"""The debug module contains utilities and functions for better 
debugging Eventlet-powered applications."""

__all__ = ['spew', 'unspew']


class Spew(object):
    """
    """
    def __init__(self, trace_names=None, show_values=True):
        self.trace_names = trace_names
        self.show_values = show_values

    def __call__(self, frame, event, arg):
        if event == 'line':
            lineno = frame.f_lineno
            if '__file__' in frame.f_globals:
                filename = frame.f_globals['__file__']
                if (filename.endswith('.pyc') or
                    filename.endswith('.pyo')):
                    filename = filename[:-1]
                name = frame.f_globals['__name__']
                line = linecache.getline(filename, lineno)
            else:
                name = '[unknown]'
                try:
                    src = inspect.getsourcelines(frame)
                    line = src[lineno]
                except IOError:
                    line = 'Unknown code named [%s].  VM instruction #%d' % (
                        frame.f_code.co_name, frame.f_lasti)
            if self.trace_names is None or name in self.trace_names:
                print '%s:%s: %s' % (name, lineno, line.rstrip())
                if not self.show_values:
                    return self
                details = '\t'
                tokens = line.translate(
                    string.maketrans(' ,.()', '\0' * 5)).split('\0')
                for tok in tokens:
                    if tok in frame.f_globals:
                        details += '%s=%r ' % (tok, frame.f_globals[tok])
                    if tok in frame.f_locals:
                        details += '%s=%r ' % (tok, frame.f_locals[tok])
                if details.strip():
                    print details
        return self


def spew(trace_names=None, show_values=False):
    """Install a trace hook which writes incredibly detailed logs
    about what code is being executed to stdout.
    """
    sys.settrace(Spew(trace_names, show_values))


def unspew():
    """Remove the trace hook installed by spew.
    """
    sys.settrace(None)