// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Linq;
using Microsoft.AspNetCore.Mvc.Abstractions;
using Microsoft.AspNetCore.Mvc.ApplicationModels;
using Microsoft.AspNetCore.Mvc.Infrastructure;
using Microsoft.AspNetCore.Mvc.Razor.Compilation;
using Microsoft.AspNetCore.Mvc.Razor.Extensions;
using Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation;
using Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure;
using Microsoft.AspNetCore.Razor.Language;
using Microsoft.AspNetCore.Routing;
using Microsoft.CodeAnalysis.Razor;
using Microsoft.Extensions.DependencyInjection.Extensions;
using Microsoft.Extensions.Options;
 
namespace Microsoft.Extensions.DependencyInjection;
 
/// <summary>
/// Static class that adds razor runtime compilation extension methods.
/// </summary>
[Obsolete("Razor runtime compilation is obsolete and is not recommended for production scenarios. For production scenarios, use the default build time compilation. For development scenarios, use Hot Reload instead. For more information, visit https://aka.ms/aspnet/deprecate/003.", DiagnosticId = "ASPDEPR003")]
public static class RazorRuntimeCompilationMvcCoreBuilderExtensions
{
    /// <summary>
    /// Configures <see cref="IMvcCoreBuilder" /> to support runtime compilation of Razor views and Razor Pages.
    /// </summary>
    /// <param name="builder">The <see cref="IMvcCoreBuilder" />.</param>
    /// <returns>The <see cref="IMvcCoreBuilder"/>.</returns>
    public static IMvcCoreBuilder AddRazorRuntimeCompilation(this IMvcCoreBuilder builder)
    {
        ArgumentNullException.ThrowIfNull(builder);
 
        AddServices(builder.Services);
        return builder;
    }
 
    /// <summary>
    /// Configures <see cref="IMvcCoreBuilder" /> to support runtime compilation of Razor views and Razor Pages.
    /// </summary>
    /// <param name="builder">The <see cref="IMvcCoreBuilder" />.</param>
    /// <param name="setupAction">An action to configure the <see cref="MvcRazorRuntimeCompilationOptions"/>.</param>
    /// <returns>The <see cref="IMvcCoreBuilder"/>.</returns>
    public static IMvcCoreBuilder AddRazorRuntimeCompilation(this IMvcCoreBuilder builder, Action<MvcRazorRuntimeCompilationOptions> setupAction)
    {
        ArgumentNullException.ThrowIfNull(builder);
        ArgumentNullException.ThrowIfNull(setupAction);
 
        AddServices(builder.Services);
        builder.Services.Configure(setupAction);
        return builder;
    }
 
    // Internal for testing.
    internal static void AddServices(IServiceCollection services)
    {
        services.TryAddEnumerable(
            ServiceDescriptor.Transient<IConfigureOptions<MvcRazorRuntimeCompilationOptions>, MvcRazorRuntimeCompilationOptionsSetup>());
 
        var compilerProvider = services.FirstOrDefault(f =>
            f.ServiceType == typeof(IViewCompilerProvider) &&
            f.ImplementationType?.Assembly == typeof(IViewCompilerProvider).Assembly &&
            f.ImplementationType.FullName == "Microsoft.AspNetCore.Mvc.Razor.Compilation.DefaultViewCompilerProvider");
 
        if (compilerProvider != null)
        {
            // Replace the default implementation of IViewCompilerProvider
            services.Remove(compilerProvider);
        }
 
        services.TryAddSingleton<IViewCompilerProvider, RuntimeViewCompilerProvider>();
 
        var actionDescriptorProvider = services.FirstOrDefault(f =>
            f.ServiceType == typeof(IActionDescriptorProvider) &&
            f.ImplementationType == typeof(CompiledPageActionDescriptorProvider));
 
        if (actionDescriptorProvider != null)
        {
            // RuntimeCompilation registers an instance of PageActionDescriptorProvider(PageADP). CompiledPageADP and runtime compilation
            // cannot co-exist since CompiledPageADP will attempt to resolve action descriptors for lazily compiled views (such as for
            // ones from non-physical file providers). We'll instead remove CompiledPageActionDescriptors from the DI container if present.
            services.Remove(actionDescriptorProvider);
        }
 
        services.TryAddEnumerable(
            ServiceDescriptor.Singleton<IActionDescriptorProvider, PageActionDescriptorProvider>());
        services.TryAddEnumerable(ServiceDescriptor.Singleton<MatcherPolicy, PageLoaderMatcherPolicy>());
 
        services.TryAddSingleton<RuntimeCompilationFileProvider>();
        services.TryAddSingleton<RazorReferenceManager>();
        services.TryAddSingleton<CSharpCompiler>();
 
        services.TryAddSingleton<RazorProjectFileSystem, FileProviderRazorProjectFileSystem>();
        services.TryAddSingleton(s =>
        {
            var fileSystem = s.GetRequiredService<RazorProjectFileSystem>();
            var csharpCompiler = s.GetRequiredService<CSharpCompiler>();
            var projectEngine = RazorProjectEngine.Create(RazorConfiguration.Default, fileSystem, builder =>
            {
                RazorExtensions.Register(builder);
 
                // Roslyn + TagHelpers infrastructure
                var referenceManager = s.GetRequiredService<RazorReferenceManager>();
                builder.Features.Add(new LazyMetadataReferenceFeature(referenceManager));
                builder.Features.Add(new CompilationTagHelperFeature());
 
                // TagHelperDescriptorProviders (actually do tag helper discovery)
                builder.Features.Add(new DefaultTagHelperDescriptorProvider());
                builder.Features.Add(new ViewComponentTagHelperDescriptorProvider());
                builder.SetCSharpLanguageVersion(csharpCompiler.ParseOptions.LanguageVersion);
            });
 
            return projectEngine;
        });
 
        //
        // Razor Pages
        //
        services.TryAddEnumerable(
            ServiceDescriptor.Singleton<IPageRouteModelProvider, RazorProjectPageRouteModelProvider>());
 
        services.TryAddEnumerable(
            ServiceDescriptor.Singleton<IActionDescriptorChangeProvider, PageActionDescriptorChangeProvider>());
    }
}