// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System;

namespace Microsoft.Extensions.Logging.Abstractions
{
    /// <summary>
    /// Minimalistic logger that does nothing.
    /// </summary>
    public sealed class NullLogger : ILogger
    {
        /// <summary>
        /// Returns the shared instance of <see cref="NullLogger"/>.
        /// </summary>
        public static NullLogger Instance { get; } = new NullLogger();

        /// <summary>
        /// Initializes a new instance of the <see cref="NullLogger"/> class.
        /// </summary>
        private NullLogger()
        {
        }

        /// <inheritdoc />
        public IDisposable BeginScope<TState>(TState state) where TState : notnull
        {
            return NullScope.Instance;
        }

        /// <inheritdoc />
        public bool IsEnabled(LogLevel logLevel)
        {
            return false;
        }

        /// <inheritdoc />
        public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception?, string> formatter)
        {
        }
    }
}