From 393c3f0d97c88ce2e1fec43264ae2a6639a48b65 Mon Sep 17 00:00:00 2001
From: Nathan Walker <walkerrunpdx@gmail.com>
Date: Wed, 15 Mar 2023 20:59:55 -0700
Subject: [PATCH] feat: interactive dismissal for shared element transitions

---
 apps/toolbox/src/pages/transitions.ts         |   1 +
 .../pages/transitions/transitions-modal.xml   |   2 +-
 packages/core/ui/core/view/index.ios.ts       |  76 ++++++++++++-
 packages/core/ui/core/view/view-common.ts     |  38 +++++--
 packages/core/ui/transition/index.ios.ts      |   4 +-
 .../ui/transition/modal-transition.ios.ts     | 107 +++++++++++++++++-
 .../core/ui/transition/shared-transition.ts   |   4 +
 packages/core/utils/number-utils.ts           |  13 +++
 8 files changed, 224 insertions(+), 21 deletions(-)

diff --git a/apps/toolbox/src/pages/transitions.ts b/apps/toolbox/src/pages/transitions.ts
index 826d3711f..6859885a2 100644
--- a/apps/toolbox/src/pages/transitions.ts
+++ b/apps/toolbox/src/pages/transitions.ts
@@ -27,6 +27,7 @@ export class TransitionsModel extends Observable {
 	openModal() {
 		page.showModal('pages/transitions/transitions-modal', {
 			transition: SharedTransition.custom(new ModalTransition(), {
+				interactiveDismissal: true,
 				toPageStart: {
 					y: 200,
 					duration: 1000,
diff --git a/apps/toolbox/src/pages/transitions/transitions-modal.xml b/apps/toolbox/src/pages/transitions/transitions-modal.xml
index 25062599a..538b7e051 100644
--- a/apps/toolbox/src/pages/transitions/transitions-modal.xml
+++ b/apps/toolbox/src/pages/transitions/transitions-modal.xml
@@ -8,7 +8,7 @@
       <Label text="Opened Modal" verticalAlignment="top" marginTop="20" class="text-center" fontSize="28" color="black" />
 
       <ContentView row="1" sharedTransitionTag="open-modal-box2" marginTop="20" width="75" height="75" borderRadius="37" backgroundColor="orange" />
-      <ContentView row="2" sharedTransitionTag="open-modal-box" marginTop="20" width="200" height="200" borderRadius="100" backgroundColor="purple" />
+      <ContentView row="2" sharedTransitionTag="open-modal-box1" marginTop="20" width="200" height="200" borderRadius="100" backgroundColor="purple" />
       <ContentView row="2" sharedTransitionTag="open-modal-box3" marginTop="20" width="30" height="30" borderRadius="15" backgroundColor="red" horizontalAlignment="right" marginRight="50" />
       <ContentView row="1" sharedTransitionTag="open-modal-box4" marginTop="20" width="30" height="30" borderRadius="15" backgroundColor="pink" horizontalAlignment="left" marginLeft="50" />
     </GridLayout>
diff --git a/packages/core/ui/core/view/index.ios.ts b/packages/core/ui/core/view/index.ios.ts
index 7454b1c98..136ab4807 100644
--- a/packages/core/ui/core/view/index.ios.ts
+++ b/packages/core/ui/core/view/index.ios.ts
@@ -14,6 +14,8 @@ import { accessibilityEnabledProperty, accessibilityHiddenProperty, accessibilit
 import { IOSPostAccessibilityNotificationType, isAccessibilityServiceEnabled, updateAccessibilityProperties, AccessibilityEventOptions, AccessibilityRole, AccessibilityState } from '../../../accessibility';
 import { CoreTypes } from '../../../core-types';
 import type { ModalTransition } from '../../transition/modal-transition';
+import { SharedTransition } from '../../transition/shared-transition';
+import { GestureStateTypes, PanGestureEventData } from '../../gestures';
 
 export * from './view-common';
 // helpers (these are okay re-exported here)
@@ -30,9 +32,11 @@ const majorVersion = iOSNativeHelper.MajorVersion;
 export class View extends ViewCommon implements ViewDefinition {
 	nativeViewProtected: UIView;
 	viewController: UIViewController;
+	transitionIteractiveCtrl: UIPercentDrivenInteractiveTransition;
 	private _popoverPresentationDelegate: IOSHelper.UIPopoverPresentationControllerDelegateImp;
 	private _adaptivePresentationDelegate: IOSHelper.UIAdaptivePresentationControllerDelegateImp;
 	private _transitioningDelegate: UIViewControllerTransitioningDelegateImpl;
+	private _interactiveDismissGesture: (args: PanGestureEventData) => void;
 
