using AudibleApi.Common;
using System;
using System.Linq;

namespace AudibleUtilities;

public static class Extensions
{
	extension(Item item)
	{
		/// <summary>
		/// Determines when your audible plus or free book will expire from your library  
		/// plan.IsAyce from underlying AudibleApi project determines the plans to look at, first plan found is used.
		/// In some cases current date is later than end date so exclude.
		/// </summary>
		/// <returns>The DateTime that this title will become unavailable, otherwise null</returns>
		public DateTime? GetExpirationDate()
			  => item.Plans
			  ?.Where(p => p.IsAyce)
			  .Select(p => p.EndDate)
			  .FirstOrDefault(end => end.HasValue && end.Value.Year is not (2099 or 9999) && end.Value.LocalDateTime >= DateTime.Now)
			  ?.DateTime;

		/// <summary>
		/// The book's summary with Audible's HTML markup flattened away, ready to be stored and used
		/// as-is. See <see cref="HtmlText.ToPlainText"/>.
		/// </summary>
		public string PlainTextDescription()
			=> HtmlText.ToPlainText(item.Description);

		/// <summary>
		/// The publisher's copyright line, e.g. "&#169;2024 Bentley Little (P)2025 Journalstone".
		/// Only present when the product_details response group was requested, and often null anyway.
		/// </summary>
		/// <remarks><see cref="Item.Copyright"/> is typed as <see cref="object"/> because Audible has
		/// never been observed returning anything but a string or null there. Anything else is
		/// discarded rather than stringified, so a shape we do not understand cannot reach a file tag.
		/// </remarks>
		public string? CopyrightString()
			=> item.Copyright is string copyright && !string.IsNullOrWhiteSpace(copyright)
			? copyright.Trim()
			: null;
	}
}