using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using AMWD.Common.Packing.Ar;
using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace UnitTests.Common.Packing.Ar
{
	[TestClass]
	[System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
	public class ArReaderTests
	{
		private readonly DateTime _fixedDateTime = new(2023, 03, 01, 10, 20, 30, 0, DateTimeKind.Utc);

		private Dictionary<string, ArFileInfo> _files;

		private Stream inStream;

		[TestInitialize]
		public void Initialize()
		{
			_files = new Dictionary<string, ArFileInfo>
			{
				{
					"abcd.tmp",
					new ArFileInfo
					{
						FileName = "abcd.tmp",
						FileSize = 14,
						GroupId = 456,
						Mode = 33188,
						ModifyTime = _fixedDateTime,
						UserId = 123
					}
				},
				{
					"efgh.tmp",
					new ArFileInfo
					{
						FileName = "efgh.tmp",
						FileSize = 14,
						GroupId = 456,
						Mode = 33188,
						ModifyTime = _fixedDateTime,
						UserId = 123
					}
				},
				{
					"ijkl.tmp",
					new ArFileInfo
					{
						FileName = "ijkl.tmp",
						FileSize = 13,
						GroupId = 456,
						Mode = 33188,
						ModifyTime = _fixedDateTime,
						UserId = 123
					}
				}
			};

			inStream = new MemoryStream();
			inStream.Write(Encoding.ASCII.GetBytes("!<arch>\n"));

			foreach (var file in _files)
			{
				int unixSeconds = (int)file.Value.ModifyTime.Subtract(DateTime.UnixEpoch).TotalSeconds;

				inStream.Write(Encoding.ASCII.GetBytes($"{file.Key,-16}{unixSeconds,-12}123   456   100644  {file.Value.FileSize,-10}`\n"));
				inStream.Write(Encoding.UTF8.GetBytes(new string('a', (int)file.Value.FileSize)));
				if (file.Value.FileSize % 2 != 0)
					inStream.Write(Encoding.ASCII.GetBytes("\n"));
			}

			inStream.Seek(0, SeekOrigin.Begin);
		}

		[TestCleanup]
		public void Cleanup()
		{
			inStream.Dispose();
			inStream = null;
		}

		[TestMethod]
		public void ShouldInitializeArchive()
		{
			// Arrange
			inStream.Dispose();
			inStream = new MemoryStream();
			inStream.Write(Encoding.ASCII.GetBytes("!<arch>\n"));
			inStream.Seek(0, SeekOrigin.Begin);

			// Act
			var reader = new ArReader(inStream);

			// Assert
			Assert.IsNotNull(reader);
			Assert.IsFalse(reader.GetFileList().Any());
		}

		[TestMethod]
		public void ShouldInitializeWithFiles()
		{
			// Arrange

			// Act
			var reader = new ArReader(inStream);

			// Assert
			Assert.IsNotNull(reader);
			Assert.IsTrue(reader.GetFileList().Any());
		}

		[TestMethod]
		public void ShouldListFileNames()
		{
			// Arrange
			var reader = new ArReader(inStream);

			// Act
			var fileList = reader.GetFileList().ToList();

			// Assert
			Assert.IsNotNull(reader);
			Assert.AreEqual(_files.Count, fileList.Count);

			foreach (string name in _files.Keys)
				Assert.IsTrue(fileList.Contains(name));
		}

		[TestMethod]
		public void ShouldReturnValidFileInfo()
		{
			// Arrange
			var infos = new List<ArFileInfo>();
			var reader = new ArReader(inStream);

			// Act
			foreach (string name in _files.Keys)
				infos.Add(reader.GetFileInfo(name));

			// Assert
			Assert.IsNotNull(reader);
			Assert.AreEqual(_files.Count, infos.Count);

			foreach (var expected in _files.Values)
			{
				var actual = infos.Single(fi => fi.FileName == expected.FileName);

				Assert.AreEqual(expected.FileName, actual.FileName);
				Assert.AreEqual(expected.FileSize, actual.FileSize);
				Assert.AreEqual(expected.GroupId, actual.GroupId);
				Assert.AreEqual(expected.Mode, actual.Mode);
				Assert.AreEqual(expected.ModifyTime, actual.ModifyTime);
				Assert.AreEqual(expected.UserId, actual.UserId);
			}
		}

		[TestMethod]
		public void ShouldReturnValidFileContent()
		{
			// Arrange
			var contents = new Dictionary<string, string>();
			var reader = new ArReader(inStream);

