godot-host-test/addons/AetherBind/ServiceSource.cs

using System;
using System.Linq;
using Godot;
using Microsoft.Extensions.Logging;
using OwofGames.AetherBind;
using OwofGames.GodotLume;

namespace GodotHostTest.AetherBind;

[Icon("res://addons/AetherBind/ServiceSource.svg")]
public partial class ServiceSource : Node
{
    private static readonly string RootScopeQualifiedName = typeof(RootScope).AssemblyQualifiedName!;
    [Export] protected Node?[] InjectedNodes = [];
    [Export] private string _serviceScope = RootScopeQualifiedName;

    internal void ResolveInjectedNodes(IProvider provider, Delegate? onScopeCreated)
    {
        var logger = provider.Get<ILogger<ServiceSource>>();

        // if this service source must also act as a scope, create the scope and use its service provider
        if (_serviceScope != RootScopeQualifiedName)
        {
            // create the scoped provider
            var serviceScope = ScopeTypesAndNames.GetType(_serviceScope);
            provider = provider.GetScopedProvider(serviceScope);
            // invoke onScopeCreated, if present
            if (onScopeCreated != null)
            {
                var parameters = onScopeCreated.Method
                    .GetParameters()
                    .Select(parameterInfo => provider.Get(parameterInfo.ParameterType))
                    .ToArray();
                onScopeCreated.DynamicInvoke(parameters);
            }

            OnScopeCreated(provider);
        }
        else if (onScopeCreated != null)
        {
            logger.LogWarning("onScopeCreated passed during instantiation, but no scoped provider was created.");
        }

        // resolve the injected nodes against the chosen service provider
        foreach (var node in InjectedNodes)
        {
            if (node == null) continue;
            logger.LogTrace("Injecting {Node}.", node.Name);

            if (node is IInjectable injectable)
            {
                injectable.Inject(provider);
            }
        }
    }

    // TODO: also add source generator to mark methods in derived classes with [OnScopeCreated] and perform parameter injection
    protected virtual void OnScopeCreated(IProvider serviceProvider)
    {
    }
}