using LibationWinForms.BookLiberation;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace LibationWinForms.ProcessQueue
{
	internal partial class ProcessQueueControl : UserControl, ILogForm
	{
		private TrackedQueue<ProcessBook> Queue = new();
		private readonly LogMe Logger;
		private SynchronizationContext SyncContext { get; } = SynchronizationContext.Current;
		private int QueuedCount
		{
			set
			{
				queueNumberLbl.Text = value.ToString();
				queueNumberLbl.Visible = value > 0;
			}
		}
		private int ErrorCount
		{
			set
			{
				errorNumberLbl.Text = value.ToString();
				errorNumberLbl.Visible = value > 0;
			}
		}

		private int CompletedCount
		{
			set
			{
				completedNumberLbl.Text = value.ToString();
				completedNumberLbl.Visible = value > 0;
			}
		}


		public Task QueueRunner { get; private set; }
		public bool Running => !QueueRunner?.IsCompleted ?? false;
		public ToolStripButton popoutBtn = new();

		public ProcessQueueControl()
		{
			InitializeComponent();
			Logger = LogMe.RegisterForm(this);

			runningTimeLbl.Text = string.Empty;
			popoutBtn.DisplayStyle = ToolStripItemDisplayStyle.Text;
			popoutBtn.Name = "popoutBtn";
			popoutBtn.Text = "Pop Out";
			popoutBtn.TextAlign = System.Drawing.ContentAlignment.MiddleCenter;
			popoutBtn.Alignment = ToolStripItemAlignment.Right;
			popoutBtn.Anchor = AnchorStyles.Bottom | AnchorStyles.Right;

			statusStrip1.Items.Add(popoutBtn);

			virtualFlowControl2.RequestData += VirtualFlowControl1_RequestData;
			virtualFlowControl2.ButtonClicked += VirtualFlowControl2_ButtonClicked;

			Queue.QueuededCountChanged += Queue_QueuededCountChanged;
			Queue.CompletedCountChanged += Queue_CompletedCountChanged;

			QueuedCount = 0;
			ErrorCount = 0;
			CompletedCount = 0;
		}

		public void AddDownloadPdf(IEnumerable<DataLayer.LibraryBook> entries)
		{
			Action<IEnumerable<DataLayer.LibraryBook>> makeAll = (lb) =>
			{
				foreach (var entry in entries)
					AddDownloadPdf(entry);
			};
			//IEnumerable<DataLayer.LibraryBook> are run on non-ui thread, so send collection to UI first
			PassToUIThread(entries, makeAll);
		}

		public void AddDownloadDecrypt(IEnumerable<DataLayer.LibraryBook> entries)
		{
			Action<IEnumerable<DataLayer.LibraryBook>> makeAll = (lb) =>
			{
				foreach (var entry in entries)
					AddDownloadDecrypt(entry);
			};
			//IEnumerable<DataLayer.LibraryBook> are run on non-ui thread, so send collection to UI first
			PassToUIThread(entries, makeAll);
		}
		
		public void AddConvertMp3(IEnumerable<DataLayer.LibraryBook> entries)
		{
			Action<IEnumerable<DataLayer.LibraryBook>> makeAll = (lb) =>
			{
				foreach (var entry in entries)
					AddConvertMp3(entry);
			};
			//IEnumerable<DataLayer.LibraryBook> are run on non-ui thread, so send collection to UI first
			PassToUIThread(entries, makeAll);
		}

		public void AddDownloadPdf(DataLayer.LibraryBook libraryBook)
		{
			if (Queue.Any(b => b?.LibraryBook?.Book?.AudibleProductId == libraryBook.Book.AudibleProductId))
				return;

			ProcessBook pbook = new(libraryBook, Logger);
			pbook.PropertyChanged += Pbook_DataAvailable;
			pbook.AddDownloadPdf();
			AddToQueue(pbook);
		}

		public void AddDownloadDecrypt(DataLayer.LibraryBook libraryBook)
		{
			if (Queue.Any(b => b?.LibraryBook?.Book?.AudibleProductId == libraryBook.Book.AudibleProductId))
				return;

			ProcessBook pbook = new(libraryBook, Logger);
			pbook.PropertyChanged += Pbook_DataAvailable;
			pbook.AddDownloadDecryptBook();
			pbook.AddDownloadPdf();
			AddToQueue(pbook);
		}

		public void AddConvertMp3(DataLayer.LibraryBook libraryBook)
		{
			if (Queue.Any(b => b?.LibraryBook?.Book?.AudibleProductId == libraryBook.Book.AudibleProductId))
				return;

