using System.IO;
using System.Linq;
using EmbyToolbox.Models;

namespace EmbyToolbox.Services;

public sealed class ExternalFileCleanupService
{
    public IReadOnlyList<string> MoveUsedToUseless(string sourceVideoPath, IReadOnlyList<SidecarFile> usedFiles)
    {
        if (usedFiles.Count == 0)
        {
            return [];
        }

        // Шрифты считаются переиспользуемыми ресурсами каталога и не перемещаются.
        var movable = usedFiles
            .Where(f => !f.IsFont)
            .DistinctBy(x => x.FullPath)
            .ToList();
        if (movable.Count == 0)
        {
            return [];
        }

        var dir = Path.GetDirectoryName(sourceVideoPath);
        if (string.IsNullOrWhiteSpace(dir))
        {
            return [];
        }

        var useless = Path.Combine(dir, "useless");
        Directory.CreateDirectory(useless);
        var moved = new List<string>();
        foreach (var f in movable)
        {
            if (!File.Exists(f.FullPath))
            {
                continue;
            }

            var target = BuildUniqueTarget(useless, Path.GetFileName(f.FullPath));
            File.Move(f.FullPath, target, overwrite: false);
            moved.Add(target);
        }

        return moved;
    }

    private static string BuildUniqueTarget(string dir, string fileName)
    {
        var name = Path.GetFileNameWithoutExtension(fileName);
        var ext = Path.GetExtension(fileName);
        var candidate = Path.Combine(dir, fileName);
        var i = 1;
        while (File.Exists(candidate))
        {
            candidate = Path.Combine(dir, $"{name}_{i}{ext}");
            i++;
        }

        return candidate;
    }
}