using System.Diagnostics;
using TvApi.Models;
using TvApi.Services;
namespace TvApi.Data
{
    public static class DbInitializer
    {
        static List<List<Cast>> listedCasts;
        static List<List<ShowCast>> listedShowCasts;
        static List<Show> listedShows;
        public static async Task InitializeAsync(TvMazeContext context)
        {
            for (long i= 1;i < 10; i++)
            {
                long ShowId = i;
                Show show = await Crawler.CrawlShowAsync(ShowId);
                listedShows.Add(show);
                List<Cast> casts = await Crawler.GetCastsAsync(ShowId);
                listedCasts.Add(casts);
                List<ShowCast> showCasts = new List<ShowCast>();
                foreach (var item in casts)
                {
                    showCasts.Add(new ShowCast(show.ShowId, item));
                }
                listedShowCasts.Add(showCasts);
            }
            context.Database.EnsureCreated();
            if (context.shows.Any())
            {
                return;   // DB has been seeded
            }
            
            foreach (Show s in listedShows)
            {
                context.shows.Add(s);
            }
            context.SaveChanges();
            foreach (List<Cast> castsList in listedCasts)
            {
                foreach(Cast cast in castsList)
                {
                    context.casts.Add(cast);
                }
            }
            foreach (List<ShowCast> showCastsList in listedShowCasts)
            {
                foreach (ShowCast showCast in showCastsList)
                {
                    context.showCasts.Add(showCast);
                }
            }
        }
    }
}

//My version of program.cs
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using TvApi.Data;
var builder = WebApplication.CreateBuilder(args);
ConfigurationManager configuration = builder.Configuration;
//Database
builder.Services.AddDbContext<TvMazeContext>(options =>
options.UseSqlServer(configuration.GetConnectionString("DefaultConnection")));
builder.Services.AddDatabaseDeveloperPageExceptionFilter();
/*
 * My attempt to initialize
var host = CreateHostBuilder(args).Build();
IHost host; 
using (var scope = host.Services.CreateScope())
{
    var services = scope.ServiceProvider;
    try
    {
        var context = services.GetRequiredService<TvMazeContext>();
        await DbInitializer.InitializeAsync(context);
    }
    catch (Exception ex)
    {
        var logger = services.GetRequiredService<ILogger<Program>>();
        logger.LogError(ex, "An error occurred creating the DB.");
    }
}
*/
// Add services to the container.
builder.Services.AddControllers();
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
var app = builder.Build();
// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}
app.UseHttpsRedirection();
app.UseAuthorization();
app.MapControllers();
app.Run();

public static class DbInitializer
    {
        public static async Task InitializeAsync(ApplicationDbContext context)
        {
            List<SeedModel> seedDatas = new List<SeedModel>();
            seedDatas.Add(new SeedModel()
            {
                Name = "AAAA",
                Age = 2
            });
            seedDatas.Add(new SeedModel()
            {
                Name = "BBB",
                Age = 3
            });
            seedDatas.Add(new SeedModel()
            {
                Name = "AAAA",
                Age = 2
            });
            await context.SeedModels.AddRangeAsync(seedDatas);
            await context.SaveChangesAsync();
        }
    }

//.......    
var app = builder.Build();    
//.....
   
using (var scope = app.Services.CreateScope())
{
    //Resolve dbcontext with DI help
    var dbcontext = (ApplicationDbContext)scope.ServiceProvider.GetService(typeof(ApplicationDbContext));
    //call your static method herer
    await DbInitializer.InitializeAsync(dbcontext);
}
//......