 	/**
 	 * Track modal open animated options to use same option upon close
@@ -466,8 +470,16 @@ export class View extends ViewCommon implements ViewDefinition {
 		if (options.transition) {
 			controller.modalPresentationStyle = UIModalPresentationStyle.Custom;
 			if (options.transition.instance) {
-				this._transitioningDelegate = UIViewControllerTransitioningDelegateImpl.initWithOwner(new WeakRef(options.transition.instance));
+				this._transitioningDelegate = UIViewControllerTransitioningDelegateImpl.initWithOwner(new WeakRef(options.transition.instance), new WeakRef(this));
 				controller.transitioningDelegate = this._transitioningDelegate;
+				const transitionState = SharedTransition.getState(options.transition.instance.id);
+				if (transitionState?.interactiveDismissal) {
+					// interactive transitions via gestures
+					// TODO - these could be typed as: boolean | (view: View) => void
+					// to allow users to define their own custom gesture dismissals
+					this._interactiveDismissGesture = this._interactiveDismissGestureHandler.bind(this);
+					this.on('pan', this._interactiveDismissGesture);
+				}
 			}
 		} else if (options.fullscreen) {
 			controller.modalPresentationStyle = UIModalPresentationStyle.FullScreen;
@@ -549,6 +561,41 @@ export class View extends ViewCommon implements ViewDefinition {
 		controller = null;
 	}
 
+	private _interactiveDismissGestureHandler(args: PanGestureEventData) {
+		if (args?.ios?.view) {
+			this.interactiveDismissGestureBegan = true;
+			this.interactiveDismissGestureCancelled = false;
+			const percent = args.deltaY / (args.ios.view.bounds.size.height / 2);
+			console.log('pan:', percent);
+			switch (args.state) {
+				case GestureStateTypes.began:
+					if (this._closeModalCallback) {
+						this._closeModalCallback();
+					}
+					break;
+				case GestureStateTypes.changed:
+					// TODO: allow customization of threshold
+					if (percent < 1) {
+						if (this.transitionIteractiveCtrl) {
+							this.transitionIteractiveCtrl.updateInteractiveTransition(percent);
+						}
+					}
+					break;
+				case GestureStateTypes.cancelled:
+				case GestureStateTypes.ended:
+					if (this.transitionIteractiveCtrl) {
+						if (percent > 0.5) {
+							this.transitionIteractiveCtrl.finishInteractiveTransition();
+						} else {
+							this.interactiveDismissGestureCancelled = true;
+							this.transitionIteractiveCtrl.cancelInteractiveTransition();
+						}
+					}
+					break;
+			}
+		}
+	}
+
 	protected _hideNativeModalView(parent: View, whenClosedCallback: () => void) {
 		if (!parent || !parent.viewController) {
 			Trace.error('Trying to hide modal view but no parent with viewController specified.');
@@ -564,10 +611,20 @@ export class View extends ViewCommon implements ViewDefinition {
 		}
 
 		const parentController = parent.viewController;
-		const animated = this._modalAnimatedOptions ? !!this._modalAnimatedOptions.pop() : true;
+		let animated = true;
+		if (this._modalAnimatedOptions?.length) {
+			animated = this._modalAnimatedOptions.slice(-1)[0];
+		}
 
 		parentController.dismissViewControllerAnimatedCompletion(animated, () => {
-			this._transitioningDelegate = null;
+			if (!this.interactiveDismissGestureCancelled) {
+				this._transitioningDelegate = null;
+				this.transitionIteractiveCtrl = null;
+				this.off('pan', this._interactiveDismissGesture);
+				if (this._modalAnimatedOptions) {
+					this._modalAnimatedOptions.pop();
+				}
+			}
 			whenClosedCallback();
 		});
 	}
@@ -923,11 +980,13 @@ View.prototype._nativeBackgroundState = 'unset';
 @NativeClass
 class UIViewControllerTransitioningDelegateImpl extends NSObject implements UIViewControllerTransitioningDelegate {
 	owner: WeakRef<ModalTransition>;
+	ownerView: WeakRef<View>;
 	static ObjCProtocols = [UIViewControllerTransitioningDelegate];
 
