import re


def meant_to_say(client, channel, nick, message, matches):
    """
    A plugin so users can correct what they have said. For example::

        <sduncan> this is a foo message
        <sduncan> s/foo/bar
        <helga> sduncan meant to say: this is a bar message
    """
    try:
        last = client.last_message[channel][nick]
    except KeyError:
        return None

    old, new, reflags = matches[0]
    count = 1

    if re.search('g', reflags, re.I):
        count = 0
    if re.search('i', reflags, re.I):
        regex = re.compile(old, re.I)
    else:
        regex = re.compile(old)

    modified = regex.sub(new, last, count)

    # Don't respond if we don't replace anything ... it's annoying
    if modified != last:
        return u'{0} meant to say: {1}'.format(nick, modified)