using Nacos.V2;
using Newtonsoft.Json;
using System.Threading.Tasks;
using Yarp.ReverseProxy.Configuration;

namespace YuanXuan.IM.Api.Proxy
{
    /// <summary>
    /// Nacos代理配置提供者
    /// </summary>
    public class NacosProxyConfigProvider : IProxyConfigProvider
    {
        private readonly INacosNamingService _nacosNamingService;
        private readonly IConfiguration _configuration;
        private volatile IProxyConfig _config;
        private CancellationTokenSource _cts;

        public NacosProxyConfigProvider(INacosNamingService nacosNamingService, IConfiguration configuration)
        {
            _nacosNamingService = nacosNamingService;
            _configuration = configuration;
            
            // 立即从Nacos获取服务实例
            _config = CreateConfig();
            // 通知YARP配置已变更
            ProxyConfig.SignalChange();
            _cts = new CancellationTokenSource();

            // 启动后台任务，定期从Nacos更新服务实例
            Task.Run(async () => await UpdateConfigPeriodically(), _cts.Token);
        }

        /// <summary>
        /// 创建配置
        /// </summary>
        /// <returns></returns>
        private IProxyConfig CreateConfig()
        {
            var routes = new List<RouteConfig>
            {
                new RouteConfig
                {
                    RouteId = "api_route",
                    ClusterId = "api_cluster",
                    Match = new RouteMatch
                    {
                        Path = "/api/{**catch-all}"
                    }
                },
                new RouteConfig
                {
                    RouteId = "user_route",
                    ClusterId = "user_cluster",
                    Match = new RouteMatch
                    {
                        Path = "/user/{**catch-all}"
                    }
                },
                new RouteConfig
                {
                    RouteId = "testdemo1",
                    ClusterId = "test_cluster",
                    Match = new RouteMatch
                    {
                        Path = "/test/{**catch-all}"
                    }
                }
            };

            var clusters = new List<ClusterConfig>();

            try
            {
                // 从Nacos获取YuanXuan.Api服务实例，指定分组为qx-im
                var apiServiceInstances = _nacosNamingService.GetAllInstances("YuanXuan.Api", "qx-im").Result;

                if (apiServiceInstances.Any())
                {
                    // 创建api_cluster集群配置
                    var apiDestinations = new Dictionary<string, DestinationConfig>();

                    foreach (var instance in apiServiceInstances)
                    {
                        if (instance.Healthy)
                        {
                            var destinationId = $"{instance.Ip}:{instance.Port}";
                            apiDestinations.Add(destinationId, new DestinationConfig
                            {
                                Address = $"http://{instance.Ip}:{instance.Port}"
                            });
                        }
                    }

                    clusters.Add(new ClusterConfig
                    {
                        ClusterId = "api_cluster",
                        Destinations = apiDestinations
                    });
                }

                // 从Nacos获取User.Service服务实例，指定分组为qx-im
                try
                {
                    var userServiceInstances = _nacosNamingService.GetAllInstances("User.Service", "qx-im").Result;

                    if (userServiceInstances.Any())
                    {
                        // 创建user_cluster集群配置
                        var userDestinations = new Dictionary<string, DestinationConfig>();

                        foreach (var instance in userServiceInstances)
                        {
                            if (instance.Healthy)
                            {
                                var destinationId = $"{instance.Ip}:{instance.Port}";
                                userDestinations.Add(destinationId, new DestinationConfig
                                {
                                    Address = $"http://{instance.Ip}:{instance.Port}"
                                });
                            }
                        }

                        clusters.Add(new ClusterConfig
                        {
                            ClusterId = "user_cluster",
                            Destinations = userDestinations
                        });
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"从Nacos获取User.Service服务实例失败: {ex.Message}");
                }

                // 从Nacos获取Test.Service服务实例，指定分组为qx-im
                try
                {
                    var testServiceInstances = _nacosNamingService.GetAllInstances("Test.Service", "qx-im").Result;

                    if (testServiceInstances.Any())
                    {
                        // 创建test_cluster集群配置
                        var testDestinations = new Dictionary<string, DestinationConfig>();

                        foreach (var instance in testServiceInstances)
                        {
                            if (instance.Healthy)
                            {
                                var destinationId = $"{instance.Ip}:{instance.Port}";
                                testDestinations.Add(destinationId, new DestinationConfig
                                {
                                    Address = $"http://{instance.Ip}:{instance.Port}"
                                });
                            }
                        }

                        clusters.Add(new ClusterConfig
                        {
                            ClusterId = "test_cluster",
                            Destinations = testDestinations
                        });
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"从Nacos获取Test.Service服务实例失败: {ex.Message}");
                }

                Console.WriteLine($"{DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss")}：" + JsonConvert.SerializeObject(clusters));
            }
            catch (Exception ex)
            {
                Console.WriteLine($"从Nacos获取服务实例失败: {ex.Message}");
            }

            // 如果没有从Nacos获取到api_cluster集群，使用默认配置
            if (!clusters.Any(c => c.ClusterId == "api_cluster"))
            {
                clusters.Add(new ClusterConfig
                {
                    ClusterId = "api_cluster",
                    Destinations = new Dictionary<string, DestinationConfig>
                    {
                        { 
                            "default", new DestinationConfig { Address = "http://localhost:5001" } 
                        }
                    }
                });
            }

            // 如果没有从Nacos获取到user_cluster集群，使用默认配置
            if (!clusters.Any(c => c.ClusterId == "user_cluster"))
            {
                clusters.Add(new ClusterConfig
                {
                    ClusterId = "user_cluster",
                    Destinations = new Dictionary<string, DestinationConfig>
                    {
                        { 
                            "default", new DestinationConfig { Address = "http://localhost:5181" } 
                        }
                    }
                });
            }

            // 如果没有从Nacos获取到test_cluster集群，使用默认配置
            if (!clusters.Any(c => c.ClusterId == "test_cluster"))
            {
                clusters.Add(new ClusterConfig
                {
                    ClusterId = "test_cluster",
                    Destinations = new Dictionary<string, DestinationConfig>
                    {
                        { 
                            "default", new DestinationConfig { Address = "http://localhost:5252" } 
                        }
                    }
                });
            }

            return new ProxyConfig(routes, clusters, DateTime.UtcNow);
        }

        /// <summary>
        /// 获取代理配置
        /// </summary>
        /// <returns></returns>
        public IProxyConfig GetConfig() => _config;

        /// <summary>
        /// 定期更新配置
        /// </summary>
        /// <returns></returns>
        private async Task UpdateConfigPeriodically()
        {
            while (!_cts.Token.IsCancellationRequested)
            {
                try
                {
                    await Task.Delay(TimeSpan.FromSeconds(30), _cts.Token); // 每30秒更新一次
                    await UpdateConfig();
                }
                catch (TaskCanceledException)
                {
                    // 任务被取消，退出循环
                    break;
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"更新Nacos代理配置失败: {ex.Message}");
                }
            }
        }

        /// <summary>
        /// 更新配置
        /// </summary>
        /// <returns></returns>
        private async Task UpdateConfig()
        {
            // 重新从Nacos获取服务实例并更新配置
            _config = CreateConfig();
            // 通知YARP配置已变更
            ProxyConfig.SignalChange();
        }

    }

}