using DataLayer;
using Dinah.Core;
using Dinah.Core.Collections.Generic;
using Dinah.Core.WindowsDesktop.Forms;
using LibationFileManager;
using LibationUiBase.GridView;
using System;
using System.Collections.Generic;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Forms;
#nullable enable

namespace LibationWinForms.GridView
{
	public delegate void GridEntryClickedEventHandler(GridEntry liveGridEntry);
	public delegate void LibraryBookEntryClickedEventHandler(LibraryBookEntry liveGridEntry);
	public delegate void GridEntryRectangleClickedEventHandler(GridEntry liveGridEntry, Rectangle cellRectangle);
	public delegate void ProductsGridCellContextMenuStripNeededEventHandler(GridEntry[] liveGridEntry, ContextMenuStrip ctxMenu);

	public partial class ProductsGrid : UserControl
	{
		/// <summary>Number of visible rows has changed</summary>
		public event EventHandler<int>? VisibleCountChanged;
		public event LibraryBookEntryClickedEventHandler? LiberateClicked;
		public event GridEntryClickedEventHandler? CoverClicked;
		public event LibraryBookEntryClickedEventHandler? DetailsClicked;
		public event GridEntryRectangleClickedEventHandler? DescriptionClicked;
		public new event EventHandler<ScrollEventArgs>? Scroll;
		public event EventHandler? RemovableCountChanged;
		public event ProductsGridCellContextMenuStripNeededEventHandler? LiberateContextMenuStripNeeded;

		private GridEntryBindingList? bindingList;
		internal IEnumerable<LibraryBook> GetVisibleBooks()
			=> bindingList
			?.GetFilteredInItems()
			.Select(lbe => lbe.LibraryBook) ?? Enumerable.Empty<LibraryBook>();
		internal IEnumerable<LibraryBookEntry> GetAllBookEntries()
			=> bindingList?.AllItems().BookEntries() ?? Enumerable.Empty<LibraryBookEntry>();

		public ProductsGrid()
		{
			InitializeComponent();
			EnableDoubleBuffering();
			gridEntryDataGridView.Scroll += (_, s) => Scroll?.Invoke(this, s);
			gridEntryDataGridView.CellContextMenuStripNeeded += GridEntryDataGridView_CellContextMenuStripNeeded;
			removeGVColumn.Frozen = false;

			defaultFont = gridEntryDataGridView.DefaultCellStyle.Font;
			setGridFontScale(Configuration.Instance.GridFontScaleFactor);
			setGridScale(Configuration.Instance.GridScaleFactor);
			Configuration.Instance.PropertyChanged += Configuration_ScaleChanged;
			Configuration.Instance.PropertyChanged += Configuration_FontScaleChanged;

			gridEntryDataGridView.Disposed += (_, _) =>
			{
				Configuration.Instance.PropertyChanged -= Configuration_ScaleChanged;
				Configuration.Instance.PropertyChanged -= Configuration_FontScaleChanged;
			};
		}

		#region Scaling

		[PropertyChangeFilter(nameof(Configuration.GridFontScaleFactor))]
		private void Configuration_FontScaleChanged(object sender, PropertyChangedEventArgsEx e)
		{
			if (e.NewValue is float v)
				setGridFontScale(v);
		}

		[PropertyChangeFilter(nameof(Configuration.GridScaleFactor))]
		private void Configuration_ScaleChanged(object sender, PropertyChangedEventArgsEx e)
		{
			if (e.NewValue is float v)
				setGridScale(v);
		}

		/// <summary>
		/// Keep track of the original dimensions for rescaling
		/// </summary>
		private static readonly Dictionary<DataGridViewElement, int> originalDims = new();
		private readonly Font defaultFont;
		private void setGridScale(float scale)
		{
			foreach (var col in gridEntryDataGridView.Columns.Cast<DataGridViewColumn>())
			{
				//Only resize fixed-width columns. The rest can be adjusted by users.
				if (col.Resizable is DataGridViewTriState.False)
				{
					if (!originalDims.ContainsKey(col))
						originalDims[col] = col.Width;

