using System;
using System.Runtime.InteropServices;

namespace AlicizaX
{
    /// <summary>
    /// 内存池信息。
    /// </summary>
    [StructLayout(LayoutKind.Auto)]
    public struct MemoryPoolInfo
    {
        private readonly Type _type;
        private readonly int _unusedCount;
        private readonly int _usingCount;
        private readonly int _acquireCount;
        private readonly int _releaseCount;
        private readonly int _createCount;
        private readonly int _highWaterMark;
        private readonly int _maxCapacity;
        private readonly int _idleFrames;
        private readonly int _poolArrayLength;

        public MemoryPoolInfo(Type type, int unusedCount, int usingCount,
            int acquireCount, int releaseCount, int createCount,
            int highWaterMark, int maxCapacity,
            int idleFrames, int poolArrayLength)
        {
            _type = type;
            _unusedCount = unusedCount;
            _usingCount = usingCount;
            _acquireCount = acquireCount;
            _releaseCount = releaseCount;
            _createCount = createCount;
            _highWaterMark = highWaterMark;
            _maxCapacity = maxCapacity;
            _idleFrames = idleFrames;
            _poolArrayLength = poolArrayLength;
        }

        /// <summary>
        /// 池类型。
        /// </summary>
        public Type Type => _type;

        /// <summary>
        /// 池中空闲对象数量（可立即借出）。
        /// </summary>
        public int UnusedCount => _unusedCount;

        /// <summary>
        /// 当前被借出、尚未归还的对象数量。
        /// </summary>
        public int UsingCount => _usingCount;

        /// <summary>
        /// 累计 Acquire 调用次数（仅开发模式有效）。
        /// </summary>
        public int AcquireCount => _acquireCount;

        /// <summary>
        /// 累计 Release 调用次数（仅开发模式有效）。
        /// </summary>
        public int ReleaseCount => _releaseCount;

        /// <summary>
        /// 累计 new T() 创建次数（池不够时的实际分配，仅开发模式有效）。
        /// </summary>
        public int CreateCount => _createCount;

        /// <summary>
        /// 近期峰值并发使用量。回收策略据此决定保留多少对象。
        /// </summary>
        public int HighWaterMark => _highWaterMark;

        /// <summary>
        /// 池容量硬上限。超出后 Release 的对象直接丢弃交给 GC。
        /// </summary>
        public int MaxCapacity => _maxCapacity;

        /// <summary>
        /// 连续无 Acquire 的帧数。>=300 开始温和回收，>=900 激进回收+高水位衰减。
        /// </summary>
        public int IdleFrames => _idleFrames;

        /// <summary>
        /// 底层 T[] 数组的实际长度。反映真实内存占用（含空槽）。
        /// </summary>
        public int PoolArrayLength => _poolArrayLength;
    }
}