using ApplicationServices;
using DataLayer;
using Dinah.Core;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;

namespace LibationWinForms.GridView
{
	/// <summary>
	/// The View Model for a LibraryBook
	/// </summary>
	public class LibraryBookEntry : GridEntry
	{
		#region implementation properties NOT exposed to the view
		// hide from public fields from Data Source GUI with [Browsable(false)]

		[Browsable(false)]
		public string AudibleProductId => Book.AudibleProductId;
		[Browsable(false)]
		public LibraryBook LibraryBook { get; private set; }
		[Browsable(false)]
		public string LongDescription { get; private set; }
		#endregion

		protected override Book Book => LibraryBook.Book;

		#region Model properties exposed to the view

		private DateTime lastStatusUpdate = default;
		private LiberatedStatus _bookStatus;
		private LiberatedStatus? _pdfStatus;

		public override DateTime DateAdded => LibraryBook.DateAdded;
		public override float SeriesIndex => Book.SeriesLink.FirstOrDefault()?.Index ?? 0;
		public override string ProductRating { get; protected set; }
		public override string PurchaseDate { get; protected set; }
		public override string MyRating { get; protected set; }
		public override string Series { get; protected set; }
		public override string Title { get; protected set; }
		public override string Length { get; protected set; }
		public override string Authors { get; protected set; }
		public override string Narrators { get; protected set; }
		public override string Category { get; protected set; }
		public override string Misc { get; protected set; }
		public override string Description { get; protected set; }
		public override string DisplayTags => string.Join("\r\n", Book.UserDefinedItem.TagsEnumerated);

		// these 2 values being in 1 field is the trick behind getting the liberated+pdf 'stoplight' icon to draw. See: LiberateDataGridViewImageButtonCell.Paint
		public override LiberateButtonStatus Liberate
		{
			get
			{
				//Cache these statuses for faster sorting.
				if ((DateTime.Now - lastStatusUpdate).TotalSeconds > 2)
				{
					_bookStatus = LibraryCommands.Liberated_Status(LibraryBook.Book);
					_pdfStatus = LibraryCommands.Pdf_Status(LibraryBook.Book);
					lastStatusUpdate = DateTime.Now;
				}
				return new LiberateButtonStatus { BookStatus = _bookStatus, PdfStatus = _pdfStatus, IsSeries = false };
			}
		}
		#endregion

		public LibraryBookEntry(LibraryBook libraryBook)
		{
			setLibraryBook(libraryBook);
			LoadCover();
		}

		public SeriesEntry Parent { get; init; }
		public void UpdateLibraryBook(LibraryBook libraryBook)
		{
			if (AudibleProductId != libraryBook.Book.AudibleProductId)
				throw new Exception("Invalid grid entry update. IDs must match");

			UserDefinedItem.ItemChanged -= UserDefinedItem_ItemChanged;
			setLibraryBook(libraryBook);

			NotifyPropertyChanged();
		}

		private void setLibraryBook(LibraryBook libraryBook)
		{
			LibraryBook = libraryBook;

			// Immutable properties
			{
				Title = Book.Title;
				Series = Book.SeriesNames();
				Length = Book.LengthInMinutes == 0 ? "" : $"{Book.LengthInMinutes / 60} hr {Book.LengthInMinutes % 60} min";
				MyRating = Book.UserDefinedItem.Rating?.ToStarString()?.DefaultIfNullOrWhiteSpace("");
				PurchaseDate = libraryBook.DateAdded.ToString("d");
				ProductRating = Book.Rating?.ToStarString()?.DefaultIfNullOrWhiteSpace("");
				Authors = Book.AuthorNames();
				Narrators = Book.NarratorNames();
				Category = string.Join(" > ", Book.CategoriesNames());
				Misc = GetMiscDisplay(libraryBook);
				LongDescription = GetDescriptionDisplay(Book);
				Description = TrimTextToWord(LongDescription, 62);
			}

			UserDefinedItem.ItemChanged += UserDefinedItem_ItemChanged;
		}


		#region detect changes to the model, update the view, and save to database.

