// 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.Text.RegularExpressions;
using Microsoft.Extensions.DependencyInjection;
using Xunit;

namespace Microsoft.Extensions.Logging.Testing.Tests
{
    public class XunitLoggerProviderTest
    {
        [Fact]
        public void LoggerProviderWritesToTestOutputHelper()
        {
            var testTestOutputHelper = new TestTestOutputHelper();

            var loggerFactory = CreateTestLogger(builder => builder
                .SetMinimumLevel(LogLevel.Trace)
                .AddXunit(testTestOutputHelper));

            var logger = loggerFactory.CreateLogger("TestCategory");
            logger.LogInformation("This is some great information");
            logger.LogTrace("This is some unimportant information");

            var expectedOutput =
                "| [TIMESTAMP] TestCategory Information: This is some great information" + Environment.NewLine +
                "| [TIMESTAMP] TestCategory Trace: This is some unimportant information" + Environment.NewLine;

            Assert.Equal(expectedOutput, MakeConsistent(testTestOutputHelper.Output));
        }

        [Fact]
        public void LoggerProviderDoesNotWriteLogMessagesBelowMinimumLevel()
        {
            var testTestOutputHelper = new TestTestOutputHelper();
            var loggerFactory = CreateTestLogger(builder => builder
                .AddXunit(testTestOutputHelper, LogLevel.Warning));

            var logger = loggerFactory.CreateLogger("TestCategory");
            logger.LogInformation("This is some great information");
            logger.LogError("This is a bad error");

            Assert.Equal("| [TIMESTAMP] TestCategory Error: This is a bad error" + Environment.NewLine, MakeConsistent(testTestOutputHelper.Output));
        }

        [Fact]
        public void LoggerProviderPrependsPrefixToEachLine()
        {
            var testTestOutputHelper = new TestTestOutputHelper();
            var loggerFactory = CreateTestLogger(builder => builder
                .AddXunit(testTestOutputHelper));

            var logger = loggerFactory.CreateLogger("TestCategory");
            logger.LogInformation("This is a" + Environment.NewLine + "multi-line" + Environment.NewLine + "message");

            // The lines after the first one are indented more because the indentation was calculated based on the timestamp's actual length.
            var expectedOutput =
                "| [TIMESTAMP] TestCategory Information: This is a" + Environment.NewLine +
                "|                                                 multi-line" + Environment.NewLine +
                "|                                                 message" + Environment.NewLine;

            Assert.Equal(expectedOutput, MakeConsistent(testTestOutputHelper.Output));
        }

        [Fact]
        public void LoggerProviderDoesNotThrowIfOutputHelperThrows()
        {
            var testTestOutputHelper = new TestTestOutputHelper();
            var loggerFactory = CreateTestLogger(builder => builder

                .AddXunit(testTestOutputHelper));

            testTestOutputHelper.Throw = true;

            var logger = loggerFactory.CreateLogger("TestCategory");
            logger.LogInformation("This is a" + Environment.NewLine + "multi-line" + Environment.NewLine + "message");

            Assert.Equal(0, testTestOutputHelper.Output.Length);
        }

        private static readonly Regex TimestampRegex = new Regex(@"\d+-\d+-\d+T\d+:\d+:\d+");

        private string MakeConsistent(string input) => TimestampRegex.Replace(input, "TIMESTAMP");

        private static ILoggerFactory CreateTestLogger(Action<ILoggingBuilder> configure)
        {
            return new ServiceCollection()
                .AddLogging(configure)
                .BuildServiceProvider()
                .GetRequiredService<ILoggerFactory>();
        }
    }
}