// Copyright © WireMock.Net

#if !USE_ASPNETCORE
using Microsoft.Owin.Hosting;
using Owin;
using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using JetBrains.Annotations;
using WireMock.Logging;
using WireMock.Owin.Mappers;
using Stef.Validation;
using WireMock.Services;
using WireMock.Util;

namespace WireMock.Owin;

internal class OwinSelfHost : IOwinSelfHost
{
    private readonly IWireMockMiddlewareOptions _options;
    private readonly CancellationTokenSource _cts = new();
    private readonly IWireMockLogger _logger;

    private Exception? _runningException;

    public OwinSelfHost(IWireMockMiddlewareOptions options, HostUrlOptions urlOptions)
    {
        Guard.NotNull(urlOptions);

        _options = Guard.NotNull(options);
        _logger = options.Logger ?? new WireMockConsoleLogger();

        foreach (var detail in urlOptions.GetDetails())
        {
            Urls.Add(detail.Url);
            Ports.Add(detail.Port);
        }
    }

    public bool IsStarted { get; private set; }

    public List<string> Urls { get; } = new();

    public List<int> Ports { get; } = new();

    public Exception? RunningException => _runningException;

    [PublicAPI]
    public Task StartAsync()
    {
        return Task.Run(StartServers, _cts.Token);
    }

    [PublicAPI]
    public Task StopAsync()
    {
        _cts.Cancel();

        return Task.FromResult(true);
    }

    private void StartServers()
    {
#if NET46
        _logger.Info("Server using .net 4.6");
#else
        _logger.Info("Server using .net 4.5.x");
#endif
        var servers = new List<IDisposable>();

        try
        {
            var requestMapper = new OwinRequestMapper();
            var responseMapper = new OwinResponseMapper(_options);
            var matcher = new MappingMatcher(_options, new RandomizerDoubleBetween0And1());
            var guidUtils = new GuidUtils();

            Action<IAppBuilder> startup = app =>
            {
                app.Use<GlobalExceptionMiddleware>(_options, responseMapper);
                _options.PreWireMockMiddlewareInit?.Invoke(app);
                app.Use<WireMockMiddleware>(_options, requestMapper, responseMapper, matcher, guidUtils);
                _options.PostWireMockMiddlewareInit?.Invoke(app);
            };

            foreach (var url in Urls)
            {
                servers.Add(WebApp.Start(url, startup));
            }

            IsStarted = true;

            // WaitHandle is signaled when the token is cancelled,
            // which will be more efficient than Thread.Sleep in while loop
            _cts.Token.WaitHandle.WaitOne();
        }
        catch (Exception e)
        {
            // Expose exception of starting host, otherwise it's hard to be troubleshooting if keeping quiet
            // For example, WebApp.Start will fail with System.MissingMemberException if Microsoft.Owin.Host.HttpListener.dll is being located
            // https://stackoverflow.com/questions/25090211/owin-httplistener-not-located/31369857
            _runningException = e;
            _logger.Error(e.ToString());
        }
        finally
        {
            IsStarted = false;
            // Dispose all servers in finally block to make sure clean up allocated resource on error happening
            servers.ForEach(s => s.Dispose());
        }
    }
}
#endif