ConstructorActivator.cs

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using System;
using System.Linq;
using Dreamine.MVVM.Interfaces.DependencyInjection;
 
namespace Dreamine.MVVM.Core.DependencyInjection
{
    public sealed class ConstructorActivator : IObjectActivator
    {
        private readonly IConstructorSelector _constructorSelector;

        public ConstructorActivator(IConstructorSelector constructorSelector)
        {
            _constructorSelector = constructorSelector
                ?? throw new ArgumentNullException(nameof(constructorSelector));
        }

        public object CreateInstance(Type implementationType, IServiceResolver resolver)
        {
            if (implementationType is null)
            {
                throw new ArgumentNullException(nameof(implementationType));
            }
 
            if (resolver is null)
            {
                throw new ArgumentNullException(nameof(resolver));
            }
 
            var constructor = _constructorSelector.SelectConstructor(implementationType);
 
            object[] arguments = constructor
                .GetParameters()
                .Select(parameter => resolver.Resolve(parameter.ParameterType))
                .ToArray();
 
            return Activator.CreateInstance(implementationType, arguments)
                ?? throw new InvalidOperationException(
                    $"Failed to create instance of [{implementationType.FullName}].");
        }
    }
}