// Copyright (c) 2016 Daniel Grunwald
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

using System;
using System.Diagnostics;
using System.IO;
using System.Reflection.PortableExecutable;
using System.Text.RegularExpressions;
using System.Threading;
using System.Threading.Tasks;

using CliWrap;

using ICSharpCode.Decompiler.CSharp;
using ICSharpCode.Decompiler.CSharp.ProjectDecompiler;
using ICSharpCode.Decompiler.Metadata;
using ICSharpCode.Decompiler.Tests.Helpers;

using NUnit.Framework;

namespace ICSharpCode.Decompiler.Tests
{
	[TestFixture, Parallelizable(ParallelScope.All)]
	public class RoundtripAssembly
	{
		public static readonly string TestDir = Path.GetFullPath(Path.Combine(Tester.TestCasePath, "../../ILSpy-tests"));
		static readonly string nunit = Path.Combine(TestDir, "nunit", "nunit3-console.exe");

		[Test]
		public async Task Cecil_net45()
		{
			await RunWithTest("Mono.Cecil-net45", "Mono.Cecil.dll", "Mono.Cecil.Tests.dll");
		}

		[Test]
		public async Task NewtonsoftJson_net45()
		{
			await RunWithTest("Newtonsoft.Json-net45", "Newtonsoft.Json.dll", "Newtonsoft.Json.Tests.dll");
		}

		[Test]
		public async Task NewtonsoftJson_pcl_debug()
		{
			try
			{
				await RunWithTest("Newtonsoft.Json-pcl-debug", "Newtonsoft.Json.dll", "Newtonsoft.Json.Tests.dll", useOldProjectFormat: true);
			}
			catch (CompilationFailedException)
			{
				Assert.Ignore("Cannot yet re-compile PCL projects.");
			}
		}

		[Test]
		public async Task NRefactory_CSharp()
		{
			await RunWithTest("NRefactory", "ICSharpCode.NRefactory.CSharp.dll", "ICSharpCode.NRefactory.Tests.dll");
		}

		[Test]
		public async Task ICSharpCode_Decompiler()
		{
			await RunOnly("ICSharpCode.Decompiler", "ICSharpCode.Decompiler.dll");
		}

		[Test]
		public async Task ImplicitConversions()
		{
			await RunWithOutput("Random Tests\\TestCases", "ImplicitConversions.exe");
		}

		[Test]
		public async Task ImplicitConversions_32()
		{
			await RunWithOutput("Random Tests\\TestCases", "ImplicitConversions_32.exe");
		}

		[Test]
		public async Task ExplicitConversions()
		{
			await RunWithOutput("Random Tests\\TestCases", "ExplicitConversions.exe", LanguageVersion.CSharp8_0);
		}

		[Test]
		public async Task ExplicitConversions_32()
		{
			await RunWithOutput("Random Tests\\TestCases", "ExplicitConversions_32.exe", LanguageVersion.CSharp8_0);
		}

		[Test]
		public async Task ExplicitConversions_With_NativeInts()
		{
			await RunWithOutput("Random Tests\\TestCases", "ExplicitConversions.exe", LanguageVersion.CSharp9_0);
		}

		[Test]
		public async Task ExplicitConversions_32_With_NativeInts()
		{
			await RunWithOutput("Random Tests\\TestCases", "ExplicitConversions_32.exe", LanguageVersion.CSharp9_0);
		}

		[Test]
		public async Task Random_TestCase_1()
		{
			await RunWithOutput("Random Tests\\TestCases", "TestCase-1.exe", LanguageVersion.CSharp8_0);
		}

		[Test]
		[Ignore("See https://github.com/icsharpcode/ILSpy/issues/2541 - Waiting for https://github.com/dotnet/roslyn/issues/45929")]
		public async Task Random_TestCase_1_With_NativeInts()
		{
			await RunWithOutput("Random Tests\\TestCases", "TestCase-1.exe", LanguageVersion.CSharp9_0);
		}

