// Copyright © 2017-2025 QL-Win Contributors
//
// This file is part of QuickLook program.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

using QuickLook.Common.Helpers;
using QuickLook.Common.Plugin;
using System;
using System.IO;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Media.Animation;
using System.Windows.Media.Imaging;
using System.Xml.Linq;

namespace QuickLook.Plugin.ImageViewer.AnimatedImage.Providers;

internal class PdnProvider : AnimationProvider
{
    public PdnProvider(Uri path, MetaProvider meta, ContextObject contextObject) : base(path, meta, contextObject)
    {
        Animator = new Int32AnimationUsingKeyFrames();
        Animator.KeyFrames.Add(new DiscreteInt32KeyFrame(0,
            KeyTime.FromTimeSpan(TimeSpan.Zero)));
    }

    public override Task<BitmapSource> GetThumbnail(Size renderSize)
    {
        // Skip thumbnail
        return new Task<BitmapSource>(() => null);
    }

    public override Task<BitmapSource> GetRenderedFrame(int index)
    {
        return new Task<BitmapSource>(() =>
        {
            try
            {
                using TextReader reader = new StreamReader(Path.LocalPath, Encoding.UTF8);
                string line = reader.ReadLine();

                if (!line.StartsWith("PDN"))
                    return null;

                int indexOfStart = line.IndexOf("<");
                int indexOfEnd = line.LastIndexOf(">");

                if (indexOfStart < 0 || indexOfEnd < 0)
                    return null;

                string xml = line.Substring(indexOfStart, indexOfEnd - indexOfStart + 1);

                // <pdnImage>
                //   <custom>
                //     <thumb png="..." />
                //   </custom>
                // </pdnImage>
                XDocument doc = XDocument.Parse(xml);
                var pngBase64 = doc.Root
                    ?.Element("custom")
                    ?.Element("thumb")
                    ?.Attribute("png")
                    ?.Value;

                if (pngBase64 != null)
                {
                    byte[] imageBytes = Convert.FromBase64String(pngBase64);
                    MemoryStream ms = new(imageBytes);
                    BitmapImage bitmap = new();
                    bitmap.BeginInit();
                    bitmap.CacheOption = BitmapCacheOption.OnLoad;
                    bitmap.StreamSource = ms;
                    bitmap.EndInit();
                    bitmap.Freeze();
                    return bitmap;
                }

                return null;
            }
            catch (Exception e)
            {
                ProcessHelper.WriteLog(e.ToString());
                return null;
            }
        });
    }

    public override void Dispose()
    {
    }
}