import Foundation
import UIKit
import AsyncDisplayKit
import Display
import TelegramPresentationData
import AccountContext
import AnimationCache
import MultiAnimationRenderer
import TelegramCore

final class ShimmerEffectNode: ASDisplayNode {
    private var currentBackgroundColor: UIColor?
    private var currentForegroundColor: UIColor?
    private let imageNodeContainer: ASDisplayNode
    private let imageNode: ASImageNode
    
    private var absoluteLocation: (CGRect, CGSize)?
    private var isCurrentlyInHierarchy = false
    private var shouldBeAnimating = false
    
    override init() {
        self.imageNodeContainer = ASDisplayNode()
        self.imageNodeContainer.isLayerBacked = true
        
        self.imageNode = ASImageNode()
        self.imageNode.isLayerBacked = true
        self.imageNode.displaysAsynchronously = false
        self.imageNode.displayWithoutProcessing = true
        self.imageNode.contentMode = .scaleToFill
        
        super.init()
        
        self.isLayerBacked = true
        self.clipsToBounds = true
        
        self.imageNodeContainer.addSubnode(self.imageNode)
        self.addSubnode(self.imageNodeContainer)
    }
    
    override func didEnterHierarchy() {
        super.didEnterHierarchy()
        
        self.isCurrentlyInHierarchy = true
        self.updateAnimation()
    }
    
    override func didExitHierarchy() {
        super.didExitHierarchy()
        
        self.isCurrentlyInHierarchy = false
        self.updateAnimation()
    }
    
    func update(backgroundColor: UIColor, foregroundColor: UIColor) {
        if let currentBackgroundColor = self.currentBackgroundColor, currentBackgroundColor.isEqual(backgroundColor), let currentForegroundColor = self.currentForegroundColor, currentForegroundColor.isEqual(foregroundColor) {
            return
        }
        self.currentBackgroundColor = backgroundColor
        self.currentForegroundColor = foregroundColor
        
        self.imageNode.image = generateImage(CGSize(width: 4.0, height: 320.0), opaque: true, scale: 1.0, rotatedContext: { size, context in
            context.setFillColor(backgroundColor.cgColor)
            context.fill(CGRect(origin: CGPoint(), size: size))
            
            context.clip(to: CGRect(origin: CGPoint(), size: size))
            
            let transparentColor = foregroundColor.withAlphaComponent(0.0).cgColor
            let peakColor = foregroundColor.cgColor
            
            var locations: [CGFloat] = [0.0, 0.5, 1.0]
            let colors: [CGColor] = [transparentColor, peakColor, transparentColor]
            
            let colorSpace = CGColorSpaceCreateDeviceRGB()
            let gradient = CGGradient(colorsSpace: colorSpace, colors: colors as CFArray, locations: &locations)!
            
            context.drawLinearGradient(gradient, start: CGPoint(x: 0.0, y: 0.0), end: CGPoint(x: 0.0, y: size.height), options: CGGradientDrawingOptions())
        })
    }
    
    func updateAbsoluteRect(_ rect: CGRect, within containerSize: CGSize) {
        if let absoluteLocation = self.absoluteLocation, absoluteLocation.0 == rect && absoluteLocation.1 == containerSize {
            return
        }
        let sizeUpdated = self.absoluteLocation?.1 != containerSize
        let frameUpdated = self.absoluteLocation?.0 != rect
        self.absoluteLocation = (rect, containerSize)
        
        if sizeUpdated {
            if self.shouldBeAnimating {
                self.imageNode.layer.removeAnimation(forKey: "shimmer")
                self.addImageAnimation()
            }
        }
        
        if frameUpdated {
            self.imageNodeContainer.frame = CGRect(origin: CGPoint(x: -rect.minX, y: -rect.minY), size: containerSize)
        }
        
        self.updateAnimation()
    }
    
    private func updateAnimation() {
        let shouldBeAnimating = self.isCurrentlyInHierarchy && self.absoluteLocation != nil
        if shouldBeAnimating != self.shouldBeAnimating {
            self.shouldBeAnimating = shouldBeAnimating
            if shouldBeAnimating {
                self.addImageAnimation()
            } else {
                self.imageNode.layer.removeAnimation(forKey: "shimmer")
            }
        }
    }
    
