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

using Microsoft.AspNetCore.Http;
using System;
using System.Security.Principal;
using System.Threading.Tasks;


namespace AspnetCoreModule.TestSites.Standard

{
    public class TestMiddleWareBeforeIISMiddleWare
    {
        private readonly RequestDelegate next;

        public TestMiddleWareBeforeIISMiddleWare(RequestDelegate next)
        {
            this.next = next;
        }

        public async Task Invoke(HttpContext context)
        {
            // if the given request is shutdown message from ANCM and the value of GracefulShutdown environment variable is set,
            // the shutdown message is handled by this middleware instead of IISMiddleware.

            if (HttpMethods.IsPost(context.Request.Method) &&
                context.Request.Path.ToString().EndsWith("/iisintegration") &&
                string.Equals("shutdown", context.Request.Headers["MS-ASPNETCORE-EVENT"], StringComparison.OrdinalIgnoreCase))
            {
                string shutdownMode = Environment.GetEnvironmentVariable("GracefulShutdown");
                if (!string.IsNullOrWhiteSpace(shutdownMode) && shutdownMode.ToLower().StartsWith("disabled"))
                {
                    //ignore shutdown Message returning 200 instead of 202 because the gracefulshutdown is disabled
                    context.Response.StatusCode = StatusCodes.Status200OK;
                    await context.Response.WriteAsync("Called ShutdownMessage with disabled of GracefulShutdown");
                    return;
                }
            }
            await next.Invoke(context);
        }
    }
}