		/// <summary>
		/// This event handler receives notifications from the model that it has changed.
		/// Notify the view that it's changed.
		/// </summary>
		private void UserDefinedItem_ItemChanged(object sender, string itemName)
		{
			var udi = sender as UserDefinedItem;

			if (udi.Book.AudibleProductId != Book.AudibleProductId)
				return;

			// UDI changed, possibly in a different context/view. Update this viewmodel. Call NotifyPropertyChanged to notify view.
			// - This method responds to tons of incidental changes. Do not persist to db from here. Committing to db must be a volitional action by the caller, not incidental. Otherwise batch changes would be impossible; we would only have slow one-offs
			// - Don't restrict notifying view to 'only if property changed'. This same book instance can get passed to a different view, then changed there. When the chain of events makes its way back here, the property is unchanged (because it's the same instance), but this view is out of sync. NotifyPropertyChanged will then update this view.
			switch (itemName)
			{
				case nameof(udi.Tags):
					Book.UserDefinedItem.Tags = udi.Tags;
					NotifyPropertyChanged(nameof(DisplayTags));
					break;
				case nameof(udi.BookStatus):
					Book.UserDefinedItem.BookStatus = udi.BookStatus;
					_bookStatus = udi.BookStatus;
					NotifyPropertyChanged(nameof(Liberate));
					break;
				case nameof(udi.PdfStatus):
					Book.UserDefinedItem.PdfStatus = udi.PdfStatus;
					_pdfStatus = udi.PdfStatus;
					NotifyPropertyChanged(nameof(Liberate));
					break;
			}
		}

		/// <summary>Save edits to the database</summary>
		public void Commit(string newTags, LiberatedStatus bookStatus, LiberatedStatus? pdfStatus)
			// MVVM pass-through
			=> Book.UpdateBook(newTags, bookStatus: bookStatus, pdfStatus: pdfStatus);

		#endregion

		#region Data Sorting

		/// <summary>Create getters for all member object values by name </summary>
		protected override Dictionary<string, Func<object>> CreateMemberValueDictionary() => new()
		{
			{ nameof(Title), () => Book.TitleSortable() },
			{ nameof(Series), () => Book.SeriesSortable() },
			{ nameof(Length), () => Book.LengthInMinutes },
			{ nameof(MyRating), () => Book.UserDefinedItem.Rating.FirstScore() },
			{ nameof(PurchaseDate), () => LibraryBook.DateAdded },
			{ nameof(ProductRating), () => Book.Rating.FirstScore() },
			{ nameof(Authors), () => Authors },
			{ nameof(Narrators), () => Narrators },
			{ nameof(Description), () => Description },
			{ nameof(Category), () => Category },
			{ nameof(Misc), () => Misc },
			{ nameof(DisplayTags), () => DisplayTags },
			{ nameof(Liberate), () => Liberate },
			{ nameof(DateAdded), () => DateAdded },
		};


		#endregion

		#region Static library display functions

		/// <summary>
		/// This information should not change during <see cref="LibraryBookEntry"/> lifetime, so call only once.
		/// </summary>
		private static string GetDescriptionDisplay(Book book)
		{
			var doc = new HtmlAgilityPack.HtmlDocument();
			doc.LoadHtml(book?.Description?.Replace("</p> ", "\r\n\r\n</p>") ?? "");
			return doc.DocumentNode.InnerText.Trim();
		}

		private static string TrimTextToWord(string text, int maxLength)
		{
			return
				text.Length <= maxLength ?
				text :
				text.Substring(0, maxLength - 3) + "...";
		}

		/// <summary>
		/// This information should not change during <see cref="LibraryBookEntry"/> lifetime, so call only once.
		/// Maximum of 5 text rows will fit in 80-pixel row height.
		/// </summary>
		private static string GetMiscDisplay(LibraryBook libraryBook)
		{
			var details = new List<string>();

			var locale = libraryBook.Book.Locale.DefaultIfNullOrWhiteSpace("[unknown]");
			var acct = libraryBook.Account.DefaultIfNullOrWhiteSpace("[unknown]");

			details.Add($"Account: {locale} - {acct}");

			if (libraryBook.Book.HasPdf())
				details.Add("Has PDF");
			if (libraryBook.Book.IsAbridged)
				details.Add("Abridged");
			if (libraryBook.Book.DatePublished.HasValue)
				details.Add($"Date pub'd: {libraryBook.Book.DatePublished.Value:MM/dd/yyyy}");
			// this goes last since it's most likely to have a line-break
			if (!string.IsNullOrWhiteSpace(libraryBook.Book.Publisher))
				details.Add($"Pub: {libraryBook.Book.Publisher.Trim()}");

			if (!details.Any())
				return "[details not imported]";

			return string.Join("\r\n", details);
		}

		#endregion

		~LibraryBookEntry()
		{
			UserDefinedItem.ItemChanged -= UserDefinedItem_ItemChanged;
		}
	}
}