			ProcessBook pbook = new(libraryBook, Logger);
			pbook.PropertyChanged += Pbook_DataAvailable;
			pbook.AddConvertToMp3();
			AddToQueue(pbook);
		}

		private void PassToUIThread(IEnumerable<DataLayer.LibraryBook> libraryBooks, Action<IEnumerable<DataLayer.LibraryBook>> onComplete)
		{
			void OnSendOrPostCallback(object asyncArgs)
			{
				onComplete((IEnumerable<DataLayer.LibraryBook>)asyncArgs);
			}
			SyncContext.Send(OnSendOrPostCallback, libraryBooks);
		}

		private void AddToQueue(ProcessBook pbook)
		{
			Queue.Enqueue(pbook);

			if (!Running)
			{
				QueueRunner = QueueLoop();
			}
		}

		DateTime StartintTime;
		private async Task QueueLoop()
		{
			StartintTime = DateTime.Now;
			counterTimer.Start();

			while (Queue.MoveNext())
			{
				var nextBook = Queue.Current;

				var result = await nextBook.ProcessOneAsync();

				if (result == ProcessBookResult.FailedRetry)
					Queue.Enqueue(nextBook);
				else if (result == ProcessBookResult.ValidationFail)
					Queue.ClearCurrent();
				else if (result == ProcessBookResult.FailedAbort)
					return;
			}

			Queue_CompletedCountChanged(this, 0);
			counterTimer.Stop();
			virtualFlowControl2.VirtualControlCount = Queue.Count;
			UpdateAllControls();
		}

		public void WriteLine(string text)
		{
			if (IsDisposed) return;

			var timeStamp = DateTime.Now;
			logDGV.Rows.Add(timeStamp, text.Trim());
		}

		#region Control event handlers

		private void Queue_CompletedCountChanged(object sender, int e)
		{
			int errCount = Queue.Completed.Count(p => p.Result is ProcessBookResult.FailedAbort or ProcessBookResult.FailedSkip or ProcessBookResult.ValidationFail);
			int completeCount = Queue.Completed.Count(p => p.Result is ProcessBookResult.Success);

			ErrorCount = errCount;
			CompletedCount = completeCount;
			UpdateProgressBar();
		}
		private void Queue_QueuededCountChanged(object sender, int cueCount)
		{
			QueuedCount = cueCount;
			virtualFlowControl2.VirtualControlCount = Queue.Count;
			UpdateProgressBar();
		}
		private void UpdateProgressBar()
		{
				toolStripProgressBar1.Maximum = Queue.Count;
				toolStripProgressBar1.Value = Queue.Completed.Count;
		}

		private void cancelAllBtn_Click(object sender, EventArgs e)
		{
			Queue.ClearQueue();
			Queue.Current?.Cancel();
			virtualFlowControl2.VirtualControlCount = Queue.Count;
			UpdateAllControls();
		}

		private void btnClearFinished_Click(object sender, EventArgs e)
		{
			Queue.ClearCompleted();
			virtualFlowControl2.VirtualControlCount = Queue.Count;
			UpdateAllControls();

			if (!Running)
				runningTimeLbl.Text = string.Empty;
		}

		private void CounterTimer_Tick(object sender, EventArgs e)
		{
			string timeToStr(TimeSpan time)
			{
				string minsSecs = $"{time:mm\\:ss}";
				if (time.TotalHours >= 1)
					return $"{time.TotalHours:F0}:{minsSecs}";
				return minsSecs;
			}

			if (Running)
				runningTimeLbl.Text = timeToStr(DateTime.Now - StartintTime);
		}

		private void clearLogBtn_Click(object sender, EventArgs e)
		{
			logDGV.Rows.Clear();
		}

		private void LogCopyBtn_Click(object sender, EventArgs e)
		{
			string logText = string.Join("\r\n", logDGV.Rows.Cast<DataGridViewRow>().Select(r => $"{r.Cells[0].Value}\t{r.Cells[1].Value}"));
			Clipboard.SetDataObject(logText, false, 5, 150);
		}

		private void LogDGV_Resize(object sender, EventArgs e)
		{
			logDGV.Columns[1].Width = logDGV.Width - logDGV.Columns[0].Width;
		}

