Swiftgram/TelegramUI/StickersChatInputPanelItem.swift

import Foundation
import AsyncDisplayKit
import Display
import TelegramCore
import SwiftSignalKit
import Postbox

final class StickersChatInputPanelItem: ListViewItem {
    fileprivate let theme: PresentationTheme
    fileprivate let text: String
    private let hashtagSelected: (String) -> Void
    
    let selectable: Bool = true
    
    public init(theme: PresentationTheme, text: String, hashtagSelected: @escaping (String) -> Void) {
        self.theme = theme
        self.text = text
        self.hashtagSelected = hashtagSelected
    }
    
    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) {
        let configure = { () -> Void in
            let node = StickersChatInputPanelItemNode()
            
            let nodeLayout = node.asyncLayout()
            let (top, bottom) = (previousItem != nil, nextItem != nil)
            let (layout, apply) = nodeLayout(self, params, top, bottom)
            
            node.contentSize = layout.contentSize
            node.insets = layout.insets
            
            Queue.mainQueue().async {
                completion(node, {
                    return (nil, { _ in apply(.None) })
                })
            }
        }
        if Thread.isMainThread {
            async {
                configure()
            }
        } else {
            configure()
        }
    }
    
    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 {
            if let nodeValue = node() as? StickersChatInputPanelItemNode {
                let nodeLayout = nodeValue.asyncLayout()
                
                async {
                    let (top, bottom) = (previousItem != nil, nextItem != nil)
                    
                    let (layout, apply) = nodeLayout(self, params, top, bottom)
                    Queue.mainQueue().async {
                        completion(layout, { _ in
                            apply(animation)
                        })
                    }
                }
            } else {
                assertionFailure()
            }
        }
    }
}

private let textFont = Font.medium(14.0)

final class StickersChatInputPanelItemNode: ListViewItemNode {
    static let itemHeight: CGFloat = 42.0
    private let textNode: TextNode
    private let topSeparatorNode: ASDisplayNode
    private let highlightedBackgroundNode: ASDisplayNode
    
    init() {
        self.textNode = TextNode()
        
        self.topSeparatorNode = ASDisplayNode()
        self.topSeparatorNode.isLayerBacked = true

        self.highlightedBackgroundNode = ASDisplayNode()
        self.highlightedBackgroundNode.isLayerBacked = true
        
        super.init(layerBacked: false, dynamicBounce: false)
        
        self.addSubnode(self.topSeparatorNode)
        self.addSubnode(self.textNode)
    }
    
    override public func layoutForParams(_ params: ListViewItemLayoutParams, item: ListViewItem, previousItem: ListViewItem?, nextItem: ListViewItem?) {
        if let item = item as? StickersChatInputPanelItem {
            let doLayout = self.asyncLayout()
            let merged = (top: previousItem != nil, bottom: nextItem != nil)
            let (layout, apply) = doLayout(item, params, merged.top, merged.bottom)
            self.contentSize = layout.contentSize
            self.insets = layout.insets
            apply(.None)
        }
    }
    
    func asyncLayout() -> (_ item: StickersChatInputPanelItem, _ params: ListViewItemLayoutParams, _ mergedTop: Bool, _ mergedBottom: Bool) -> (ListViewItemNodeLayout, (ListViewItemUpdateAnimation) -> Void) {
        let makeTextLayout = TextNode.asyncLayout(self.textNode)
        return { [weak self] item, params, mergedTop, mergedBottom in
            let baseWidth = params.width - params.leftInset - params.rightInset
            
            let leftInset: CGFloat = 15.0 + params.leftInset
            let rightInset: CGFloat = 10.0 + params.rightInset
            
            let (textLayout, textApply) = makeTextLayout(TextNodeLayoutArguments(attributedString: NSAttributedString(string: "#\(item.text)", font: textFont, textColor: item.theme.list.itemPrimaryTextColor), backgroundColor: nil, maximumNumberOfLines: 1, truncationType: .end, constrainedSize: CGSize(width: params.width - leftInset - rightInset, height: 100.0), alignment: .natural, cutout: nil, insets: UIEdgeInsets()))
            
            let nodeLayout = ListViewItemNodeLayout(contentSize: CGSize(width: params.width, height: HashtagChatInputPanelItemNode.itemHeight), insets: UIEdgeInsets())
            
            return (nodeLayout, { _ in
                if let strongSelf = self {
                    strongSelf.topSeparatorNode.backgroundColor = item.theme.list.itemPlainSeparatorColor
                    strongSelf.backgroundColor = item.theme.list.plainBackgroundColor
                    strongSelf.highlightedBackgroundNode.backgroundColor = item.theme.list.itemHighlightedBackgroundColor
                    
                    let _ = textApply()
                    strongSelf.textNode.frame = CGRect(origin: CGPoint(x: leftInset, y: floor((nodeLayout.contentSize.height - textLayout.size.height) / 2.0)), size: textLayout.size)
                    
                    strongSelf.topSeparatorNode.isHidden = mergedTop
                    
                    
                    strongSelf.topSeparatorNode.frame = CGRect(origin: CGPoint(x: 0.0, y: 0.0), size: CGSize(width: params.width, height: UIScreenPixel))
                    
                    strongSelf.highlightedBackgroundNode.frame = CGRect(origin: CGPoint(x: 0.0, y: 0.0), size: CGSize(width: params.width, height: nodeLayout.size.height + UIScreenPixel))
                }
            })
        }
    }
}