using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SKMC.Api.Common.Types
{
    /// <summary>
    /// 包含时间戳的数据集
    /// </summary>
    public class TimestampSet
    {

        private readonly int capacity;
        private readonly (long Ticks, int Value)[] buffer;
        private int currentIndex;
        private long oldestTicks;
        private readonly object _lock = new object();

        public TimestampSet(int capacity)
        {
            this.capacity = capacity;
            buffer = new (long, int)[capacity];
            currentIndex = 0;
            oldestTicks = long.MaxValue;
        }

        /// <summary>
        /// 添加与时间戳相关的数据
        /// </summary>
        /// <param name="ticks"></param>
        /// <param name="value"></param>
        public void Add(long ticks, int value)
        {
            lock (_lock)
            {
                buffer[currentIndex] = (ticks, value);
                currentIndex = (currentIndex + 1) % capacity;

                if (currentIndex == 0)
                {
                    oldestTicks = buffer[currentIndex].Ticks;
                }
            }
        }

        /// <summary>
        /// 添加当前"时间戳"的数据, 该"时间戳"为简化版: ticks/10000
        /// </summary>
        /// <param name="value"></param>
        public void Add(int value)
        {
            Add(DateTime.Now.Ticks / 10000, value);
        }

        /// <summary>
        /// 获取最新的一个数值
        /// </summary>
        /// <returns></returns>
        public int Take() => (currentIndex > 0) ? buffer[currentIndex - 1].Value : buffer[capacity - 1].Value;

        /// <summary>
        /// 获取某个时间戳之后的所有数据
        /// </summary>
        /// <param name="ticks">该"时间戳"为简化版: ticks/10000</param>
        /// <returns></returns>
        public List<int> GetDataAfter(long ticks)
        {
            List<int> result = new List<int>();

            lock (_lock)
            {
                for (int i = 0; i < capacity; i++)
                {
                    var entry = buffer[i];
                    if (entry.Ticks > ticks)
                    {
                        result.Add(entry.Value);
                    }
                }
            }
            return result;
        }
    }
}