cs

using System;
using System.Text;
using Microsoft.AspNetCore.WebUtilities;

namespace LiveBoat.Web.Services
{
    public class ImageProxyOptions
    {
        public int? Width { get; set; }
        public int? Height { get; set; }
        public string Format { get; set; }
        public string ResizeType { get; set; } = "fill";
        public bool Enlarge { get; set; } = false;
        public int Dpr { get; set; } = 2;
    }


    public class ImageProxyService
    {
        public string GetUrl(string originalUrl, ImageProxyOptions options = null)
        {
            if (string.IsNullOrEmpty(originalUrl))
            {
                return originalUrl;
            }

            if (options == null)
            {
                options = new ImageProxyOptions();
            }

            var baseUrl = "https://img.unitee.io";
            var b64 = WebEncoders.Base64UrlEncode(Encoding.UTF8.GetBytes(originalUrl));

            var processingOptions = new StringBuilder();

            if (options.Width.HasValue && !options.Height.HasValue)
            {
                options.Height = 0; // valeur 0 veut dire de garder l'aspect ratio
            }

            if (options.Height.HasValue && !options.Width.HasValue)
            {
                options.Width = 0;
            }

            if (options.Width.HasValue && options.Height.HasValue)
            {
                processingOptions.Append($"resize:{options.ResizeType}:{options.Width}:{options.Height}:{(options.Enlarge ? 1 : 0)}:0/");

                // doubler la densité de pixel pour les écrans rétina (= dpr:2)
                processingOptions.Append($"dpr:{options.Dpr}/");
            }

            if (options.Format != null)
            {
                processingOptions.Append($"format:{options.Format}/");
            }

            return $"{baseUrl}/insecure/{processingOptions}{b64}";
        }
    }
}