// ***********************************************************************
// Assembly         : Construction
// Author           : flythink
// Created          : 06-05-2020
//
// Last Modified By : flythink
// Last Modified On : 09-01-2020
// ***********************************************************************
// <copyright file="SlowDownTimer.cs" company="jindongfang">
// Copyright (c) jindongfang. All rights reserved.
// </copyright>
// <summary></summary>
// ***********************************************************************

namespace Fk.Utils
{
    using System;
    using System.Threading;

    using Timer = System.Timers.Timer;

    /// <summary>
    /// Delegate SlowDownAction
    /// </summary>
    public delegate void SlowDownAction();

    /// <summary>
    /// Class SlowDownTimer.
    /// </summary>
    public class SlowDownTimer : IDisposable
    {
        private SlowDownAction action;

        private Timer onceTimer;

        private SynchronizationContext synchronizationContext;

        private bool disposed = false;
        /// <summary>
        /// Initializes a new instance of the <see cref="SlowDownTimer" /> class.
        /// </summary>
        /// <param name="interval">The interval.</param>
        /// <param name="autoReset">是否重复执行</param>
        public SlowDownTimer(double interval, bool autoReset = false)
        {
            this.synchronizationContext = SynchronizationContext.Current;

            this.onceTimer = new Timer(interval);
            this.onceTimer.AutoReset = autoReset;
            this.onceTimer.Elapsed += this.OnceTimer_Elapsed;
        }
        /// <summary>
        /// Finalizes an instance of the <see cref="SlowDownTimer"/> class.
        /// </summary>
        ~SlowDownTimer()
        {
            this.Dispose(false);
        }
        /// <inheritdoc/>
        public void Dispose()
        {
            if (!this.disposed)
            {
                this.Dispose(true);
            }
            GC.SuppressFinalize(this);
        }
        /// <summary>
        /// 释放非托管数据
        /// </summary>
        /// <param name="disposing">是否非托管</param>
        protected virtual void Dispose(bool disposing)
        {
            if (!this.disposed)
            {
                if (this.onceTimer != null)
                {
                    this.onceTimer.Elapsed -= this.OnceTimer_Elapsed;
                    this.onceTimer.Close();
                    this.onceTimer.Dispose();
                }

                // Violates rule: DisposableFieldsShouldBeDisposed.
                // Should call aFieldOfADisposableType.Dispose();
                this.disposed = true;
                // Suppress finalization of this disposed instance.
                if (disposing)
                {
                    GC.SuppressFinalize(this);
                }
            }
        }

        /// <summary>
        /// Invokes the specified action.
        /// </summary>
        /// <param name="action">The action.</param>
        public void Invoke(SlowDownAction action)
        {
            this.onceTimer.Stop();

            this.action = action;

            this.onceTimer.Start();
        }

        private void OnceTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        {
            this.synchronizationContext.Post(_ => { this.action?.Invoke(); }, null);
        }
    }
}