    private func addImageAnimation() {
        guard let containerSize = self.absoluteLocation?.1 else {
            return
        }
        let gradientHeight: CGFloat = 250.0
        self.imageNode.frame = CGRect(origin: CGPoint(x: 0.0, y: -gradientHeight), size: CGSize(width: containerSize.width, height: gradientHeight))
        let animation = self.imageNode.layer.makeAnimation(from: 0.0 as NSNumber, to: (containerSize.height + gradientHeight) as NSNumber, keyPath: "position.y", timingFunction: CAMediaTimingFunctionName.easeOut.rawValue, duration: 1.3 * 1.0, delay: 0.0, mediaTimingFunction: nil, removeOnCompletion: true, additive: true)
        animation.repeatCount = Float.infinity
        animation.beginTime = 1.0
        self.imageNode.layer.add(animation, forKey: "shimmer")
    }
}

public final class ChatListShimmerNode: ASDisplayNode {
    private let backgroundColorNode: ASDisplayNode
    private let effectNode: ShimmerEffectNode
    private let maskNode: ASImageNode
    private var currentParams: (size: CGSize, presentationData: PresentationData)?
    
    override public init() {
        self.backgroundColorNode = ASDisplayNode()
        self.effectNode = ShimmerEffectNode()
        self.maskNode = ASImageNode()
        
        super.init()
        
        self.isUserInteractionEnabled = false
        
        self.addSubnode(self.backgroundColorNode)
        self.addSubnode(self.effectNode)
        self.addSubnode(self.maskNode)
    }
    
    public func update(context: AccountContext, animationCache: AnimationCache, animationRenderer: MultiAnimationRenderer, size: CGSize, isInlineMode: Bool, presentationData: PresentationData, transition: ContainedViewLayoutTransition) {
        if self.currentParams?.size != size || self.currentParams?.presentationData !== presentationData {
            self.currentParams = (size, presentationData)
                        
            let chatListPresentationData = ChatListPresentationData(theme: presentationData.theme, fontSize: presentationData.chatFontSize, strings: presentationData.strings, dateTimeFormat: presentationData.dateTimeFormat, nameSortOrder: presentationData.nameSortOrder, nameDisplayOrder: presentationData.nameDisplayOrder, disableAnimations: true)
            
            let peer1: EnginePeer = .user(TelegramUser(id: EnginePeer.Id(namespace: Namespaces.Peer.CloudUser, id: EnginePeer.Id.Id._internalFromInt64Value(0)), accessHash: nil, firstName: "FirstName", lastName: nil, username: nil, phone: nil, photo: [], botInfo: nil, restrictionInfo: nil, flags: [], emojiStatus: nil, usernames: [], storiesHidden: nil, nameColor: nil, backgroundEmojiId: nil, profileColor: nil, profileBackgroundEmojiId: nil))
            let timestamp1: Int32 = 100000
            let peers: [EnginePeer.Id: EnginePeer] = [:]
            let interaction = ChatListNodeInteraction(context: context, animationCache: animationCache, animationRenderer: animationRenderer, activateSearch: {}, peerSelected: { _, _, _, _ in }, disabledPeerSelected: { _, _, _ in }, togglePeerSelected: { _, _ in }, togglePeersSelection: { _, _ in }, additionalCategorySelected: { _ in
            }, messageSelected: { _, _, _, _ in}, groupSelected: { _ in }, addContact: { _ in }, setPeerIdWithRevealedOptions: { _, _ in }, setItemPinned: { _, _ in }, setPeerMuted: { _, _ in }, setPeerThreadMuted: { _, _, _ in }, deletePeer: { _, _ in }, deletePeerThread: { _, _ in }, setPeerThreadStopped: { _, _, _ in }, setPeerThreadPinned: { _, _, _ in }, setPeerThreadHidden: { _, _, _ in }, updatePeerGrouping: { _, _ in }, togglePeerMarkedUnread: { _, _ in}, toggleArchivedFolderHiddenByDefault: {}, toggleThreadsSelection: { _, _ in }, hidePsa: { _ in }, activateChatPreview: { _, _, _, gesture, _ in
                gesture?.cancel()
            }, present: { _ in }, openForumThread: { _, _ in }, openStorageManagement: {}, openPasswordSetup: {}, openPremiumIntro: {}, openPremiumGift: {}, openActiveSessions: {}, performActiveSessionAction: { _, _ in }, openChatFolderUpdates: {}, hideChatFolderUpdates: {}, openStories: { _, _ in }, dismissNotice: { _ in
            })
            interaction.isInlineMode = isInlineMode
            
