timestamp.swift

//
//  main.swift
//  timestamp
//
//  Created by Huw Rowlands on 24/3/18.
//  Copyright © 2018 Huw Rowlands. All rights reserved.
//

import Foundation

let BINARY_NAME = CommandLine.arguments[0]
let USAGE = "usage: \(BINARY_NAME) [TIMESTAMP]..."

let dateFormatter = ISO8601DateFormatter()

func convert(fromTimestamps timestamps: [Double]) -> [String] {
    return timestamps
        .map { Date(timeIntervalSince1970: $0) }
        .map { dateFormatter.string(from: $0) }
}

func santise(commandLineArguments arguments: [String]) -> [Double] {
    let arguments = CommandLine.arguments.dropFirst()
    return arguments.flatMap { Double($0) }
}

let cleanArgs = santise(commandLineArguments: CommandLine.arguments)

if cleanArgs.count < 2 {
    print(USAGE)
    exit(2)
} else {
    let iso8601s = convert(fromTimestamps: cleanArgs)
    iso8601s.forEach {
        print($0)
    }
}