import Foundation
import UIKit
import Display
import AsyncDisplayKit
import SwiftSignalKit
import Postbox
import TelegramCore
import TelegramPresentationData
import MergeLists
import TelegramUIPreferences
import ItemListUI
import PresentationDataUtils
import WallpaperResources
import AccountContext
import AppBundle
import ContextUI
import AnimatedStickerNode
import TelegramAnimatedStickerNode
import ShimmerEffect
import StickerResources

private struct ThemeCarouselThemeEntry: Comparable, Identifiable {
    let index: Int
    let emojiFile: TelegramMediaFile?
    let themeReference: PresentationThemeReference
    let nightMode: Bool
    let themeSpecificAccentColors: [Int64: PresentationThemeAccentColor]
    let themeSpecificChatWallpapers: [Int64: TelegramWallpaper]
    var selected: Bool
    let theme: PresentationTheme
    let strings: PresentationStrings
    let wallpaper: TelegramWallpaper?
    
    var stableId: Int {
        return index
    }
    
    static func ==(lhs: ThemeCarouselThemeEntry, rhs: ThemeCarouselThemeEntry) -> Bool {
        if lhs.index != rhs.index {
            return false
        }
        if lhs.emojiFile?.fileId != rhs.emojiFile?.fileId {
            return false
        }
        if lhs.themeReference.index != rhs.themeReference.index {
            return false
        }
        if lhs.nightMode != rhs.nightMode {
            return false
        }
        if lhs.themeSpecificAccentColors != rhs.themeSpecificAccentColors {
            return false
        }
        if lhs.themeSpecificChatWallpapers != rhs.themeSpecificChatWallpapers {
            return false
        }
        if lhs.selected != rhs.selected {
            return false
        }
        if lhs.theme !== rhs.theme {
            return false
        }
        if lhs.strings !== rhs.strings {
            return false
        }
        if lhs.wallpaper != rhs.wallpaper {
            return false
        }
        return true
    }
    
    static func <(lhs: ThemeCarouselThemeEntry, rhs: ThemeCarouselThemeEntry) -> Bool {
        return lhs.index < rhs.index
    }
    
    func item(context: AccountContext, action: @escaping (PresentationThemeReference) -> Void, contextAction: ((PresentationThemeReference, ASDisplayNode, ContextGesture?) -> Void)?) -> ListViewItem {
        return ThemeCarouselThemeIconItem(context: context, emojiFile: self.emojiFile, themeReference: self.themeReference, nightMode: self.nightMode, themeSpecificAccentColors: self.themeSpecificAccentColors, themeSpecificChatWallpapers: self.themeSpecificChatWallpapers, selected: self.selected, theme: self.theme, strings: self.strings, wallpaper: self.wallpaper, action: action, contextAction: contextAction)
    }
}


class ThemeCarouselThemeIconItem: ListViewItem {
    let context: AccountContext
    let emojiFile: TelegramMediaFile?
    let themeReference: PresentationThemeReference
    let nightMode: Bool
    let themeSpecificAccentColors: [Int64: PresentationThemeAccentColor]
    let themeSpecificChatWallpapers: [Int64: TelegramWallpaper]
    let selected: Bool
    let theme: PresentationTheme
    let strings: PresentationStrings
    let wallpaper: TelegramWallpaper?
    let action: (PresentationThemeReference) -> Void
    let contextAction: ((PresentationThemeReference, ASDisplayNode, ContextGesture?) -> Void)?
    
    public init(context: AccountContext, emojiFile: TelegramMediaFile?, themeReference: PresentationThemeReference, nightMode: Bool, themeSpecificAccentColors: [Int64: PresentationThemeAccentColor], themeSpecificChatWallpapers: [Int64: TelegramWallpaper], selected: Bool, theme: PresentationTheme, strings: PresentationStrings, wallpaper: TelegramWallpaper?, action: @escaping (PresentationThemeReference) -> Void, contextAction: ((PresentationThemeReference, ASDisplayNode, ContextGesture?) -> Void)?) {
        self.context = context
        self.emojiFile = emojiFile
        self.themeReference = themeReference
        self.nightMode = nightMode
        self.themeSpecificAccentColors = themeSpecificAccentColors
        self.themeSpecificChatWallpapers = themeSpecificChatWallpapers
        self.selected = selected
        self.theme = theme
        self.strings = strings
        self.wallpaper = wallpaper
        self.action = action
        self.contextAction = contextAction
    }
    
    public func nodeConfiguredForParams(async: @escaping (@escaping () -> Void) -> Void, params: ListViewItemLayoutParams, synchronousLoads: Bool, previousItem: ListViewItem?, nextItem: ListViewItem?, completion: @escaping (ListViewItemNode, @escaping () -> (Signal<Void, NoError>?, (ListViewItemApply) -> Void)) -> Void) {
        async {
            let node = ThemeCarouselThemeItemIconNode()
            let (nodeLayout, apply) = node.asyncLayout()(self, params)
            node.insets = nodeLayout.insets
            node.contentSize = nodeLayout.contentSize
            
