/// <summary>
/// Checks to see if there is an existing tsv file;
/// and if so, checks if it is valid and the last saved message exists.
/// (Note the possible thrown ValidationException).
/// </summary>
/// <returns>Null if does not exist. The IMessage of the last saved message if exists.</returns>
/// <exception cref="ValidationException">Thrown upon invalid file (wrong header, message ID invalid, etc).</exception>
private async Task <IMessage> CheckExisting()
{
string tsvPath = Path.Join(_path, WriterThread.TSV_FILE_NAME);
if (!File.Exists(tsvPath))
{
return(null);
}
using (StreamReader stream = new StreamReader(tsvPath))
using (CsvReader csv = new CsvReader(stream, WriterThread.CSV_CONFIG))
{
string tsvChronPath = Path.Join(_path, TSV_CHRON);
if (File.Exists(tsvChronPath))
{
throw new FieldValidationException(csv.Context, $"{tsvChronPath} exists.");
}
csv.Read(); // advance to beginning of file
CsvMessage csvMsg = csv.GetRecords <CsvMessage>().Last(); // expensive?
IMessage msg = await _channel.GetMessageAsync(csvMsg.Id);
if (msg == null)
{
throw new FieldValidationException(csv.Context, $"Discord message {csvMsg.Id} not found in channel.");
}
return(msg);
}
}
/// <summary>
/// Converts the Discord.Net IMessage, downloads atatchments, and writes.
/// </summary>
/// <param name="message">The Discord.Net IMessage to be written.</param>
/// <returns>The CsvMessage version of the Discord.Net IMessage.</returns>
private CsvMessage ConvertMessageAndWrite(IMessage message)
{
DownloadResults attachments = DownloadAttachments(message);
CsvMessage msg = new CsvMessage(message, attachments, _timeZone);
_csv.WriteRecord(msg);
_csv.NextRecord();
Console.WriteLine($"Wrote message #{_msgWritten}");
_msgWritten++;
return(msg);
}