    self.touchHandler?.attach(to: subview)
+    self.innerView = subview
+  }
+
+  // We'll grab the content height from here so we know the initial detent to set
+  override func layoutSubviews() {
+    super.layoutSubviews()
+
+    guard let innerView = self.innerView else {
+      return
+    }
+
+    if innerView.subviews.count != 1 {
+      return
+    }
+
+    self.present()
+  }
+
+  private func destroy() {
+    self.isClosing = false
+    self.isOpen = false
+    self.sheetVc = nil
+    self.touchHandler?.detach(from: self.innerView)
+    self.touchHandler = nil
+    self.innerView = nil
+    SheetManager.shared.remove(self)
+  }
+
+  // MARK: - Presentation
+
+  func present() {
+    guard !self.isOpen,
+          !self.isOpening,
+          !self.isClosing,
+          let innerView = self.innerView,
+          let contentHeight = innerView.subviews.first?.frame.height,
+          let rvc = self.reactViewController() else {
+      return
+    }
+
+    let sheetVc = SheetViewController()
+    sheetVc.setDetents(contentHeight: self.clampHeight(contentHeight), preventExpansion: self.preventExpansion)
+    if let sheet = sheetVc.sheetPresentationController {
+      sheet.delegate = self
+      sheet.preferredCornerRadius = self.cornerRadius
+      self.selectedDetentIdentifier = sheet.selectedDetentIdentifier
+    }
+    sheetVc.view.addSubview(innerView)
+
+    self.sheetVc = sheetVc
+    self.isOpening = true
+
+    rvc.present(sheetVc, animated: true) { [weak self] in
+      self?.isOpening = false
+      self?.isOpen = true
+    }
+  }
+
+  func updateLayout() {
+    if let contentHeight = self.innerView?.subviews.first?.frame.size.height {
+      self.sheetVc?.updateDetents(contentHeight: self.clampHeight(contentHeight),
+                               preventExpansion: self.preventExpansion)
+      self.selectedDetentIdentifier = self.sheetVc?.getCurrentDetentIdentifier()
+    }
+  }
+
+  func dismiss() {
+    self.isClosing = true
+    self.sheetVc?.dismiss(animated: true) { [weak self] in
+      self?.destroy()
+    }
+  }
+
+  // MARK: - Utils
+
+  private func clampHeight(_ height: CGFloat) -> CGFloat {
+    if height < self.minHeight {
+      return self.minHeight
+    } else if height > self.maxHeight {
+      return self.maxHeight
+    }
+    return height
+  }
+
+  // MARK: - UISheetPresentationControllerDelegate
+
+  func presentationControllerShouldDismiss(_ presentationController: UIPresentationController) -> Bool {
+    self.onAttemptDismiss()
+    return !self.preventDismiss
+  }
+
+  func presentationControllerWillDismiss(_ presentationController: UIPresentationController) {
+    self.isClosing = true
+  }
+
+  func presentationControllerDidDismiss(_ presentationController: UIPresentationController) {
+    self.destroy()
+  }
+
+  func sheetPresentationControllerDidChangeSelectedDetentIdentifier(_ sheetPresentationController: UISheetPresentationController) {
+    self.selectedDetentIdentifier = sheetPresentationController.selectedDetentIdentifier
+  }
+}