using System;
using System.Collections.Concurrent;
using System.Linq;
using NewLife.Log;
using NewLife.Threading;
using Stardust.Data.Monitors;

namespace Stardust.Server.Services
{
    /// <summary>跟踪项统计服务</summary>
    public interface ITraceItemStatService
    {
        /// <summary>添加需要统计的应用，去重</summary>
        /// <param name="appId"></param>
        void Add(Int32 appId);

        /// <summary>统计指定应用</summary>
        /// <param name="appId"></param>
        /// <param name="days"></param>
        void Process(Int32 appId, Int32 days);
    }

    /// <summary>跟踪项统计服务</summary>
    public class TraceItemStatService : ITraceItemStatService
    {
        /// <summary>批计算周期。默认600秒</summary>
        public Int32 BatchPeriod { get; set; } = 600;

        private TimerX _timer;
        private readonly ConcurrentBag<Int32> _bag = new();
        private readonly ITracer _tracer;

        public TraceItemStatService(ITracer tracer) => _tracer = tracer;

        /// <summary>添加需要统计的应用，去重</summary>
        /// <param name="appId"></param>
        public void Add(Int32 appId)
        {
            if (!_bag.Contains(appId)) _bag.Add(appId);

            // 初始化定时器
            if (_timer == null && BatchPeriod > 0)
            {
                lock (this)
                {
                    if (_timer == null && BatchPeriod > 0) _timer = new TimerX(DoTraceStat, null, 1_000, BatchPeriod * 1000) { Async = true };
                }
            }

            //if (_timer.NextTime > DateTime.Now.AddSeconds(5)) _timer.SetNext(-1);
        }

        private void DoTraceStat(Object state)
        {
            while (_bag.TryTake(out var appId))
            {
                using var span = _tracer?.NewSpan("TraceItemStat-Process", appId);
                try
                {
                    Process(appId, 7);
                }
                catch (Exception ex)
                {
                    span.SetError(ex, null);
                    throw;
                }
            }
        }

        public void Process(Int32 appId, Int32 days = 7)
        {
            var startTime = DateTime.Today.AddDays(-days);

            var app = AppTracer.FindByID(appId);
            var list = TraceItem.GetValids(appId, startTime);
            var sts = TraceDayStat.SearchGroupItemByApp(appId, startTime);
            foreach (var st in sts)
            {
                var ti = list.FirstOrDefault(e => e.Id == st.ItemId);
                if (ti == null && st.ItemId > 0) ti = TraceItem.FindById(st.ItemId);

                // 只统计能找到的跟踪项
                if (ti != null)
                {
                    ti.Days = st.ID;
                    ti.Total = st.Total;
                    ti.Errors = st.Errors;
                    ti.Cost = st.Cost;
                    ti.Update();
                }
            }
        }
    }
}