ios/MullvadVPN/Extensions/NSAttributedString+Markdown.swift


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//
//  NSAttributedString+Markdown.swift
//  MullvadVPN
//
//  Created by pronebird on 19/11/2021.
//  Copyright © 2021 Mullvad VPN AB. All rights reserved.
//

import UIKit

extension NSAttributedString {
    convenience init(
        markdownString: String,
        font: UIFont,
        applyEffect: ((String) -> [NSAttributedString.Key: Any])? = nil
    ) {
        let attributedString = NSMutableAttributedString()
        let components = markdownString.components(separatedBy: "**")

        let fontDescriptor = font.fontDescriptor.withSymbolicTraits(.traitBold) ?? font
            .fontDescriptor
        let boldFont = UIFont(descriptor: fontDescriptor, size: font.pointSize)

        for (index, string) in components.enumerated() {
            var attributes = [NSAttributedString.Key: Any]()

            if index % 2 == 0 {
                attributes[.font] = font
            } else {
                attributes[.font] = boldFont
                attributes.merge(applyEffect?(string) ?? [:], uniquingKeysWith: { $1 })
            }

            attributedString.append(NSAttributedString(string: string, attributes: attributes))
        }

        self.init(attributedString: attributedString)
    }
}