					col.Width = this.DpiScale(originalDims[col], scale);
				}

				if (col is IDataGridScaleColumn scCol)
					scCol.ScaleFactor = scale;
			}

			if (!originalDims.ContainsKey(gridEntryDataGridView.RowTemplate))
				originalDims[gridEntryDataGridView.RowTemplate] = gridEntryDataGridView.RowTemplate.Height;

			var height = gridEntryDataGridView.RowTemplate.Height = this.DpiScale(originalDims[gridEntryDataGridView.RowTemplate], scale);

			foreach (var row in gridEntryDataGridView.Rows.Cast<DataGridViewRow>())
				row.Height = height;
		}

		private void setGridFontScale(float scale)
			=> gridEntryDataGridView.DefaultCellStyle.Font = new Font(defaultFont.FontFamily, defaultFont.Size * scale);

		#endregion

		private static string? RemoveLineBreaks(string? text)
			=> text?.Replace("\r\n", "").Replace('\r', ' ').Replace('\n', ' ');

		private void GridEntryDataGridView_CellContextMenuStripNeeded(object? sender, DataGridViewCellContextMenuStripNeededEventArgs e)
		{
			// header
			if (e.RowIndex < 0 || sender is not DataGridView dgv)
				return;

			e.ContextMenuStrip = new ContextMenuStrip();
			// any column except cover & stop light
			if (e.ColumnIndex != liberateGVColumn.Index && e.ColumnIndex != coverGVColumn.Index)
			{
				e.ContextMenuStrip.Items.Add("Copy Cell Contents", null, (_, __) =>
				{
					try
					{
						string clipboardText;

						if (dgv.SelectedCells.Count <= 1)
						{
							//Copy contents only of cell that was right-clicked on.
							clipboardText = dgv[e.ColumnIndex, e.RowIndex].FormattedValue?.ToString() ?? string.Empty;
						}
						else
						{
							//Copy contents of selected cells. Each row is a new line,
							//and columns are separated with tabs. Similar formatting to Microsoft Excel.
							var selectedCells
							= dgv.SelectedCells
							.OfType<DataGridViewCell>()
							.Where(c => c.OwningColumn is not null && c.OwningRow is not null)
							.OrderBy(c => c.RowIndex)
							.ThenBy(c => c.OwningColumn!.DisplayIndex)
							.ToList();

							var headerText
							= string.Join("\t",
								selectedCells
								.Select(c => c.OwningColumn)
								.Distinct()
								.Select(c => RemoveLineBreaks(c?.HeaderText))
								.OfType<string>());

							List<string> linesOfText = [headerText];
							foreach (var distinctRow in selectedCells.Select(c => c.RowIndex).Distinct())
							{
								linesOfText.Add(string.Join("\t",
									selectedCells
									.Where(c => c.RowIndex == distinctRow)
									.Select(c => RemoveLineBreaks(c.FormattedValue?.ToString()) ?? string.Empty)
									));
							}
							clipboardText = string.Join(Environment.NewLine, linesOfText);
						}
						Clipboard.SetDataObject(clipboardText, false, 5, 150);
					}
					catch(Exception ex)
					{
						Serilog.Log.Logger.Error(ex, "Error copying text to clipboard");
					}
				});
				e.ContextMenuStrip.Items.Add(new ToolStripSeparator());
			}

			var clickedEntry = getGridEntry(e.RowIndex);

			var allSelected
				= gridEntryDataGridView
				.SelectedCells
				.OfType<DataGridViewCell>()
				.Select(c => c.OwningRow)
				.OfType<DataGridViewRow>()
				.Distinct()
				.OrderBy(r => r.Index)
				.Select(r => r.DataBoundItem)
				.OfType<GridEntry>()
				.ToArray();

			var clickedIndex = Array.IndexOf(allSelected, clickedEntry);
			if (clickedIndex == -1)
			{
				//User didn't right-click on a selected cell
				gridEntryDataGridView.ClearSelection();
				gridEntryDataGridView[e.ColumnIndex, e.RowIndex].Selected = true;
				allSelected = [clickedEntry];
			}
			else if (clickedIndex > 0)
			{
				//Ensure the clicked entry is first in the list
				(allSelected[0], allSelected[clickedIndex]) = (allSelected[clickedIndex], allSelected[0]);
			}
			LiberateContextMenuStripNeeded?.Invoke(allSelected, e.ContextMenuStrip);
		}

