using System;
using System.IO;

namespace Microsoft.AspNetCore.WebSockets.ConformanceTest.Autobahn
{
    /// <summary>
    /// Wrapper around the Autobahn Test Suite's "wstest" app.
    /// </summary>
    public class Wstest : Executable
    {
        private static Lazy<Wstest> _instance = new Lazy<Wstest>(Create);

        public static readonly string DefaultLocation = LocateWstest();

        public static Wstest Default => _instance.Value;

        public Wstest(string path) : base(path) { }

        private static Wstest Create()
        {
            var location = LocateWstest();

            return (location == null || !File.Exists(location)) ? null : new Wstest(location);
        }

        private static string LocateWstest()
        {
            var location = Environment.GetEnvironmentVariable("ASPNETCORE_WSTEST_PATH");
            if (string.IsNullOrEmpty(location))
            {
                location = Locate("wstest");
            }

            return location;
        }
    }
}