            let items = (0 ..< 2).map { _ -> ChatListItem in
                let message = EngineMessage(
                    stableId: 0,
                    stableVersion: 0,
                    id: EngineMessage.Id(peerId: peer1.id, namespace: 0, id: 0),
                    globallyUniqueId: nil,
                    groupingKey: nil,
                    groupInfo: nil,
                    threadId: nil,
                    timestamp: timestamp1,
                    flags: [],
                    tags: [],
                    globalTags: [],
                    localTags: [],
                    customTags: [],
                    forwardInfo: nil,
                    author: peer1,
                    text: "Text",
                    attributes: [],
                    media: [],
                    peers: peers,
                    associatedMessages: [:],
                    associatedMessageIds: [],
                    associatedMedia: [:],
                    associatedThreadInfo: nil,
                    associatedStories: [:]
                )
                let readState = EnginePeerReadCounters()

                return ChatListItem(presentationData: chatListPresentationData, context: context, chatListLocation: .chatList(groupId: .root), filterData: nil, index: .chatList(EngineChatList.Item.Index.ChatList(pinningIndex: 0, messageIndex: EngineMessage.Index(id: EngineMessage.Id(peerId: peer1.id, namespace: 0, id: 0), timestamp: timestamp1))), content: .peer(ChatListItemContent.PeerData(
                    messages: [message],
                    peer: EngineRenderedPeer(peer: peer1),
                    threadInfo: nil,
                    combinedReadState: readState,
                    isRemovedFromTotalUnreadCount: false,
                    presence: nil,
                    hasUnseenMentions: false,
                    hasUnseenReactions: false,
                    draftState: nil,
                    mediaDraftContentType: nil,
                    inputActivities: nil,
                    promoInfo: nil,
                    ignoreUnreadBadge: false,
                    displayAsMessage: false,
                    hasFailedMessages: false,
                    forumTopicData: nil,
                    topForumTopicItems: [],
                    autoremoveTimeout: nil,
                    storyState: nil,
                    requiresPremiumForMessaging: false
                )), editing: false, hasActiveRevealControls: false, selected: false, header: nil, enableContextActions: false, hiddenOffset: false, interaction: interaction)
            }
            
            var itemNodes: [ChatListItemNode] = []
            for i in 0 ..< items.count {
                items[i].nodeConfiguredForParams(async: { f in f() }, params: ListViewItemLayoutParams(width: size.width, leftInset: 0.0, rightInset: 0.0, availableHeight: 100.0), synchronousLoads: false, previousItem: i == 0 ? nil : items[i - 1], nextItem: (i == items.count - 1) ? nil : items[i + 1], completion: { node, apply in
                    if let itemNode = node as? ChatListItemNode {
                        itemNodes.append(itemNode)
                    }
                    apply().1(ListViewItemApply(isOnScreen: true))
                })
            }
            
            self.backgroundColorNode.backgroundColor = presentationData.theme.list.mediaPlaceholderColor
            
            self.maskNode.image = generateImage(size, rotatedContext: { size, context in
                context.setFillColor(presentationData.theme.chatList.backgroundColor.cgColor)
                context.fill(CGRect(origin: CGPoint(), size: size))
                
                var currentY: CGFloat = 0.0
                let fakeLabelPlaceholderHeight: CGFloat = 8.0
                