		private void EnableDoubleBuffering()
		{
			var propertyInfo = gridEntryDataGridView.GetType().GetProperty("DoubleBuffered", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic);

			propertyInfo?.SetValue(gridEntryDataGridView, true, null);
		}

		#region Button controls
		private void DataGridView_CellContentClick(object sender, DataGridViewCellEventArgs e)
		{
			try
			{
				// handle grid button click: https://stackoverflow.com/a/13687844
				if (e.RowIndex < 0)
					return;

				var entry = getGridEntry(e.RowIndex);
				if (entry is LibraryBookEntry lbEntry)
				{
					if (e.ColumnIndex == liberateGVColumn.Index)
						LiberateClicked?.Invoke(lbEntry);
					else if (e.ColumnIndex == tagAndDetailsGVColumn.Index)
						DetailsClicked?.Invoke(lbEntry);
					else if (e.ColumnIndex == descriptionGVColumn.Index)
						DescriptionClicked?.Invoke(lbEntry, gridEntryDataGridView.GetCellDisplayRectangle(e.ColumnIndex, e.RowIndex, false));
					else if (e.ColumnIndex == coverGVColumn.Index)
						CoverClicked?.Invoke(lbEntry);
				}
				else if (entry is SeriesEntry sEntry)
				{
					if (e.ColumnIndex == liberateGVColumn.Index)
					{
						if (sEntry.Liberate.Expanded)
							bindingList?.CollapseItem(sEntry);
						else
							bindingList?.ExpandItem(sEntry);

						VisibleCountChanged?.Invoke(this, bindingList?.GetFilteredInItems().Count() ?? 0);
					}
					else if (e.ColumnIndex == descriptionGVColumn.Index)
						DescriptionClicked?.Invoke(sEntry, gridEntryDataGridView.GetCellDisplayRectangle(e.ColumnIndex, e.RowIndex, false));
					else if (e.ColumnIndex == coverGVColumn.Index)
						CoverClicked?.Invoke(sEntry);
				}

				if (e.ColumnIndex == removeGVColumn.Index)
				{
					gridEntryDataGridView.CommitEdit(DataGridViewDataErrorContexts.Commit);
					RemovableCountChanged?.Invoke(this, EventArgs.Empty);
				}
			}
			catch (Exception ex)
			{
				Serilog.Log.Logger.Error(ex, $"An error was encountered while processing a user click in the {nameof(ProductsGrid)}");
			}
		}

		private GridEntry getGridEntry(int rowIndex) => gridEntryDataGridView.GetBoundItem<GridEntry>(rowIndex);

		#endregion

		#region UI display functions

		internal bool RemoveColumnVisible
		{
			get => removeGVColumn.Visible;
			set
			{
				if (value && bindingList is not null)
				{
					foreach (var book in bindingList.AllItems())
						book.Remove = false;
				}

				removeGVColumn.DisplayIndex = 0;
				removeGVColumn.Frozen = value;
				removeGVColumn.Visible = value;
			}
		}

		internal async Task BindToGridAsync(List<LibraryBook> dbBooks)
		{
			//Get the UI thread's synchronization context and set it on the current thread to ensure
			//it's available for GetAllProductsAsync and GetAllSeriesEntriesAsync
			var sc = Invoke(() => System.Threading.SynchronizationContext.Current);
			System.Threading.SynchronizationContext.SetSynchronizationContext(sc);

			var geList = await LibraryBookEntry.GetAllProductsAsync(dbBooks);
			var seriesEntries = await SeriesEntry.GetAllSeriesEntriesAsync(dbBooks);

			geList.AddRange(seriesEntries);
			//Sort descending by date (default sort property)
			var comparer = new RowComparer();
			geList.Sort((a, b) => comparer.Compare(b, a));

