private IEnumerable <BillBase> GenerateBills(IEnumerable <MultiFileMessage> messages, BillType type, string saveFolderName)
{
TextExtractor textExtractor = new TextExtractor();
foreach (MultiFileMessage message in messages)
{
foreach (FileModel file in message.Files)
{
Debug.Assert(file != null);
string localFilePath = _fileManager.CopyToLocalStorage(file, saveFolderName);
string fullText = textExtractor.ExtractFullText(localFilePath);
BillBase bill = BillBase.CreateBill(type, fullText);
string readableFilename = Path.Combine(Path.GetDirectoryName(localFilePath), GetBillFilename(bill));
if (!File.Exists(readableFilename))
{
File.Copy(localFilePath, readableFilename);
}
yield return(bill);
}
}
}