// 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.Diagnostics.CodeAnalysis;
using System.IO;

namespace System.Web.Mvc
{
    public abstract class ViewResultBase : ActionResult
    {
        private DynamicViewDataDictionary _dynamicViewData;
        private TempDataDictionary _tempData;
        private ViewDataDictionary _viewData;
        private ViewEngineCollection _viewEngineCollection;
        private string _viewName;

        public object Model
        {
            get { return ViewData.Model; }
        }

        [SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly", Justification = "This entire type is meant to be mutable.")]
        public TempDataDictionary TempData
        {
            get
            {
                if (_tempData == null)
                {
                    _tempData = new TempDataDictionary();
                }
                return _tempData;
            }
            set { _tempData = value; }
        }

        public IView View { get; set; }

        public dynamic ViewBag
        {
            get
            {
                if (_dynamicViewData == null)
                {
                    _dynamicViewData = new DynamicViewDataDictionary(() => ViewData);
                }
                return _dynamicViewData;
            }
        }

        [SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly", Justification = "This entire type is meant to be mutable.")]
        public ViewDataDictionary ViewData
        {
            get
            {
                if (_viewData == null)
                {
                    _viewData = new ViewDataDictionary();
                }
                return _viewData;
            }
            set { _viewData = value; }
        }

        [SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly", Justification = "This entire type is meant to be mutable.")]
        public ViewEngineCollection ViewEngineCollection
        {
            get { return _viewEngineCollection ?? ViewEngines.Engines; }
            set { _viewEngineCollection = value; }
        }

        public string ViewName
        {
            get { return _viewName ?? String.Empty; }
            set { _viewName = value; }
        }

        public override void ExecuteResult(ControllerContext context)
        {
            if (context == null)
            {
                throw new ArgumentNullException("context");
            }
            if (String.IsNullOrEmpty(ViewName))
            {
                ViewName = context.RouteData.GetRequiredString("action");
            }

            ViewEngineResult result = null;

            if (View == null)
            {
                result = FindView(context);
                View = result.View;
            }

            TextWriter writer = context.HttpContext.Response.Output;
            ViewContext viewContext = new ViewContext(context, View, ViewData, TempData, writer);
            View.Render(viewContext, writer);

            if (result != null)
            {
                result.ViewEngine.ReleaseView(context, View);
            }
        }

        protected abstract ViewEngineResult FindView(ControllerContext context);
    }
}
