using System;
using System.ComponentModel;
using System.Threading;

namespace CoreUnit.Common
{
    public class BackgroundWorkerUnit : IDisposable
    {
        delegate void UpdatePageCallBack();

        public delegate void EventDoWork();
        public EventDoWork evtDoWork;

        protected BackgroundWorker m_backgroundWorker;
        public BackgroundWorker backgroundWorker {
            get { lock (this) { return m_backgroundWorker; } }
            set { lock (this) { m_backgroundWorker = value; } }
        }

        int m_progressPercentage = 0;
        public int ProgressPercentage {
            get { lock (this) { return m_progressPercentage; } }
            set { lock (this) { m_progressPercentage = value; } }
        }

        bool m_isDoWorkCompleted = false;
        public bool IsDoWorkCompleted {
            get { lock (this) { return m_isDoWorkCompleted; } }
            set { lock (this) { m_isDoWorkCompleted = value; } }
        }

        System.Windows.Forms.Control m_ctrl = null;

        System.Threading.Timer m_backgroundWorkerTimer = null;
        int m_period = 0;
        public int Period {
            get { lock (this) { return m_period; } }
            set { lock (this) { m_period = value; } }
        }

        public void StartBackgroundWorker()
        {
            m_backgroundWorkerTimer = new System.Threading.Timer(RunDoWork, null, 0, m_period);
        }

        public void StopBackgroundWorker()
        {
            if (m_backgroundWorkerTimer != null) {
                m_backgroundWorkerTimer.Dispose();
            }
        }

        public BackgroundWorkerUnit(System.Windows.Forms.Control ctrl, int period = 300)
        {
            m_ctrl = ctrl;
            m_period = period;
            m_backgroundWorker = new BackgroundWorker();
            m_backgroundWorker.WorkerReportsProgress = true;
            m_backgroundWorker.WorkerSupportsCancellation = true;
            m_backgroundWorker.DoWork += new DoWorkEventHandler(DoWork);
            m_backgroundWorker.ProgressChanged += new ProgressChangedEventHandler(ProgressChanged);
            m_backgroundWorker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(RunWorkerCompleted);
        }

        //public void DoWork(object sender, DoWorkEventArgs e)
        //{

        //    while (backgroundWorker.CancellationPending != true)
        //    {
        //        if (m_ctrl.InvokeRequired)
        //        {
        //            UpdatePageCallBack d = new UpdatePageCallBack(evtDoWork);
        //            m_ctrl.Invoke(d, new object[] { });
        //        }
        //        else
        //        {
        //            evtDoWork();
        //        }

        //        Thread.Sleep(m_period);
        //    }

        //}

        //public void ProgressChanged(object sender, ProgressChangedEventArgs e)
        //{
        //    ProgressPercentage = e.ProgressPercentage;
        //}
        public void ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            evtDoWork();
        }

        public void DoWork(object sender, DoWorkEventArgs e)
        {
            while (m_backgroundWorker.CancellationPending != true) {
                m_backgroundWorker.ReportProgress(0);
                Thread.Sleep(Period);
            }

            e.Cancel = true;
        }
        private void RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (e.Error != null) {
                return;
            }

            IsDoWorkCompleted = true;
        }

        public void RunDoWork(object obj)
        {
            if (!backgroundWorker.IsBusy) {
                IsDoWorkCompleted = false;
                backgroundWorker.RunWorkerAsync();
            }
        }

        public void StopDoWork()
        {
            if (backgroundWorker.CancellationPending != true) {
                backgroundWorker.CancelAsync();
            }
        }

        public void Dispose()
        {
            StopBackgroundWorker();
            backgroundWorker.CancelAsync();
        }
    }
}