mfgames-nitride-cil/src/MfGames.Nitride/NitrideBuilder.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Reflection;
using System.Threading.Tasks;

using Autofac;

using MfGames.ToolBuilder;

using Serilog;

using Zio;
using Zio.FileSystems;

using Module = Autofac.Module;

namespace MfGames.Nitride;

/// <summary>
/// A class that implements a builder pattern for gathering all the
/// components of a static website. Once everything is build, then calling
/// `Build()` will generate the resulting website.
/// </summary>
public class NitrideBuilder
{
    private readonly string[] arguments;

    private readonly List<Action<ContainerBuilder>> configureContainerCallbacks;

    /// <summary>
    /// An event that is called after the container is built but before
    /// the application runs.
    /// </summary>
    private readonly List<Action<NitrideBuilder, ILifetimeScope>>
        configureSiteCallbacks;

    private readonly NitrideModule nitrideModule;

    public NitrideBuilder(string[] arguments)
    {
        this.arguments = arguments;
        this.configureSiteCallbacks =
            new List<Action<NitrideBuilder, ILifetimeScope>>();
        this.configureContainerCallbacks = new List<Action<ContainerBuilder>>();
        this.nitrideModule = new NitrideModule();

        this.nitrideModule.ApplicationName = Assembly.GetExecutingAssembly()
            .GetName()
            .Name!;
    }

    /// <summary>
    /// Gets or sets the input directory to automatically register as the
    /// source of the files. If this is not set, then no Zio.IFileSystem
    /// will be registered and it will have to be done manually.
    /// </summary>
    public DirectoryInfo? RootDirectory { get; set; }

    /// <summary>
    /// Allows for configuration of the Autofac container to register
    /// additional types, pipelines, and modules.
    /// </summary>
    /// <param name="callback">The callback to configure the container.</param>
    /// <returns>The builder to chain operations.</returns>
    public NitrideBuilder ConfigureContainer(Action<ContainerBuilder> callback)
    {
        this.configureContainerCallbacks.Add(callback);

        return this;
    }

    /// <summary>
    /// Registers a callback to be called after the container is built but
    /// before the application runs.
    /// </summary>
    /// <param name="callback">The callback to register.</param>
    /// <returns>The builder for chaining.</returns>
    public NitrideBuilder ConfigureSite(
        Action<NitrideBuilder, ILifetimeScope> callback)
    {
        this.configureSiteCallbacks.Add(callback);

        return this;
    }

    /// <summary>
    /// Generates or builds the resulting website based on the given
    /// command.
    /// </summary>
    /// <returns>The task once completed.</returns>
    public async Task<int> RunAsync()
    {
        if (this.nitrideModule.ApplicationName == null)
        {
            throw new InvalidOperationException(
                "Application name must be set, such as with the NitrideBuilder.WithApplicationName() to properly run.");
        }

        return await ToolBoxBuilder
            .Create(this.nitrideModule.ApplicationName, this.arguments)
            .ConfigureContainer(this.ConfigureContainer)
            .Build()
            .RunAsync();
    }

    /// <summary>
    /// Initialize the builder with a given Autofac module.
    /// </summary>
    /// <typeparam name="TModule">The type of module to use.</typeparam>
    /// <returns>The builder to chain operations.</returns>
    public NitrideBuilder UseModule<TModule>()
        where TModule : Module, new()
    {
        this.ConfigureContainer(x => x.RegisterModule<TModule>());

        return this;
    }

    /// <summary>
    /// Initialize the builder with a given Autofac module.
    /// </summary>
    /// <typeparam name="TModule">The type of module to use.</typeparam>
    /// <returns>The builder to chain operations.</returns>
    public NitrideBuilder UseModule(Module module)
    {
        this.ConfigureContainer(x => x.RegisterModule(module));

        return this;
    }

    /// <summary>
    /// Sets the description of the builder.
    /// </summary>
    public NitrideBuilder WithApplicationDescription(string value)
    {
        this.nitrideModule.Description = value;

        return this;
    }

    /// <summary>
    /// Sets the name of the application, which is displayed in the help screen.
    /// </summary>
    public NitrideBuilder WithApplicationName(string value)
    {
        this.nitrideModule.ApplicationName = value;

        return this;
    }

    /// <summary>
    /// Sets the root directory to a common value by creating a
    /// IFileSystem (from Zio) of the root directory and registering it.
    /// This will be used for both input and output.
    /// </summary>
    /// <param name="directory">
    /// The path to the directory that represents "/" while
    /// building.
    /// </param>
    /// <returns>The builder to chain calls.</returns>
    public NitrideBuilder WithRootDirectory(DirectoryInfo directory)
    {
        this.RootDirectory = directory;

        return this;
    }

    private void ConfigureContainer(ContainerBuilder builder)
    {
        // Hook up the rest of the modules.
        builder.RegisterModule(this.nitrideModule);

        // Set up our file system.
        // TODO Wrong logger
        this.RegisterRootDirectory(Log.Logger, builder);

        // Finish up the registration by running our events.
        foreach (Action<NitrideBuilder, ILifetimeScope>? callback in this
                     .configureSiteCallbacks)
        {
            builder.RegisterBuildCallback(scope => callback(this, scope));
        }

        foreach (Action<ContainerBuilder>? configureContainer in this
                     .configureContainerCallbacks)
        {
            configureContainer.Invoke(builder);
        }
    }

    private void RegisterRootDirectory(
        ILogger logger,
        ContainerBuilder builder)
    {
        if (this.RootDirectory == null)
        {
            logger.Verbose("No root directory is registered");

            return;
        }

        logger.Debug(
            "Setting root directory to {Path}",
            this.RootDirectory.FullName);

        var rootFileSystem = new PhysicalFileSystem();
        var subFileSystem = new SubFileSystem(
            rootFileSystem,
            this.RootDirectory.FullName);

        builder.RegisterInstance(subFileSystem)
            .As<IFileSystem>()
            .SingleInstance();
    }
}