using Hopetry.Provider;
using Newtonsoft.Json;
using StackExchange.Redis;

namespace Hopetry.Services
{
    public class RedisService : IDisposable
    {
        private readonly ConnectionMultiplexer _redis;
        private readonly IDatabase _db;
        private const string Prefix = "client:";

        public RedisService(string connectionString)
        {
            var config = ConfigurationOptions.Parse(connectionString);
            config.AbortOnConnectFail = false;
            config.ConnectTimeout = 5000;
            _redis = ConnectionMultiplexer.Connect(config);
            _db = _redis.GetDatabase();
        }

        // 存储客户端信息（自动过期30天）
        public async Task StoreClientInfoAsync(SystemInfo info)
        {
            var key = $"{Prefix}{info.MachineId}";
            var json = JsonConvert.SerializeObject(info);
            await _db.StringSetAsync(key, json, TimeSpan.FromMinutes(5));
        }

        // 获取单个客户端信息
        public async Task<SystemInfo> GetClientInfoAsync(string machineId)
        {
            var json = await _db.StringGetAsync($"{Prefix}{machineId}");
            return json.HasValue ? JsonConvert.DeserializeObject<SystemInfo>(json) : null;
        }

        // 获取所有客户端信息
        public async Task<List<SystemInfo>> GetAllClientsAsync()
        {
            var endpoints = _redis.GetEndPoints();
            var server = _redis.GetServer(endpoints.First());
            var keys = server.Keys(pattern: $"{Prefix}*").ToArray();

            var results = new List<SystemInfo>();
            foreach (var key in keys)
            {
                var json = await _db.StringGetAsync(key);
                if (json.HasValue)
                {
                    results.Add(JsonConvert.DeserializeObject<SystemInfo>(json));
                }
            }
            return results;
        }

        // 删除客户端信息
        public async Task<bool> DeleteClientAsync(string machineId)
        {
            return await _db.KeyDeleteAsync($"{Prefix}{machineId}");
        }

        // 新增心跳键前缀
        private const string HeartbeatPrefix = "heartbeat:";

        // 更新客户端心跳（核心新增方法）
        public async Task UpdateClientHeartbeatAsync(string machineId)
        {
            // 同时更新两个键的过期时间：
            // 1. 客户端信息键（保持长期有效）
            // 2. 心跳状态键（短期存活检测）
            var tasks = new List<Task>
            {
                // 刷新客户端信息过期时间（30天）
                _db.KeyExpireAsync($"{Prefix}{machineId}", TimeSpan.FromMinutes(5)),
                
                // 设置/更新心跳状态（带5分钟过期）
                _db.StringSetAsync(
                    $"{HeartbeatPrefix}{machineId}",
                    DateTime.UtcNow.ToString("o"),
                    expiry: TimeSpan.FromMinutes(5)
                )
            };

            await Task.WhenAll(tasks);
        }

        // 获取所有活跃客户端ID（基于心跳键）
        public async Task<List<string>> GetActiveClientIdsAsync()
        {
            var endpoints = _redis.GetEndPoints();
            var server = _redis.GetServer(endpoints.First());

            // 注意：生产环境应改用SCAN
            var heartbeatKeys = server.Keys(pattern: $"{HeartbeatPrefix}*");

            return heartbeatKeys
                .Select(k => k.ToString().Substring(HeartbeatPrefix.Length))
                .ToList();
        }

        // 检查客户端是否活跃
        public async Task<bool> IsClientActiveAsync(string machineId)
        {
            return await _db.KeyExistsAsync($"{HeartbeatPrefix}{machineId}");
        }

        public void Dispose()
        {
            _redis?.Dispose();
        }
    }
}