/* ****************************************************************************
 *
 * Copyright (c) Microsoft Corporation. All rights reserved.
 *
 * This software is subject to the Microsoft Public License (Ms-PL). 
 * A copy of the license can be found in the license.htm file included 
 * in this distribution.
 *
 * You must not remove this notice, or any other, from this software.
 *
 * ***************************************************************************/

namespace System.Web.Mvc {
    using System.Diagnostics.CodeAnalysis;
    using System.Net;
    using System.Web;

    public class WebFormViewEngine : VirtualPathProviderViewEngine {

        private IBuildManager _buildManager;

        public WebFormViewEngine() {
            MasterLocationFormats = new[] {
                "~/Views/{1}/{0}.master",
                "~/Views/Shared/{0}.master"
            };

            ViewLocationFormats = new[] {
                "~/Views/{1}/{0}.aspx",
                "~/Views/{1}/{0}.ascx",
                "~/Views/Shared/{0}.aspx",
                "~/Views/Shared/{0}.ascx"
            };

            PartialViewLocationFormats = ViewLocationFormats;
        }

        internal IBuildManager BuildManager {
            get {
                if (_buildManager == null) {
                    _buildManager = new BuildManagerWrapper();
                }
                return _buildManager;
            }
            set {
                _buildManager = value;
            }
        }

        protected override IView CreatePartialView(ControllerContext controllerContext, string partialPath) {
            return new WebFormView(partialPath, null);
        }

        protected override IView CreateView(ControllerContext controllerContext, string viewPath, string masterPath) {
            return new WebFormView(viewPath, masterPath);
        }

        [SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes",
            Justification = "Exceptions are interpreted as indicating that the file does not exist.")]
        protected override bool FileExists(ControllerContext controllerContext, string virtualPath) {
            try {
                object viewInstance = BuildManager.CreateInstanceFromVirtualPath(virtualPath, typeof(object));

                return viewInstance != null;
            }
            catch (HttpException he) {
                if (he.GetHttpCode() == (int)HttpStatusCode.NotFound) {
                    // If BuildManager returns a 404 (Not Found) that means the file did not exist
                    return false;
                }
                else {
                    // All other error codes imply other errors such as compilation or parsing errors
                    throw;
                }
            }
            catch {
                return false;
            }
        }
    }
}