// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Testing;
using Xunit;

namespace Microsoft.Extensions.Logging.Testing.Tests
{
    public class AssemblyTestLogTests : LoggedTest
    {
        private static readonly Assembly ThisAssembly = typeof(AssemblyTestLogTests).GetTypeInfo().Assembly;
        private static readonly string ThisAssemblyName = ThisAssembly.GetName().Name;
        private static readonly string TFM = new DirectoryInfo(AppContext.BaseDirectory).Name;

        [Fact]
        public void FunctionalLogs_LogsPreservedFromNonFlakyRun()
        {
        }

        [Fact]
        [Flaky("http://example.com", FlakyOn.All)]
        public void FunctionalLogs_LogsPreservedFromFlakyRun()
        {
        }

        [Fact]
        public void ForAssembly_ReturnsSameInstanceForSameAssembly()
        {
            Assert.Same(
                AssemblyTestLog.ForAssembly(ThisAssembly),
                AssemblyTestLog.ForAssembly(ThisAssembly));
        }

        [Fact]
        public void TestLogWritesToITestOutputHelper()
        {
            var output = new TestTestOutputHelper();
            var assemblyLog = AssemblyTestLog.Create(ThisAssemblyName, baseDirectory: null);

            using (assemblyLog.StartTestLog(output, "NonExistant.Test.Class", out var loggerFactory))
            {
                var logger = loggerFactory.CreateLogger("TestLogger");
                logger.LogInformation("Information!");

                // Trace is disabled by default
                logger.LogTrace("Trace!");
            }

            var testLogContent = MakeConsistent(output.Output);

            Assert.Equal(
@"[OFFSET] TestLifetime Information: Starting test TestLogWritesToITestOutputHelper at TIMESTAMP
[OFFSET] TestLogger Information: Information!
[OFFSET] TestLifetime Information: Finished test TestLogWritesToITestOutputHelper in DURATION
", testLogContent, ignoreLineEndingDifferences: true);
        }

        [Fact]
        public Task TestLogEscapesIllegalFileNames() =>
            RunTestLogFunctionalTest((tempDir) =>
            {
                var illegalTestName = "T:e/s//t";
                var escapedTestName = "T_e_s_t";
                using (var testAssemblyLog = AssemblyTestLog.Create(ThisAssemblyName, baseDirectory: tempDir))
                using (testAssemblyLog.StartTestLog(output: null, className: "FakeTestAssembly.FakeTestClass", loggerFactory: out var testLoggerFactory, minLogLevel: LogLevel.Trace, resolvedTestName: out var resolvedTestname, out var _, testName: illegalTestName))
                {
                    Assert.Equal(escapedTestName, resolvedTestname);
                }
            });

        [Fact]
        public Task TestLogWritesToGlobalLogFile() =>
            RunTestLogFunctionalTest((tempDir) =>
            {
                // Because this test writes to a file, it is a functional test and should be logged
                // but it's also testing the test logging facility. So this is pretty meta ;)
                var logger = LoggerFactory.CreateLogger("Test");

                using (var testAssemblyLog = AssemblyTestLog.Create(ThisAssemblyName, tempDir))
                {
                    logger.LogInformation("Created test log in {baseDirectory}", tempDir);

                    using (testAssemblyLog.StartTestLog(output: null, className: $"{ThisAssemblyName}.FakeTestClass", loggerFactory: out var testLoggerFactory, minLogLevel: LogLevel.Trace, testName: "FakeTestName"))
                    {
                        var testLogger = testLoggerFactory.CreateLogger("TestLogger");
                        testLogger.LogInformation("Information!");
                        testLogger.LogTrace("Trace!");
                    }
                }

                logger.LogInformation("Finished test log in {baseDirectory}", tempDir);

                var globalLogPath = Path.Combine(tempDir, ThisAssemblyName, TFM, "global.log");
                var testLog = Path.Combine(tempDir, ThisAssemblyName, TFM, "FakeTestClass", "FakeTestName.log");

                Assert.True(File.Exists(globalLogPath), $"Expected global log file {globalLogPath} to exist");
                Assert.True(File.Exists(testLog), $"Expected test log file {testLog} to exist");

                var globalLogContent = MakeConsistent(File.ReadAllText(globalLogPath));
                var testLogContent = MakeConsistent(File.ReadAllText(testLog));

                Assert.Equal(
@"[OFFSET] [GlobalTestLog] [Information] Global Test Logging initialized at TIMESTAMP. Configure the output directory via 'LoggingTestingFileLoggingDirectory' MSBuild property or set 'LoggingTestingDisableFileLogging' to 'true' to disable file logging.
[OFFSET] [GlobalTestLog] [Information] Starting test FakeTestName
[OFFSET] [GlobalTestLog] [Information] Finished test FakeTestName in DURATION
", globalLogContent, ignoreLineEndingDifferences: true);
                Assert.Equal(
@"[OFFSET] [TestLifetime] [Information] Starting test FakeTestName at TIMESTAMP
[OFFSET] [TestLogger] [Information] Information!
[OFFSET] [TestLogger] [Verbose] Trace!
[OFFSET] [TestLifetime] [Information] Finished test FakeTestName in DURATION
", testLogContent, ignoreLineEndingDifferences: true);
            });