			//Add all children beneath their parent
			foreach (var series in seriesEntries)
			{
				var seriesIndex = geList.IndexOf(series);
				foreach (var child in series.Children)
					geList.Insert(++seriesIndex, child);
			}
			System.Threading.SynchronizationContext.SetSynchronizationContext(null);
						
			bindingList = new GridEntryBindingList(geList);
			bindingList.CollapseAll();

			//The syncBindingSource ensures that the IGridEntry list is added on the UI thread 
			syncBindingSource.DataSource = bindingList;
			VisibleCountChanged?.Invoke(this, bindingList.GetFilteredInItems().Count());
		}

		internal void UpdateGrid(List<LibraryBook> dbBooks)
		{
			if (bindingList == null)
				throw new InvalidOperationException($"Must call {nameof(BindToGridAsync)} before calling {nameof(UpdateGrid)}");

			//First row that is in view in the DataGridView
			var topRow = gridEntryDataGridView.Rows.Cast<DataGridViewRow>().FirstOrDefault(r => r.Displayed)?.Index ?? 0;

			#region Add new or update existing grid entries

			//Remove filter prior to adding/updating books
			string? existingFilter = syncBindingSource.Filter;
			Filter(null);

			//Add absent entries to grid, or update existing entry

			var allEntries = bindingList.AllItems().BookEntries().ToDictionarySafe(b => b.AudibleProductId);
			var seriesEntries = bindingList.AllItems().SeriesEntries().ToList();
			var parentedEpisodes = dbBooks.ParentedEpisodes().ToHashSet();

			//Get the UI thread's synchronization context and set it on the current thread to ensure
			//it's available for creation of new IGridEntry items during upsert
			var sc = Invoke(() => System.Threading.SynchronizationContext.Current);
			System.Threading.SynchronizationContext.SetSynchronizationContext(sc);

			bindingList.RaiseListChangedEvents = false;
			foreach (var libraryBook in dbBooks.OrderBy(e => e.DateAdded))
			{
				var existingEntry = allEntries.TryGetValue(libraryBook.Book.AudibleProductId, out var e) ? e : null;

				if (libraryBook.Book.IsProduct())
				{
					AddOrUpdateBook(libraryBook, existingEntry);
					continue;
				}
				if (parentedEpisodes.Contains(libraryBook))
				{
					//Only try to add or update is this LibraryBook is a know child of a parent
					AddOrUpdateEpisode(libraryBook, existingEntry, seriesEntries, dbBooks);
				}
			}
			bindingList.RaiseListChangedEvents = true;

			//Re-apply filter after adding new/updating existing books to capture any changes
			//The Filter call also ensures that the binding list is reset so the DataGridView
			//is made aware of all changes that were made while RaiseListChangedEvents was false
			Filter(existingFilter);

			#endregion

			// remove deleted from grid.
			// note: actual deletion from db must still occur via the RemoveBook feature. deleting from audible will not trigger this
			var removedBooks =
				bindingList
				.AllItems()
				.BookEntries()
				.ExceptBy(dbBooks.Select(lb => lb.Book.AudibleProductId), ge => ge.AudibleProductId);

			RemoveBooks(removedBooks);

			gridEntryDataGridView.FirstDisplayedScrollingRowIndex = topRow;
		}

		public void RemoveBooks(IEnumerable<LibraryBookEntry> removedBooks)
		{
			if (bindingList == null)
				throw new InvalidOperationException($"Must call {nameof(BindToGridAsync)} before calling {nameof(RemoveBooks)}");

			//Remove books in series from their parents' Children list
			foreach (var removed in removedBooks.Where(b => b.Liberate.IsEpisode))
				removed.Parent.RemoveChild(removed);

			//Remove series that have no children
			var removedSeries =
				bindingList
				.AllItems()
				.EmptySeries();

			foreach (var removed in removedBooks.Cast<GridEntry>().Concat(removedSeries))
				//no need to re-filter for removed books
				bindingList.Remove(removed);

