using System.Linq;
using System.Reflection;
using LinFu.IoC.Configuration.Interfaces;
using LinFu.IoC.Interfaces;

namespace LinFu.IoC.Configuration
{
    /// <summary>
    ///     A class that automatically injects property dependencies into
    ///     service instances.
    /// </summary>
    public class AutoPropertyInjector : AutoMemberInjector<PropertyInfo>
    {
        /// <summary>
        ///     Injects services from the <paramref name="container" /> into the target <see cref="PropertyInfo" /> instance.
        /// </summary>
        /// <param name="target">The target object.</param>
        /// <param name="property">The <see cref="PropertyInfo" /> instance that will store the service instance.</param>
        /// <param name="resolver">
        ///     The <see cref="IArgumentResolver" /> that will determine which arguments will be assigned to the
        ///     target member.
        /// </param>
        /// <param name="additionalArguments">
        ///     The additional arguments that were passed to the <see cref="IServiceRequestResult" />
        ///     during the instantiation process.
        /// </param>
        /// <param name="container">The container that will provide the service instances.</param>
        protected override void Inject(object target, PropertyInfo property,
            IArgumentResolver resolver, IServiceContainer container,
            object[] additionalArguments)
        {
            var setter = container.GetService<IPropertySetter>();
            if (setter == null)
                return;

            // Determine the property value
            var results = resolver.ResolveFrom(new[] {new NamedType(property)}, container);
            var propertyValue = results.FirstOrDefault();

            if (propertyValue == null)
                return;

            // Call the setter against the target property
            setter.Set(target, property, propertyValue);
        }
    }
}