-	static initWithOwner(owner: WeakRef<ModalTransition>) {
+	static initWithOwner(owner: WeakRef<ModalTransition>, ownerView: WeakRef<View>) {
 		const delegate = <UIViewControllerTransitioningDelegateImpl>UIViewControllerTransitioningDelegateImpl.new();
 		delegate.owner = owner;
+		delegate.ownerView = ownerView;
 		return delegate;
 	}
 
@@ -950,7 +1009,14 @@ class UIViewControllerTransitioningDelegateImpl extends NSObject implements UIVi
 	interactionControllerForDismissal?(animator: UIViewControllerAnimatedTransitioning): UIViewControllerInteractiveTransitioning {
 		const owner = this.owner?.deref();
 		if (owner?.iosInteractionDismiss) {
-			return owner.iosInteractionDismiss(animator);
+			const ownerView = this.ownerView?.deref();
+			if (ownerView) {
+				if (ownerView.interactiveDismissGestureBegan) {
+					console.log('interactionControllerForDismissal!');
+					ownerView.transitionIteractiveCtrl = owner.iosInteractionDismiss(animator);
+					return ownerView.transitionIteractiveCtrl;
+				}
+			}
 		}
 		return null;
 	}
diff --git a/packages/core/ui/core/view/view-common.ts b/packages/core/ui/core/view/view-common.ts
index e1d1a96cb..a8648792a 100644
--- a/packages/core/ui/core/view/view-common.ts
+++ b/packages/core/ui/core/view/view-common.ts
@@ -94,6 +94,8 @@ export abstract class ViewCommon extends ViewBase implements ViewDefinition {
 	public _modalParent: ViewCommon;
 	private _modalContext: any;
 	private _modal: ViewCommon;
+	interactiveDismissGestureBegan = false;
+	interactiveDismissGestureCancelled = false;
 
 	private _measuredWidth: number;
 	private _measuredHeight: number;
@@ -401,27 +403,39 @@ export abstract class ViewCommon extends ViewBase implements ViewDefinition {
 		this.style._fontScale = getCurrentFontScale();
 		this._modalParent = parent;
 		this._modalContext = options.context;
-		const that = this;
-		this._closeModalCallback = function (...originalArgs) {
-			if (that._closeModalCallback) {
-				const modalIndex = _rootModalViews.indexOf(that);
+		this._closeModalCallback = (...originalArgs) => {
+			const cleanupModalViews = () => {
+				const modalIndex = _rootModalViews.indexOf(this);
 				_rootModalViews.splice(modalIndex);
-				that._modalParent = null;
-				that._modalContext = null;
-				that._closeModalCallback = null;
-				that._dialogClosed();
+				this._modalParent = null;
+				this._modalContext = null;
+				this._closeModalCallback = null;
+				this._dialogClosed();
 				parent._modal = null;
+			};
 
-				const whenClosedCallback = () => {
+			const whenClosedCallback = () => {
+				if (this.interactiveDismissGestureBegan) {
+					this.interactiveDismissGestureBegan = false;
+					if (!this.interactiveDismissGestureCancelled) {
+						cleanupModalViews();
+					}
+				}
+
+				if (!this.interactiveDismissGestureCancelled) {
 					if (typeof options.closeCallback === 'function') {
 						options.closeCallback.apply(undefined, originalArgs);
 					}
 
-					that._tearDownUI(true);
-				};
+					this._tearDownUI(true);
+				}
+			};
 
