Swiftgram/TelegramUI/WebpagePreviewAccessoryPanelNode.swift

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

private let lineImage = generateVerticallyStretchableFilledCircleImage(radius: 1.0, color: UIColor(0x007ee5))
private let closeButtonImage = generateImage(CGSize(width: 12.0, height: 12.0), contextGenerator: { size, context in
    context.clear(CGRect(origin: CGPoint(), size: size))
    context.setStrokeColor(UIColor(0x9099A2).cgColor)
    context.setLineWidth(2.0)
    context.setLineCap(.round)
    context.move(to: CGPoint(x: 1.0, y: 1.0))
    context.addLine(to: CGPoint(x: size.width - 1.0, y: size.height - 1.0))
    context.strokePath()
    context.move(to: CGPoint(x: size.width - 1.0, y: 1.0))
    context.addLine(to: CGPoint(x: 1.0, y: size.height - 1.0))
    context.strokePath()
})

final class WebpagePreviewAccessoryPanelNode: AccessoryPanelNode {
    private let webpageDisposable = MetaDisposable()
    
    private(set) var webpage: TelegramMediaWebpage
    
    let closeButton: ASButtonNode
    let lineNode: ASImageNode
    let titleNode: ASTextNode
    let textNode: ASTextNode
    
    init(account: Account, webpage: TelegramMediaWebpage) {
        self.webpage = webpage
        
        self.closeButton = ASButtonNode()
        self.closeButton.setImage(closeButtonImage, for: [])
        self.closeButton.hitTestSlop = UIEdgeInsetsMake(-8.0, -8.0, -8.0, -8.0)
        self.closeButton.displaysAsynchronously = false
        
        self.lineNode = ASImageNode()
        self.lineNode.displayWithoutProcessing = true
        self.lineNode.displaysAsynchronously = false
        self.lineNode.image = lineImage
        
        self.titleNode = ASTextNode()
        self.titleNode.truncationMode = .byTruncatingTail
        self.titleNode.maximumNumberOfLines = 1
        self.titleNode.displaysAsynchronously = false
        
        self.textNode = ASTextNode()
        self.textNode.truncationMode = .byTruncatingTail
        self.textNode.maximumNumberOfLines = 1
        self.textNode.displaysAsynchronously = false
        
        super.init()
        
        self.closeButton.addTarget(self, action: #selector(self.closePressed), forControlEvents: [.touchUpInside])
        self.addSubnode(self.closeButton)
        
        self.addSubnode(self.lineNode)
        self.addSubnode(self.titleNode)
        self.addSubnode(self.textNode)
        
        self.updateWebpage()
    }
    
    deinit {
        self.webpageDisposable.dispose()
    }
    
    func replaceWebpage(_ webpage: TelegramMediaWebpage) {
        if !self.webpage.isEqual(webpage) {
            self.webpage = webpage
            self.updateWebpage()
        }
    }
    
    private func updateWebpage() {
        var authorName = ""
        var text = ""
        switch self.webpage.content {
            case .Pending:
                authorName = "Loading..."
            case let .Loaded(content):
                if let title = content.title {
                    authorName = title
                } else if let websiteName = content.websiteName {
                    authorName = websiteName
                } else {
                    authorName = content.displayUrl
                }
                text = content.text ?? ""
        }
        
        self.titleNode.attributedText = NSAttributedString(string: authorName, font: Font.medium(15.0), textColor: UIColor(0x007ee5))
        self.textNode.attributedText = NSAttributedString(string: text, font: Font.regular(15.0), textColor: UIColor.black)
        
        self.setNeedsLayout()
    }
    
    override func calculateSizeThatFits(_ constrainedSize: CGSize) -> CGSize {
        return CGSize(width: constrainedSize.width, height: 45.0)
    }
    
    override func layout() {
        super.layout()
        
        let bounds = self.bounds
        let leftInset: CGFloat = 55.0
        let textLineInset: CGFloat = 10.0
        let rightInset: CGFloat = 55.0
        let textRightInset: CGFloat = 20.0
        
        let closeButtonSize = self.closeButton.measure(CGSize(width: 100.0, height: 100.0))
        self.closeButton.frame = CGRect(origin: CGPoint(x: bounds.size.width - rightInset - closeButtonSize.width, y: 19.0), size: closeButtonSize)
        
        self.lineNode.frame = CGRect(origin: CGPoint(x: leftInset, y: 8.0), size: CGSize(width: 2.0, height: bounds.size.height - 10.0))
        
        let titleSize = self.titleNode.measure(CGSize(width: bounds.size.width - leftInset - textLineInset - rightInset - textRightInset, height: bounds.size.height))
        self.titleNode.frame = CGRect(origin: CGPoint(x: leftInset + textLineInset, y: 7.0), size: titleSize)
        
        let textSize = self.textNode.measure(CGSize(width: bounds.size.width - leftInset - textLineInset - rightInset - textRightInset, height: bounds.size.height))
        self.textNode.frame = CGRect(origin: CGPoint(x: leftInset + textLineInset, y: 25.0), size: textSize)
    }
    
    @objc func closePressed() {
        if let dismiss = self.dismiss {
            dismiss()
        }
    }
}