godot-host-test/addons/GodotDI/RootServiceSource.cs

using System;
using System.Linq;
using Godot;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using OwofGames.GodotHost;
using OwofGames.GodotLume;
using OwofGames.GodotLume.Microsoft.DependencyInjection;

namespace GodotHostTest.GodotDI;

/// <summary>
/// The base class for a root scope. Implement this class and its abstract methods to kick off the DI system.
/// </summary>
public abstract partial class RootServiceSource : ServiceSource, ISceneInstantiator
{
    private Host? _host;

    private ILogger<RootServiceSource>? _logger;

    private Host Host
    {
        get => _host ??
               throw new InvalidOperationException(
                   "Some method of RootScope has been invoked before it entered the tree");
        set => _host = value;
    }

    private ILogger<RootServiceSource> Logger => _logger ??= Host.GetLogger<RootServiceSource>();

    /// <inheritdoc />
    public Node Instantiate(PackedScene packedScene, Delegate? onScopeCreated = null)
    {
        var node = packedScene.Instantiate();
        var scope = node.GetChildren().OfType<ServiceSource>().SingleOrDefault();
        if (scope == null)
            Logger.LogDebug(
                "Instantiated the scene {PackedSceneName} through ISceneInstantiator.Instantiate, but no scope found.",
                packedScene.GetName());
        else
            scope.ResolveInjectedNodes(Host.ServiceProvider, onScopeCreated);

        return node;
    }

    /// <inheritdoc />
    public T Instantiate<T>(PackedScene packedScene, Delegate? onScopeCreated = null)
        where T : Node
    {
        return (T)Instantiate(packedScene, onScopeCreated);
    }

    public override void _EnterTree()
    {
        // create the host
        Host = new HostBuilder()
            .SetServiceCollectionBuilder(InnerConfigure)
            .SetServiceProviderFactory(new LumeServiceProviderFactory(), Configure)
            .Build();

        // resolve nodes
        ResolveInjectedNodes(Host.ServiceProvider, null);
    }

    private void InnerConfigure(IServiceCollection serviceCollection)
    {
        serviceCollection.AddSingleton<ISceneInstantiator>(this);
        ConfigureServices(serviceCollection);
    }

    /// <summary>
    ///     Configure the service collection by adding the registrations your game needs.
    /// </summary>
    /// <param name="builder">The builder to enrich with your services.</param>
    protected abstract void Configure(Builder builder);

    /// <summary>
    /// Configure the service collection by adding the registrations your game needs.
    /// </summary>
    /// <param name="serviceCollection">The service collection to enrich.</param>
    protected virtual void ConfigureServices(IServiceCollection serviceCollection)
    {
    }
}