// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Collections.Concurrent;
using System.Reflection;
using Microsoft.Extensions.Internal;
 
namespace Microsoft.AspNetCore.Mvc.ViewComponents;
 
/// <summary>
/// Default implementation for <see cref="IViewComponentFactory"/>.
/// </summary>
public class DefaultViewComponentFactory : IViewComponentFactory
{
    private readonly IViewComponentActivator _activator;
    private readonly Func<Type, PropertyActivator<ViewComponentContext>[]> _getPropertiesToActivate;
    private readonly ConcurrentDictionary<Type, PropertyActivator<ViewComponentContext>[]> _injectActions;
 
    /// <summary>
    /// Creates a new instance of <see cref="DefaultViewComponentFactory"/>
    /// </summary>
    /// <param name="activator">
    /// The <see cref="IViewComponentActivator"/> used to create new view component instances.
    /// </param>
    public DefaultViewComponentFactory(IViewComponentActivator activator)
    {
        ArgumentNullException.ThrowIfNull(activator);
 
        _activator = activator;
 
        _getPropertiesToActivate = type => PropertyActivator<ViewComponentContext>.GetPropertiesToActivate(
            type,
            typeof(ViewComponentContextAttribute),
            CreateActivateInfo);
 
        _injectActions = new ConcurrentDictionary<Type, PropertyActivator<ViewComponentContext>[]>();
    }
 
    /// <inheritdoc />
    public object CreateViewComponent(ViewComponentContext context)
    {
        ArgumentNullException.ThrowIfNull(context);
 
        var component = _activator.Create(context);
 
        InjectProperties(context, component);
 
        return component;
    }
 
    private void InjectProperties(ViewComponentContext context, object viewComponent)
    {
        var propertiesToActivate = _injectActions.GetOrAdd(
            viewComponent.GetType(),
            _getPropertiesToActivate);
 
        for (var i = 0; i < propertiesToActivate.Length; i++)
        {
            var activateInfo = propertiesToActivate[i];
            activateInfo.Activate(viewComponent, context);
        }
    }
 
    private static PropertyActivator<ViewComponentContext> CreateActivateInfo(PropertyInfo property)
    {
        return new PropertyActivator<ViewComponentContext>(property, context => context);
    }
 
    /// <inheritdoc />
    public void ReleaseViewComponent(ViewComponentContext context, object component)
    {
        ArgumentNullException.ThrowIfNull(context);
        ArgumentNullException.ThrowIfNull(component);
 
        _activator.Release(context, component);
    }
 
    /// <inheritdoc />
    public ValueTask ReleaseViewComponentAsync(ViewComponentContext context, object component)
    {
        ArgumentNullException.ThrowIfNull(context);
        ArgumentNullException.ThrowIfNull(component);
 
        return _activator.ReleaseAsync(context, component);
    }
}