			VisibleCountChanged?.Invoke(this, bindingList.GetFilteredInItems().Count());
		}

		private void AddOrUpdateBook(LibraryBook book, LibraryBookEntry? existingBookEntry)
		{
			if (bindingList == null)
				throw new InvalidOperationException($"Must call {nameof(BindToGridAsync)} before calling {nameof(AddOrUpdateBook)}");

			if (existingBookEntry is null)
				// Add the new product to top
				bindingList.Insert(0, new LibraryBookEntry(book));
			else
				// update existing
				existingBookEntry.UpdateLibraryBook(book);
		}

		private void AddOrUpdateEpisode(LibraryBook episodeBook, LibraryBookEntry? existingEpisodeEntry, List<SeriesEntry> seriesEntries, IEnumerable<LibraryBook> dbBooks)
		{
			if (bindingList == null)
				throw new InvalidOperationException($"Must call {nameof(BindToGridAsync)} before calling {nameof(AddOrUpdateEpisode)}");

			if (existingEpisodeEntry is null)
			{
				LibraryBookEntry episodeEntry;

				var seriesEntry = seriesEntries.FindSeriesParent(episodeBook);

				if (seriesEntry is null)
				{
					//Series doesn't exist yet, so create and add it
					var seriesBook = dbBooks.FindSeriesParent(episodeBook);

					if (seriesBook is null)
					{
						//This is only possible if the user's db  has some malformed
						//entries from earlier Libation releases that could not be
						//automatically fixed. Log, but don't throw.
						Serilog.Log.Logger.Error("Episode={0}, Episode Series: {1}", episodeBook, episodeBook.Book.SeriesNames());
						return;
					}

					seriesEntry = new SeriesEntry(seriesBook, episodeBook);
					seriesEntries.Add(seriesEntry);

					episodeEntry = seriesEntry.Children[0];
					seriesEntry.Liberate.Expanded = true;
					bindingList.Insert(0, seriesEntry);
				}
				else
				{
					//Series exists. Create and add episode child then update the SeriesEntry
					episodeEntry = new LibraryBookEntry(episodeBook, seriesEntry);
					seriesEntry.Children.Add(episodeEntry);
					seriesEntry.Children.Sort((c1, c2) => c1.SeriesIndex.CompareTo(c2.SeriesIndex));
					var seriesBook = dbBooks.Single(lb => lb.Book.AudibleProductId == seriesEntry.LibraryBook.Book.AudibleProductId);
					seriesEntry.UpdateLibraryBook(seriesBook);
				}

				//Series entry must be expanded so its child can
				//be placed in the correct position beneath it.
				var isExpanded = seriesEntry.Liberate.Expanded;
				bindingList.ExpandItem(seriesEntry);

				//Add episode to the grid beneath the parent
				int seriesIndex = bindingList.IndexOf(seriesEntry);
				int episodeIndex = seriesEntry.Children.IndexOf(episodeEntry);
				bindingList.Insert(seriesIndex + 1 + episodeIndex, episodeEntry);

				if (isExpanded)
					bindingList.ExpandItem(seriesEntry);
				else
					bindingList.CollapseItem(seriesEntry);
			}
			else
				existingEpisodeEntry.UpdateLibraryBook(episodeBook);
		}

		#endregion

		#region Filter

		public void Filter(string? searchString)
		{
			if (bindingList is null) return;

			int visibleCount = bindingList.Count;

			if (string.IsNullOrEmpty(searchString))
				syncBindingSource.RemoveFilter();
			else
				syncBindingSource.Filter = searchString;

			if (visibleCount != bindingList.Count)
				VisibleCountChanged?.Invoke(this, bindingList.GetFilteredInItems().Count());
		}

		#endregion

		#region Column Customizations

		private void ProductsGrid_Load(object sender, EventArgs e)
		{
			//https://stackoverflow.com/a/4498512/3335599
			if (System.ComponentModel.LicenseManager.UsageMode == System.ComponentModel.LicenseUsageMode.Designtime) return;

			gridEntryDataGridView.ColumnWidthChanged += gridEntryDataGridView_ColumnWidthChanged;
			gridEntryDataGridView.ColumnDisplayIndexChanged += gridEntryDataGridView_ColumnDisplayIndexChanged;

			showHideColumnsContextMenuStrip.Items.Add(new ToolStripLabel("Show / Hide Columns"));
			showHideColumnsContextMenuStrip.Items.Add(new ToolStripSeparator());

