session-ios/SessionUtilitiesKit/General/String+Utilities.swift

// Copyright © 2022 Rangeproof Pty Ltd. All rights reserved.

import SignalCoreKit

public extension String {
    var glyphCount: Int {
        let richText = NSAttributedString(string: self)
        let line = CTLineCreateWithAttributedString(richText)
        
        return CTLineGetGlyphCount(line)
    }

    var isSingleEmoji: Bool {
        return (glyphCount == 1 && containsEmoji)
    }

    var containsEmoji: Bool {
        return unicodeScalars.contains { $0.isEmoji }
    }

    var containsOnlyEmoji: Bool {
        return (
            !isEmpty &&
            !unicodeScalars.contains(where: {
                !$0.isEmoji &&
                !$0.isZeroWidthJoiner
            })
        )
    }
    
    func localized() -> String {
        // If the localized string matches the key provided then the localisation failed
        let localizedString = NSLocalizedString(self, comment: "")
        owsAssertDebug(localizedString != self, "Key \"\(self)\" is not set in Localizable.strings")

        return localizedString
    }
    
    func dataFromHex() -> Data? {
        guard self.count > 0 && (self.count % 2) == 0 else { return nil }

        let chars = self.map { $0 }
        let bytes: [UInt8] = stride(from: 0, to: chars.count, by: 2)
            .map { index -> String in String(chars[index]) + String(chars[index + 1]) }
            .compactMap { (str: String) -> UInt8? in UInt8(str, radix: 16) }
        
        guard bytes.count > 0 else { return nil }
        guard (self.count / bytes.count) == 2 else { return nil }
        
        return Data(bytes)
    }
    
    func ranges(of substring: String, options: CompareOptions = [], locale: Locale? = nil) -> [Range<Index>] {
        var ranges: [Range<Index>] = []
        
        while
            (ranges.last.map({ $0.upperBound < self.endIndex }) ?? true),
            let range = self.range(
                of: substring,
                options: options,
                range: (ranges.last?.upperBound ?? self.startIndex)..<self.endIndex,
                locale: locale
            )
        {
            ranges.append(range)
        }
        
        return ranges
    }
    
    static func filterNotificationText(_ text: String?) -> String? {
        guard let text = text?.filterStringForDisplay() else { return nil }

        // iOS strips anything that looks like a printf formatting character from
        // the notification body, so if we want to dispay a literal "%" in a notification
        // it must be escaped.
        // see https://developer.apple.com/documentation/uikit/uilocalnotification/1616646-alertbody
        // for more details.
        return text.replacingOccurrences(of: "%", with: "%%")
    }
}