using LY.App.Extensions.DI;
using StackExchange.Redis;
using System.Text.Json;

namespace LY.App.Common.Redis
{
    /// <summary>
    /// redis 连接服务
    /// </summary>
    public class RedisService
    {
        private readonly IDatabase _db;

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="connectionString"></param>
        public RedisService(string connectionString)
        {
            var redis = ConnectionMultiplexer.Connect(connectionString);
            _db = redis.GetDatabase();
        }

        /// <summary>
        /// 泛型存储数据到 Redis
        /// </summary>
        public async Task<bool> SetAsync<T>(string key, T value, TimeSpan? expiry = null)
        {
            string jsonData = JsonSerializer.Serialize(value);
            return await _db.StringSetAsync(key, jsonData, expiry);
        }

        /// <summary>
        /// 泛型获取数据
        /// </summary>
        public async Task<T?> GetAsync<T>(string key)
        {
            string jsonData = await _db.StringGetAsync(key);
            return jsonData is not null ? JsonSerializer.Deserialize<T>(jsonData) : default;
        }

        /// <summary>
        /// 删除 Key
        /// </summary>
        public async Task<bool> DeleteAsync(string key)
        {
            return await _db.KeyDeleteAsync(key);
        }

        /// <summary>
        /// 检查 Key 是否存在
        /// </summary>
        public async Task<bool> ExistsAsync(string key)
        {
            return await _db.KeyExistsAsync(key);
        }
        /// <summary>
        /// 获取数据，如果不存在则从数据源获取并存入 Redis
        /// </summary>
        /// <typeparam name="T">数据类型</typeparam>
        /// <param name="key">Redis Key</param>
        /// <param name="factory">数据源方法</param>
        /// <param name="expiry">可选的过期时间</param>
        /// <returns>获取到的值</returns>
        public async Task<T?> GetOrSetAsync<T>(string key, Func<Task<T>> factory, TimeSpan? expiry = null)
        {
            var value = await GetAsync<T>(key);
            if (value is not null)
            {
                return value;
            }

            value = await factory();
            if (value is not null)
            {
                await SetAsync(key, value, expiry);
            }
            return value;
        }
    }
}