            Queue.mainQueue().async {
                completion(node, {
                    return (nil, { _ in
                        apply(false)
                    })
                })
            }
        }
    }
    
    public func updateNode(async: @escaping (@escaping () -> Void) -> Void, node: @escaping () -> ListViewItemNode, params: ListViewItemLayoutParams, previousItem: ListViewItem?, nextItem: ListViewItem?, animation: ListViewItemUpdateAnimation, completion: @escaping (ListViewItemNodeLayout, @escaping (ListViewItemApply) -> Void) -> Void) {
        Queue.mainQueue().async {
            assert(node() is ThemeCarouselThemeItemIconNode)
            if let nodeValue = node() as? ThemeCarouselThemeItemIconNode {
                let layout = nodeValue.asyncLayout()
                async {
                    let (nodeLayout, apply) = layout(self, params)
                    Queue.mainQueue().async {
                        completion(nodeLayout, { _ in
                            apply(animation.isAnimated)
                        })
                    }
                }
            }
        }
    }
    
    public var selectable = true
    public func selected(listView: ListView) {
        self.action(self.themeReference)
    }
}


private let textFont = Font.regular(12.0)
private let selectedTextFont = Font.bold(12.0)

private var cachedBorderImages: [String: UIImage] = [:]
private func generateBorderImage(theme: PresentationTheme, bordered: Bool, selected: Bool) -> UIImage? {
    let key = "\(theme.list.itemBlocksBackgroundColor.hexString)_\(selected ? "s" + theme.list.itemAccentColor.hexString : theme.list.disclosureArrowColor.hexString)"
    if let image = cachedBorderImages[key] {
        return image
    } else {
        let image = generateImage(CGSize(width: 18.0, height: 18.0), rotatedContext: { size, context in
            let bounds = CGRect(origin: CGPoint(), size: size)
            context.clear(bounds)

            let lineWidth: CGFloat
            if selected {
                lineWidth = 2.0
                context.setLineWidth(lineWidth)
                context.setStrokeColor(theme.list.itemBlocksBackgroundColor.cgColor)
                
                context.strokeEllipse(in: bounds.insetBy(dx: 3.0 + lineWidth / 2.0, dy: 3.0 + lineWidth / 2.0))
                
                var accentColor = theme.list.itemAccentColor
                if accentColor.rgb == 0xffffff {
                    accentColor = UIColor(rgb: 0x999999)
                }
                context.setStrokeColor(accentColor.cgColor)
            } else {
                context.setStrokeColor(theme.list.disclosureArrowColor.withAlphaComponent(0.4).cgColor)
                lineWidth = 1.0
            }

            if bordered || selected {
                context.setLineWidth(lineWidth)
                context.strokeEllipse(in: bounds.insetBy(dx: 1.0 + lineWidth / 2.0, dy: 1.0 + lineWidth / 2.0))
            }
        })?.stretchableImage(withLeftCapWidth: 9, topCapHeight: 9)
        cachedBorderImages[key] = image
        return image
    }
}


private final class ThemeCarouselThemeItemIconNode : ListViewItemNode {
    private let containerNode: ASDisplayNode
    private let emojiContainerNode: ASDisplayNode
    private let imageNode: TransformImageNode
    private let overlayNode: ASImageNode
    private let textNode: TextNode
    private let emojiNode: TextNode
    private let emojiImageNode: TransformImageNode
    private var animatedStickerNode: AnimatedStickerNode?
    private var placeholderNode: StickerShimmerEffectNode
    var snapshotView: UIView?
    
    var item: ThemeCarouselThemeIconItem?
    
    override var visibility: ListViewItemNodeVisibility {
        didSet {
            self.visibilityStatus = self.visibility != .none
        }
    }
    
    private var visibilityStatus: Bool = false {
        didSet {
            if self.visibilityStatus != oldValue {
                self.animatedStickerNode?.visibility = self.visibilityStatus
            }
        }
    }
    
    private let stickerFetchedDisposable = MetaDisposable()

    init() {
        self.containerNode = ASDisplayNode()
        self.emojiContainerNode = ASDisplayNode()

        self.imageNode = TransformImageNode()
        self.imageNode.frame = CGRect(origin: CGPoint(), size: CGSize(width: 82.0, height: 108.0))
        self.imageNode.isLayerBacked = true
        self.imageNode.cornerRadius = 8.0
        self.imageNode.clipsToBounds = true
        
        self.overlayNode = ASImageNode()
        self.overlayNode.frame = CGRect(origin: CGPoint(), size: CGSize(width: 84.0, height: 110.0))
        self.overlayNode.isLayerBacked = true

        self.textNode = TextNode()
        self.textNode.isUserInteractionEnabled = false
        self.textNode.displaysAsynchronously = false
        
        self.emojiNode = TextNode()
        self.emojiNode.isUserInteractionEnabled = false
        self.emojiNode.displaysAsynchronously = false
        
        self.emojiImageNode = TransformImageNode()
        
        self.placeholderNode = StickerShimmerEffectNode()

