using System.Security.Claims;
using Microsoft.AspNetCore.Http;
using Microsoft.IdentityModel.JsonWebTokens;
using mws.backend.dotnet.application.Common;

namespace mws.backend.dotnet.api.Authentication;

public class HttpCurrentUser(IHttpContextAccessor accessor) : ICurrentUser
{
    public Guid? UserId
    {
        get
        {
            var value = accessor.HttpContext?.User.FindFirstValue(JwtRegisteredClaimNames.Sub)
                ?? accessor.HttpContext?.User.FindFirstValue(ClaimTypes.NameIdentifier)
                ?? accessor.HttpContext?.User.FindFirstValue("sub");
            return value is not null && Guid.TryParse(value, out var id) ? id : null;
        }
    }

    public string? Username =>
        accessor.HttpContext?.User.FindFirstValue(ClaimTypes.Name)
        ?? accessor.HttpContext?.User.FindFirstValue("name");

    public string? IpAddress
    {
        get
        {
            var context = accessor.HttpContext;
            if (context is null) return null;
            var forwarded = context.Request.Headers["X-Forwarded-For"].FirstOrDefault();
            if (!string.IsNullOrWhiteSpace(forwarded))
            {
                var first = forwarded.Split(',')[0].Trim();
                if (first.Length > 0) return Truncate(first, 45);
            }
            return Truncate(context.Connection.RemoteIpAddress?.ToString(), 45);
        }
    }

    public string? UserAgent =>
        Truncate(accessor.HttpContext?.Request.Headers.UserAgent.ToString(), 512);

    private static string? Truncate(string? value, int max) =>
        string.IsNullOrEmpty(value) ? value : (value.Length <= max ? value : value[..max]);
}