-				that._hideNativeModalView(parent, whenClosedCallback);
+			if (!this.interactiveDismissGestureBegan) {
+				cleanupModalViews();
 			}
+
+			this._hideNativeModalView(parent, whenClosedCallback);
 		};
 	}
 
diff --git a/packages/core/ui/transition/index.ios.ts b/packages/core/ui/transition/index.ios.ts
index 6d04db109..4aee7e43b 100644
--- a/packages/core/ui/transition/index.ios.ts
+++ b/packages/core/ui/transition/index.ios.ts
@@ -56,14 +56,14 @@ export function iosMatchLayerProperties(view: UIView, toView: UIView) {
 
 	viewPropertiesToMatch.forEach((property) => {
 		if (view[property] !== toView[property]) {
-			console.log('|    -- matching view property:', property);
+			// console.log('|    -- matching view property:', property);
 			view[property as any] = toView[property];
 		}
 	});
 
 	layerPropertiesToMatch.forEach((property) => {
 		if (view.layer[property] !== toView.layer[property]) {
-			console.log('|    -- matching layer property:', property);
+			// console.log('|    -- matching layer property:', property);
 			view.layer[property as any] = toView.layer[property];
 		}
 	});
diff --git a/packages/core/ui/transition/modal-transition.ios.ts b/packages/core/ui/transition/modal-transition.ios.ts
index b50b1dfd4..7821db7aa 100644
--- a/packages/core/ui/transition/modal-transition.ios.ts
+++ b/packages/core/ui/transition/modal-transition.ios.ts
@@ -1,11 +1,13 @@
 import { querySelectorAll } from '../core/view-base';
 import type { View } from '../core/view';
 import { Screen } from '../../platform';
+import { valueMap } from '../../utils/number-utils';
 import { Transition, iosMatchLayerProperties, iosPrintRect, iosSnapshotView } from '.';
 import { SharedTransition, SharedTransitionAnimationType, DEFAULT_DURATION } from './shared-transition';
 
 export class ModalTransition extends Transition {
 	transitionController: ModalTransitionController;
+	interactiveController: UIPercentDrivenInteractiveTransition;
 	presented: UIViewController;
 	presenting: UIViewController;
 	sharedElements: {
@@ -28,7 +30,8 @@ export class ModalTransition extends Transition {
 
 	iosInteractionDismiss(animator: UIViewControllerAnimatedTransitioning): UIViewControllerInteractiveTransitioning {
 		console.log('-- iosInteractionDismiss --');
-		return null;
+		this.interactiveController = PercentInteractiveController.initWithOwner(new WeakRef(this));
+		return this.interactiveController;
 	}
 
 	iosInteractionPresented(animator: UIViewControllerAnimatedTransitioning): UIViewControllerInteractiveTransitioning {
@@ -42,6 +45,108 @@ export class ModalTransition extends Transition {
 	}
 }
 
