using System.Reflection;

namespace CirculateTool;
/*
 * 作者：菻蔃
 * 版本时间：2023年04月15日
 *
 * 注意配合特性使用
 *
 */

/// <summary>
/// 定时任务类
/// </summary>
public class StartCirculation
{

    /// <summary>
    /// 触发的异常
    /// </summary>
    public event ExceptionHandlerEvent? ExceptionHandler;

    public delegate void ExceptionHandlerEvent(string methodDescription, Exception ex);

    /// <summary>
    /// 显示相关信息
    /// </summary>
    public event MessageHandlerEvent? MessageHandler;

    public delegate void MessageHandlerEvent(string message);

    /// <summary>
    /// 默认的循环时间
    /// </summary>
    private readonly int _defaultCirculationTime = 500;

    /// <summary>
    /// 启动一个程序集里面带有<see cref="CirculationAttribute"/>的类里面的定时方法
    /// </summary>
    /// <param name="assembly"></param>
    /// <param name="instanceParams"></param>
    public virtual void StartAssemblyCirculation(Assembly assembly, object[]? instanceParams = null)
    {
        Type[] types = assembly.GetTypes();
        if (types.Length == 0) return;
        foreach (Type type in types)
        {
            var attributes = type.GetCustomAttributes(false);
            foreach (var attribute in attributes)
            {
                if (attribute is not CirculationAttribute) continue;
                StartTask(type, instanceParams);
                break;
            }
        }
    }

    /// <summary>
    /// 开启一个实例里面所有已经添加了特性<see cref="CirculationAttribute"/>的方法
    /// </summary>
    /// <param name="type"></param>
    /// <param name="instanceParams"></param>
    public virtual void StartTask(Type type, object[]? instanceParams = null)
    {
        var methods = type.GetMethods();
        foreach (var method in methods)
        {
            var attributes = method.GetCustomAttributes(false);
            foreach (var attribute in attributes)
            {
                if (attribute is not CirculationAttribute needDurable) continue;
                string methodDescription = needDurable.MethodDescription ?? $"{type.Name}.{method.Name}";
                bool Action() => (bool)(method.Invoke(Activator.CreateInstance(type, instanceParams), []) ?? false);
                StartTask(Action, methodDescription, needDurable.CirculationTime);
                break;
            }
        }
    }

    /// <summary>
    /// 开启一个方法
    /// </summary>
    /// <param name="action"></param>
    /// <param name="description"></param>
    /// <param name="durableTime"></param>
    /// <returns></returns>
    public virtual async void StartTask(Func<bool> action, string? description = null, int? durableTime = null)
    {
        int durableTimeValue = durableTime ?? _defaultCirculationTime;
        string methodDescription = description ?? action.Method.Name;
        CancellationTokenSource cts = new();
        PeriodicTimer timer = new(new TimeSpan(0, 0, 0, 0, durableTimeValue));
        MessageHandler?.Invoke($"定时器：{methodDescription}，已经启动，执行间隔为：{durableTimeValue} 毫秒。");
        while (await timer.WaitForNextTickAsync(cts.Token))
        {
            try
            {
                var result = action();
                if (result) continue;
                await cts.CancelAsync();
                MessageHandler?.Invoke($"定时器：{methodDescription}，主动结束。");
                return; // 该return会结束这个线程
            }
            catch (Exception ex)
            {
                ExceptionHandler?.Invoke(methodDescription, ex);
            }
        }
    }
}