//
//  HexEncode.swift
//  PirateLightClientKit
//
//  Created by Francisco Gindre on 12/13/19.
//

import Foundation
import CommonCrypto

/**
Thanks Stack Overflow (once again) https://stackoverflow.com/questions/39075043/how-to-convert-data-to-hex-string-in-swift
*/
struct HexEncodingOptions: OptionSet {
    public static let upperCase = HexEncodingOptions(rawValue: 1 << 0)

    public let rawValue: Int

    public init(rawValue: Int) {
        self.rawValue = rawValue
    }
}

extension Data {
    func hexEncodedString(options: HexEncodingOptions = []) -> String {
        z_hexEncodedString(data: self, options: options)
    }
}

func z_hexEncodedString(data: Data, options: HexEncodingOptions = []) -> String {
    let hexDigits = Array((options.contains(.upperCase) ? "0123456789ABCDEF" : "0123456789abcdef").utf16)
    var chars: [unichar] = []

    chars.reserveCapacity(2 * data.count)
    for byte in data {
        chars.append(hexDigits[Int(byte / 16)])
        chars.append(hexDigits[Int(byte % 16)])
    }

    return String(utf16CodeUnits: chars, count: chars.count)
}