using Microsoft.Extensions.Logging;
using GitConverter.Lib.Logging;

namespace GitConverter.TestsApp.Logging
{
    /// <summary>
    /// Unit tests for <see cref="MsLoggerAdapter"/>.
    /// </summary>
    /// <remarks>
    /// - These tests exercise that messages sent through the adapter reach the underlying Microsoft.Extensions.Logging
    ///   <see cref="ILogger"/> as formatted strings.
    /// - A lightweight <see cref="CollectingLogger"/> implementing <see cref="ILogger"/> collects formatted messages for assertions,
    ///   avoiding any external dependencies.
    /// - Tests are tolerant to minor formatting differences by using case-insensitive containment assertions.
    /// </remarks>
    public partial class MsLoggerAdapterTests
    {
        // Minimal disposable scope returned by BeginScope
        private sealed class NullScope : IDisposable
        {
            public static readonly NullScope Instance = new NullScope();
            private NullScope() { }
            public void Dispose() { }
        }

        /// <summary>
        /// A simple <see cref="ILogger"/> that collects formatted messages for assertions.
        /// </summary>
        private class CollectingLogger : ILogger
        {
            public List<string> Messages { get; } = new();

            public IDisposable BeginScope<TState>(TState state) => NullScope.Instance;
            public bool IsEnabled(LogLevel logLevel) => true;

            public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception exception, Func<TState, Exception, string> formatter)
            {
                var msg = formatter != null ? formatter(state, exception) : state?.ToString();
                if (!string.IsNullOrEmpty(msg)) Messages.Add(msg);
            }
        }

        /// <summary>
        /// Verifies the adapter forwards Info/Debug/Warn/Error calls to the underlying <see cref="ILogger"/>.
        /// </summary>
        [Fact]
        public void MsLoggerAdapter_ForwardsMessages()
        {
            var msLogger = new CollectingLogger();
            var adapter = new MsLoggerAdapter(msLogger);

            adapter.Info("hello");
            adapter.Debug("dbg");
            adapter.Warn("warn");
            adapter.Error("err", null);

            Assert.True(msLogger.Messages.Any(m => m.IndexOf("hello", StringComparison.OrdinalIgnoreCase) >= 0));
            Assert.True(msLogger.Messages.Any(m => m.IndexOf("dbg", StringComparison.OrdinalIgnoreCase) >= 0));
            Assert.True(msLogger.Messages.Any(m => m.IndexOf("warn", StringComparison.OrdinalIgnoreCase) >= 0));
            Assert.True(msLogger.Messages.Any(m => m.IndexOf("err", StringComparison.OrdinalIgnoreCase) >= 0));
        }
    }
}