Swiftgram/TelegramUI/Pasteboard.swift

import Foundation
import UIKit
import Display
import TelegramCore
import MobileCoreServices

private func rtfStringWithAppliedEntities(_ text: String, entities: [MessageTextEntity]) -> String {
    var string: String = """
    {\\rtf1\\ansi\\ansicpg1252{\\fonttbl\\f0\\fnil\\fcharset0 .SFUIText;\\f1\\fnil\\fcharset0 .SFUIText-Semibold;\\f2\\fnil\\fcharset0 .SFUIText-Italic;\\f3\\fnil\\fcharset0 Menlo-Regular;}
    """
    
    string.append("\\f0 ")
    
    let nsString = text as NSString
    
    var remainingRange = NSMakeRange(0, text.count)
    for i in 0 ..< entities.count {
        let entity = entities[i]
        var range = NSRange(location: entity.range.lowerBound, length: entity.range.upperBound - entity.range.lowerBound)
        if range.location + range.length > text.count {
            range.location = max(0, text.count - range.length)
            range.length = text.count - range.location
        }
        
        if range.location != remainingRange.location {
            string.append(nsString.substring(with: NSMakeRange(remainingRange.location, range.location - remainingRange.location)))
            remainingRange = NSMakeRange(range.location, remainingRange.location + remainingRange.length - range.location)
        }
        
        switch entity.type {
            case let .TextUrl(url):
                string.append("{\\field{\\*\\fldinst HYPERLINK \"\(url)\"}{\\fldrslt ")
                string.append(nsString.substring(with: range))
                string.append("}}")
            case .Bold:
                string.append("\\f1\\b ")
                string.append(nsString.substring(with: range))
                string.append("\\b0\\f0 ")
            case .Italic:
                string.append("\\f2\\i ")
                string.append(nsString.substring(with: range))
                string.append("\\i0\\f0 ")
            case .Code, .Pre:
                string.append("\\f3 ")
                string.append(nsString.substring(with: range))
                string.append("\\f0 ")
            default:
                string.append(nsString.substring(with: range))
                break
        }
        remainingRange = NSMakeRange(range.location + range.length, remainingRange.location + remainingRange.length - (range.location + range.length))
    }
    
    if remainingRange.length > 0 {
        string.append(nsString.substring(with: NSMakeRange(remainingRange.location, remainingRange.length)))
    }
    
    string.append("}")
    
    string = string.replacingOccurrences(of: "\n", with: "\\line")
    
    return string
}

func chatInputStateStringFromRTF(_ data: Data, type: NSAttributedString.DocumentType) -> NSAttributedString? {
    if let attributedString = try? NSAttributedString(data: data, options: [NSAttributedString.DocumentReadingOptionKey.documentType: type], documentAttributes: nil) {
        
        let string = NSMutableAttributedString(string: attributedString.string)
        attributedString.enumerateAttributes(in: NSRange(location: 0, length: attributedString.length), options: [], using: { attributes, range, _ in
            if let value = attributes[.link], let url = (value as? URL)?.absoluteString {
                string.addAttribute(ChatTextInputAttributes.textUrl, value: ChatTextInputTextUrlAttribute(url: url), range: range)
            }
            else if let value = attributes[.font], let font = value as? UIFont {
                let fontName = font.fontName.lowercased()
                if fontName.contains("bold") {
                    string.addAttribute(ChatTextInputAttributes.bold, value: true as NSNumber, range: range)
                } else if fontName.contains("italic") {
                    string.addAttribute(ChatTextInputAttributes.italic, value: true as NSNumber, range: range)
                } else if fontName.contains("menlo") {
                    string.addAttribute(ChatTextInputAttributes.monospace, value: true as NSNumber, range: range)
                }
            }
        })
        return string
    }
    return nil
}

func storeMessageTextInPasteboard(_ text: String, entities: [MessageTextEntity]?) {
    var items: [String: Any] = [:]
    items[kUTTypeUTF8PlainText as String] = text
    
    if let entities = entities {
        items[kUTTypeRTF as String] = rtfStringWithAppliedEntities(text, entities: entities)
    }
    UIPasteboard.general.items = [items]
}

func storeInputTextInPasteboard(_ text: NSAttributedString) {
    let entities = generateChatInputTextEntities(text)
    storeMessageTextInPasteboard(text.string, entities: entities)
}