Aligns paragraphs according to each's dominant language.

ParagraphsNaturallyAligned.swift

protocol ParagraphsNaturallyAligned: NSAttributedString {}
extension ParagraphsNaturallyAligned {
    var paragraphsNaturallyAligned: Self {
        let mutable = NSMutableAttributedString(attributedString: self)
        mutable.alignParagraphsNaturally()
        return (self is NSMutableAttributedString ? mutable : NSAttributedString(attributedString: mutable)) as! Self
    }
}
extension ParagraphsNaturallyAligned where Self == NSMutableAttributedString {
    func alignParagraphsNaturally() {
        (string as NSString).enumerateSubstrings(in: NSRange(location: 0, length: length), options: .byParagraphs) { (paragaphContent, paragraphRange, _, _) in
            
            guard let paragaphContent = paragaphContent else { return }
            
            var existingParaghStyle: NSParagraphStyle?
            self.enumerateAttribute(.paragraphStyle, in: paragraphRange, options: []) { (value, _, _) in
                if let value = value as? NSParagraphStyle {
                    existingParaghStyle = value
                }
            }
            let newParagraphStyle = existingParaghStyle == nil ? NSMutableParagraphStyle() : existingParaghStyle!.mutableCopy() as! NSMutableParagraphStyle
            let isRTL = paragaphContent.isRTL
            newParagraphStyle.baseWritingDirection = isRTL ? .rightToLeft : .leftToRight
            if newParagraphStyle.alignment != .justified {
                newParagraphStyle.alignment = isRTL ? .right : .left
            }
            
            self.addAttribute(.paragraphStyle, value: newParagraphStyle, range: paragraphRange)
        }
    }
}
extension NSAttributedString: ParagraphsNaturallyAligned {}

extension String {
    var isRTL: Bool {
        guard let dominantLanguage = NLLanguageRecognizer.dominantLanguage(for: self) else { return false }
        let rtlLanguageIds = ["ar", "fa", "he", "ckb-IQ","ckb-IR", "ur", "ckb"] // credits: https://github.com/MoathOthman/MOLH/blob/313691443043f0da83502040f39b852cd9e3e0e8/Sources/MOLH/MOLHLanguage.swift#L120
        return rtlLanguageIds.contains(dominantLanguage.rawValue)
    }
}