global using System;
global using System.Collections.Generic;
global using System.Text;
global using System.Threading;
global using System.Threading.Tasks;
global using DTLib.Filesystem;
global using DTLib.Logging;
global using System.Net;
using System.Diagnostics;
using DTLib.Extensions;
using DTLib.Web.Routes;

namespace DTLib.Web;

public class WebApp
{
    private readonly string _baseUrl;
    private readonly ContextLogger _logger;
    private readonly IRouter _router;
    private readonly CancellationToken _stopToken;
    
    public WebApp(string baseUrl, ILogger logger, IRouter router, CancellationToken stopToken = default)
    {
        _logger = new ContextLogger(nameof(WebApp), logger);
        _baseUrl = baseUrl;
        _stopToken = stopToken;
        _router = router;
    }

    public async Task Run()
    {
        _logger.LogInfo($"starting server at '{_baseUrl}'...");
        HttpListener server = new HttpListener();
        server.Prefixes.Add(_baseUrl);
        server.Start();
        _logger.LogInfo("server started");
        long requestId = 1;

        try
        {
            while (!_stopToken.IsCancellationRequested)
            {
                var ctx = await server.GetContextAsync().AsCancellable(_stopToken);
                HandleRequestAsync(ctx, requestId++);
            }
        }
        catch (OperationCanceledException)
        {}

        server.Stop();
        _logger.LogInfo("server stopped");
    }

    // ReSharper disable once AsyncVoidMethod
    private async void HandleRequestAsync(HttpListenerContext ctx, long requestId)
    {
        string logContext = $"Request-{requestId}";
        try
        {
            _logger.LogInfo(logContext, $"[{ctx.Request.HttpMethod}] {ctx.Request.RawUrl} from {ctx.Request.RemoteEndPoint}...");
            var stopwatch = new Stopwatch();
            stopwatch.Start();
            var status = await _router.Resolve(ctx);
            stopwatch.Stop();
            _logger.LogInfo(logContext, $"responded {(int)status} ({status}) in {stopwatch.ElapsedMilliseconds}ms");
        }
        catch (Exception ex)
        {
            _logger.LogWarn(logContext, ex);
        }
    }
    
}