        super.init(layerBacked: false, dynamicBounce: false, rotated: false, seeThrough: false)
        
        self.addSubnode(self.containerNode)
        self.containerNode.addSubnode(self.imageNode)
        self.containerNode.addSubnode(self.overlayNode)
        self.containerNode.addSubnode(self.textNode)
        
        self.addSubnode(self.emojiContainerNode)
        self.emojiContainerNode.addSubnode(self.emojiNode)
        self.emojiContainerNode.addSubnode(self.emojiImageNode)
        self.emojiContainerNode.addSubnode(self.placeholderNode)
        
        var firstTime = true
        self.emojiImageNode.imageUpdated = { [weak self] image in
            guard let strongSelf = self else {
                return
            }
            if image != nil {
                strongSelf.removePlaceholder(animated: !firstTime)
                if firstTime {
                    strongSelf.emojiImageNode.layer.animateAlpha(from: 0.0, to: 1.0, duration: 0.2)
                }
            }
            firstTime = false
        }
    }

    deinit {
        self.stickerFetchedDisposable.dispose()
    }
    
    private func removePlaceholder(animated: Bool) {
        if !animated {
            self.placeholderNode.removeFromSupernode()
        } else {
            self.placeholderNode.alpha = 0.0
            self.placeholderNode.layer.animateAlpha(from: 1.0, to: 0.0, duration: 0.2, completion: { [weak self] _ in
                self?.placeholderNode.removeFromSupernode()
            })
        }
    }
    
    override func updateAbsoluteRect(_ rect: CGRect, within containerSize: CGSize) {
        let emojiFrame = CGRect(origin: CGPoint(x: 33.0, y: 79.0), size: CGSize(width: 24.0, height: 24.0))
        self.placeholderNode.updateAbsoluteRect(CGRect(origin: CGPoint(x: rect.minX + emojiFrame.minX, y: rect.minY + emojiFrame.minY), size: emojiFrame.size), within: containerSize)
    }
    
    override func selected() {
        let wasSelected = self.item?.selected ?? false
        super.selected()
        
        if let animatedStickerNode = self.animatedStickerNode {
            Queue.mainQueue().after(0.1) {
                if !wasSelected {
                    animatedStickerNode.seekTo(.frameIndex(0))
                    animatedStickerNode.play(firstFrame: false, fromIndex: nil)
                    
                    let scale: CGFloat = 2.6
                    animatedStickerNode.transform = CATransform3DMakeScale(scale, scale, 1.0)
                    animatedStickerNode.layer.animateSpring(from: 1.0 as NSNumber, to: scale as NSNumber, keyPath: "transform.scale", duration: 0.45)
                    
                    animatedStickerNode.completed = { [weak animatedStickerNode, weak self] _ in
                        guard let item = self?.item, item.selected else {
                            return
                        }
                        animatedStickerNode?.transform = CATransform3DIdentity
                        animatedStickerNode?.layer.animateSpring(from: scale as NSNumber, to: 1.0 as NSNumber, keyPath: "transform.scale", duration: 0.45)
                    }
                }
            }
        }
        
    }
    
    func asyncLayout() -> (ThemeCarouselThemeIconItem, ListViewItemLayoutParams) -> (ListViewItemNodeLayout, (Bool) -> Void) {
        let makeEmojiLayout = TextNode.asyncLayout(self.emojiNode)
        let makeImageLayout = self.imageNode.asyncLayout()
        
        let currentItem = self.item

        return { [weak self] item, params in
            var updatedThemeReference = false
            var updatedTheme = false
            var updatedNightMode = false
            var updatedWallpaper = false
            var updatedSelected = false
            
            if currentItem?.themeReference != item.themeReference {
                updatedThemeReference = true
            }
            if currentItem?.nightMode != item.nightMode {
                updatedNightMode = true
            }
            if currentItem?.wallpaper != item.wallpaper {
                updatedWallpaper = true
            }
            if currentItem?.theme !== item.theme {
                updatedTheme = true
            }
            if currentItem?.selected != item.selected {
                updatedSelected = true
            }
            

            var string: String?
            if let _ = item.themeReference.emoticon {
            } else {
                string = "🎨"
            }
            
            let emojiTitle = NSAttributedString(string: string ?? "", font: Font.regular(20.0), textColor: .black)
            let (_, emojiApply) = makeEmojiLayout(TextNodeLayoutArguments(attributedString: emojiTitle, backgroundColor: nil, maximumNumberOfLines: 1, truncationType: .end, constrainedSize: CGSize(width: params.width, height: CGFloat.greatestFiniteMagnitude), alignment: .center, cutout: nil, insets: UIEdgeInsets()))
            
            let itemLayout = ListViewItemNodeLayout(contentSize: CGSize(width: 120.0, height: 90.0), insets: UIEdgeInsets())
            return (itemLayout, { animated in
                if let strongSelf = self {
                    strongSelf.item = item
                        
                    if updatedThemeReference || updatedWallpaper || updatedNightMode {
                        var themeReference = item.themeReference
                        if case .builtin = themeReference, item.nightMode {
                            themeReference = .builtin(.night)
                        }
                        
