Population.cs

namespace Platform;

public class Population
{
    private RequestDelegate? next;
    
    public Population() { }

    public Population(RequestDelegate nextDelegate)
    {
        next = nextDelegate;
    }

    public static async Task NewEndpoint(HttpContext context)
    {
        foreach (var item in context.Request.RouteValues)
        {
            await context.Response.WriteAsync($"Key: {item.Key}, Value: {item.Value}\n");
        }
    }

    public static async Task Endpoint(HttpContext context)
    {
        string? city = context.Request.RouteValues["city"] as string;
        int? pop = null;
        
        switch ((city ?? "").ToLower())
        {
            case "london":
                pop = 8_136_000;
                break;
            case "paris":
                pop = 2_141_000;
                break;
            case "monaco":
                pop = 39_000;
                break;
        }

        if (pop.HasValue)
        {
            await context.Response.WriteAsync($"City: {city}, Population: {pop}");

        }
        else
        {
            context.Response.StatusCode = StatusCodes.Status404NotFound;
        }
    }
    public async Task Invoke(HttpContext context)
    {
        string[] parts = context.Request.Path.ToString().Split("/", StringSplitOptions.RemoveEmptyEntries);
        if (parts.Length == 2 && parts[0] == "population")
        {
            string city = parts[1];
            int? pop = null;
            switch (city.ToLower())
            {
                case "london":
                    pop = 8_136_000;
                    break;
                case "paris":
                    pop = 2_141_000;
                    break;
                case "monaco":
                    pop = 39_000;
                    break;
            }

            if (pop.HasValue)
            {
                await context.Response.WriteAsync($"City: {city}, Population: {pop}");
                return;
            }
        }

        if (next != null)
        {
            await next(context);
        }
        
    }
}