bark.api/Program.cs

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddDbContext<TodoDb>(opt => opt.UseInMemoryDatabase("TodoDb"));
builder.Services.AddDatabaseDeveloperPageExceptionFilter();
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddOpenApiDocument(cfg =>
{ 
    cfg.DocumentName = "BarkAPI";
    cfg.Title = "BarkAPI v1";
    cfg.Version = "v1";
});
var app = builder.Build();

if (app.Environment.IsDevelopment())
{
    app.UseOpenApi();
    app.UseSwaggerUi(cfg =>
    {
        cfg.DocumentTitle = "BarkAPI";
        cfg.Path = "/api";
        cfg.DocumentPath = "/api/{documentName}/swagger.json}";
        cfg.DocExpansion = "list";
    });
}

app.MapGet("/", () => "Bark API");

app.MapGet("/todo", async (TodoDb db) 
    => await db.Todos.ToListAsync());

app.MapGet("/todo", async (TodoDb db) 
    => await db.Todos.Where(t => t.IsCompleted).ToListAsync());

app.MapGet("/todo/{id}", async (int id, TodoDb db) => 
    await db.Todos.FindAsync(id) is Todo todo ? Results.Ok() :  Results.NotFound());

app.MapGet("/todo", async (Todo todo, TodoDb db)
    =>
{
    db.Todos.Add(todo);
    await db.SaveChangesAsync();
    
    return Results.Created($"/todo/{todo.Id}", todo);
});

app.MapGet("/todo/{id}", async (int id, Todo input, TodoDb db) =>
{
    var todo = await db.Todos.FindAsync(id);
    
    if (todo is null) return Results.NotFound();

    todo.Name = input.Name;
    todo.IsCompleted = input.IsCompleted;

    await db.SaveChangesAsync();
    
    return Results.NoContent();
});

app.MapGet("/todo/{id}", async (int id, TodoDb db) =>
{
    if (await db.Todos.FindAsync(id) is Todo todo)
    {
        db.Todos.Remove(todo);
        await db.SaveChangesAsync();
        return Results.NoContent();
    }
    
    return Results.NotFound();
});

app.Run();