                        let color = item.themeSpecificAccentColors[themeReference.index]
                        let wallpaper = item.themeSpecificChatWallpapers[themeReference.index]
                        
                        strongSelf.imageNode.setSignal(themeIconImage(account: item.context.account, accountManager: item.context.sharedContext.accountManager, theme: themeReference, color: color, wallpaper: wallpaper ?? item.wallpaper, nightMode: item.nightMode, emoticon: true))
                        strongSelf.imageNode.backgroundColor = nil
                    }
                    
                    if updatedTheme || updatedSelected {
                        strongSelf.overlayNode.image = generateBorderImage(theme: item.theme, bordered: false, selected: item.selected)
                    }
                    
                    if !item.selected && currentItem?.selected == true, let animatedStickerNode = strongSelf.animatedStickerNode {
                        animatedStickerNode.transform = CATransform3DIdentity
                        
                        let initialScale: CGFloat = CGFloat((animatedStickerNode.value(forKeyPath: "layer.presentationLayer.transform.scale.x") as? NSNumber)?.floatValue ?? 1.0)
                        animatedStickerNode.layer.animateSpring(from: initialScale as NSNumber, to: 1.0 as NSNumber, keyPath: "transform.scale", duration: 0.45)
                    }
                                        
                    strongSelf.containerNode.transform = CATransform3DMakeRotation(CGFloat.pi / 2.0, 0.0, 0.0, 1.0)
                    strongSelf.containerNode.frame = CGRect(origin: CGPoint(x: 15.0, y: -15.0), size: CGSize(width: 90.0, height: 120.0))
                    
                    strongSelf.emojiContainerNode.transform = CATransform3DMakeRotation(CGFloat.pi / 2.0, 0.0, 0.0, 1.0)
                    strongSelf.emojiContainerNode.frame = CGRect(origin: CGPoint(x: 15.0, y: -15.0), size: CGSize(width: 90.0, height: 120.0))
                    
                    let _ = emojiApply()

                    let imageSize = CGSize(width: 82.0, height: 108.0)
                    strongSelf.imageNode.frame = CGRect(origin: CGPoint(x: 4.0, y: 6.0), size: imageSize)
                    let applyLayout = makeImageLayout(TransformImageArguments(corners: ImageCorners(), imageSize: imageSize, boundingSize: imageSize, intrinsicInsets: UIEdgeInsets(), emptyColor: .clear))
                    applyLayout()
                    
                    strongSelf.overlayNode.frame = strongSelf.imageNode.frame.insetBy(dx: -1.0, dy: -1.0)
                    strongSelf.emojiNode.frame = CGRect(origin: CGPoint(x: 0.0, y: 78.0), size: CGSize(width: 90.0, height: 30.0))
                    strongSelf.emojiNode.isHidden = string == nil
                    
                    let emojiFrame = CGRect(origin: CGPoint(x: 33.0, y: 79.0), size: CGSize(width: 24.0, height: 24.0))
                    if let file = item.emojiFile, currentItem?.emojiFile == nil {
                        let imageApply = strongSelf.emojiImageNode.asyncLayout()(TransformImageArguments(corners: ImageCorners(), imageSize: emojiFrame.size, boundingSize: emojiFrame.size, intrinsicInsets: UIEdgeInsets()))
                        imageApply()
                        strongSelf.emojiImageNode.setSignal(chatMessageStickerPackThumbnail(postbox: item.context.account.postbox, resource: file.resource, animated: true, nilIfEmpty: true))
                        strongSelf.emojiImageNode.frame = emojiFrame
                        
                        let animatedStickerNode: AnimatedStickerNode
                        if let current = strongSelf.animatedStickerNode {
                            animatedStickerNode = current
                        } else {
                            animatedStickerNode = DefaultAnimatedStickerNodeImpl()
                            animatedStickerNode.started = { [weak self] in
                                self?.emojiImageNode.isHidden = true
                            }
                            strongSelf.animatedStickerNode = animatedStickerNode
                            strongSelf.emojiContainerNode.insertSubnode(animatedStickerNode, belowSubnode: strongSelf.placeholderNode)
                            let pathPrefix = item.context.account.postbox.mediaBox.shortLivedResourceCachePathPrefix(file.resource.id)
                            animatedStickerNode.setup(source: AnimatedStickerResourceSource(account: item.context.account, resource: file.resource), width: 128, height: 128, playbackMode: .still(.start), mode: .direct(cachePathPrefix: pathPrefix))
                            
                            animatedStickerNode.anchorPoint = CGPoint(x: 0.5, y: 1.0)
                        }
                        animatedStickerNode.autoplay = true
                        animatedStickerNode.visibility = strongSelf.visibilityStatus
                        
                        strongSelf.stickerFetchedDisposable.set(fetchedMediaResource(mediaBox: item.context.account.postbox.mediaBox, reference: MediaResourceReference.media(media: .standalone(media: file), resource: file.resource)).start())
                        