        [Fact]
        public Task TestLogTruncatesTestNameToAvoidLongPaths() =>
            RunTestLogFunctionalTest((tempDir) =>
            {
                var longTestName = new string('0', 50) + new string('1', 50) + new string('2', 50) + new string('3', 50) + new string('4', 50);
                var logger = LoggerFactory.CreateLogger("Test");
                using (var testAssemblyLog = AssemblyTestLog.Create(ThisAssemblyName, tempDir))
                {
                    logger.LogInformation("Created test log in {baseDirectory}", tempDir);

                    using (testAssemblyLog.StartTestLog(output: null, className: $"{ThisAssemblyName}.FakeTestClass", loggerFactory: out var testLoggerFactory, minLogLevel: LogLevel.Trace, testName: longTestName))
                    {
                        testLoggerFactory.CreateLogger("TestLogger").LogInformation("Information!");
                    }
                }
                logger.LogInformation("Finished test log in {baseDirectory}", tempDir);

                var testLogFiles = new DirectoryInfo(Path.Combine(tempDir, ThisAssemblyName, TFM, "FakeTestClass")).EnumerateFiles();
                var testLog = Assert.Single(testLogFiles);
                var testFileName = Path.GetFileNameWithoutExtension(testLog.Name);

                // The first half of the file comes from the beginning of the test name passed to the logger
                Assert.Equal(longTestName.Substring(0, testFileName.Length / 2), testFileName.Substring(0, testFileName.Length / 2));
                // The last half of the file comes from the ending of the test name passed to the logger
                Assert.Equal(longTestName.Substring(longTestName.Length - testFileName.Length / 2, testFileName.Length / 2), testFileName.Substring(testFileName.Length - testFileName.Length / 2, testFileName.Length / 2));
            });

        [Fact]
        public  Task TestLogEnumerateFilenamesToAvoidCollisions() =>
            RunTestLogFunctionalTest((tempDir) =>
            {
                var logger = LoggerFactory.CreateLogger("Test");
                using (var testAssemblyLog = AssemblyTestLog.Create(ThisAssemblyName, tempDir))
                {
                    logger.LogInformation("Created test log in {baseDirectory}", tempDir);

                    for (var i = 0; i < 10; i++)
                    {
                        using (testAssemblyLog.StartTestLog(output: null, className: $"{ThisAssemblyName}.FakeTestClass", loggerFactory: out var testLoggerFactory, minLogLevel: LogLevel.Trace, testName: "FakeTestName"))
                        {
                            testLoggerFactory.CreateLogger("TestLogger").LogInformation("Information!");
                        }
                    }
                }
                logger.LogInformation("Finished test log in {baseDirectory}", tempDir);

                // The first log file exists
                Assert.True(File.Exists(Path.Combine(tempDir, ThisAssemblyName, TFM, "FakeTestClass", "FakeTestName.log")));

                // Subsequent files exist
                for (var i = 0; i < 9; i++)
                {
                    Assert.True(File.Exists(Path.Combine(tempDir, ThisAssemblyName, TFM, "FakeTestClass", $"FakeTestName.{i}.log")));
                }
            });

        private static readonly Regex TimestampRegex = new Regex(@"\d+-\d+-\d+T\d+:\d+:\d+");
        private static readonly Regex TimestampOffsetRegex = new Regex(@"\d+\.\d+s");
        private static readonly Regex DurationRegex = new Regex(@"[^ ]+s$");

        private async Task RunTestLogFunctionalTest(Action<string> action, [CallerMemberName] string testName = null)
        {
            var tempDir = Path.Combine(Path.GetTempPath(), $"TestLogging_{Guid.NewGuid().ToString("N")}");
            try
            {
                action(tempDir);
            }
            finally
            {
                if (Directory.Exists(tempDir))
                {
                    try
                    {
                        Directory.Delete(tempDir, recursive: true);
                    }
                    catch
                    {
                        await Task.Delay(100);
                        Directory.Delete(tempDir, recursive: true);
                    }
                }
            }
        }

        private static string MakeConsistent(string input)
        {
            return string.Join(Environment.NewLine, input.Split(new[] { Environment.NewLine }, StringSplitOptions.None)
                .Select(line =>
                {
                    var strippedPrefix = line.IndexOf("[") >= 0 ? line.Substring(line.IndexOf("[")) : line;

                    var strippedDuration = DurationRegex.Replace(strippedPrefix, "DURATION");
                    var strippedTimestamp = TimestampRegex.Replace(strippedDuration, "TIMESTAMP");
                    var strippedTimestampOffset = TimestampOffsetRegex.Replace(strippedTimestamp, "OFFSET");
                    return strippedTimestampOffset;
                }));
        }
    }
}