package jalview.io;

import java.io.File;
import java.io.FilenameFilter;

public class BackupFileFilter implements FilenameFilter
{

  public String base;

  public String template;

  public int digits;

  public String extension;

  public BackupFileFilter(String base, String template, int digits,
          String extension)
  {
    this.base = base;
    this.template = template;
    this.digits = digits;
    this.extension = extension;
  }

  @Override
  public boolean accept(File file, String filename)
  {
    if (file.isDirectory())
    {
      return true;
    }
    else
    {
      int numcharstart = template.indexOf(BackupFiles.NUM_PLACEHOLDER);
      String templateStart = template;
      String templateEnd = "";
      if (numcharstart > -1)
      {
        templateStart = template.substring(0, numcharstart);
        templateEnd = template.substring(numcharstart + BackupFiles.NUM_PLACEHOLDER.length());
      }
      int startLength = base.length() + templateStart.length();
      int endLength = templateEnd.length() + extension.length();
      if (filename.length() == startLength + digits + endLength
              && filename.startsWith(base + templateStart)
              && filename.endsWith(templateEnd + extension)
              && filename
                      .substring(startLength,
                              filename.length() - endLength + 1)
                      .matches("[0-9]+"))
      {
        return true;
      }

    }
    return false;
  }

}