// ==========================================================================
//  Squidex Headless CMS
// ==========================================================================
//  Copyright (c) Squidex UG (haftungsbeschränkt)
//  All rights reserved. Licensed under the MIT license.
// ==========================================================================

using System;
using System.Collections.Generic;
using System.Linq;
using FakeItEasy;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using NodaTime;
using Squidex.Infrastructure.Log.Adapter;
using Xunit;

namespace Squidex.Infrastructure.Log
{
    public class SemanticLogTests
    {
        private readonly List<ILogAppender> appenders = new List<ILogAppender>();
        private readonly List<ILogChannel> channels = new List<ILogChannel>();
        private readonly IOptions<SemanticLogOptions> options = Options.Create(new SemanticLogOptions());
        private readonly Lazy<SemanticLog> log;
        private readonly ILogChannel channel = A.Fake<ILogChannel>();
        private string output = string.Empty;

        public SemanticLog Log
        {
            get { return log.Value; }
        }

        public SemanticLogTests()
        {
            options.Value.Level = SemanticLogLevel.Trace;

            channels.Add(channel);

            A.CallTo(() => channel.Log(A<SemanticLogLevel>._, A<string>._))
                .Invokes((SemanticLogLevel level, string message) =>
                {
                    output += message;
                });

            log = new Lazy<SemanticLog>(() => new SemanticLog(options, channels, appenders, JsonLogWriterFactory.Default()));
        }

        [Fact]
        public void Should_log_multiple_lines()
        {
            Log.Log(SemanticLogLevel.Error, null, w => w.WriteProperty("logMessage", "Msg1"));
            Log.Log(SemanticLogLevel.Error, null, w => w.WriteProperty("logMessage", "Msg2"));

            var expected1 =
                LogTest(w => w
                    .WriteProperty("logLevel", "Error")
                    .WriteProperty("logMessage", "Msg1"));

            var expected2 =
                LogTest(w => w
                    .WriteProperty("logLevel", "Error")
                    .WriteProperty("logMessage", "Msg2"));

            Assert.Equal(expected1 + expected2, output);
        }

        [Fact]
        public void Should_log_timestamp()
        {
            var clock = A.Fake<IClock>();

            A.CallTo(() => clock.GetCurrentInstant())
                .Returns(SystemClock.Instance.GetCurrentInstant().WithoutMs());

            appenders.Add(new TimestampLogAppender(clock));

            Log.LogFatal(w => { /* Do Nothing */ });

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Fatal")
                    .WriteProperty("timestamp", clock.GetCurrentInstant()));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_values_with_appender()
        {
            appenders.Add(new ConstantsLogWriter(w => w.WriteProperty("logValue", 1500)));

            Log.LogFatal(m => { });

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Fatal")
                    .WriteProperty("logValue", 1500));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_application_info()
        {
            var sessionId = Guid.NewGuid();

            appenders.Add(new ApplicationInfoLogAppender(GetType(), sessionId));

            Log.LogFatal(m => { });

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Fatal")
                    .WriteObject("app", a => a
                        .WriteProperty("name", "Squidex.Infrastructure.Tests")
                        .WriteProperty("version", "1.0.0.0")
                        .WriteProperty("sessionId", sessionId.ToString())));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_with_trace()
        {
            Log.LogTrace(w => w.WriteProperty("logValue", 1500));

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Trace")
                    .WriteProperty("logValue", 1500));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_with_trace_and_context()
        {
            Log.LogTrace(1500, (ctx, w) => w.WriteProperty("logValue", ctx));

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Trace")
                    .WriteProperty("logValue", 1500));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_with_debug()
        {
            Log.LogDebug(w => w.WriteProperty("logValue", 1500));

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Debug")
                    .WriteProperty("logValue", 1500));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_with_debug_and_context()
        {
            Log.LogDebug(1500, (ctx, w) => w.WriteProperty("logValue", ctx));

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Debug")
                    .WriteProperty("logValue", 1500));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_with_information()
        {
            Log.LogInformation(w => w.WriteProperty("logValue", 1500));

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Information")
                    .WriteProperty("logValue", 1500));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_with_information_and_context()
        {
            Log.LogInformation(1500, (ctx, w) => w.WriteProperty("logValue", ctx));

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Information")
                    .WriteProperty("logValue", 1500));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_with_warning()
        {
            Log.LogWarning(w => w.WriteProperty("logValue", 1500));

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Warning")
                    .WriteProperty("logValue", 1500));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_with_warning_and_context()
        {
            Log.LogWarning(1500, (ctx, w) => w.WriteProperty("logValue", ctx));

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Warning")
                    .WriteProperty("logValue", 1500));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_with_warning_exception()
        {
            var exception = new InvalidOperationException();

            Log.LogWarning(exception, w => { });

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Warning")
                    .WriteException(exception));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_with_warning_exception_and_context()
        {
            var exception = new InvalidOperationException();

            Log.LogWarning(exception, 1500, (ctx, w) => w.WriteProperty("logValue", ctx));

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Warning")
                    .WriteProperty("logValue", 1500)
                    .WriteException(exception));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_with_error()
        {
            Log.LogError(w => w.WriteProperty("logValue", 1500));

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Error")
                    .WriteProperty("logValue", 1500));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_with_error_and_context()
        {
            Log.LogError(1500, (ctx, w) => w.WriteProperty("logValue", ctx));

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Error")
                    .WriteProperty("logValue", 1500));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_with_error_exception()
        {
            var exception = new InvalidOperationException();

            Log.LogError(exception, w => { });

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Error")
                    .WriteException(exception));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_with_error_exception_and_context()
        {
            var exception = new InvalidOperationException();

