generate-rules

#!/usr/bin/env swift

import Foundation

let filePath = CommandLine.arguments[1]
let filename = filePath.split(separator: "/")[1]

struct Group: Encodable {
    let description: String
    let name: String
    let deniedRemoteDomains: [String]

    private enum CodingKeys : String, CodingKey {
        case description
        case name
        case deniedRemoteDomains = "denied-remote-domains"
    }
}

do {
    let data = try Data(contentsOf: URL(fileURLWithPath: filePath))
    let hosts = String(decoding: data, as: UTF8.self).split(separator: "\n")

    var domains: [String] = []
    for host in hosts {
        if host.hasPrefix("0.0.0.0") {
            let starIndex = host.index(host.startIndex, offsetBy: 8)

            domains.append(String(host[starIndex..<host.endIndex]))
        }
    }

    let domainsCount = NumberFormatter.localizedString(from: NSNumber(value: domains.count), number: .decimal)
    let group = Group(description: "\(Date().description); Number of unique domains: \(domainsCount)",
                      name: "\(filename).lsrules",
                      deniedRemoteDomains: domains)

    let jsonEncoder = JSONEncoder()
    jsonEncoder.outputFormatting = [.prettyPrinted, .sortedKeys]
    let encode = try jsonEncoder.encode(group)

    print(String(data: encode, encoding: .utf8)!)
} catch {
    print(error)
}