                        let thumbnailDimensions = PixelDimensions(width: 512, height: 512)
                        strongSelf.placeholderNode.update(backgroundColor: nil, foregroundColor: UIColor(rgb: 0xffffff, alpha: 0.2), shimmeringColor: UIColor(rgb: 0xffffff, alpha: 0.3), data: file.immediateThumbnailData, size: emojiFrame.size, imageSize: thumbnailDimensions.cgSize)
                        strongSelf.placeholderNode.frame = emojiFrame
                    }
                    
                    if let animatedStickerNode = strongSelf.animatedStickerNode {
                        animatedStickerNode.frame = emojiFrame
                        animatedStickerNode.updateLayout(size: emojiFrame.size)
                    }
                }
            })
        }
    }
    
    func prepareCrossfadeTransition() {
        guard self.snapshotView == nil else {
            return
        }
        
        if let snapshotView = self.containerNode.view.snapshotView(afterScreenUpdates: false) {
            snapshotView.transform = self.containerNode.view.transform
            snapshotView.frame = self.containerNode.view.frame
            self.view.insertSubview(snapshotView, aboveSubview: self.containerNode.view)
            self.snapshotView = snapshotView
        }
    }
    
    func animateCrossfadeTransition() {
        guard self.snapshotView?.layer.animationKeys()?.isEmpty ?? true else {
            return
        }
        
        self.snapshotView?.layer.animateAlpha(from: 1.0, to: 0.0, duration: 0.3, removeOnCompletion: false, completion: { [weak self] _ in
            self?.snapshotView?.removeFromSuperview()
            self?.snapshotView = nil
        })
    }
        
    override func animateInsertion(_ currentTimestamp: Double, duration: Double, short: Bool) {
        super.animateInsertion(currentTimestamp, duration: duration, short: short)
        
        self.layer.animateAlpha(from: 0.0, to: 1.0, duration: 0.2)
    }
    
    override func animateRemoved(_ currentTimestamp: Double, duration: Double) {
        super.animateRemoved(currentTimestamp, duration: duration)
        
        self.layer.animateAlpha(from: 1.0, to: 0.0, duration: 0.2, removeOnCompletion: false)
    }
    
    override func animateAdded(_ currentTimestamp: Double, duration: Double) {
        super.animateAdded(currentTimestamp, duration: duration)
        
        self.layer.animateAlpha(from: 0.0, to: 1.0, duration: 0.2)
    }
}

class ThemeCarouselThemeItem: ListViewItem, ItemListItem {
    var sectionId: ItemListSectionId

    let context: AccountContext
    let theme: PresentationTheme
    let strings: PresentationStrings
    let themes: [PresentationThemeReference]
    let animatedEmojiStickers: [String: [StickerPackItem]]
    let themeSpecificAccentColors: [Int64: PresentationThemeAccentColor]
    let themeSpecificChatWallpapers: [Int64: TelegramWallpaper]
    let nightMode: Bool
    let currentTheme: PresentationThemeReference
    let updatedTheme: (PresentationThemeReference) -> Void
    let contextAction: ((PresentationThemeReference, ASDisplayNode, ContextGesture?) -> Void)?
    let tag: ItemListItemTag?

    init(context: AccountContext, theme: PresentationTheme, strings: PresentationStrings, sectionId: ItemListSectionId, themes: [PresentationThemeReference], animatedEmojiStickers: [String: [StickerPackItem]], themeSpecificAccentColors: [Int64: PresentationThemeAccentColor], themeSpecificChatWallpapers: [Int64: TelegramWallpaper], nightMode: Bool, currentTheme: PresentationThemeReference, updatedTheme: @escaping (PresentationThemeReference) -> Void, contextAction: ((PresentationThemeReference, ASDisplayNode, ContextGesture?) -> Void)?, tag: ItemListItemTag? = nil) {
        self.context = context
        self.theme = theme
        self.strings = strings
        self.themes = themes
        self.animatedEmojiStickers = animatedEmojiStickers
        self.themeSpecificAccentColors = themeSpecificAccentColors
        self.themeSpecificChatWallpapers = themeSpecificChatWallpapers
        self.nightMode = nightMode
        self.currentTheme = currentTheme
        self.updatedTheme = updatedTheme
        self.contextAction = contextAction
        self.tag = tag
        self.sectionId = sectionId
    }

    func nodeConfiguredForParams(async: @escaping (@escaping () -> Void) -> Void, params: ListViewItemLayoutParams, synchronousLoads: Bool, previousItem: ListViewItem?, nextItem: ListViewItem?, completion: @escaping (ListViewItemNode, @escaping () -> (Signal<Void, NoError>?, (ListViewItemApply) -> Void)) -> Void) {
        async {
            let node = ThemeCarouselThemeItemNode()
            let (layout, apply) = node.asyncLayout()(self, params, itemListNeighbors(item: self, topItem: previousItem as? ItemListItem, bottomItem: nextItem as? ItemListItem))

