Tusker/Packages/GalleryVC/Sources/GalleryVC/GalleryViewController.swift

180 lines
6.7 KiB
Swift

//
// GalleryViewController.swift
// GalleryVC
//
// Created by Shadowfacts on 12/28/23.
//
import UIKit
public class GalleryViewController: UIPageViewController {
let galleryDataSource: GalleryDataSource
let initialItemIndex: Int
private let _itemsCount: Int
private var itemsCount: Int {
get {
precondition(_itemsCount == galleryDataSource.galleryItemsCount(), "GalleryDataSource item count cannot change")
return _itemsCount
}
}
var currentItemViewController: GalleryItemViewController {
viewControllers![0] as! GalleryItemViewController
}
private var dismissInteraction: GalleryDismissInteraction!
private var presentationAnimationCompletionHandlers: [() -> Void] = []
override public var prefersStatusBarHidden: Bool {
true
}
override public var preferredStatusBarUpdateAnimation: UIStatusBarAnimation {
.none
}
override public var childForHomeIndicatorAutoHidden: UIViewController? {
currentItemViewController
}
public init(dataSource: GalleryDataSource, initialItemIndex: Int) {
self.galleryDataSource = dataSource
self.initialItemIndex = initialItemIndex
self._itemsCount = dataSource.galleryItemsCount()
precondition(initialItemIndex >= 0 && initialItemIndex < _itemsCount, "initialItemIndex is out of bounds")
super.init(transitionStyle: .scroll, navigationOrientation: .horizontal, options: [
.interPageSpacing: 50
])
modalPresentationStyle = .fullScreen
transitioningDelegate = self
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
public override func viewDidLoad() {
super.viewDidLoad()
dismissInteraction = GalleryDismissInteraction(viewController: self)
view.backgroundColor = .black
overrideUserInterfaceStyle = .dark
dataSource = self
delegate = self
setViewControllers([makeItemVC(index: initialItemIndex)], direction: .forward, animated: false)
}
public override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
if animated {
// Wait until the transition is no longer in-progress, otherwise things will just get deferred again.
DispatchQueue.main.async {
self.presentationAnimationCompleted()
}
}
}
public override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
if isBeingDismissed {
currentItemViewController.content.galleryContentWillDisappear()
}
}
private func makeItemVC(index: Int) -> GalleryItemViewController {
let content = galleryDataSource.galleryContentViewController(forItemAt: index)
return GalleryItemViewController(delegate: self, itemIndex: index, content: content)
}
func presentationAnimationCompleted() {
for block in presentationAnimationCompletionHandlers {
block()
}
currentItemViewController.content.galleryContentDidAppear()
}
}
extension GalleryViewController: UIPageViewControllerDataSource {
public func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
guard let viewController = viewController as? GalleryItemViewController else {
preconditionFailure("VC must be GalleryItemViewController")
}
guard viewController.itemIndex > 0 else {
return nil
}
return makeItemVC(index: viewController.itemIndex - 1)
}
public func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
guard let viewController = viewController as? GalleryItemViewController else {
preconditionFailure("VC must be GalleryItemViewController")
}
guard viewController.itemIndex < itemsCount - 1 else {
return nil
}
return makeItemVC(index: viewController.itemIndex + 1)
}
}
extension GalleryViewController: UIPageViewControllerDelegate {
public func pageViewController(_ pageViewController: UIPageViewController, willTransitionTo pendingViewControllers: [UIViewController]) {
currentItemViewController.content.galleryContentWillDisappear()
}
public func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
currentItemViewController.content.galleryContentDidAppear()
}
}
extension GalleryViewController: GalleryItemViewControllerDelegate {
func isGalleryBeingPresented() -> Bool {
isBeingPresented
}
func addPresentationAnimationCompletion(_ block: @escaping () -> Void) {
presentationAnimationCompletionHandlers.append(block)
}
func galleryItemClose(_ item: GalleryItemViewController) {
dismiss(animated: true)
}
func galleryItemApplicationActivities(_ item: GalleryItemViewController) -> [UIActivity]? {
galleryDataSource.galleryApplicationActivities(forItemAt: item.itemIndex)
}
}
extension GalleryViewController: UIViewControllerTransitioningDelegate {
public func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
if let sourceView = galleryDataSource.galleryContentTransitionSourceView(forItemAt: initialItemIndex) {
return GalleryPresentationAnimationController(sourceView: sourceView)
} else {
return nil
}
}
public func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
if let sourceView = galleryDataSource.galleryContentTransitionSourceView(forItemAt: currentItemViewController.itemIndex) {
let translation: CGPoint?
let velocity: CGPoint?
if let dismissInteraction,
dismissInteraction.isActive {
translation = dismissInteraction.dismissTranslation
velocity = dismissInteraction.dismissVelocity
} else {
translation = nil
velocity = nil
}
return GalleryDismissAnimationController(sourceView: sourceView, interactiveTranslation: translation, interactiveVelocity: velocity)
} else {
return nil
}
}
}