using System.Net;
using System.Text;
using IBKRTrader.Core.Database;
using IBKRTrader.Core.Logging;
using IBKRTrader.Core.Settings;

namespace IBKRTrader.Core.Workers.BuiltIn;

/// <summary>
/// WebserverService – permanenter Service auf Basis von System.Net.HttpListener.
/// Lauscht auf http://localhost:{port}/ und liefert einen Status-JSON.
/// Wird später durch vollständige Web-UI erweitert.
/// </summary>
public class WebserverService : WorkerBase
{
    private readonly SettingsService _settings;
    private HttpListener?            _listener;

    public override string     Name   => "WebserverService";
    public override string     Module => "Core";
    public override WorkerType Type   => WorkerType.Service;

    protected override TimeSpan? Interval => null; // Service = permanent

    public WebserverService(LoggingService logger, DatabaseService db, SettingsService settings)
        : base(logger, db)
    {
        _settings = settings;
        Info.Active  = settings.Settings.Webserver.Enabled;
        Info.RunEvery = "Service";
    }

    protected override async Task ExecuteAsync(CancellationToken ct)
    {
        var port = _settings.Settings.Webserver.Port;
        _listener = new HttpListener();
        _listener.Prefixes.Add($"http://localhost:{port}/");

        try
        {
            _listener.Start();
            Logger.Info(Module, $"Webserver gestartet auf http://localhost:{port}/");
            Info.Info = $"http://localhost:{port}/";

            while (!ct.IsCancellationRequested)
            {
                // GetContextAsync blockiert – abbrechen via ct
                var contextTask = _listener.GetContextAsync();
                var cancelTask  = Task.Delay(Timeout.Infinite, ct);

                var completed = await Task.WhenAny(contextTask, cancelTask);
                if (completed == cancelTask) break;

                var ctx = await contextTask;
                _ = HandleRequestAsync(ctx); // fire-and-forget pro Request
            }
        }
        finally
        {
            _listener.Stop();
            Logger.Info(Module, "Webserver gestoppt.");
        }
    }

    private async Task HandleRequestAsync(HttpListenerContext ctx)
    {
        try
        {
            const string json = """{"status":"ok","app":"IBKRTrader","version":"1.0.0"}""";
            var bytes = Encoding.UTF8.GetBytes(json);

            ctx.Response.ContentType     = "application/json";
            ctx.Response.ContentLength64 = bytes.Length;
            ctx.Response.StatusCode      = 200;

            await ctx.Response.OutputStream.WriteAsync(bytes);
            ctx.Response.Close();
        }
        catch { /* Client hat getrennt */ }
    }
}