            node.contentSize = layout.contentSize
            node.insets = layout.insets

            Queue.mainQueue().async {
                completion(node, {
                    return (nil, { _ in apply() })
                })
            }
        }
    }

    func updateNode(async: @escaping (@escaping () -> Void) -> Void, node: @escaping () -> ListViewItemNode, params: ListViewItemLayoutParams, previousItem: ListViewItem?, nextItem: ListViewItem?, animation: ListViewItemUpdateAnimation, completion: @escaping (ListViewItemNodeLayout, @escaping (ListViewItemApply) -> Void) -> Void) {
        Queue.mainQueue().async {
            if let nodeValue = node() as? ThemeCarouselThemeItemNode {
                let makeLayout = nodeValue.asyncLayout()

                async {
                    let (layout, apply) = makeLayout(self, params, itemListNeighbors(item: self, topItem: previousItem as? ItemListItem, bottomItem: nextItem as? ItemListItem))
                    Queue.mainQueue().async {
                        completion(layout, { _ in
                            apply()
                        })
                    }
                }
            }
        }
    }
}

private struct ThemeCarouselThemeItemNodeTransition {
    let deletions: [ListViewDeleteItem]
    let insertions: [ListViewInsertItem]
    let updates: [ListViewUpdateItem]
    let crossfade: Bool
    let entries: [ThemeCarouselThemeEntry]
    let updatePosition: Bool
}

private func preparedTransition(context: AccountContext, action: @escaping (PresentationThemeReference) -> Void, contextAction: ((PresentationThemeReference, ASDisplayNode, ContextGesture?) -> Void)?, from fromEntries: [ThemeCarouselThemeEntry], to toEntries: [ThemeCarouselThemeEntry], crossfade: Bool, updatePosition: Bool) -> ThemeCarouselThemeItemNodeTransition {
    let (deleteIndices, indicesAndItems, updateIndices) = mergeListsStableWithUpdates(leftList: fromEntries, rightList: toEntries)
    
    let deletions = deleteIndices.map { ListViewDeleteItem(index: $0, directionHint: nil) }
    let insertions = indicesAndItems.map { ListViewInsertItem(index: $0.0, previousIndex: $0.2, item: $0.1.item(context: context, action: action, contextAction: contextAction), directionHint: .Down) }
    let updates = updateIndices.map { ListViewUpdateItem(index: $0.0, previousIndex: $0.2, item: $0.1.item(context: context, action: action, contextAction: contextAction), directionHint: nil) }
    
    return ThemeCarouselThemeItemNodeTransition(deletions: deletions, insertions: insertions, updates: updates, crossfade: crossfade, entries: toEntries, updatePosition: false)
}

private func ensureThemeVisible(listNode: ListView, themeReference: PresentationThemeReference, animated: Bool) -> Bool {
    var resultNode: ThemeCarouselThemeItemIconNode?
    listNode.forEachItemNode { node in
        if resultNode == nil, let node = node as? ThemeCarouselThemeItemIconNode {
            if node.item?.themeReference.index == themeReference.index {
                resultNode = node
            }
        }
    }
    if let resultNode = resultNode {
        listNode.ensureItemNodeVisible(resultNode, animated: animated, overflow: 57.0)
        return true
    } else {
        return false
    }
}

class ThemeCarouselThemeItemNode: ListViewItemNode, ItemListItemNode {
    private let containerNode: ASDisplayNode
    private let backgroundNode: ASDisplayNode
    private let topStripeNode: ASDisplayNode
    private let bottomStripeNode: ASDisplayNode
    private let maskNode: ASImageNode
    private var snapshotView: UIView?
    
    private let listNode: ListView
    private var entries: [ThemeCarouselThemeEntry]?
    private var enqueuedTransitions: [ThemeCarouselThemeItemNodeTransition] = []
    private var initialized = false

    private var item: ThemeCarouselThemeItem?
    private var layoutParams: ListViewItemLayoutParams?

    private var tapping = false
    
    var tag: ItemListItemTag? {
        return self.item?.tag
    }

    init() {
        self.containerNode = ASDisplayNode()
        
        self.backgroundNode = ASDisplayNode()
        self.backgroundNode.isLayerBacked = true

        self.topStripeNode = ASDisplayNode()
        self.topStripeNode.isLayerBacked = true

        self.bottomStripeNode = ASDisplayNode()
        self.bottomStripeNode.isLayerBacked = true

        self.maskNode = ASImageNode()

        self.listNode = ListView()
        self.listNode.transform = CATransform3DMakeRotation(-CGFloat.pi / 2.0, 0.0, 0.0, 1.0)

        super.init(layerBacked: false, dynamicBounce: false)

        self.addSubnode(self.containerNode)
        self.addSubnode(self.listNode)
    }

    override func didLoad() {
        super.didLoad()
        self.listNode.view.disablesInteractiveTransitionGestureRecognizer = true
    }
    
    private func enqueueTransition(_ transition: ThemeCarouselThemeItemNodeTransition) {
        self.enqueuedTransitions.append(transition)
        
