// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc.Controllers;
using Microsoft.AspNetCore.Mvc.Infrastructure;
using Microsoft.AspNetCore.Mvc.ViewEngines;
using Microsoft.AspNetCore.Mvc.ViewFeatures;
using Microsoft.Extensions.DependencyInjection;

namespace Microsoft.AspNetCore.Mvc
{
    /// <summary>
    /// Represents an <see cref="ActionResult"/> that renders a view to the response.
    /// </summary>
    public class ViewResult : ActionResult, IStatusCodeActionResult
    {
        /// <summary>
        /// Gets or sets the HTTP status code.
        /// </summary>
        public int? StatusCode { get; set; }

        /// <summary>
        /// Gets or sets the name or path of the view that is rendered to the response.
        /// </summary>
        /// <remarks>
        /// When <c>null</c>, defaults to <see cref="ControllerActionDescriptor.ActionName"/>.
        /// </remarks>
        public string ViewName { get; set; }

        /// <summary>
        /// Gets the view data model.
        /// </summary>
        public object Model => ViewData?.Model;

        /// <summary>
        /// Gets or sets the <see cref="ViewDataDictionary"/> for this result.
        /// </summary>
        public ViewDataDictionary ViewData { get; set; }

        /// <summary>
        /// Gets or sets the <see cref="ITempDataDictionary"/> for this result.
        /// </summary>
        public ITempDataDictionary TempData { get; set; }

        /// <summary>
        /// Gets or sets the <see cref="IViewEngine"/> used to locate views.
        /// </summary>
        /// <remarks>When <c>null</c>, an instance of <see cref="ICompositeViewEngine"/> from
        /// <c>ActionContext.HttpContext.RequestServices</c> is used.</remarks>
        public IViewEngine ViewEngine { get; set; }

        /// <summary>
        /// Gets or sets the Content-Type header for the response.
        /// </summary>
        public string ContentType { get; set; }

        /// <inheritdoc />
        public override async Task ExecuteResultAsync(ActionContext context)
        {
            if (context == null)
            {
                throw new ArgumentNullException(nameof(context));
            }

            var executor = context.HttpContext.RequestServices.GetService<IActionResultExecutor<ViewResult>>();
            if (executor == null)
            {
                throw new InvalidOperationException(Mvc.Core.Resources.FormatUnableToFindServices(
                    nameof(IServiceCollection),
                    "AddControllersWithViews()",
                    "ConfigureServices(...)"));
            }

            await executor.ExecuteAsync(context, this);
        }
    }
}
