// Copyright 2009-2022 Josh Close
// This file is a part of CsvHelper and is dual licensed under MS-PL and Apache 2.0.
// See LICENSE.txt for details or visit http://www.opensource.org/licenses/ms-pl.html for MS-PL and http://opensource.org/licenses/Apache-2.0 for Apache 2.0.
// https://github.com/JoshClose/CsvHelper
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Text;
using CsvHelper.Configuration;
using Xunit;

namespace CsvHelper.Tests
{
	
	public class CsvWriterReferenceMappingTests
	{
		[Fact]
		public void NestedReferencesTest()
		{
			using (var stream = new MemoryStream())
			using (var reader = new StreamReader(stream))
			using (var writer = new StreamWriter(stream))
			using (var csv = new CsvWriter(writer, CultureInfo.InvariantCulture))
			{
				csv.Context.RegisterClassMap<AMap>();

				var list = new List<A>();
				for (var i = 0; i < 4; i++)
				{
					var row = i + 1;
					list.Add(
							 new A
							 {
								 Id = "a" + row,
								 B = new B
								 {
									 Id = "b" + row,
									 C = new C
									 {
										 Id = "c" + row,
										 D = new D
										 {
											 Id = "d" + row
										 }
									 }
								 }
							 });
				};

				csv.WriteRecords(list);
				writer.Flush();
				stream.Position = 0;

				var data = reader.ReadToEnd();

				var expected = new TestStringBuilder(csv.Configuration.NewLine);
				expected.AppendLine("AId,BId,CId,DId");
				expected.AppendLine("a1,b1,c1,d1");
				expected.AppendLine("a2,b2,c2,d2");
				expected.AppendLine("a3,b3,c3,d3");
				expected.AppendLine("a4,b4,c4,d4");
				Assert.Equal(expected.ToString(), data);
			}
		}

		[Fact]
		public void NullReferenceTest()
		{
			using (var stream = new MemoryStream())
			using (var reader = new StreamReader(stream))
			using (var writer = new StreamWriter(stream))
			using (var csv = new CsvWriter(writer, CultureInfo.InvariantCulture))
			{
				csv.Context.RegisterClassMap<AMap>();

				var list = new List<A>
				{
					new A
					{
						Id = "1",
					}
				};
				csv.WriteRecords(list);
				writer.Flush();
				stream.Position = 0;

				var data = reader.ReadToEnd();
				var expected = new TestStringBuilder(csv.Configuration.NewLine);
				expected.AppendLine("AId,BId,CId,DId");
				expected.AppendLine("1,,,");
				Assert.Equal(expected.ToString(), data);
			}
		}

		private class A
		{
			public string Id { get; set; }

			public B B { get; set; }
		}

		private class B
		{
			public string Id { get; set; }

			public C C { get; set; }
		}

		private class C
		{
			public string Id { get; set; }

			public D D { get; set; }
		}

		private class D
		{
			public string Id { get; set; }
		}

		private sealed class AMap : ClassMap<A>
		{
			public AMap()
			{
				Map(m => m.Id).Name("AId");
				References<BMap>(m => m.B);
			}
		}

		private sealed class BMap : ClassMap<B>
		{
			public BMap()
			{
				Map(m => m.Id).Name("BId");
				References<CMap>(m => m.C);
			}
		}

		private sealed class CMap : ClassMap<C>
		{
			public CMap()
			{
				Map(m => m.Id).Name("CId");
				References<DMap>(m => m.D);
			}
		}

		private sealed class DMap : ClassMap<D>
		{
			public DMap()
			{
				Map(m => m.Id).Name("DId");
			}
		}
	}
}