LoadSubtitle From Subtitle edit project

==== original
public SubtitleFormat LoadSubtitle(string fileName, out Encoding encoding, Encoding useThisEncoding, bool batchMode, double? sourceFrameRate = null, bool loadSubtitle = true)
        {
            FileName = fileName;
            Paragraphs = new List<Paragraph>();
            List<string> lines;
            try
            {
                lines = ReadLinesFromFile(fileName, useThisEncoding, out encoding);
            }
            catch (Exception exception)
            {
                System.Diagnostics.Debug.WriteLine(exception.Message);
                encoding = Encoding.UTF8;
                return null;
            }

            var ext = Path.GetExtension(fileName).ToLowerInvariant();
            foreach (var subtitleFormat in SubtitleFormat.AllSubtitleFormats.Where(p => p.Extension == ext && !p.Name.StartsWith("Unknown", StringComparison.Ordinal)))
            {
                if (subtitleFormat.IsMine(lines, fileName))
                {
                    return FinalizeFormat(fileName, batchMode, sourceFrameRate, lines, subtitleFormat, loadSubtitle);
                }
            }

            foreach (var subtitleFormat in SubtitleFormat.AllSubtitleFormats.Where(p => p.Extension != ext || p.Name.StartsWith("Unknown", StringComparison.Ordinal)))
            {
                if (subtitleFormat.IsMine(lines, fileName))
                {
                    return FinalizeFormat(fileName, batchMode, sourceFrameRate, lines, subtitleFormat, loadSubtitle);
                }
            }

            if (useThisEncoding == null)
            {
                return LoadSubtitle(fileName, out encoding, Encoding.Unicode);
            }

            return null;
        }

=== ai refact suggestion



public SubtitleFormat LoadSubtitle(string fileName, out Encoding encoding, Encoding useThisEncoding = null, bool batchMode = false, double? sourceFrameRate = null, bool loadSubtitle = true)
{
    FileName = fileName;
    Paragraphs = new List<Paragraph>();
    List<string> lines = ReadLinesFromFileSafely(fileName, useThisEncoding, out encoding);

    if (lines == null)
    {
        return null;
    }

    return DetermineSubtitleFormat(fileName, batchMode, sourceFrameRate, lines, loadSubtitle);
}

private List<String> ReadLinesFromFileSafely(string fileName, Encoding useThisEncoding, out Encoding encoding)
{
    try
    {
        return ReadLinesFromFile(fileName, useThisEncoding, out encoding);
    }
    catch (Exception exception)
    {
        System.Diagnostics.Debug.WriteLine(exception.Message);
        encoding = Encoding.UTF8;
        return null;
    }
}

private SubtitleFormat DetermineSubtitleFormat(string fileName, bool batchMode, double? sourceFrameRate, List<String> lines, bool loadSubtitle)
{
    var ext = Path.GetExtension(fileName).ToLowerInvariant();
    var allFormats = SubtitleFormat.AllSubtitleFormats;

    foreach (var order in new[] { true, false })
    {
        foreach (var subtitleFormat in allFormats.Where(p => p.Extension == ext == order && !p.Name.StartsWith("Unknown", StringComparison.Ordinal) == order))
        {
            if (subtitleFormat.IsMine(lines, fileName))
            {
                return FinalizeFormat(fileName, batchMode, sourceFrameRate, lines, subtitleFormat, loadSubtitle);
            }
        }
    }

    if (useThisEncoding == Encoding.Unicode)
    {
        return null;
    }

    return LoadSubtitle(fileName, out _, Encoding.Unicode);
}