+@NativeClass()
+class PercentInteractiveController extends UIPercentDrivenInteractiveTransition implements UIViewControllerInteractiveTransitioning {
+	static ObjCProtocols = [UIViewControllerInteractiveTransitioning];
+	owner: WeakRef<ModalTransition>;
+	started = false;
+	transitionContext: UIViewControllerContextTransitioning;
+	backgroundAnimation: UIViewPropertyAnimator;
+
+	static initWithOwner(owner: WeakRef<ModalTransition>) {
+		const ctrl = <PercentInteractiveController>PercentInteractiveController.new();
+		ctrl.owner = owner;
+		return ctrl;
+	}
+
+	startInteractiveTransition(transitionContext: UIViewControllerContextTransitioning) {
+		console.log('startInteractiveTransition');
+		this.transitionContext = transitionContext;
+	}
+
+	updateInteractiveTransition(percentComplete: number) {
+		// console.log('percentComplete:', percentComplete);
+		const owner = this.owner?.deref();
+		if (owner) {
+			if (!this.started) {
+				this.started = true;
+				for (const p of owner.sharedElements.presented) {
+					p.view.opacity = 0;
+				}
+				for (const p of owner.sharedElements.presenting) {
+					p.snapshot.alpha = p.endOpacity;
+					this.transitionContext.containerView.addSubview(p.snapshot);
+				}
+				this.backgroundAnimation = UIViewPropertyAnimator.alloc().initWithDurationDampingRatioAnimations(1, 1, () => {
+					for (const p of owner.sharedElements.presenting) {
+						p.snapshot.frame = p.startFrame;
+						iosMatchLayerProperties(p.snapshot, p.view.ios);
+
+						p.snapshot.alpha = 1;
+					}
+					owner.presented.view.alpha = 0;
+					owner.presented.view.frame = CGRectMake(0, 200, owner.presented.view.bounds.size.width, owner.presented.view.bounds.size.height);
+				});
+			}
+
+			this.backgroundAnimation.fractionComplete = percentComplete;
+		}
+	}
+
+	cancelInteractiveTransition() {
+		console.log('cancelInteractiveTransition');
+		const owner = this.owner?.deref();
+		if (owner && this.started) {
+			const state = SharedTransition.getState(owner.id);
+			if (!state) {
+				return;
+			}
+			if (this.backgroundAnimation) {
+				this.backgroundAnimation.reversed = true;
+				const duration = typeof state.toPageStart?.duration === 'number' ? state.toPageStart?.duration / 1000 : DEFAULT_DURATION;
+				this.backgroundAnimation.continueAnimationWithTimingParametersDurationFactor(null, duration);
+				setTimeout(() => {
+					for (const p of owner.sharedElements.presented) {
+						p.view.opacity = 1;
+					}
+					for (const p of owner.sharedElements.presenting) {
+						p.snapshot.removeFromSuperview();
+					}
+					owner.presented.view.alpha = 1;
+					this.backgroundAnimation = null;
+					this.started = false;
+					this.transitionContext.completeTransition(false);
+				}, duration * 1000);
+			}
+		}
+	}
+
+	finishInteractiveTransition() {
+		console.log('finishInteractiveTransition');
+		const owner = this.owner?.deref();
+		if (owner && this.started) {
+			if (this.backgroundAnimation) {
+				const state = SharedTransition.getState(owner.id);
+				if (!state) {
+					SharedTransition.finishState(owner.id);
+					this.transitionContext.completeTransition(true);
+					return;
+				}
+
+				const duration = typeof state.fromPageEnd?.duration === 'number' ? state.fromPageEnd?.duration / 1000 : DEFAULT_DURATION;
+				this.backgroundAnimation.continueAnimationWithTimingParametersDurationFactor(null, duration);
+				setTimeout(() => {
+					for (const presenting of owner.sharedElements.presenting) {
+						presenting.view.opacity = presenting.startOpacity;
+					}
+					SharedTransition.finishState(owner.id);
+					this.transitionContext.completeTransition(true);
+				}, duration * 1000);
+			}
+		}
+	}
+}
+
 @NativeClass()
 class ModalTransitionController extends NSObject implements UIViewControllerAnimatedTransitioning {
 	static ObjCProtocols = [UIViewControllerAnimatedTransitioning];
diff --git a/packages/core/ui/transition/shared-transition.ts b/packages/core/ui/transition/shared-transition.ts
index ff48464ba..4d9c0dc9c 100644
--- a/packages/core/ui/transition/shared-transition.ts
+++ b/packages/core/ui/transition/shared-transition.ts
@@ -17,6 +17,10 @@ export interface SharedTransitionConfig {
 	 * Preconfigured transition or your own custom configured one
 	 */
 	instance?: Transition;
+	/**
+	 * Whether you want to allow interactive dismissal
+	 */
+	interactiveDismissal?: boolean;
 	/**
 	 * View settings to start your transition.
 	 */
diff --git a/packages/core/utils/number-utils.ts b/packages/core/utils/number-utils.ts
index 3805977d5..5deeb085f 100644
--- a/packages/core/utils/number-utils.ts
+++ b/packages/core/utils/number-utils.ts
@@ -31,3 +31,16 @@ export function notNegative(value: Object): boolean {
 export const radiansToDegrees = (a: number) => a * (180 / Math.PI);
 
 export const degreesToRadians = (a: number) => a * (Math.PI / 180);
+
+/**
+ * Map value changes across a set of criteria
+ * @param val value to map
+ * @param in_min minimum
+ * @param in_max maximum
+ * @param out_min starting value
+ * @param out_max ending value
+ * @returns
+ */
+export function valueMap(val: number, in_min: number, in_max: number, out_min: number, out_max: number) {
+	return ((val - in_min) * (out_max - out_min)) / (in_max - in_min) + out_min;
+}