// Copyright Epic Games, Inc. All Rights Reserved.

using System;
using System.IO;
using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace EpicGames.Core.Tests
{
	[TestClass]
	public class FileUtilsTest
	{
		private readonly DirectoryReference _tempDir;

		public FileUtilsTest()
		{
			_tempDir = CreateTempDir();
		}

		[TestMethod]
		public void ForceDeleteDirectoryNormalPath()
		{
			string subDir = Path.Join(_tempDir.FullName, "Foo");
			Directory.CreateDirectory(subDir);
			FileUtils.ForceDeleteDirectory(subDir);
			Assert.IsFalse(Directory.Exists(subDir));
		}
		
		[TestMethod]
		public void ForceDeleteDirectoryLongPath()
		{
			string subDir = CreateSubDirWithLongPath();
			FileUtils.ForceDeleteDirectory(subDir);
			Assert.IsFalse(Directory.Exists(subDir));
		}
		
		[TestMethod]
		public void ForceDeleteDirectoryContentsNormalPath()
		{
			string subDir = Path.Join(_tempDir.FullName, "Foo");
			Directory.CreateDirectory(subDir);
			string filePath = Path.Join(subDir, "file.txt");
			File.WriteAllText(filePath, "placeholder");
			
			FileUtils.ForceDeleteDirectoryContents(subDir);
			Assert.IsTrue(Directory.Exists(subDir));
			Assert.IsFalse(File.Exists(filePath));
		}
		
		[TestMethod]
		public void ForceDeleteDirectoryContentsLongPath()
		{
			string subDir = CreateSubDirWithLongPath();
			string filePath = Path.Join(subDir, "file.txt");
			File.WriteAllText(filePath, "placeholder");

			FileUtils.ForceDeleteDirectoryContents(subDir);
			Assert.IsTrue(Directory.Exists(subDir));
			Assert.IsFalse(File.Exists(filePath));
		}

		[TestCleanup]
		public void RemoveTempDir()
		{
			if (Directory.Exists(_tempDir.FullName))
			{
				Directory.Delete(_tempDir.FullName, true);
			}
		}

		private string CreateSubDirWithLongPath()
		{
			const string LongDirNameA = "ThisIsAVeryLongDirectoryName";
			const string LongDirNameB = "AnotherLongDirectoryNameThatIsUsed";
			string subDir = Path.Join(_tempDir.FullName, "Foo", LongDirNameA, LongDirNameB, LongDirNameA, LongDirNameB, LongDirNameA, LongDirNameB, LongDirNameA, LongDirNameB);
			Assert.IsTrue(subDir.Length > 260, "Longer than Windows MAX_PATH");
			Directory.CreateDirectory(subDir);
			return subDir;
		}
		
		private static DirectoryReference CreateTempDir()
		{
			string tempDir = Path.Join(Path.GetTempPath(), "epicgames-core-tests-" + Guid.NewGuid().ToString()[..8]);
			Directory.CreateDirectory(tempDir);
			return new DirectoryReference(tempDir);
		}
	}
}