bark.api/Program.cs

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddDbContext<TodoDb>(opt => opt.UseInMemoryDatabase("TodoDb"));
builder.Services.AddDatabaseDeveloperPageExceptionFilter();
var app = builder.Build();

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();