using FileShare_Common.Core;
using FileShare_Services.Core;
using QRCoder;
using System.Net;
using System.Net.NetworkInformation;
using System.Net.Sockets;

namespace FileShare_Services.Services.QrCode
{
    public sealed class QrCodeService : IQrCodeService
    {
        public Task<object?> GenerateQrCodeAsync(ServiceEndpointContext ctx)
        {
            var ip = GetLanIpAddress();
            if (ip is null)
                throw new InvalidOperationException("无法获取局域网IP地址");

            var url = $"http://{ip}:5206";
            var base64 = GeneratePngBase64(url);
            return Task.FromResult<object?>(ResponseHelper.Ok(new QrCodeResponse(url, base64)));
        }

        private static string GeneratePngBase64(string content)
        {
            using var generator = new QRCodeGenerator();
            using var data = generator.CreateQrCode(content, QRCodeGenerator.ECCLevel.Q);
            using var png = new PngByteQRCode(data);
            var bytes = png.GetGraphic(20);
            return $"data:image/png;base64,{Convert.ToBase64String(bytes)}";
        }

        private static string? GetLanIpAddress()
        {
            return NetworkInterface.GetAllNetworkInterfaces()
                .Where(ni => ni.OperationalStatus == OperationalStatus.Up
                             && ni.NetworkInterfaceType != NetworkInterfaceType.Loopback)
                .SelectMany(ni => ni.GetIPProperties().UnicastAddresses)
                .Select(ua => ua.Address)
                .FirstOrDefault(ip =>
                    ip.AddressFamily == AddressFamily.InterNetwork
                    && !IPAddress.IsLoopback(ip)
                    && !ip.ToString().StartsWith("169.254"))
                ?.ToString();
        }
    }
}