using Microsoft.AspNetCore.Hosting.Server;
using Microsoft.AspNetCore.Http.Features;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Nacos.V2;
using Nacos.V2.Naming.Core;
using Nacos.V2.Naming.Dtos;

namespace Ocelot.Provider.Nacos.NacosClient.V2;

public class RegSvcBgTask
{
    private static readonly string MetadataNetVersion = "DOTNET_VERSION";
    private static readonly string MetadataHostOs = "HOST_OS";
    private static readonly string MetadataSecure = "secure";

    private readonly ILogger _logger;
    private readonly INacosNamingService _svc;
    private readonly IFeatureCollection _features;
    private NacosAspNetOptions _options;

    private IEnumerable<Uri> uris = null;

    public RegSvcBgTask(
        ILoggerFactory loggerFactory,
        INacosNamingService svc,
        IServer server,
        IOptionsMonitor<NacosAspNetOptions> optionsAccs)
    {
        _logger = loggerFactory.CreateLogger<RegSvcBgTask>();
        _svc = svc;
        _options = optionsAccs.CurrentValue;
        _features = server.Features;
    }

    public async Task StartAsync()
    {
        if (!_options.RegisterEnabled)
        {
            _logger.LogInformation("setting RegisterEnabled to false, will not register to nacos");
            return;
        }

        uris = UriTool.GetUri(_features, _options.Ip, _options.Port, _options.PreferredNetworks);

        var metadata = new Dictionary<string, string>()
        {
            { PreservedMetadataKeys.REGISTER_SOURCE, $"ASPNET_CORE" },
            { MetadataNetVersion, Environment.Version.ToString() },
            { MetadataHostOs, Environment.OSVersion.ToString() },
        };

        if (_options.Secure) metadata[MetadataSecure] = "true";

        foreach (var item in _options.Metadata)
        {
            if (!metadata.ContainsKey(item.Key))
            {
                metadata.TryAdd(item.Key, item.Value);
            }
        }

        foreach (var uri in uris)
        {
            for (int i = 0; i < 3; i++)
            {
                try
                {
                    var instance = new Instance
                    {
                        Ephemeral = _options.Ephemeral,
                        ServiceName = _options.ServiceName,
                        ClusterName = _options.ClusterName,
                        Enabled = _options.InstanceEnabled,
                        Healthy = true,
                        Ip = uri.Host,
                        Port = uri.Port,
                        Weight = _options.Weight,
                        Metadata = metadata,
                        InstanceId = ""
                    };

                    _logger.LogInformation("register instance to nacos server, 【{0}】", instance);

                    await _svc.RegisterInstance(_options.ServiceName, _options.GroupName, instance);
                    break;
                }
                catch (Exception ex)
                {
                    _logger.LogError(ex, "register instance error, count = {0}", i + 1);
                }
            }
        }
    }

    public async Task StopAsync()
    {
        if (_options.RegisterEnabled)
        {
            _logger.LogWarning("deregister instance from nacos server, serviceName={0}", _options.ServiceName);

            foreach (var uri in uris)
            {
                for (int i = 0; i < 3; i++)
                {
                    try
                    {
                        _logger.LogWarning("begin to remove instance");
                        await _svc.DeregisterInstance(_options.ServiceName, _options.GroupName, uri.Host, uri.Port, _options.ClusterName);
                        _logger.LogWarning("removed instance");
                        break;
                    }
                    catch (Exception ex)
                    {
                        _logger.LogError(ex, "deregister instance error, count = {0}", i + 1);
                    }
                }
            }
        }
    }
}