			// Act
			foreach (string name in _files.Keys)
			{
				using var ms = new MemoryStream();
				reader.ReadFile(name, ms);
				ms.Seek(0, SeekOrigin.Begin);

				contents.Add(name, Encoding.UTF8.GetString(ms.ToArray()));
			}

			// Assert
			Assert.IsNotNull(reader);
			Assert.AreEqual(_files.Count, contents.Count);

			foreach (var expected in _files.Values)
			{
				string content = contents[expected.FileName];

				if (expected.FileSize % 2 != 0)
					Assert.AreEqual(13, content.Length);
				else
					Assert.AreEqual(14, content.Length);

				Assert.AreEqual(new string('a', (int)expected.FileSize), content);
			}
		}

		[TestMethod]
		public void ShouldWriteFileToDisk()
		{
			// Arrange
			string tmpFile = Path.GetTempFileName();
			var reader = new ArReader(inStream);

			try
			{
				// Act
				using var ms = new MemoryStream();

				reader.ReadFile("abcd.tmp", ms);
				reader.ReadFile("abcd.tmp", tmpFile);

				// Assert
				CollectionAssert.AreEqual(ms.ToArray(), File.ReadAllBytes(tmpFile));
			}
			finally
			{
				File.Delete(tmpFile);
			}
		}

		[TestMethod]
		[ExpectedException(typeof(ArgumentException))]
		public void ShouldThrowExceptionOnMissingRead()
		{
			// Arrange
			using var stream = new OverrideStream();
			stream.CanReadOR = false;
			stream.CanSeekOR = true;
			stream.CanWriteOR = true;

			// Act
			var reader = new ArReader(stream);

			// Assert - ArgumentException
			Assert.Fail();
		}

		[TestMethod]
		[ExpectedException(typeof(ArgumentException))]
		public void ShouldThrowExceptionOnMissingSeek()
		{
			// Arrange
			using var stream = new OverrideStream();
			stream.CanReadOR = true;
			stream.CanSeekOR = false;
			stream.CanWriteOR = true;

			// Act
			var reader = new ArReader(stream);

			// Assert - ArgumentException
			Assert.Fail();
		}

		[TestMethod]
		[ExpectedException(typeof(ArgumentException))]
		public void ShouldThrowExceptionOnMissingWrite()
		{
			// Arrange
			using var stream = new OverrideStream();
			stream.CanReadOR = true;
			stream.CanSeekOR = true;
			stream.CanWriteOR = false;

			var reader = new ArReader(inStream);

			// Act
			reader.ReadFile("abcd.tmp", stream);

			// Assert - ArgumentException
			Assert.Fail();
		}

		[TestMethod]
		[ExpectedException(typeof(FormatException))]
		public void ShouldThrowExceptionOnInvalidArchive()
		{
			// Arrange
			inStream.Seek(8, SeekOrigin.Begin);

			// Act
			_ = new ArReader(inStream);

			// Assert - FormatException
			Assert.Fail();
		}

		[TestMethod]
		[ExpectedException(typeof(FormatException))]
		public void ShouldThrowExceptionOnInvalidMagic()
		{
			// Arrange
			inStream.Seek(0, SeekOrigin.End);
			inStream.Write(Encoding.ASCII.GetBytes($"{"foo.bar",-16}{"123456789",-12}123   456   100644  {"0",-10}´\n"));
			inStream.Seek(0, SeekOrigin.Begin);

			// Act
			_ = new ArReader(inStream);

			// Assert - FormatException
			Assert.Fail();
		}

		[TestMethod]
		public void ShouldWriteNothingToStreamForMissingFile()
		{
			// Arrange
			var reader = new ArReader(inStream);

			// Act
			using var ms = new MemoryStream();

			reader.ReadFile("foo.bar", ms);
			ms.Seek(0, SeekOrigin.Begin);

			// Assert
			Assert.AreEqual(0, ms.Length);
		}

		[TestMethod]
		public void ShouldWriteNothingToDiskForMissingFile()
		{
			// Arrange
			string tmpFile = Path.GetTempFileName();
			var reader = new ArReader(inStream);

			try
			{
				// Act
				reader.ReadFile("foo.bar", tmpFile);

				// Assert
				Assert.AreEqual(0, new FileInfo(tmpFile).Length);
			}
			finally
			{
				File.Delete(tmpFile);
			}
		}

		private class OverrideStream : MemoryStream
		{
			public override bool CanWrite => CanWriteOR;

			public bool CanWriteOR { get; set; }

			public override bool CanSeek => CanSeekOR;

			public bool CanSeekOR { get; set; }

			public override bool CanRead => CanReadOR;

			public bool CanReadOR { get; set; }
		}
	}
}