                func fillLabelPlaceholderRect(origin: CGPoint, width: CGFloat) {
                    let startPoint = origin
                    let diameter = fakeLabelPlaceholderHeight
                    context.fillEllipse(in: CGRect(origin: startPoint, size: CGSize(width: diameter, height: diameter)))
                    context.fillEllipse(in: CGRect(origin: CGPoint(x: startPoint.x + width - diameter, y: startPoint.y), size: CGSize(width: diameter, height: diameter)))
                    context.fill(CGRect(origin: CGPoint(x: startPoint.x + diameter / 2.0, y: startPoint.y), size: CGSize(width: width - diameter, height: diameter)))
                }
                
                while currentY < size.height {
                    let sampleIndex = 0
                    let itemHeight: CGFloat = itemNodes[sampleIndex].contentSize.height
                    
                    context.setBlendMode(.copy)
                    context.setFillColor(UIColor.clear.cgColor)
                    
                    if !isInlineMode {
                        if !itemNodes[sampleIndex].avatarNode.isHidden {
                            context.fillEllipse(in: itemNodes[sampleIndex].avatarNode.view.convert(itemNodes[sampleIndex].avatarNode.bounds, to: itemNodes[sampleIndex].view).offsetBy(dx: 0.0, dy: currentY))
                        }
                    }
                    
                    let titleFrame = itemNodes[sampleIndex].titleNode.frame.offsetBy(dx: 0.0, dy: currentY)
                    if isInlineMode {
                        fillLabelPlaceholderRect(origin: CGPoint(x: titleFrame.minX + 22.0, y: floor(titleFrame.midY - fakeLabelPlaceholderHeight / 2.0)), width: 60.0 - 22.0)
                    } else {
                        fillLabelPlaceholderRect(origin: CGPoint(x: titleFrame.minX, y: floor(titleFrame.midY - fakeLabelPlaceholderHeight / 2.0)), width: 60.0)
                    }
                    
                    let textFrame = itemNodes[sampleIndex].textNode.textNode.frame.offsetBy(dx: 0.0, dy: currentY)
                    
                    if isInlineMode {
                        context.fillEllipse(in: CGRect(origin: CGPoint(x: textFrame.minX, y: titleFrame.minY + 2.0), size: CGSize(width: 16.0, height: 16.0)))
                    }
                    
                    fillLabelPlaceholderRect(origin: CGPoint(x: textFrame.minX, y: currentY + itemHeight - floor(itemNodes[sampleIndex].titleNode.frame.midY - fakeLabelPlaceholderHeight / 2.0) - fakeLabelPlaceholderHeight), width: 60.0)
                    
                    fillLabelPlaceholderRect(origin: CGPoint(x: textFrame.minX, y: currentY + floor((itemHeight - fakeLabelPlaceholderHeight) / 2.0)), width: 120.0)
                    fillLabelPlaceholderRect(origin: CGPoint(x: textFrame.minX + 120.0 + 10.0, y: currentY + floor((itemHeight - fakeLabelPlaceholderHeight) / 2.0)), width: 60.0)
                    
                    let dateFrame = itemNodes[sampleIndex].dateNode.frame.offsetBy(dx: 0.0, dy: currentY)
                    fillLabelPlaceholderRect(origin: CGPoint(x: dateFrame.maxX - 30.0, y: dateFrame.minY), width: 30.0)
                    
                    context.setBlendMode(.normal)
                    context.setFillColor(presentationData.theme.chatList.itemSeparatorColor.cgColor)
                    context.fill(itemNodes[sampleIndex].separatorNode.frame.offsetBy(dx: 0.0, dy: currentY))
                    
                    currentY += itemHeight
                }
            })
            
            self.effectNode.update(backgroundColor: presentationData.theme.list.mediaPlaceholderColor, foregroundColor: presentationData.theme.list.itemBlocksBackgroundColor.withAlphaComponent(0.4))
            self.effectNode.updateAbsoluteRect(CGRect(origin: CGPoint(), size: size), within: size)
        }
        transition.updateFrame(node: self.backgroundColorNode, frame: CGRect(origin: CGPoint(x: 0.0, y: 0.0), size: size))
        transition.updateFrame(node: self.maskNode, frame: CGRect(origin: CGPoint(x: 0.0, y: 0.0), size: size))
        transition.updateFrame(node: self.effectNode, frame: CGRect(origin: CGPoint(x: 0.0, y: 0.0), size: size))
    }
}