		// Let's limit the roundtrip tests to C# 8.0 for now; because 9.0 is still in preview
		// and the generated project doesn't build as-is.
		const LanguageVersion defaultLanguageVersion = LanguageVersion.CSharp8_0;

		async Task RunWithTest(string dir, string fileToRoundtrip, string fileToTest, LanguageVersion languageVersion = defaultLanguageVersion, string keyFile = null, bool useOldProjectFormat = false)
		{
			await RunInternal(dir, fileToRoundtrip, outputDir => RunTest(outputDir, fileToTest).GetAwaiter().GetResult(), languageVersion, snkFilePath: keyFile, useOldProjectFormat: useOldProjectFormat);
		}

		async Task RunWithOutput(string dir, string fileToRoundtrip, LanguageVersion languageVersion = defaultLanguageVersion)
		{
			string inputDir = Path.Combine(TestDir, dir);
			await RunInternal(dir, fileToRoundtrip,
				outputDir => Tester.RunAndCompareOutput(fileToRoundtrip, Path.Combine(inputDir, fileToRoundtrip), Path.Combine(outputDir, fileToRoundtrip)).GetAwaiter().GetResult(),
				languageVersion);
		}

		async Task RunOnly(string dir, string fileToRoundtrip, LanguageVersion languageVersion = defaultLanguageVersion)
		{
			await RunInternal(dir, fileToRoundtrip, outputDir => { }, languageVersion);
		}

		async Task RunInternal(string dir, string fileToRoundtrip, Action<string> testAction, LanguageVersion languageVersion, string snkFilePath = null, bool useOldProjectFormat = false)
		{
			if (!Directory.Exists(TestDir))
			{
				Assert.Ignore($"Assembly-roundtrip test ignored: test directory '{TestDir}' needs to be checked out separately." + Environment.NewLine +
							  $"git clone https://github.com/icsharpcode/ILSpy-tests \"{TestDir}\"");
			}
			string inputDir = Path.Combine(TestDir, dir);
			string decompiledDir = inputDir + "-decompiled";
			string outputDir = inputDir + "-output";
			if (inputDir.EndsWith("TestCases"))
			{
				// make sure output dir names are unique so that we don't get trouble due to parallel test execution
				decompiledDir += Path.GetFileNameWithoutExtension(fileToRoundtrip) + "_" + languageVersion.ToString();
				outputDir += Path.GetFileNameWithoutExtension(fileToRoundtrip) + "_" + languageVersion.ToString();
			}
			ClearDirectory(decompiledDir);
			ClearDirectory(outputDir);
			string projectFile = null;
			foreach (string file in Directory.EnumerateFiles(inputDir, "*", SearchOption.AllDirectories))
			{
				if (!file.StartsWith(inputDir + Path.DirectorySeparatorChar, StringComparison.OrdinalIgnoreCase))
				{
					Assert.Fail($"Unexpected file name: {file}");
				}
				string relFile = file.Substring(inputDir.Length + 1);
				Directory.CreateDirectory(Path.Combine(outputDir, Path.GetDirectoryName(relFile)));
				if (relFile.Equals(fileToRoundtrip, StringComparison.OrdinalIgnoreCase))
				{
					Console.WriteLine($"Decompiling {fileToRoundtrip}...");
					Stopwatch w = Stopwatch.StartNew();
					using (var fileStream = new FileStream(file, FileMode.Open, FileAccess.Read))
					{
						PEFile module = new PEFile(file, fileStream, PEStreamOptions.PrefetchEntireImage);
						var resolver = new TestAssemblyResolver(file, inputDir, module.Metadata.DetectTargetFrameworkId());
						resolver.AddSearchDirectory(inputDir);
						resolver.RemoveSearchDirectory(".");