            Log.LogError(exception, 1500, (ctx, w) => w.WriteProperty("logValue", ctx));

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Error")
                    .WriteProperty("logValue", 1500)
                    .WriteException(exception));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_with_fatal()
        {
            Log.LogFatal(w => w.WriteProperty("logValue", 1500));

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Fatal")
                    .WriteProperty("logValue", 1500));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_with_fatal_and_context()
        {
            Log.LogFatal(1500, (ctx, w) => w.WriteProperty("logValue", ctx));

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Fatal")
                    .WriteProperty("logValue", 1500));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_with_fatal_exception()
        {
            var exception = new InvalidOperationException();

            Log.LogFatal(exception, w => { });

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Fatal")
                    .WriteException(exception));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_log_with_fatal_exception_and_context()
        {
            var exception = new InvalidOperationException();

            Log.LogFatal(exception, 1500, (ctx, w) => w.WriteProperty("logValue", ctx));

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Fatal")
                    .WriteProperty("logValue", 1500)
                    .WriteException(exception));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_measure_trace()
        {
            Log.MeasureTrace(w => w.WriteProperty("message", "My Message")).Dispose();

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Trace")
                    .WriteProperty("message", "My Message")
                    .WriteProperty("elapsedMs", 0));

            Assert.StartsWith(expected.Substring(0, 55), output, StringComparison.Ordinal);
        }

        [Fact]
        public void Should_measure_trace_with_contex()
        {
            Log.MeasureTrace("My Message", (ctx, w) => w.WriteProperty("message", ctx)).Dispose();

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Trace")
                    .WriteProperty("message", "My Message")
                    .WriteProperty("elapsedMs", 0));

            Assert.StartsWith(expected.Substring(0, 55), output, StringComparison.Ordinal);
        }

        [Fact]
        public void Should_measure_debug()
        {
            Log.MeasureDebug(w => w.WriteProperty("message", "My Message")).Dispose();

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Debug")
                    .WriteProperty("message", "My Message")
                    .WriteProperty("elapsedMs", 0));

            Assert.StartsWith(expected.Substring(0, 55), output, StringComparison.Ordinal);
        }

        [Fact]
        public void Should_measure_debug_with_contex()
        {
            Log.MeasureDebug("My Message", (ctx, w) => w.WriteProperty("message", ctx)).Dispose();

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Debug")
                    .WriteProperty("message", "My Message")
                    .WriteProperty("elapsedMs", 0));

            Assert.StartsWith(expected.Substring(0, 55), output, StringComparison.Ordinal);
        }

        [Fact]
        public void Should_measure_information()
        {
            Log.MeasureInformation(w => w.WriteProperty("message", "My Message")).Dispose();

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Information")
                    .WriteProperty("message", "My Message")
                    .WriteProperty("elapsedMs", 0));

            Assert.StartsWith(expected.Substring(0, 55), output, StringComparison.Ordinal);
        }

        [Fact]
        public void Should_measure_information_with_contex()
        {
            Log.MeasureInformation("My Message", (ctx, w) => w.WriteProperty("message", ctx)).Dispose();

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Information")
                    .WriteProperty("message", "My Message")
                    .WriteProperty("elapsedMs", 0));

            Assert.StartsWith(expected.Substring(0, 55), output, StringComparison.Ordinal);
        }

        [Fact]
        public void Should_log_with_extensions_logger()
        {
            var exception = new InvalidOperationException();

            var loggerFactory =
                new LoggerFactory()
                    .AddSemanticLog(Log);
            var loggerInstance = loggerFactory.CreateLogger<SemanticLogTests>();

            loggerInstance.LogCritical(new EventId(123, "EventName"), exception, "Log {0}", 123);

            var expected =
                LogTest(w => w
                    .WriteProperty("logLevel", "Fatal")
                    .WriteProperty("message", "Log 123")
                    .WriteObject("eventId", e => e
                        .WriteProperty("id", 123)
                        .WriteProperty("name", "EventName"))
                    .WriteProperty("category", "Squidex.Infrastructure.Log.SemanticLogTests")
                    .WriteException(exception));

            Assert.Equal(expected, output);
        }

        [Fact]
        public void Should_catch_all_exceptions_from_all_channels_when_exceptions_are_thrown()
        {
            var exception1 = new InvalidOperationException();
            var exception2 = new InvalidOperationException();

            var channel1 = A.Fake<ILogChannel>();
            var channel2 = A.Fake<ILogChannel>();

            A.CallTo(() => channel1.Log(A<SemanticLogLevel>._, A<string>._)).Throws(exception1);
            A.CallTo(() => channel2.Log(A<SemanticLogLevel>._, A<string>._)).Throws(exception2);

            var sut = new SemanticLog(options, new[] { channel1, channel2 }, Enumerable.Empty<ILogAppender>(), JsonLogWriterFactory.Default());

            try
            {
                sut.Log(SemanticLogLevel.Debug, null, w => w.WriteProperty("should", "throw"));

                Assert.False(true);
            }
            catch (AggregateException ex)
            {
                Assert.Equal(exception1, ex.InnerExceptions[0]);
                Assert.Equal(exception2, ex.InnerExceptions[1]);
            }
        }

        [Fact]
        public void Should_not_log_if_level_is_too_low()
        {
            options.Value.Level = SemanticLogLevel.Error;

            Log.LogWarning(w => w.WriteProperty("Property", "Value"));

            Assert.Equal(string.Empty, output);
        }

        private static string LogTest(Action<IObjectWriter> writer)
        {
            var sut = JsonLogWriterFactory.Default().Create();

            writer(sut);

            return sut.ToString();
        }
    }
}