        if let _ = self.item {
            while !self.enqueuedTransitions.isEmpty {
                self.dequeueTransition()
            }
        }
    }
    
    private func dequeueTransition() {
        guard let item = self.item, let transition = self.enqueuedTransitions.first else {
            return
        }
        self.enqueuedTransitions.remove(at: 0)
        
        var options = ListViewDeleteAndInsertOptions()
        if transition.crossfade {
            options.insert(.AnimateCrossfade)
        }
        options.insert(.Synchronous)
        
        var scrollToItem: ListViewScrollToItem?
        if !self.initialized || !self.tapping {
            if let index = transition.entries.firstIndex(where: { entry in
                return entry.themeReference.index == item.currentTheme.index
            }) {
                scrollToItem = ListViewScrollToItem(index: index, position: .bottom(-57.0), animated: false, curve: .Default(duration: 0.0), directionHint: .Down)
                self.initialized = true
            }
        }
        
        self.listNode.transaction(deleteIndices: transition.deletions, insertIndicesAndItems: transition.insertions, updateIndicesAndItems: transition.updates, options: options, scrollToItem: scrollToItem, updateSizeAndInsets: nil, updateOpaqueState: nil, completion: { _ in
        })
    }

    func asyncLayout() -> (_ item: ThemeCarouselThemeItem, _ params: ListViewItemLayoutParams, _ neighbors: ItemListNeighbors) -> (ListViewItemNodeLayout, () -> Void) {
        return { item, params, neighbors in
            let contentSize: CGSize
            let insets: UIEdgeInsets
            let separatorHeight = UIScreenPixel

            contentSize = CGSize(width: params.width, height: 133.0)
            insets = itemListNeighborsGroupedInsets(neighbors, params)

            let layout = ListViewItemNodeLayout(contentSize: contentSize, insets: insets)
            let layoutSize = layout.size

            return (layout, { [weak self] in
                if let strongSelf = self {
                    strongSelf.item = item
                    strongSelf.layoutParams = params

                    strongSelf.listNode.backgroundColor = item.theme.list.itemBlocksBackgroundColor
                    strongSelf.backgroundNode.backgroundColor = item.theme.list.itemBlocksBackgroundColor
                    strongSelf.topStripeNode.backgroundColor = item.theme.list.itemBlocksSeparatorColor
                    strongSelf.bottomStripeNode.backgroundColor = item.theme.list.itemBlocksSeparatorColor

                    if strongSelf.backgroundNode.supernode == nil {
                        strongSelf.containerNode.insertSubnode(strongSelf.backgroundNode, at: 0)
                    }
                    if strongSelf.topStripeNode.supernode == nil {
                        strongSelf.containerNode.insertSubnode(strongSelf.topStripeNode, at: 1)
                    }
                    if strongSelf.bottomStripeNode.supernode == nil {
                        strongSelf.containerNode.insertSubnode(strongSelf.bottomStripeNode, at: 2)
                    }
                    if strongSelf.maskNode.supernode == nil {
                        strongSelf.containerNode.insertSubnode(strongSelf.maskNode, at: 3)
                    }

                    let hasCorners = itemListHasRoundedBlockLayout(params)
                    var hasTopCorners = false
                    var hasBottomCorners = false
                    switch neighbors.top {
                        case .sameSection(false):
                            strongSelf.topStripeNode.isHidden = true
                        default:
                            hasTopCorners = true
                            strongSelf.topStripeNode.isHidden = hasCorners
                    }
                    let bottomStripeInset: CGFloat
                    let bottomStripeOffset: CGFloat
                    switch neighbors.bottom {
                        case .sameSection(false):
                            bottomStripeInset = params.leftInset + 16.0
                            bottomStripeOffset = -separatorHeight
                            strongSelf.bottomStripeNode.isHidden = false
                        default:
                            bottomStripeInset = 0.0
                            bottomStripeOffset = 0.0
                            hasBottomCorners = true
                            strongSelf.bottomStripeNode.isHidden = hasCorners
                    }
                    
                    strongSelf.bottomStripeNode.isHidden = true

                    strongSelf.containerNode.frame = CGRect(x: 0.0, y: 0.0, width: contentSize.width, height: contentSize.height)
                    strongSelf.maskNode.image = hasCorners ? PresentationResourcesItemList.cornersImage(item.theme, top: hasTopCorners, bottom: hasBottomCorners) : nil

                    strongSelf.backgroundNode.frame = CGRect(origin: CGPoint(x: 0.0, y: -min(insets.top, separatorHeight)), size: CGSize(width: params.width, height: contentSize.height + min(insets.top, separatorHeight) + min(insets.bottom, separatorHeight)))
                    strongSelf.maskNode.frame = strongSelf.backgroundNode.frame.insetBy(dx: params.leftInset, dy: 0.0)
                    strongSelf.topStripeNode.frame = CGRect(origin: CGPoint(x: 0.0, y: -min(insets.top, separatorHeight)), size: CGSize(width: layoutSize.width, height: separatorHeight))
                    strongSelf.bottomStripeNode.frame = CGRect(origin: CGPoint(x: bottomStripeInset, y: contentSize.height + bottomStripeOffset), size: CGSize(width: layoutSize.width - bottomStripeInset, height: separatorHeight))

