// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System;
using System.Diagnostics.CodeAnalysis;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Shared.DiagnosticIds;
using Microsoft.Shared.Diagnostics;
 
namespace Microsoft.Extensions.AI;
 
/// <summary>Provides extensions for configuring <see cref="LoggingImageGenerator"/> instances.</summary>
[Experimental(DiagnosticIds.Experiments.AIImageGeneration, UrlFormat = DiagnosticIds.UrlFormat)]
public static class LoggingImageGeneratorBuilderExtensions
{
    /// <summary>Adds logging to the image generator pipeline.</summary>
    /// <param name="builder">The <see cref="ImageGeneratorBuilder"/>.</param>
    /// <param name="loggerFactory">
    /// An optional <see cref="ILoggerFactory"/> used to create a logger with which logging should be performed.
    /// If not supplied, a required instance will be resolved from the service provider.
    /// </param>
    /// <param name="configure">An optional callback that can be used to configure the <see cref="LoggingImageGenerator"/> instance.</param>
    /// <returns>The <paramref name="builder"/>.</returns>
    /// <exception cref="ArgumentNullException"><paramref name="builder"/> is <see langword="null"/>.</exception>
    /// <remarks>
    /// <para>
    /// When the employed <see cref="ILogger"/> enables <see cref="Logging.LogLevel.Trace"/>, the contents of
    /// prompts and options are logged. These prompts and options may contain sensitive application data.
    /// <see cref="Logging.LogLevel.Trace"/> is disabled by default and should never be enabled in a production environment.
    /// Prompts and options are not logged at other logging levels.
    /// </para>
    /// </remarks>
    public static ImageGeneratorBuilder UseLogging(
        this ImageGeneratorBuilder builder,
        ILoggerFactory? loggerFactory = null,
        Action<LoggingImageGenerator>? configure = null)
    {
        _ = Throw.IfNull(builder);
 
        return builder.Use((innerGenerator, services) =>
        {
            loggerFactory ??= services.GetRequiredService<ILoggerFactory>();
 
            // If the factory we resolve is for the null logger, the LoggingImageGenerator will end up
            // being an expensive nop, so skip adding it and just return the inner generator.
            if (loggerFactory == NullLoggerFactory.Instance)
            {
                return innerGenerator;
            }
 
            var imageGenerator = new LoggingImageGenerator(innerGenerator, loggerFactory.CreateLogger(typeof(LoggingImageGenerator)));
            configure?.Invoke(imageGenerator);
            return imageGenerator;
        });
    }
}