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

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

        public IConfiguration Configuration { get; }

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

                // Registers a health check for the MyContext type. By default the name of the health check will be the
                // name of the DbContext type. There are other options available through AddDbContextCheck to configure
                // failure status, tags, and custom test query.
                .AddDbContextCheck<MyContext>();

            // Registers the MyContext type and configures the database provider.
            //
            // The health check added by AddDbContextCheck will create instances of MyContext from the service provider,
            // and so will reuse the configuration provided here.
            services.AddDbContext<MyContext>(options =>
            {
                options.UseSqlServer(Configuration["ConnectionStrings:DefaultConnection"]);
            });
        }

        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            // This will register the health checks middleware at the URL /health.
            //
            // Since this sample doesn't do anything to create the database by default, this will
            // return unhealthy by default.
            //
            // You can to to /createdatabase and /deletedatabase to create and delete the database
            // (respectively), and see how it immediately effects the health status.
            //
            app.UseHealthChecks("/health");

            app.Map("/createdatabase", b => b.Run(async (context) =>
            {
                await context.Response.WriteAsync("Creating the database...\n");
                await context.Response.Body.FlushAsync();

                var myContext = context.RequestServices.GetRequiredService<MyContext>();
                await myContext.Database.EnsureCreatedAsync();

                await context.Response.WriteAsync("Done\n");
                await context.Response.WriteAsync("Go to /health to see the health status\n");
            }));

            app.Map("/deletedatabase", b => b.Run(async (context) =>
            {
                await context.Response.WriteAsync("Deleting the database...\n");
                await context.Response.Body.FlushAsync();

                var myContext = context.RequestServices.GetRequiredService<MyContext>();
                await myContext.Database.EnsureDeletedAsync();

                await context.Response.WriteAsync("Done\n");
                await context.Response.WriteAsync("Go to /health to see the health status\n");
            }));

            app.Run(async (context) =>
            {
                await context.Response.WriteAsync("Go to /health to see the health status\n");
                await context.Response.WriteAsync("Go to /createdatabase to create the database\n");
                await context.Response.WriteAsync("Go to /deletedatabase to create the database\n");
            });
        }
    }
}