                    var listInsets = UIEdgeInsets()
                    listInsets.top += params.leftInset + 12.0
                    listInsets.bottom += params.rightInset + 12.0
                    
                    strongSelf.listNode.bounds = CGRect(x: 0.0, y: 0.0, width: contentSize.height, height: contentSize.width)
                    strongSelf.listNode.position = CGPoint(x: contentSize.width / 2.0, y: contentSize.height / 2.0 - 2.0)
                    strongSelf.listNode.transaction(deleteIndices: [], insertIndicesAndItems: [], updateIndicesAndItems: [], options: [.Synchronous], scrollToItem: nil, updateSizeAndInsets: ListViewUpdateSizeAndInsets(size: CGSize(width: contentSize.height, height: contentSize.width), insets: listInsets, duration: 0.0, curve: .Default(duration: nil)), stationaryItemRange: nil, updateOpaqueState: nil, completion: { _ in })
                    
                    var entries: [ThemeCarouselThemeEntry] = []
                    var index: Int = 0
                    
                    var hasCurrentTheme = false
                    for theme in item.themes {
                        let selected = item.currentTheme.index == theme.index
                        if selected {
                            hasCurrentTheme = true
                        }
                        let emojiFile = theme.emoticon.flatMap { item.animatedEmojiStickers[$0]?.first?.file }
                        entries.append(ThemeCarouselThemeEntry(index: index, emojiFile: emojiFile, themeReference: theme, nightMode: item.nightMode, themeSpecificAccentColors: item.themeSpecificAccentColors, themeSpecificChatWallpapers: item.themeSpecificChatWallpapers, selected: selected, theme: item.theme, strings: item.strings, wallpaper: nil))
                        index += 1
                    }
                    
                    if !hasCurrentTheme {
                        entries.append(ThemeCarouselThemeEntry(index: index, emojiFile: nil, themeReference: item.currentTheme, nightMode: false, themeSpecificAccentColors: item.themeSpecificAccentColors, themeSpecificChatWallpapers: item.themeSpecificChatWallpapers, selected: true, theme: item.theme, strings: item.strings, wallpaper: nil))
                    }
                    
                    let action: (PresentationThemeReference) -> Void = { [weak self] themeReference in
                        if let strongSelf = self {
                            strongSelf.tapping = true
                            strongSelf.item?.updatedTheme(themeReference)
                            let _ = ensureThemeVisible(listNode: strongSelf.listNode, themeReference: themeReference, animated: true)
                            Queue.mainQueue().after(0.4) {
                                strongSelf.tapping = false
                            }
                        }
                    }
                    let previousEntries = strongSelf.entries ?? []
                    let crossfade = (previousEntries.count > 0 && previousEntries.count != entries.count) || (previousEntries.count > 0 && previousEntries.count < 3 && entries.count > 3)
                    let transition = preparedTransition(context: item.context, action: action, contextAction: item.contextAction, from: previousEntries, to: entries, crossfade: crossfade, updatePosition: false)
                    strongSelf.enqueueTransition(transition)
                    
                    strongSelf.entries = entries
                }
            })
        }
    }
    
    override func animateInsertion(_ currentTimestamp: Double, duration: Double, short: Bool) {
        self.layer.animateAlpha(from: 0.0, to: 1.0, duration: 0.4)
    }

    override func animateRemoved(_ currentTimestamp: Double, duration: Double) {
        self.layer.animateAlpha(from: 1.0, to: 0.0, duration: 0.15, removeOnCompletion: false)
    }
    
    func prepareCrossfadeTransition() {
        guard self.snapshotView == nil else {
            return
        }
        
        if let snapshotView = self.containerNode.view.snapshotView(afterScreenUpdates: false) {
            self.view.insertSubview(snapshotView, aboveSubview: self.containerNode.view)
            self.snapshotView = snapshotView
        }
        
        self.listNode.forEachVisibleItemNode { node in
            if let node = node as? ThemeCarouselThemeItemIconNode {
                node.prepareCrossfadeTransition()
            }
        }
    }
    
    func animateCrossfadeTransition() {
        guard self.snapshotView?.layer.animationKeys()?.isEmpty ?? true else {
            return
        }
        
        var views: [UIView] = []
        if let snapshotView = self.snapshotView {
            views.append(snapshotView)
            self.snapshotView = nil
        }
        
        self.listNode.forEachVisibleItemNode { node in
            if let node = node as? ThemeCarouselThemeItemIconNode {
                if let snapshotView = node.snapshotView {
                    views.append(snapshotView)
                    node.snapshotView = nil
                }
            }
        }
        
        UIView.animate(withDuration: 0.3, animations: {
            for view in views {
                view.alpha = 0.0
            }
        }, completion: { _ in
            for view in views {
                view.removeFromSuperview()
            }
        })
    }
}