using ApplicationServices;
using CommandLine;
using DataLayer;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;

namespace LibationCli;

[Verb("export", HelpText = "Must include path and flag for export file type: --xlsx , --csv , --json")]
public class ExportOptions : OptionsBase
{
	[Option(shortName: 'p', longName: "path", Required = true, HelpText = "Path to save file to.")]
	public string? FilePath { get; set; }

	#region explanation of mutually exclusive options
	/*
	giving these SetName values makes them mutually exclusive. they are in different sets. eg:
	class Options
	{
	    [Option("username", SetName = "auth")]
	    public string Username { get; set; }
	    [Option("password", SetName = "auth")]
	    public string Password { get; set; }

	    [Option("guestaccess", SetName = "guest")]
	    public bool GuestAccess { get; set; }
	}
	*/
	#endregion
	[Option(shortName: 'x', longName: "xlsx", HelpText = "Microsoft Excel Spreadsheet", SetName = "xlsx")]
	public bool xlsx { get; set; }

	[Option(shortName: 'c', longName: "csv", HelpText = "Comma-separated values", SetName = "csv")]
	public bool csv { get; set; }

	[Option(shortName: 'j', longName: "json", HelpText = "JavaScript Object Notation", SetName = "json")]
	public bool json { get; set; }

	[Value(0, MetaName = "[asins]", HelpText = "Optional product IDs of books to process.")]
	public IEnumerable<string>? Asins { get; set; }

	protected override Task ProcessAsync()
	{
		Action<string, IEnumerable<LibraryBook>?>? exporter
			= csv ? LibraryExporter.ToCsv
			: json ? LibraryExporter.ToJson
			: xlsx ? LibraryExporter.ToXlsx
			: Path.GetExtension(FilePath)?.ToLower() switch
			{
				".xlsx" => LibraryExporter.ToXlsx,
				".csv" => LibraryExporter.ToCsv,
				".json" => LibraryExporter.ToJson,
				_ => null
			};

		if (exporter is null)
		{
			PrintVerbUsage($"Undefined export format for file type \"{Path.GetExtension(FilePath)}\"");
		}
		else if (FilePath is null)
		{
			PrintVerbUsage($"Undefined export file name");
		}
		else
		{
			IEnumerable<LibraryBook>? booksToScan = null;
			if (Asins?.Any() is true)
			{
				booksToScan = DbContexts.GetLibrary_Flat_NoTracking().IntersectBy(Asins, l => l.Book.AudibleProductId);
			}
			exporter(FilePath, booksToScan);
			Console.WriteLine($"Library exported to: {FilePath}");
		}
		return Task.CompletedTask;
	}
}