RRAC/RecRoomArchive/Services/ImageService.cs

namespace RecRoomArchive.Services
{
    public class ImageService(FileService fileService)
    {
        private static readonly HttpClient httpClient = new();

        private readonly FileService _fileService = fileService;

        public async Task<Stream?> GetImage(string imageName)
        {
            var path = $"images/{imageName}";

            if (!_fileService.FileExists(path))
            {
                var response = await httpClient.GetAsync($"https://cdn.rec.net/img/{imageName}");
                if (!response.IsSuccessStatusCode)
                    return null;

                return await response.Content.ReadAsStreamAsync();
            }

            return new FileStream(Path.Combine("data", path), FileMode.Open, FileAccess.Read, FileShare.Read);
        }

        public async Task<string> SaveImageAsync(Stream imageStream)
        {
            var imageName = $"{GetRandomFileName()}.jpg";

            var path = ("data/images");
            var fullPath = Path.Combine(path, imageName);

            await using var fileStream = new FileStream(fullPath, FileMode.Create, FileAccess.Write, FileShare.None, bufferSize: 81920, useAsync: true);

            await imageStream.CopyToAsync(fileStream);

            return imageName;
        }

        private static string GetRandomFileName()
        {
            return Convert.ToBase64String(Guid.NewGuid().ToByteArray()).Replace('+', '-').Replace('/', '_').TrimEnd('=');
        }
    }
}