using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;

namespace CoreAgent.ProtocolClient.Context.UeStateManager
{
    /// <summary>
    /// UeIdentifierManager 字符串ID管理部分
    /// </summary>
    public partial class UeIdentifierManager
    {
        #region 字符串ID管理方法

        /// <summary>
        /// 将字符串转换为ID，如果不存在则创建新的ID
        /// 性能优化：使用缓存减少重复计算
        /// </summary>
        /// <param name="str">要转换的字符串</param>
        /// <returns>对应的ID</returns>
        /// <exception cref="ArgumentNullException">字符串为空时抛出</exception>
        public int StringToId(string str)
        {
            if (string.IsNullOrEmpty(str))
            {
                _logger?.LogWarning("尝试转换空字符串为ID");
                return 0;
            }

            lock (_lockObject)
            {
                IncrementCacheStat("StringToId");

                if (_stringIdCache.TryGetValue(str, out int existingId))
                {
                    IncrementCacheStat("CacheHits");
                    return existingId;
                }

                IncrementCacheStat("CacheMisses");
                int newId = _stringList.Count + 1;
                _stringIdCache[str] = newId;
                _stringList.Add(str);

                _logger?.LogDebug("创建新的字符串ID映射: '{String}' -> {Id}", str, newId);
                return newId;
            }
        }

        /// <summary>
        /// 根据ID获取对应的字符串
        /// 性能优化：使用缓存减少重复计算
        /// </summary>
        /// <param name="id">字符串ID</param>
        /// <returns>对应的字符串，如果ID无效则返回空字符串</returns>
        public string IdToString(int id)
        {
            if (id <= 0)
            {
                _logger?.LogWarning("尝试获取无效ID的字符串: {Id}", id);
                return string.Empty;
            }

            lock (_lockObject)
            {
                IncrementCacheStat("IdToString");

                if (id <= _stringList.Count)
                {
                    IncrementCacheStat("CacheHits");
                    return _stringList[id - 1];
                }

                IncrementCacheStat("CacheMisses");
                _logger?.LogWarning("ID超出范围: {Id}, 最大ID: {MaxId}", id, _stringList.Count);
                return string.Empty;
            }
        }

        /// <summary>
        /// 批量转换字符串为ID
        /// 性能优化：批量处理减少锁开销
        /// </summary>
        /// <param name="strings">字符串列表</param>
        /// <returns>对应的ID列表</returns>
        public List<int> StringToIdBatch(IEnumerable<string> strings)
        {
            if (strings == null)
            {
                throw new ArgumentNullException(nameof(strings));
            }

            var results = new List<int>();
            lock (_lockObject)
            {
                foreach (var str in strings)
                {
                    results.Add(StringToId(str));
                }
            }

            _logger?.LogDebug("批量转换字符串为ID，共处理 {Count} 个字符串", results.Count);
            return results;
        }

        /// <summary>
        /// 获取字符串缓存信息
        /// </summary>
        /// <returns>缓存信息</returns>
        public (int CacheSize, int ListSize) GetStringCacheInfo()
        {
            lock (_lockObject)
            {
                return (_stringIdCache.Count, _stringList.Count);
            }
        }

        #endregion

        #region 私有辅助方法

        /// <summary>
        /// 增加缓存统计计数
        /// </summary>
        /// <param name="statName">统计名称</param>
        private void IncrementCacheStat(string statName)
        {
            if (_cacheStats.ContainsKey(statName))
            {
                _cacheStats[statName]++;
            }
        }

        #endregion
    }
}