using System.Security.Cryptography.X509Certificates;
using Uwaa.HTTP;
using Uwaa.HTTP.Routing;
using Uwaa.PNG;

namespace GeneratorServer;

internal class Program
{
    static void Main(string[] args)
    {
        Console.WriteLine("Creating router");
        Router router = CreateRouter();

        Console.WriteLine("Starting HTTP");
        HttpServer http = new HttpServer(80, null, router);
        http.Start();

        if (!File.Exists("certs/certificate.crt") || !File.Exists("certs/private.key"))
        {
            #if RELEASE
            Console.WriteLine("Warning: No HTTPS, \"certificate.crt\" and/or \"private.key\" are missing in \"certs\" directory.");
            #endif
        }
        else
        {
            Console.WriteLine("Starting HTTPS");
            HttpServer https = new HttpServer(443, X509Certificate2.CreateFromPemFile("certs/certificate.crt", "certs/private.key"), router);
            https.Start();
        }

        Console.WriteLine("Ready");
        Task.Delay(-1).Wait();
    }

    static Router CreateRouter()
    {
        var router = new Router();
        router.Add("background", new BGGenerator());
        router.Add(new StaticEndpoint(HttpResponse.NotFound()));
        return router;
    }
}

class BGGenerator : RouterBase
{
    public override HttpMethod Method => HttpMethod.GET;

    public override int Arguments => 0;

    protected override Task<HttpResponse?> GetResponseInner(HttpRequest req, HttpClientInfo info, ArraySegment<string> path)
    {
        MIMEType contentType = new MIMEType("image", "png");
        if (!req.CanAccept(contentType))
            return Task.FromResult(HttpResponse.NotAcceptable())!;

        const int width = 100;
        const int height = 100;
        PngBuilder png = PngBuilder.Create(width, height, false);

        Pixel left = new Pixel((byte)Random.Shared.Next(0, 256), (byte)Random.Shared.Next(0, 256), (byte)Random.Shared.Next(0, 256));
        Pixel right = new Pixel((byte)Random.Shared.Next(0, 256), (byte)Random.Shared.Next(0, 256), (byte)Random.Shared.Next(0, 256));
        Pixel top = new Pixel((byte)Random.Shared.Next(0, 256), (byte)Random.Shared.Next(0, 256), (byte)Random.Shared.Next(0, 256));
        Pixel bottom = new Pixel((byte)Random.Shared.Next(0, 256), (byte)Random.Shared.Next(0, 256), (byte)Random.Shared.Next(0, 256));
        for (int y = 0; y < height; y++)
            for (int x = 0; x < width; x++)
            {
                Pixel px = Lerp(Lerp(left, right, (float)x / width), Lerp(top, bottom, (float)y / height), 0.5f);
                png.SetPixel(px, x, y);
            }

        return Task.FromResult(HttpResponse.OK(new HttpContent(contentType, png.Save())))!;
    }

    static Pixel Lerp(Pixel min, Pixel max, float factor)
    {
        return new Pixel(Lerp(min.R, max.R, factor), Lerp(min.G, max.G, factor), Lerp(min.B, max.B, factor));
    }

    static byte Lerp(byte min, byte max, float factor)
    {
        return (byte)(min + (max - min) * factor);
    }

    static float Lerp(float min, float max, float factor)
    {
        return min + (max - min) * factor;
    }
}