namespace AmiReel.Services;

/// <summary>
/// Locates sequential WinUAE-style recordings: output.avi, output_1.avi, output_2.avi, ...
/// Stopping at the first missing name.
/// </summary>
public static class SourceRecordingFinder
{
    public const string BaseFileName = "output";
    public const string FileExtension = ".avi";
    public const int MaximumFiles = 500;

    /// <summary>
    /// Returns existing sequential recordings in <paramref name="folder"/>, or an empty
    /// list when the folder is missing or <c>output.avi</c> is not present.
    /// </summary>
    public static IReadOnlyList<string> FindSequentialOutputs(string? folder)
    {
        if (string.IsNullOrWhiteSpace(folder) || !Directory.Exists(folder))
            return [];

        string directory = Path.GetFullPath(folder);
        List<string> found = [];

        string first = Path.Combine(directory, BaseFileName + FileExtension);
        if (!File.Exists(first))
            return found;

        found.Add(first);

        for (int index = 1; index < MaximumFiles; index++)
        {
            string next = Path.Combine(directory, $"{BaseFileName}_{index}{FileExtension}");
            if (!File.Exists(next))
                break;

            found.Add(next);
        }

        return found;
    }
}