Swift: Convert basic raw html string to attributed string

String+HTML.swift

import UIKit

extension String {

    private var attributedStringOptions: [NSAttributedString.DocumentReadingOptionKey: Any] {
        return [
            .documentType: NSAttributedString.DocumentType.html,
            .characterEncoding: String.Encoding.utf8.rawValue
        ]
    }
    var wholeRange: NSRange {
        return NSRange(location: 0, length: count)
    }

    var html2Attributed: NSAttributedString {
        return attributedString()
    }

    func html2Attributed(
        font: UIFont,
        color: UIColor,
        attributes: [NSAttributedString.Key: Any] = [:]
    ) -> NSAttributedString {
        let base = attributedString(with: """
            html * {
                font-size: \(font.pointSize)pt !important;
                font-family: \(font.familyName), Helvetica !important;
                color: \(color.hexString) !important;
            }
        """)

        base.beginEditing()
        base.replaceFonts(with: font)
        base.addAttributes(attributes, range: base.string.wholeRange)
        base.endEditing()

        return base
    }

    private func attributedString(with style: String = "") -> NSMutableAttributedString {
        let base = NSMutableAttributedString(string: self)

        guard let data = "<style>\(style)</style>\(self)".data(using: .utf8) else {
            return base
        }

        return (try? NSMutableAttributedString(
            data: data,
            options: attributedStringOptions,
            documentAttributes: nil
        )) ?? base
    }
}

extension UIColor {

    var hexString: String {
        var r: CGFloat = 0
        var g: CGFloat = 0
        var b: CGFloat = 0

        getRed(&r, green: &g, blue: &b, alpha: nil)

        let rgb: Int = (Int)(r * 255) << 16 | (Int)(g * 255) << 8 | (Int)(b * 255) << 0

        return NSString(format: "#%06x", rgb) as String
    }
}

extension NSMutableAttributedString {

    func replaceFonts(with font: UIFont) {
        let descriptor = font.fontDescriptor
        var changes: [NSRange: Any] = [:]

        enumerateAttribute(.font, in: string.wholeRange, options: []) { foundFont, range, _ in
            guard let traits = (foundFont as? UIFont)?.fontDescriptor.symbolicTraits else {
                return
            }

            guard let adjustedDescriptor = descriptor.withSymbolicTraits(traits) else {
                return
            }

            let newFont = UIFont(descriptor: adjustedDescriptor, size: font.pointSize)
            changes[range] = newFont
        }
        changes.forEach { range, newValue in
            removeAttribute(.font, range: range)
            addAttribute(.font, value: newValue, range: range)
        }
    }
}