		#endregion

		#region View-Model update event handling

		/// <summary>
		/// Index of the first <see cref="ProcessBook"/> visible in the <see cref="VirtualFlowControl"/>
		/// </summary>
		private int FirstVisible = 0;
		/// <summary>
		/// Number of <see cref="ProcessBook"/> visible in the <see cref="VirtualFlowControl"/>
		/// </summary>
		private int NumVisible = 0;
		/// <summary>
		/// Controls displaying the <see cref="ProcessBook"/> state, starting with <see cref="FirstVisible"/> 
		/// </summary>
		private IReadOnlyList<ProcessBookControl> Panels;

		/// <summary>
		/// Updates the display of a single <see cref="ProcessBookControl"/> at <paramref name="queueIndex"/> within <see cref="Queue"/>
		/// </summary>
		/// <param name="queueIndex">index of the <see cref="ProcessBook"/> within the <see cref="Queue"/></param>
		private void UpdateControl(int queueIndex, string propertyName = null)
		{
			int i = queueIndex - FirstVisible;

			if (i > NumVisible || i < 0) return;

			var proc = Queue[queueIndex];

			Panels[i].Invoke(() =>
			{
				Panels[i].SuspendLayout();
				if (propertyName is null || propertyName == nameof(proc.Cover))
					Panels[i].SetCover(proc.Cover);
				if (propertyName is null || propertyName == nameof(proc.BookText))
					Panels[i].SetBookInfo(proc.BookText);

				if (proc.Result != ProcessBookResult.None)
				{
					Panels[i].SetResult(proc.Result);
					return;
				}

				if (propertyName is null || propertyName == nameof(proc.Status))
					Panels[i].SetStatus(proc.Status);
				if (propertyName is null || propertyName == nameof(proc.Progress))
					Panels[i].SetProgrss(proc.Progress);
				if (propertyName is null || propertyName == nameof(proc.TimeRemaining))
					Panels[i].SetRemainingTime(proc.TimeRemaining);
				Panels[i].ResumeLayout();
			});
		}

		private void UpdateAllControls()
		{
			int numToShow = Math.Min(NumVisible, Queue.Count - FirstVisible);

			for (int i = 0; i < numToShow; i++)
				UpdateControl(FirstVisible + i);
		}


		/// <summary>
		/// View notified the model that a botton was clicked
		/// </summary>
		/// <param name="queueIndex">index of the <see cref="ProcessBook"/> within <see cref="Queue"/></param>
		/// <param name="panelClicked">The clicked control to update</param>
		private void VirtualFlowControl2_ButtonClicked(int queueIndex, string buttonName, ProcessBookControl panelClicked)
		{
			ProcessBook item = Queue[queueIndex];
			if (buttonName == nameof(panelClicked.cancelBtn))
			{
				item.Cancel();
				Queue.RemoveQueued(item);
				virtualFlowControl2.VirtualControlCount = Queue.Count;
				UpdateControl(queueIndex);
			}
			else if (buttonName == nameof(panelClicked.moveFirstBtn))
			{
				Queue.MoveQueuePosition(item, QueuePosition.Fisrt);
				UpdateAllControls();
			}
			else if (buttonName == nameof(panelClicked.moveUpBtn))
			{
				Queue.MoveQueuePosition(item, QueuePosition.OneUp);
				UpdateControl(queueIndex - 1);
				UpdateControl(queueIndex);
			}
			else if (buttonName == nameof(panelClicked.moveDownBtn))
			{
				Queue.MoveQueuePosition(item, QueuePosition.OneDown);
				UpdateControl(queueIndex + 1);
				UpdateControl(queueIndex);
			}
			else if (buttonName == nameof(panelClicked.moveLastBtn))
			{
				Queue.MoveQueuePosition(item, QueuePosition.Last);
				UpdateAllControls();
			}
		}

		/// <summary>
		/// View needs updating
		/// </summary>
		private void VirtualFlowControl1_RequestData(int firstIndex, int numVisible, IReadOnlyList<ProcessBookControl> panelsToFill)
		{
			FirstVisible = firstIndex;
			NumVisible = numVisible;
			Panels = panelsToFill;
			UpdateAllControls();
		}

		/// <summary>
		/// Model updates the view
		/// </summary>
		private void Pbook_DataAvailable(object sender, PropertyChangedEventArgs e)
		{
			int index = Queue.IndexOf((ProcessBook)sender);
			UpdateControl(index, e.PropertyName);
		}

		#endregion
	}
}