						// use a fixed GUID so that we can diff the output between different ILSpy runs without spurious changes
						var projectGuid = Guid.Parse("{127C83E4-4587-4CF9-ADCA-799875F3DFE6}");

						var settings = new DecompilerSettings(languageVersion);
						if (useOldProjectFormat)
						{
							settings.UseSdkStyleProjectFormat = false;
						}

						var decompiler = new TestProjectDecompiler(projectGuid, resolver, resolver, settings);

						if (snkFilePath != null)
						{
							decompiler.StrongNameKeyFile = Path.Combine(inputDir, snkFilePath);
						}
						decompiler.DecompileProject(module, decompiledDir);
						Console.WriteLine($"Decompiled {fileToRoundtrip} in {w.Elapsed.TotalSeconds:f2}");
						projectFile = Path.Combine(decompiledDir, module.Name + ".csproj");
					}
				}
				else
				{
					File.Copy(file, Path.Combine(outputDir, relFile));
				}
			}
			Assert.IsNotNull(projectFile, $"Could not find {fileToRoundtrip}");

			await Compile(projectFile, outputDir);
			testAction(outputDir);
		}

		static void ClearDirectory(string dir)
		{
			Directory.CreateDirectory(dir);
			foreach (string subdir in Directory.EnumerateDirectories(dir))
			{
				for (int attempt = 0; ; attempt++)
				{
					try
					{
						Directory.Delete(subdir, true);
						break;
					}
					catch (IOException)
					{
						if (attempt >= 10)
							throw;
						Thread.Sleep(100);
					}
				}
			}
			foreach (string file in Directory.EnumerateFiles(dir))
			{
				File.Delete(file);
			}
		}

		static async Task Compile(string projectFile, string outputDir)
		{
			Regex errorRegex = new Regex(@"^[\w\d.\\-]+\(\d+,\d+\):");
			string suffix = $" [{projectFile}]";

			var command = Cli.Wrap(await Tester.FindMSBuild())
				.WithArguments($"/nologo /v:minimal /restore /p:OutputPath=\"{outputDir}\" \"{projectFile}\"")
				.WithValidation(CommandResultValidation.None)
				.WithStandardOutputPipe(PipeTarget.ToDelegate(PrintLine));
			Console.WriteLine($"\"{command.TargetFilePath}\" {command.Arguments}");
			var result = await command.ExecuteAsync().ConfigureAwait(false);
			if (result.ExitCode != 0)
				throw new CompilationFailedException($"Compilation of {Path.GetFileName(projectFile)} failed");

			void PrintLine(string line)
			{
				if (line.EndsWith(suffix, StringComparison.OrdinalIgnoreCase))
				{
					line = line.Substring(0, line.Length - suffix.Length);
				}
				Match m = errorRegex.Match(line);
				if (m.Success)
				{
					// Make path absolute so that it gets hyperlinked
					line = Path.GetDirectoryName(projectFile) + Path.DirectorySeparatorChar + line;
				}
				Console.WriteLine(line);
			}
		}

		static async Task RunTest(string outputDir, string fileToTest)
		{
			var command = Cli.Wrap(nunit)
				.WithWorkingDirectory(outputDir)
				.WithArguments($"\"{fileToTest}\"")
				.WithValidation(CommandResultValidation.None)
				.WithStandardOutputPipe(PipeTarget.ToDelegate(Console.WriteLine));
			Console.WriteLine($"\"{command.TargetFilePath}\" {command.Arguments}");
			var result = await command.ExecuteAsync().ConfigureAwait(false);
			if (result.ExitCode != 0)
				throw new TestRunFailedException($"Test execution of {Path.GetFileName(fileToTest)} failed");
		}

		class TestProjectDecompiler : WholeProjectDecompiler
		{
			public TestProjectDecompiler(Guid projecGuid, IAssemblyResolver resolver, AssemblyReferenceClassifier assemblyReferenceClassifier, DecompilerSettings settings)
				: base(settings, projecGuid, resolver, assemblyReferenceClassifier, debugInfoProvider: null)
			{
			}
		}

		class CompilationFailedException : Exception
		{
			public CompilationFailedException(string message) : base(message)
			{
			}
		}

		class TestRunFailedException : Exception
		{
			public TestRunFailedException(string message) : base(message)
			{
			}
		}
	}
}