using Microsoft.AspNetCore.Http;
using System.Net;
using System.Net.WebSockets;

namespace EVCB_OCPP.WSServer.Service.WsService;

public class WebsocketService<T> where T : WsSession
{
    public WebsocketService() { }

    public Func<T, Task<bool>> ValidateHandshake;

    public event EventHandler<T> NewSessionConnected;

    public async Task AcceptWebSocket(HttpContext context)
    {
        if (!context.WebSockets.IsWebSocketRequest)
        {
            return;
        }

        var portocol = await AcceptWebSocketHandler(context);
        if (string.IsNullOrEmpty(portocol))
        {
            return;
        }

        using WebSocket webSocket = await context.WebSockets.AcceptWebSocketAsync(portocol);
        await AddWebSocket(webSocket, context);
    }

    internal virtual ValueTask<string> AcceptWebSocketHandler(HttpContext context)
    {
        return ValueTask.FromResult(string.Empty);
    }


    public async Task AddWebSocket(WebSocket webSocket, HttpContext context)
    {
        T data = Activator.CreateInstance<T>();
        data.ClientWebSocket = webSocket;
        data.SessionID = context.TraceIdentifier;
        data.Path = context?.Request?.Path;
        //data.UriScheme = context?.Request?.Scheme;
        data.AuthHeader = context?.Request?.Headers?.Authorization;
        //data.Origin = context.Request.Scheme;

        data.UriScheme = GetScheme(context);


        try
        {
            var ipaddress = context.Connection.RemoteIpAddress;
            var port = context.Connection.RemotePort;
            data.Endpoint = new IPEndPoint(ipaddress, port);
        }
        catch
        {
            data.Endpoint = null;
        }

        var validated = ValidateHandshake == null ? false : await ValidateHandshake(data);

        if (!validated)
        {
            return;
        }

        NewSessionConnected?.Invoke(this, data);
        await data.EndConnSemaphore.WaitAsync();
        return;
    }

    private string GetScheme(HttpContext context)
    {
        string toReturn = string.Empty;

        if (context.Request.Headers.ContainsKey("x-original-host"))
        {
            toReturn = new Uri(context.Request.Headers["x-original-host"]).Scheme;
            return toReturn;
        }

        var origin = context.Request.Headers.Origin.FirstOrDefault();
        try
        {
            toReturn = new Uri(origin).Scheme;
            return toReturn;
        }
        catch
        {
        }

        return toReturn;
    }
}