using System;
using System.IO;
using System.Threading.Tasks;

namespace ClipForge
{
    public class ThumbnailService
    {
        private string _ffmpegPath;

        public ThumbnailService()
        {
            _ffmpegPath = Path.Combine(AppContext.BaseDirectory, "ffmpeg.exe");
        }

        public async Task GenerateThumbnailAsync(ClipFile clip)
        {
            if (!File.Exists(_ffmpegPath)) return;
            if (!File.Exists(clip.Path)) return;
            if (File.Exists(clip.ThumbnailPath)) return;

            try
            {
                // Extract frame at 1 second mark
                var args = $"-ss 00:00:01 -i \"{clip.Path}\" " +
                           $"-vframes 1 -q:v 2 " +
                           $"-vf scale=220:124:force_original_aspect_ratio=increase," +
                           $"crop=220:124 " +
                           $"\"{clip.ThumbnailPath}\"";

                var process = new System.Diagnostics.Process
                {
                    StartInfo = new System.Diagnostics.ProcessStartInfo
                    {
                        FileName = _ffmpegPath,
                        Arguments = args,
                        UseShellExecute = false,
                        CreateNoWindow = true,
                        RedirectStandardError = true
                    }
                };

                process.Start();
                await Task.Run(() => process.WaitForExit(5000));

                // Notify the clip that thumbnail is ready
                if (File.Exists(clip.ThumbnailPath))
                {
                    clip.ThumbnailPath = clip.ThumbnailPath;
                }
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine(
                    $"Thumbnail error for {clip.Title}: {ex.Message}");
            }
        }

        public async Task GenerateAllThumbnailsAsync(
            System.Collections.ObjectModel.ObservableCollection<ClipFile> clips)
        {
            foreach (var clip in clips)
            {
                await GenerateThumbnailAsync(clip);
            }
        }

        public void DeleteThumbnail(ClipFile clip)
        {
            if (File.Exists(clip.ThumbnailPath))
                File.Delete(clip.ThumbnailPath);
        }
    }
}