using System;
using System.IO;
using System.IO.Abstractions;
using System.Threading;
using System.Threading.Tasks;

using Microsoft.Extensions.Logging;
using Microsoft.VisualStudio.TestTools.UnitTesting;

using Moq;

using Tgstation.Server.Host.IO;
using Tgstation.Server.Host.System;

namespace Tgstation.Server.Tests
{
	[TestClass]
	public sealed class TestSystemInteraction
	{
		[TestMethod]
		public async Task TestScriptExecutionWithStdRead()
		{
			using var loggerFactory = LoggerFactory.Create(x => { });
			var platformIdentifier = new PlatformIdentifier();
			var processExecutor = new ProcessExecutor(
				Mock.Of<IProcessFeatures>(),
				new DefaultIOManager(new FileSystem()),
				Mock.Of<ILogger<ProcessExecutor>>(),
				loggerFactory);

			await using var process = await processExecutor.LaunchProcess(
				"test." + platformIdentifier.ScriptFileExtension,
				".",
				String.Empty,
				CancellationToken.None,
				null,
				null,
				true,
				true,
				false);
			using var cts = new CancellationTokenSource();
			cts.CancelAfter(3000);
			var exitCode = await process.Lifetime.WaitAsync(cts.Token);

			Assert.AreEqual(0, exitCode);
			var result = (await process.GetCombinedOutput(default)).Trim();

			// no guarantees about order
			Assert.IsTrue(result.Contains("Hello World!"));
			Assert.IsTrue(result.Contains("Hello Error!"));
		}

		[TestMethod]
		public async Task TestScriptExecutionWithFileOutput()
		{
			using var loggerFactory = LoggerFactory.Create(builder =>
			{
				builder.AddConsole();
				builder.SetMinimumLevel(LogLevel.Trace);
			});
			var platformIdentifier = new PlatformIdentifier();
			var processExecutor = new ProcessExecutor(
				Mock.Of<IProcessFeatures>(),
				new DefaultIOManager(new FileSystem()),
				loggerFactory.CreateLogger<ProcessExecutor>(),
				loggerFactory);

			// run on a loop to spot the hang
			for (var i = 0; i < 1000; ++i)
			{
				var tempFile = Path.GetTempFileName();
				File.Delete(tempFile);
				try
				{
					await using (var process = await processExecutor.LaunchProcess(
						"test." + platformIdentifier.ScriptFileExtension,
						".",
						string.Empty,
						CancellationToken.None,
						null,
						tempFile,
						true,
						true,
						false))
					{
						using var cts = new CancellationTokenSource();
						cts.CancelAfter(3000);
						var exitCode = await process.Lifetime.WaitAsync(cts.Token);

						await process.GetCombinedOutput(cts.Token);

						Assert.AreEqual(0, exitCode);
					}

					Assert.IsTrue(File.Exists(tempFile), $"Could not find temp file: {tempFile}");
					var result = File.ReadAllText(tempFile).Trim();

					// no guarantees about order
					Assert.IsTrue(result.Contains("Hello World!"), $"Result: {result}");
					Assert.IsTrue(result.Contains("Hello Error!"), $"Result: {result}");
				}
				finally
				{
					File.Delete(tempFile);
				}
			}
		}
	}
}