using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

namespace HealthChecksSample
{
    // Pass in `--scenario port` at the command line to run this sample.
    public class ManagementPortStartup
    {
        public ManagementPortStartup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        public void ConfigureServices(IServiceCollection services)
        {
            // Registers required services for health checks
            services.AddHealthChecks();
        }

        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            // This will register the health checks middleware at the URL /health but only on the specified port.
            // 
            // By default health checks will return a 200 with 'Healthy'.
            // - No health checks are registered by default, the app is healthy if it is reachable
            // - The default response writer writes the HealthCheckStatus as text/plain content
            //
            // Use UseHealthChecks with a port will only process health checks requests on connection
            // to the specified port. This is typically used in a container environment where you can expose
            // a port for monitoring services to have access to the service.
            // - In this case the management is configured in the launchSettings.json and passed through 
            //  an environment variable
            // - Additionally, the server is also configured to listen to requests on the management port.
            app.UseHealthChecks("/health", port: Configuration["ManagementPort"]);

            app.Run(async (context) =>
            {
                await context.Response.WriteAsync($"Go to http://localhost:{Configuration["ManagementPort"]}/health to see the health status");
            });
        }
    }
}