			//Restore Grid Display Settings
			var config = Configuration.Instance;
			var gridColumnsWidths = config.GridColumnsWidths;
			var displayIndices = config.GridColumnsDisplayIndices;

			var cmsKiller = new ContextMenuStrip();

			foreach (DataGridViewColumn column in gridEntryDataGridView.Columns)
			{
				var itemName = column.DataPropertyName;
				var visible = config.GetColumnVisibility(itemName);

				var menuItem = new ToolStripMenuItem(column.HeaderText)
				{
					Checked = visible,
					Tag = itemName
				};
				menuItem.Click += HideMenuItem_Click;
				showHideColumnsContextMenuStrip.Items.Add(menuItem);

				//Only set column widths for user resizable columns.
				//Fixed column widths are set by setGridScale()
				if (column.Resizable is not DataGridViewTriState.False)
					column.Width = gridColumnsWidths.GetValueOrDefault(itemName, this.DpiScale(column.Width));

				column.MinimumWidth = 10;
				column.HeaderCell.ContextMenuStrip = showHideColumnsContextMenuStrip;
				column.Visible = visible;

				//Setting a default ContextMenuStrip will allow the columns to handle the
				//Show() event so it is not passed up to the _dataGridView.ContextMenuStrip.
				//This allows the ContextMenuStrip to be shown if right-clicking in the gray
				//background of _dataGridView but not shown if right-clicking inside cells.
				column.ContextMenuStrip = cmsKiller;
			}

			//We must set DisplayIndex properties in ascending order
			foreach (var itemName in displayIndices.OrderBy(i => i.Value).Select(i => i.Key))
			{
				var column = gridEntryDataGridView.Columns
					.Cast<DataGridViewColumn>()
					.SingleOrDefault(c => c.DataPropertyName == itemName);

				if (column is null) continue;

				column.DisplayIndex = displayIndices.GetValueOrDefault(itemName, column.Index);
			}

			//Remove column is always first;
			removeGVColumn.DisplayIndex = 0;
			removeGVColumn.Visible = false;
			removeGVColumn.ValueType = typeof(bool?);
			removeGVColumn.FalseValue = false;
			removeGVColumn.TrueValue = true;
			removeGVColumn.IndeterminateValue = null;
		}

		private void HideMenuItem_Click(object? sender, EventArgs e)
		{
			var menuItem = sender as ToolStripMenuItem;
			var propertyName = menuItem?.Tag as string;

			var column = gridEntryDataGridView.Columns
				.Cast<DataGridViewColumn>()
				.FirstOrDefault(c => c.DataPropertyName == propertyName);

			if (column != null && menuItem != null && propertyName != null)
			{
				var visible = menuItem.Checked;
				menuItem.Checked = !visible;
				column.Visible = !visible;

				var config = Configuration.Instance;

				var dictionary = config.GridColumnsVisibilities;
				dictionary[propertyName] = column.Visible;
				config.GridColumnsVisibilities = dictionary;
			}
		}

		private void gridEntryDataGridView_ColumnDisplayIndexChanged(object? sender, DataGridViewColumnEventArgs e)
		{
			var config = Configuration.Instance;

			var dictionary = config.GridColumnsDisplayIndices;
			dictionary[e.Column.DataPropertyName] = e.Column.DisplayIndex;
			config.GridColumnsDisplayIndices = dictionary;
		}

		private void gridEntryDataGridView_CellToolTipTextNeeded(object? sender, DataGridViewCellToolTipTextNeededEventArgs e)
		{
			if (e.ColumnIndex == descriptionGVColumn.Index)
				e.ToolTipText = "Click to see full description";
			else if (e.ColumnIndex == coverGVColumn.Index)
				e.ToolTipText = "Click to see full size";
		}

		private void gridEntryDataGridView_ColumnWidthChanged(object? sender, DataGridViewColumnEventArgs e)
		{
			var config = Configuration.Instance;

			var dictionary = config.GridColumnsWidths;
			dictionary[e.Column.DataPropertyName] = e.Column.Width;
			config.GridColumnsWidths = dictionary;
		}

		#endregion
	}
}